数据裘: RailsNotes

ID 标题笔记标签

Rails Flash.now not working

When redirecting use

flash[:notice] = "This message value is available in next request-response cycle"

When rendering use

flash.now[:notice] = "Message is available in same request-response cycle"

Info from here

Rails select with html options.

must put an empty option if want to use html options, e.g. class.

    # class won't work. 
    <%= form.select:status, User.statuses.keys.to_a, class:'form-control col'%> 
    # works
    <%= form.select:status, User.statuses.keys.to_a, {},class:'form-control col'%>

Rails7 Hotwire

Rails7有很大的改动。其中影响最大的一个就是Hotwire

webpacker被importmap取代
Turbolinks被Turbo取代
使用Sprocket进行静态资源管理（和Hotwire无关）

config/application.rb中改为config.load_defaults 7.0才会采用Rails7的默认值。

importmap

可以把webpacker相关的内容全部删除了，新的东西可以在rails7中生成一个新的project，相应的拷贝过来。

app/javascripts只需要application.js，删除其他所有。增加controller目录。注意该目录下需要application.js，否则js报错不能正常工作，我卡在这里好久。

Gemfile中

# Use JavaScript with ESM import maps [https://github.com/rails/importmap-rails]
gem "importmap-rails"
# remove webpacker
gem 'webpacker', '~> 4.0'

Turbo

Gemfile中

# Hotwire's SPA-like page accelerator [https://turbo.hotwired.dev]
gem "turbo-rails"

# remove
# gem 'turbolinks', '~> 5'

# Hotwire's modest JavaScript framework [https://stimulus.hotwired.dev]
gem "stimulus-rails"

需要的改动

Turbo Drive

+ 查询所有turbolinks地方，替换为turbo。如把所有 HTML 的 data 属性的data-turbolinks更新为data-turbo。turbolinks:load -> turbo:load
+ link_to data: :delete|post -> data: {turbo_method: :delete|post}
+ confirm message: data: { confirm: 'Are you sure?' } -> data:{turbo_confirm: 'Are you sure?'}. Together: data: {turbo_method: :delete, turbo_confirm: 'Are you sure?'},
+ method works for button_to

     # link_to works
      <%= link_to t('destroy'), offered_path(@offered), data: {turbo_method: :delete, turbo_confirm: 'Are you sure??'} %>
    # not working, still post method. 
      <%= button_to t('destroy'), offered_path(@offered), data: {turbo_method: :delete, turbo_confirm: 'Are you sure??'} %>
    # works
      <%= button_to t('destroy'), offered_path(@offered), method: :delete, data: {turbo_confirm: 'Are you sure??'} %>
    # confirm not work
      <%= button_to t('destroy'), offered_path(@offered), method: :delete, confirm: 'Are you sure??' %>

turobo_confirm doesn't work with link_to alone, check https://stackoverflow.com/a/75046023 ruby # not work <%= link_to t("download"), link, data: { turbo_confirm: 'sure'} %> # works, 注意，如果设置了data-turbo=false，则不work <%= link_to t("download"), link, data: { turbo_method: :get, turbo_confirm:'sure?'}%> # works <%= button_to t("download"), link, data: { turbo_method: :get, turbo_confirm: 'sure?'} %>

Turbo Frame:

+ controller中render需要增加status，否则有Form responses must redirect to another location错误例如

   format.html { render :signup }  =>
   format.html { render :signup, status: :unprocessable_entity}

+ 出错后render自身页面，需要增加redirect_to

    format.html { flash[:error] = "ERROR" } => 
    format.html { flash[:error] = "ERROR"; redirect_to({action: :login})}

The "default" rails way to do things that I usually see is:

submit a form
redirect on success
render html on error

As such, since Turbo currently requires redirects on all forms, it's a major blocker to prevent folks switching over.

Turbo Steam: 目前没使用

Sprocket

app/assets/config/manifset.js用于配置需要编译的静态内容。典型配置如

/* Sprockets config, static resources to be compiled */
//= link_tree ../images
//= link_directory ../stylesheets .css
//= link_tree ../../javascript .js
//= link_tree ../../../vendor/javascript .js

Rails 7 undefined method `javascript_pack_tag'

迁移项目到Rails7，遇到一下问题：

undefined method `javascript_pack_tag'
<%= javascript_pack_tag 'application', 'data-turbo-track': 'reload' %>

根源： javascript_pack_tag is a Webpacker-specific method, so unless you're using Webpacker, you can't use it.

Rails中webpacker被 importmapped Hotwire取代

正确的做法是

    <%= javascript_importmap_tags %>

Rails7 webpacker

奇怪的Nginx 403错误

Rails开发正常，部署之后403错误，Nginx配置之前用过，没有问题啊。

折腾半天，原来是语法错误，丢失了分号。

  server_name server1.com www.server1.com # 没分号不行
  server_name server1.com www.server1.com; # 有分号就好了

Rails Turbo & "responses must redirect to another location"

When I started a new project in Rails 7 and copy code from previous project, I encountered the several problems. For example, for login page, if password is wrong, the page doesn't show errors. For signup, similarly, it doesn't show any error messages.

I found JS console error

responses must redirect to another location

Then I found the articles 1 & 2

Here is why:

In Rails 7, Turbo replaced Turbolinks.
Turbo requires each response must redirect to another location.

    format.html { render :signup } # same page 
    format.html { flash[:error] = "ERROR" } # same page, no redirect

There are two solutions:

same page, but different status

format.html { render :signup, status: :unprocessable_entity}
format.html { flash[:error] = "ERROR"; redirect_to({action: :login})} # redirect to itself.

use turbo_frame_tag

Rails Webpacker & stylesheets

I have an issue that select2 css is not included in production, although OK in development.
Further, I found all css included in app/javascripts/packs/application.js not working
I do add stylesheets_pack_tag in views/layout/application.html, but no effect, no <link> generated. why? Seems to be a Rails6.1.3/webpacker5.0 bug
In development, according to the extract_css=false setting in config/webpacker.yml, so all css are embed in the HTML. In production, the css is extracted, put in a separated file public/packs/css/applicationxxx.css. However, it's not included in html, so not work.
One solution is to update extract_css=false for production as well, this leads to embed css in HTML, which works but is ugly.
I workaround the problem by moving all css from packs to assets/stylesheets/application.scss
To import css in node_modules, remember to use @import 'select2/dist/css/select2.min'; instead of @import 'select2/dist/css/select2.min.css';. The later cases works in development, but the file is empty in production. I guess because Rails production doesn't know the local directory of node_modules. The former case works, as the css is copied to application.css, instead of a separated file.

Rails 6.0 deploy problems.

css file not found.

/* in application.scss */
@import "./github_markdown.css";
-> 
@import "github_markdown";

Font awesome icons not found. solution

# in Gemfile
gem 'font_awesome5_rails'
# in application.scss
@import 'font_awesome5_webfont';

deploy error

/home/eda/.rbenv/versions/3.0.1/lib/ruby/gems/3.0.0/gems/net-ssh-6.1.0/lib/net/ssh/authentication/ed25519_loader.rb:21:in `raiseUnlessLoaded': OpenSSH keys only supported if ED25519 is available (NotImplementedError)
net-ssh requires the following gems for ed25519 support:
 * ed25519 (>= 1.2, < 2.0)
 * bcrypt_pbkdf (>= 1.0, < 2.0)
See https://github.com/net-ssh/net-ssh/issues/565 for more information
Gem::MissingSpecError : "Could not find 'ed25519' (~> 1.2) among 175 total gem(s)
Checked in 'GEM_PATH=/home/eda/.local/share/gem/ruby/3.0.0:/home/eda/.rbenv/versions/3.0.1/lib/ruby/gems/3.0.0' , execute `gem env` for more information"

guide

ssh-add ~/.ssh/id_rsa.pub
# error
Could not open a connection to your authentication agent.

guide

eval `ssh-agent -s`
ssh-add

Generate slug from name automatically

parameterize
- copy code from github
- but I don't want to exclude Chinese chars, based on this, I added
```
s = s.replace(/[^\x00-\x7F]/g, "")
```

add a JS function

According to this The input event is HTML5, feels like onchange without the need to lose focus on the element. It's not supported by IE8 and below, which should use onpropertychange.
For non HTML5 solution, according to this, we need onkeydown oncut onpaste
- onchange occurs only when you blur the textbox
- onkeyup & onkeypress doesn't always occur on text change
- onkeydown occurs on text change (but cannot track cut & paste with mouse click)
- onpaste & oncut occurs with keypress and even with the mouse right click.

require('./parameterize.js')
$(document).on("turbolinks:load", function() {
  $('form').on('input', '.parameterize-to', function(event) {
    console.log("parameterize value updated")
    let tid = $(this).attr('dst-id');
    console.log("DEBUG:: The dst ID is: %s!",tid)
    let content= $(this).val().trim()
    console.log("DEBUG:: The form value is: %s!",content)
    let slug = parameterize(content)
    console.log("DEBUG:: Set value of %s to is: %s!",tid,content)
    $("#"+tid).val(slug);
  });
});

Apply it in views. Set class and ID properly. It works with input, cut & paste in Chrome

Rails i18n strings auto-lowercased?

source

There should be no modifications to the content you specify as part of the internationalization process. It sounds like something is calling humanize on the string before it is output. Some of the standard Rails form helper methods do this I believe. If you just output the translation using t('email') you should see 'E-Mail' correctly.

Update: From your comments it seems like it is a label that is causing the problem. If you explicitly specify the text for the label rather than relying on the default behaviour you will get the translation exactly as you specify. So,

<%= f.label(:email, t('email')) %>

should generate the correct label from the translations.

Rails copy to clipboard with clipboard.js

clipboard.js

yarn add clipboard.js
In app/javascripts/packs/application.js

var ClipboardJS = require('clipboard')
$(document).on("turbolinks:load", function() {
  console.log("DEBUG:: turbolinks.load!")
  var clipboard = new ClipboardJS('.btn');
  console.log(clipboard);
});

clipboard-rails

Install Gem gem 'clipboard-rails'
In /app/assets/javascripts/application.js

//= require clipboard
$(document).ready(function(){  
  var clipboard = new Clipboard('.clipboard-btn');
  console.log(clipboard);
});

Usage

<!-- Target -->
<textarea id="bar">Mussum ipsum cacilds...</textarea>
<!-- Trigger -->
<button class="btn clipboard-btn" data-clipboard-action="copy" data-clipboard-target="#bar">
Cut to clipboard
</button>
<button class="btn clipboard-btn" data-clipboard-text="foo bar hello">
Cut to clipboard
</button>

Loop through all, zip and download from ActiveStorage

guide
rubyzip: zip dir recurisively

  def download
    if params[:id] # Folder ID
      folder = current_user.folders.find(params[:id])
      title = folder.name
      eids = [folder.id] | folder.descendants.map{|f| f.id}
      docs = current_user.documents.where(folder_id: eids);
    else
      title = current_user.name
      docs = current_user.documents;
    end
    title = title.downcase.gsub(/\s+/, '_');

    # Tmp folder to store the download files
    tmpd = "tmp/download/#{current_user.slug}"
    # Create a tmp folder if not exists
    FileUtils.rm_rf([tmpd,"#{tmpd}.zip"]);
    FileUtils.mkdir_p(tmpd);
    # Download and save documents to our tmp folder
    docs.each do |doc|
      file = doc.file; folder = doc.folder;
      dir = folder ? "#{tmpd}/#{folder.full_path}" : tmpd
      FileUtils.mkdir_p(dir) unless Dir.exists?(dir)
      fname = file.filename.to_s
      if File.exist?("#{dir}/#{fname}")  # incase two file with same name
        fname = "DUP_ID#{doc.id}_#{fname}"
      end
      # User should be able to download files if not yet removed from tmp folder
      # if the folder is already there, we'd get an error
      download_doc_to_dir(file, dir, fname)
    end
    #---------- Convert to .zip --------------------------------------- #
    zg = ZipFileGenerator.new(tmpd,"#{tmpd}.zip")
    zg.write
    # Sends the *.zip file to be download to the client's browser
    send_file(Rails.root.join("#{tmpd}.zip"), :type => 'application/zip', :filename => "#{title}.zip", :disposition => 'attachment')
    # TODO: Remove dir but leave zip file
    FileUtils.rm_rf(tmpd)
  end

  def download_doc_to_dir(doc, tmpd, fname)
    File.open(File.join(tmpd, fname), 'wb') do |file|
      doc.download { |chunk| file.write(chunk) }
    end
  end

Rails Upload Multiple Files

guide

View: enable multiple

      <% if false %>
        <-- Not work: InvalidSignature -->
        <%= file_field_tag('files[]',class: "form-control", multiple: true, id: :files) %>
      <% end %>
      <%= form.file_field :files, class: "form-control", multiple: true %>

Controller: handle array

      @folder = Folder.find(params[:folder_id]) if params[:folder_id].present?
      (params[:files]||[]).each do |f|
        ps = {note: params[:note], file: f, user_id: current_user.id, folder: @folder}
        @document = Document.create(ps)
      end

Rails collection_select set value for include_blank

source

options = Carmake.all.unshift Carmake.new(id: 0, name: 'Any')
collection_select(:service, :carmake_id, options, :id, :name, include_blank: 'Any')

Get all children of children and so on

source

class Customer
  def descendants
    self.children | self.children.map(&:descendants).flatten
  end
end

| is array union.

[ "a", "b", "c" ] | [ "c", "d", "a" ]    #=> [ "a", "b", "c", "d" ]
[ "c", "d", "a" ] | [ "a", "b", "c" ]    #=> [ "c", "d", "a", "b" ]

Rails ActiveStorage

Guide[Rails 6.0]

Setup

 rails active_storage:install
 rails db:migrate
 # in config/storage.yml, setup cloud if you want, I just want to use local first
 # in environments/development.rb[production.rb], set
 config.active_storage.service = :local
 # need public:true for local? Not work, error. It seems always public.

Add avatar to User

in models/user.rb

has_one_attached :avatar

in views

<%= f.file_field :avatar,  class: "form-control" %>

in controllers

# add permit to params
params.permit(:name, :password, :password_confirmation, :email, :avatar)
# remove avatar if necessary
if @user.avatar.attached? && uparams[:avatar].present?
  @user.avatar.purge_later
end

show the avatar

<%= image_tag @user.avatar, style: 'width:20%;height:auto' if @user.avatar.attached? %>

Once a file uploaded, it's located in storage directory, e.g. storage/ky/b0/kyb05r52e6l8kr6l4pfytggq6lks
In config/deploy.rb, add storage to linked_dir

FileCenter
- Folder Model: name, note, parent (for nested, could be null).
- Document Model: folder(null for root), note, has_one_attached:file
- Folder Controller & Views
  - index: for showing root directory folders and documents,
  - show: for showing specific directory folders and documents
  - new: for new folder
  - update: for rename
  - destroy: for delete, destroy recursively by model.
- Document Controller & Views
  - new: for upload file. Redirect to folder
  - update: for rename note ? Redirect to folder
  - destroy: delete. Redirect to folder
- Move document/folder to other folders
  - A folder can't move to its children and so on
  - A document can be moved to any folder
- Upload multiple files
  - details
- Download directory
  - details
- Upload directory: TODO

Google Search Console DNS setting

For Godday, you need to add a text record with

type: TXT
Name: @
- I used to set as _google which worked. But this time I have to set it to @. Otherwise, Google can't find the record
Value: copy the value from Google console, e.g. google-site-verification=xxxx

Rails Sitemap

Use the 'sitemap_generator' gem
Installation
- Add to Gemfile gem 'sitemap_generator'
- Generate config/sitemap.rb
```
 bundle install
 rake sitemap:install
```
- edit the config/sitemap.rb
  - specify the domain
  - add links
  - test by rails -s sitemap:refresh, which will ping search engine by default.
Setup crontab to refresh daily

Add the link to robot.txt

Sitemap: https://www.example.com/sitemap.xml.gz

Add the link in Google search console

Build a dropbox-like File Sharing Site with ROR

References:

JavaScript string encryption and decryption?

Guide

crypto-js

install

yarn add crypto-js

javascript/packs/application.js

var CryptoJS = require("crypto-js");
$(document).on("turbolinks:load", function() {
  console.log("DEBUG:: turbolinks.load!")
  var encrypted = CryptoJS.AES.encrypt("加密Message", "Secret Passphrase");
  var decrypted = CryptoJS.AES.decrypt(encrypted, "Secret Passphrase");
  var plaintext = decrypted.toString(CryptoJS.enc.Utf8);
  $("#demo1").text(encrypted)
  $("#demo2").text(decrypted)
  $("#demo3").text(plaintext)
});

html

<br>
<label>encrypted</label>
<div id="demo1"></div>
<br>

<label>decrypted</label>
<div id="demo2"></div>

<br>
<label>Actual Message</label>
<div id="demo3"></div>

Raills secret

guide

It's not working (development OK, production empty)

Rails.application.secrets.secret_key_base

Starting from Rails 5.2 there is no more secrets.yml file and the right way to get the env variables saved in credential.yml.enc is as follows:

Rails.application.credentials.dig(:secret_key_base)

Convert HTML to Markdown

guide

html2markdown: pretty old, don't know how to use

reverse_markdown

input  = '<strong>feelings</strong>'
result = ReverseMarkdown.convert input
result.inspect # " **feelings** "

kramdown

html = 'How to convert <b>HTML</b> to <i>Markdown</i> on <a href="http://stackoverflow.com">Stack Overflow</a>.'
document = Kramdown::Document.new(html, :html_to_native => true)
document.to_kramdown
# "How to convert **HTML** to *Markdown* on [Stack Overflow][1].\n\n\n\n[1]: http://stackoverflow.com\n"

The result is :
How to convert HTML to Markdown on Stack Overflow.

HTTPS on subdomain

DNS setting: add CNAME api -> @ or * -> @
Expand certification to sub-domains sudo certonly certonly -a webroot --webroot-path=/var/www/<your site>/current/public -d www.example.com -d example.com -d api.example.com
- Must use certonly. With the webroot plugin, you probably want to use the "certonly" command, eg:
- Can't use *.example.com, requires a plugin. Client with the currently selected authenticator does not support any combination of challenges that will satisfy the CA. You may need to use an authenticator plugin that can do challenges over DNS.
- Must use the static directory, /var/www/<your site> not work for rails project.
references:
- guide1
- guide2

Sidekiq does not support logfile and pidfile since 6.0

A typical Sidekiq config file is like

:verbose: false
:concurrency: 4
:strict: false
:logfile: log/sidekiq.log
:pidfile: tmp/pids/sidekiq.pid
:queues:
  - default
  - mailers
development:
  :verbose: true
  :concurrency: 2
  :logfile: log/sidekiq_dev.log
  :pidfile: tmp/pids/sidekiq_dev.pid

However, the logfile and pidfile do not work with version 6.2.0. That's because the changes on 6.0.

Remove the daemonization
Remove logfile
Remove pidfile Check here for discussion, why daemonization is bad, the pidfile problem

My current workaround:

Logfile: redirect stdout to a file
Pidfile: get from ps

pid=`ps aux | grep sidekiq | grep -v grep | awk '{print $2}'`;
kill $pid
cd /var/www/$proj/current/
bundle exec sidekiq -e production -C config/sidekiq.yml >& log/sidekiq.log &

sidekiq

Generate PDF/DOC

What is the best way to generate PDF/HTML/DOCX in Ruby/Rails

PDF:

Prawn: native and more flexible
Wicked-PDF: Wicked depends on wkhtmltopdf and uses systems call
CombinePDF: combine PDF files
pdfcrowd: API for http://pdfcrowd.com

DOC:

Prawn Notes: guide

Add links:

methods

inline_format: works

pdf.text "<link href='#{link}'>#{table.name}</link>", align: :center, size: 32, style: :bold, inline_format: true

formatted_text: works, but can't align by center automatically, has to move_down for new text

pdf.formatted_text_box([{text: table.name, link: link, styles: [:bold], size: 32, align: :center }])

link_annotation: has to put position?

pdf.link_annotation([100, 100, 5, 5], :Border => [0,0,1], :A => { :Type => :Action, :S => :URI, :URI => Prawn::LiteralString.new("http://google.com") } )

support Chinese

gkai00mp.ttf is not downloaded by bundle install
- The standard prawn gem is of version 2.4.0, may be dated without all fonts
- Change to use the latest version from GitHub
```
 gem 'prawn', :git => 'https://github.com/prawnpdf/prawn.git'
```
Specify fonts:

  pdf.font("#{Prawn::BASEDIR}/data/fonts/gkai00mp.ttf") do
    pdf.text '测试中文'
    pdf.text 'test English'
    pdf.text 'test English 和中文'
    # NOTE: gkai doesn't support style like italic
  end

fallback fonts for both languages

guide
May have some bug, has to set font.

Prawn::Document.generate(file) do |pdf|
  kai_path = "#{Prawn::BASEDIR}/data/fonts/gkai00mp.ttf"
  kai_spec  = { file: kai_path, font: 'Kai' }
  #don't use a symbol to define the name of the font!
  pdf.font_families['Kai'] = { normal: kai_spec,
                               bold: kai_spec,
                               italic: kai_spec,
                               bold_italic: kai_spec};

  pdf.fallback_fonts(["Kai"]);
  link =  Rails.application.routes.url_helpers.table_records_path(table)
  pdf.text "<link href='#{link}'>#{table.name}</link>", align: :center, size: 32, style: :bold, inline_format: true
  pdf.text table.user.name, align: :center, size: 16 , style: :italic
  head,rows = self.get_head_rows(table,records)

  pdf.font("Kai") # Set default font as "Kai". Otherwise, my have error.
  rows.each do |row|
    pdf.start_new_page
    head.zip(row).each do |name,value|
      pdf.text "\n"+name.to_s+":"
      pdf.text "#{value}" # Not work without using "Kai"
      #pdf.text "测试中文English" # works without using "Kai"
    end
  end
end

Caracal Notes: guide

link & center

  docx.h1 do
    link(table.name, tlink)
    align :center
  end

Include vs Extend

What is the difference between include and extend in Ruby?

include: mixes in specified module methods as instance methods in the target class
extend: mixes in specified module methods as class methods in the target class

Rails

Rails Tag System

Tag

DB
1. tags: name:string counter:integer
2. taggings: tag:references table:references record_id:integer
3. I added a counter to tags for ranking. Not used yet.
4. Special tags fixed to table or table records. Use polymorphic for tagging anything.

Model

Add has_many: tags to table.rb, make sure record_id is nil for table tags. Define tag_list and tag_list= methods
Add tags, tag_list, tag_list= function to record.rb

# models/table.rb
has_many :taggings
# keep tagging order
has_many :tags, -> {Tagging.where(record_id: nil).order(id: :ASC)},  through: :taggings    attr_accessor :tag_list
def tag_list
  tags.map(&:name)
end
# Array or String, e.g. "tag1, tag2, tag3"
def tag_list=(names)
  tag_names = [];
  if names.present?
    names = names.split(',') if names.instance_of?(String)
    tag_names = names.collect(&:strip).reject(&:blank?)
  end
  self.tags = tag_names.map do |n|
    Tag.where(name: n.strip).first_or_create!
  end
end
# models/record.rb
def tags
  Tag.joins(:taggings).where({taggings: {table: self.table, record_id: self.id}).order("taggings.id": :ASC)
end
def tag_list
  self.tags.map(&:name)
end
def tag_list=(names)
  tag_names = []
  if names.present?
    names = names.split(',') if names.instance_of?(String)
    tag_names = names.collect(&:strip).reject(&:blank?)
  end
  tags = tag_names.map do |n|
    Tag.where(name: n).first_or_create!
  end
  # Create or update new tags
  taggings = tags.map do |tag|
    Tagging.where(tag:tag,table:self.table,record_id:self.id).first_or_create!
  end
  # Delete tags not used anymore
  tids = taggings.pluck(:id);
  Tagging.where(table:self.table,record_id:self.id).where.not(id: tids).delete_all
end

Controller & Views
1. Add tag_list filed to table form. Such that use can input tag list as tag1, tag2 ...
2. Process tag_list params in record_controllers. Update views similar with table.
3. We change from text_field to select for using auto-completion.

Tag Cloud
Follow guide

Define tag_count in models

class Tag < ApplicationRecord
  has_many :taggings
  has_many :tables, through: :taggings
  validates_presence_of   :name
  def to_param
    return self.name || self.id
  end
  def self.tag_counts
    Tag.select("tags.id, tags.name,count(taggings.tag_id) as count").joins(:taggings).group("taggings.tag_id, tags.id, tags.name")
  end
end

define tag_cloud in helper/application.rb

def tag_cloud(tags, classes)
max = tags.sort_by(&:count).last
tags.each do |tag|
  index = tag.count.to_f / Integer(max.count) * (classes.size - 1)
  yield(tag, classes[index.round])
end
end

Define css in javascript/stylesheets/application.scss

.tag-cloud-1 { font-size: 1.0em;}
.tag-cloud-2 { font-size: 1.2em;}
.tag-cloud-3 { font-size: 1.4em;}
.tag-cloud-4 { font-size: 1.6em;}
.tag-cloud-5 { font-size: 1.8em;}
.tag-cloud-6 { font-size: 2.0em;}

show in the views

<div class="tags-cloud glassy-bg">
  <% tag_cloud Tag.tag_counts, %w{tag-cloud-1 tag-cloud-2 tag-cloud-3 tag-cloud-4 tag-cloud-5 tag-cloud-6} do |tag, css_class| %>
    <%= link_to "#{tag.name}(#{tag.count})", tag_path(tag.name), class: css_class %>
  <% end %>
</div>

Load More

tag_controller

def show
  @limit = params[:limit] || 20;
  @section=params[:section] # operation, also section ID
  @record = params[:record];
  cond = {}
  cond[:id] = (0..@record.to_i-1) if @record

  if @section.blank? || @section=="table"
    @tables =@tag.tables.where(cond).order(id: :DESC).limit(@limit)
  end
  if @section.blank? || @section=="record"
    @taggings = Tagging.where(tag: @tag).where.not(record_id: nil).where(cond).order(id: :DESC).limit(@limit)
    @records = @taggings.map {|r| Table.find(r.table_id).find_record(r.record_id)};
  end
  respond_to do |format|
   format.html
   format.js
  end
end

show.js.erb

<% if @section.present? %>
  <% if @section=="table"%>
    <% if @tables.empty? %>
      $('#<%=@section%> .load-more-button').hide()
    <% else %>
      $('#<%=@section%> .load-more-records').append('<%= escape_javascript(render(partial: "tables/table_card",collection: @tables)) %>')
    <% end %>
  <% elsif @section=="record" %>
    <% if @records.empty? %>
      $('#<%=@section%> .load-more-button').hide()
    <% else %>
      $('#<%=@section%> .load-more-records').append('<%= escape_javascript(render("tags/tag_records", taggings: @taggings, records: @records)) %>')
    <% end %>
  <% end %>
<% else %>
  // Nothing, reload
<% end %>

views.
Note that we using tagging ID instead of record ID for record load more.

<% tabs = [:table, :record] %>
<ul class="nav nav-tabs nav-pills" role="tablist">
  <% tabs.each_with_index do |opt,idx| %>
    <% cls = idx==0 ? "active" : "" %>
    <% select = (idx==0)  %>
    <li class="nav-item">
      <a class="nav-link <%=cls%>" id="<%=opt%>-tab" href="#<%=opt%>" data-toggle="tab" role="tab" aria-controls="<%=opt%>" aria-selected="<%= select %>"><%=t("models.#{opt.to_s.capitalize}")%></a>
    </li>
  <% end %>
</ul>
<div class="tab-content mt-2">
  <% tabs.each_with_index do |opt,idx| %>
    <% cls = (idx==0) ? "active" : "" %>
    <div class="tab-pane fade show <%=cls%>" id="<%=opt%>" role="tabpanel" aria-labelledby="<%=opt%>-tab">
      <div class="load-more-records">
        <% if(opt==:table) %>
          <%= render partial: "tables/table_card", collection: @tables %>
        <% else %>
          <%= render "tags/tag_records", taggings: @taggings, records: @records %>
        <% end %>
      </div>
      <div class="load-more-button text-center mt-2">
        <%= image_tag "ajax-loader.gif", style: "display:none;", class: "loading-gif" %>
        <%= link_to t('views.load_more'), "#", class: "load-more"%>
      </div>
    </div>
  <% end %>
</div>
// _tag_records.html.erb
<% taggings.zip(records).each do |tagging,record| %>
  <div class="record" id="tagging-<%=tagging.id%>" data-id="<%=tagging.id%>">
    <%= render "records/record", record: record %>
  </div>
<% end %>

AJAX auto-completion

Install select2

yarn add select2
yarn add select2-bootstrap-theme

Apply JS

 // javascript/packs/application.js
import 'select2'
import 'select2/dist/css/select2.min.css'
import "select2-bootstrap-theme/dist/select2-bootstrap.min.css";
// javascript/packs/tag.js
import $ from 'jquery' // must import jquery
$(document).on("turbolinks:load", function() {
  $('.tag-input').select2({
    tags: true,
    multiple: true,
    theme: 'bootstrap',
    //tokenSeperators: [','],
    placeholder: 'Please enter your tags',
    minimumInputLength: 2,
    ajax: {
      url: "/tags.json",
      dataType: 'json',
      data: function (params) {
        return { term: params.term };
      },
      processResults: function (tags) {
        console.log(tags)
        var tlist = $.map(tags, function (tag) {
          return { id: tag.name, text: tag.name }
        });
        console.log(tlist)
        return {results: tlist}
      }
    }
  });
});

Tag search

def index
  cond = "";
  if params[:term].present?
    cond = "name LIKE '%#{params[:term]}%'"
  end
  @tags = Tag.where(cond).order(id: :DESC)
  respond_to do |format|
   format.html
   format.json
  end
end

Apply in views. Note, must use select_tag, text_tag not work

<%= form.select :tag_list, form.object.tag_list, {}, {multiple: true, class: "form-control tag-input"} %>
// OR
<% opt = options_for_select(@record.tag_list, @record.tag_list) %>
<%= select_tag :tag_list, opt, {multiple: true, class: "form-control tag-input"} %>

Issues

When submit form, blank value added automatically.
```
"tag_list"=>["", "adafa", "1111"]
```
Solution: add option to select include_hidden: false. See here
```
<%= form.select :tag_list, form.object.tag_list, {include_hidden: false}, {multiple: true, class: "form-control tag-input"} %>
```
DO NOT do this. This will make update tag list to empty not working. As we don't know it's emptying or keeping the tag list.
UI is ugly is using bootstrap style
Need to install select2-bootstrap-theme guide
i18n
- Failed. Seems i18n.js has syntax error. I updated the file and it passes. See here for details
```
(function(){if(jQuery&&jQuery.fn&&jQuery.fn.select2&&jQuery.fn.select2.amd){
```
- Still can't work. language: $('html').attr('lang') or language: 'zh-CN' still not work.

References

Rails

Make JQuery binding click events work for dynamically generated elements.

I have bind a click events to <a> like:

$(document).on("turbolinks:load", function() {
  $('a.click-toggle-id').click(function (e) {
    console.log("click-toggle-id clicked")
    // prevent the default click action
    e.preventDefault();
    let tid = $(this).attr('toggle-id');
    console.log(tid)
    $("#"+tid).toggle();
  });
});

This works well for static elements, but not for dynamically generated elements, e.g. elements added by js.erb files.

I found this guide. The problem is I should use on instead of click and use the top-level container document.

$(document).on("turbolinks:load", function() {
  // NOT WORK $('a').on('click','.click-toggle-id',function (e) {
  $(document).on('click','a.click-toggle-id',function (e) {
    console.log("click-toggle-id clicked")
    // prevent the default click action
    e.preventDefault();
    let tid = $(this).attr('toggle-id');
    console.log(tid)
    $("#"+tid).toggle();
  });
});

More details

$( selector ).click( function()… )
$( selector ).on( 'click', function()… )

The problem with this method is that your event handlers will need to be attached each time your DOM is modified. JS updated your DOM, but the turbolinks:load not fired.

Delegated event handling:

$( document ).on( 'click', '.click_link', function()… )

When using jQuery on() with delegate events, the event is bound to the top level element, but when it runs, the children of the element are traversed looking for matches for the selector. This has the added benefit of making your code idempotent, and further, can be used in instances where you are modifying your DOM structure on the fly and have new elements created which should handle events.

The only downside (that I know of) to this approach is that event propagation may happen more slowly.This means if you stop event propagation (using event.preventDefault() or event.stopPropagation()), it may not occur in time to prevent all the events from firing that you want. This doesn't cause problems for links to '#' which are handled with event.preventDefault(), but it may cause issues in other cases where you have multiple event handlers on one element.

Rails Render

Render function

render(options = {}, locals = {}, &block)

The primary options are:
    :partial - See ActionView::PartialRenderer.
    :file - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
    :inline - Renders an inline template similar to how it's done in the controller.
    :plain - Renders the text passed in out. Setting the content type as text/plain.
    :html - Renders the HTML safe string passed in out, otherwise performs HTML escape on the string first. Setting the content type as text/html.
    :body - Renders the text passed in, and inherits the content type of text/plain from ActionDispatch::Response object.

Specify layout

<%= render partial: "link_area", layout: "graybar" %>

Block

# users/index.html.erb
<%= render "shared/search_filters", search: @q do |form| %>
<p>
Name contains: <%= form.text_field :name_contains %>
</p>
<% end %>
#
# shared/_search_filters.html.erb
<%= form_with model: search do |form| %>
<h1>Search form:</h1>
<fieldset>
<%= yield form %>
</fieldset>
<p>
<%= form.submit "Search" %>
</p>
<% end %>

Passing local variables

<%= render partial: "form", locals: {zone: @zone} %>

:as and :object options
By default, PartialRenderer uses the template name for the local name of the object passed into the template. These examples are effectively the same:

<%= render :partial => "contract", :locals => { :contract  => @contract } %>
<%= render :partial => "contract" %>

By specifying the :as option we can change the way the local variable is named in the template. These examples are effectively the same:

<%= render :partial => "contract", :as => :agreement %>
<%= render :partial => "contract", :locals => { :agreement => @contract } %>

The :object option can be used to directly specify which object is rendered into the partial.

<%= render :partial => "contract", :object => @buyer %>
<%= render :partial => "contract", :locals => { :contact => @buyer } %>

The :object and :as options can be used together. We might have a partial which we have named genericly, such as ‘form’. Using :object and :as together helps us.

<%= render :partial => "form", :object => @contract, :as => :contract %>
<%= render :partial => "form",  :locals => {:contract => @contract} %>

Collection

<%= render :partial => "ad", :collection => @ads %>

Also, you can specify a partial which will be render as a spacer between each element by passing partial name to :spacer_template.

<%= render :partial => "ad", :collection => @ads, :spacer_template => "ad_divider" %>

Rendering the default case
Instead of explicitly naming the location of a partial, you can also let the RecordIdentifier do the work if you’re following its conventions for RecordIdentifier#partial_path.

# @account is an Account instance, so it uses the RecordIdentifier to replace
# <%= render :partial => "accounts/account", :locals => { :account => @account} %>
<%= render :partial => @account %>
# @posts is an array of Post instances, so it uses the RecordIdentifier to replace
# <%= render :partial => "posts/post", :collection => @posts %>
<%= render :partial => @posts %>

If you’re not going to be using any of the options like collections or layouts, you can also use the short-hand defaults of render to render partials. Examples:

# Instead of <%= render :partial => "account" %>
<%= render "account" %>
# Instead of <%= render :partial => "account", :locals => { :account => @buyer } %>
<%= render "account", :account => @buyer %>
# @account is an Account instance, so it uses the RecordIdentifier to replace
# <%= render :partial => "accounts/account", :locals => { :account => @account } %>
<%= render(@account) %>
# @posts is an array of Post instances, so it uses the RecordIdentifier to replace
# <%= render :partial => "posts/post", :collection => @posts %>
<%= render(@posts) %>

Question: some place says render will not accept additional local variables for the partial. But it seems I can pass multiple variables for render. New feature (Rails 6)?

<%= render 'record', table: @table, record: @record %>

Rails Comment System

Comment

DB
1. comments: user:references, table:references, record_id:integer parent:references rely:references content:text
2. limit to table or table record only. Use polymorphic for commenting anything.
3. Add parent_id/reply_id for replying comments, could be nil. Parent points to the top-level comment, reply points to the comment it replies.
Model
1. Add has_many :children and has_many: replies through parent/reply_id.
2. Once a comment deleted, we deleted all its children and replied comments recursively
3. Add cascade_reply_ids which find all comment IDs that need to be deleted.
Views
1. The comment container has two parts: new comment and current comments
2. For each comment, we show its content, followed by # of replies, which will show all replies once clicked. Also show when it's created, and icon for deleting
3. For reply part, its similar, on top, we show new reply, followed by all replies.
4. To make view nice, we show only two level of comments. All deeper comments are flatten by setting parent_id to top-level comment.
5. We use reply_id to link to the comment it replies to. We also show short notes of the comment.
6. Once a new reply added, we insert the reply on the top, update # of replies as well.
7. Once a top-level comment deleted, we delete all its children; once a reply deleted, we delete all replies recursively; update # of replies as well.

Code
1. use data-turbolinks=false to make anchor works without reloading pages
2. use js.erb file to make operating comments AJAX without reloading pages

# db/migrate/20210227120803_create_comments.rb
class CreateComments < ActiveRecord::Migration[6.0]
  def change
    create_table :comments do |t|
      t.references :user, null: false, foreign_key: true
      t.references :table, null: false, foreign_key: true
      t.integer :record_id, null: true
      # For nested comment, parent links to the top-level comment, reply links to its reply
      # parent comment
      t.references :parent, null: true, foreign_key: {to_table: "comments"}
      # reply comment
      t.references :reply,  null: true, foreign_key: {to_table: "comments"}
      t.text :content, null: false, default: ""
      t.timestamps
    end
    add_index :comments, [:table_id, :record_id]
    add_index :comments, [:table_id, :record_id, :parent_id]
  end
end

# app/models/comment.rb
class Comment < ApplicationRecord
  default_scope { order('id DESC') }
  belongs_to :user
  belongs_to :table
  belongs_to :parent, class_name: "Comment", optional: true
  belongs_to :reply, class_name: "Comment", optional: true
  has_many   :children, class_name: 'Comment', foreign_key: :parent_id, dependent: :destroy
  has_many   :replies, class_name: 'Comment', foreign_key: :reply_id, dependent: :destroy
  # delete_all has better performance if many records. InvalidForeignKey error
  #has_many   :children, class_name: 'Comment', foreign_key: :parent_id, dependent: :delete_all
  #has_many   :replies, class_name: 'Comment', foreign_key: :reply_id, dependent: :delete_all
  validates_presence_of :content

  def cascade_reply_ids
    # top-level comment
    return self.children.pluck(:id) unless self.parent_id?
    # non-top-level comment
    ids = self.replies.pluck(:id); nids=ids.clone
    while nids.any?
      id = nids.pop
      nn = Comment.where(table: self.table, record_id: self.record_id, parent_id:self.parent_id, reply_id: id).pluck(:id)
      ids += nn;
      nids.unshift(*nn)
    end
    return ids;
  end
end

# app/views/comments/_comment_section.html.erb
<div class="comment-container mt-5 small">
  <% if logged_in? %>
    <div class="new-comment" id="new-reply">
      <%= render "comments/new_comment", comment: comment %>
    </div>
  <% end %>
  <div class="comments" id="children">
    <%= render comments %>
  </div>
</div>

# app/views/comments/_comment.html.erb
<% comment_id = "comment-#{comment.id}" %>
<% reply_container_id = "reply-container-#{comment.id}" %>
<% new_reply_id = "new-reply-#{comment.id}" %>
<% children_id = "children-#{comment.id}" %>
<div class="card mx-4 my-1" id="<%=comment_id%>">
  <div class="card-body">
    <div class="card-title">
      <h6><%= link_to comment.user.name, f_user_path(comment.user) %></h6>
    </div>
    <% if (comment.parent_id && comment.reply_id && (comment.parent_id!=comment.reply_id)) %>
      <div class='markdown-body'>
        <% rc = "> @#{comment.reply.user.name} \n >> #{comment.reply.content.truncate(100)}" %>
        <a href="#comment-<%=comment.reply.id%>" data-turbolinks="false">
          <%= markdown(rc) %>
        </a>
      </div>
    <% end %>
    <div class='markdown-body'>
      <%= markdown(comment.content)%>
    </div>
    <% tstyle = fmt_sh_style(comment.children.any?) %>
    <% cid = "children-num-#{comment.id}" %>
    <% cnum = comment.children.count %>
    <% tstr = t_cat([("<div id='#{cid}' style='#{tstyle}'>"+cnum.to_s+"</div>"),t('reply'),">"]).html_safe %>
    <div class="d-flex flex-row justify-content-between mt-2">
      <div>
        <%= link_to tstr, "javascript:void(0)", class: "click-toggle-id", "toggle-id": reply_container_id%>
        <%= fmt_time(comment.created_at) %>
      </div>
      <% if logged_in? %>
        <% if current_user==comment.user  || admin? %>
          <%= link_to fa_destroy_icon, comment_path(comment), class: "#{lh_btn_cls} btn-sm", method: :delete, remote: true, data: { confirm: t('destroy_confirm') } %>
        <% end %>
      <% end %>
    </div>

    <div class="comment-reply-container" id="<%=reply_container_id%>" style="<%=fmt_hide_style%>">
      <div class="new-comment" id="<%=new_reply_id%>">
        <% if logged_in? %>
          <%= render "comments/new_comment", comment: Comment.new(table: comment.table, record_id: comment.record_id, parent_id: comment.parent_id || comment.id, reply_id: comment.id) %>
        <% end %>
      </div>
      <div class="comment-children" id="<%=children_id%>" %>
        <%= render comment.children if comment.children.any? %>
      </div>
    </div>
  </div>
</div>

# app/views/comments/_new_comment.html.erb
<%= form_with(model: comment, remote: true) do |form| %>
  <% if comment.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(comment.errors.count, "error") %> prohibited this comment from being saved:</h2>

      <ul>
        <% comment.errors.full_messages.each do |message| %>
          <li><%= message %></li>
        <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field form-group row justify-content-between">
    <%= form.hidden_field :table_id %>
    <%= form.hidden_field :record_id %>
    <%= form.hidden_field :parent_id %>
    <%= form.hidden_field :reply_id %>
    <div class="col-md-10 col-xs-12">
      <%= form.text_area :content, rows: 1, class:"form-control", placeholder: t("comment"), required: true %>
    </div>
    <div class="col-md-2 col-xs-12 text-center">
      <%= form.submit t("submit"), class: "btn btn-secondary form-control"%>
    </div>
  </div>
<% end %>

# app/views/comments/create.js.erb
<% if @comment.parent_id.present? %>
  // Clear form
  $('.comment-container #new-reply-<%=@comment.reply_id%> form')[0].reset()
  <% if @comment.reply_id!=@comment.parent_id %>
    $('.comment-container #reply-container-<%=@comment.reply_id%>').hide()
  <% end %>
  // Add comment
  $('.comment-container #children-<%=@comment.parent_id%>').prepend('<%= escape_javascript(render(@comment)) %>')
  // Update children number
  $('.comment-container #children-num-<%=@comment.parent_id%>').attr('style','display: inline-block;')
  <% cnum = @comment.parent.children.count %>
  $('.comment-container #children-num-<%=@comment.parent_id%>').text(<%=cnum%>)
<% else %>
  $('.comment-container #new-reply form')[0].reset()
  $('.comment-container #children').prepend('<%= escape_javascript(render(@comment)) %>')
<% end %>

# app/views/comments/destroy.js.erb
// Remove comments
$('.comment-container #comment-<%=@comment.id%>').remove()
<% if @comment.parent_id.present? %>
  // Remove comments's replies
  <% @reply_ids.each do |id| %>
    $('.comment-container #comment-<%=id%>').remove()
  <% end %>

  // Update children number
  <% cnum = @comment.parent.children.count %>
  // Set reply num
  $('.comment-container #children-num-<%=@comment.parent_id%>').text(<%=cnum%>)
  // Hide if no reply
  <% if cnum <=0 %>
    $('.comment-container #children-num-<%=@comment.parent_id%>').attr('style','display: none;')
  <% end %>
<% end %>

Active Job

ActiveJob provides an uniform interface for declaring and run backedn jobs. Note that it is just a wrapper, it relies on background processing. If no backend is set, the job is immediately executed. The backend is set like:

# Set in config/application.rb
# Be sure to have the adapter's gem in your Gemfile and follow
# the adapter's specific installation and deployment instructions. 
config.active_job.queue_adapter = :sidekiq

Commonly used backends include delayed job, sidekiq, Resque. For comparison, please check Delayed Job vs Resque vs Sidekiq . delayed_job is easier to use, sidekiq is faster but replies on Redis.

Sidekiq

We use Sidekiq as the backend. It has good document. Here is my configuration:

# 1. Configuration
# install redis
sudo apt-get install redis-server # 3.0.6 
sudo service redis-server restart
# install sidekiq in Gemfile 
gem 'sidekiq'
bundle install # 5.2.5
# config active job in config/application.rb
config.active_job.queue_adapter = :sidekiq # if not set, all jobs will perform immediately.
# Remember to start the sidekiq process
# use "RAILS_ENV=production" or "-e production/development" to specify environment. 
bundle exec sidekiq # connect to localhost:6379/0 by default.
# 2. Jobs, example.
# create job app/jobs/notify_iftt.rb 
class NotifyIftttJob < ApplicationJob
  queue_as :default 
  include IftttHelper
  def perform(tids)
    # Do something later notify_ifttt(tids) if tids
  end 
end
# call it
tids = tids.map{|tid| tid.tid}
NotifyIftttJob.perform_later(tids) if tids # preform_now does not go to backend.

It works as:

Rails serialize jobs into Redis database
Sidekiq process fetch jobs from Redis
restore environment in Rails code, then process it.

It is very important to start the Sidekiq process. Otherwise, the jobs will stay in the Redis unprocessed.

# use RAILS_ENV or -e to specify environment 
RAILS_ENV=production bundle exec sidekiq -e production bundle exec sidekiq -e production
# use -C to specify configuration.
bundle exec sidekiq -e production -C config/sidekiq.xml
# config/sidekiq.yml 
:verbose: false
:concurrency: 25
:strict: false
:logfile: log/sidekiq.log :pidfile: tmp/pids/sidekiq.pid development:
:verbose: true
:concurrency: 15
:logfile: log/sidekiq_dev.log :pidfile: tmp/pids/sidekiq_dev.pid
production:

It is also important to process in correct Rails environment, otherwise, error ocurrs when processing it. For example, the job is stored by production Rails, but got by Sidekiq working on development Rails. So it is better to use different database for different environments or code bases. By default, Redis provides 16 databases (0-15). Race condition is problematic to have two sidekiq/rails shares the same database.

# config/initializers/sidekiq.rb
# Redis by default have 0-15 database. Must config both server and client. 
Sidekiq.configure_server do |config|
  if Rails.env.development?
    config.redis = { url: 'redis://localhost:6379/15'}
  else
    config.redis = { url: 'redis://localhost:6379/0'}
  end 
end
Sidekiq.configure_client do |config| 
  if Rails.env.development?
    config.redis = { url: 'redis://localhost:6379/15'} 
  else
    config.redis = { url: 'redis://localhost:6379/0'} 
  end
end

Sidekiq provide a web interface.

# Add in config/routes.rb
require 'sidekiq/web'
require 'admin_constraint' # require admin for access
mount Sidekiq::Web => '/sys/sidekiq', :constraints => AdminConstraint.new
 # lib/admin_constraint.rb
 class AdminConstraint
  def matches?(request)
    return false unless request.session[:user_id] 
    user = User.find request.session[:user_id] 
    user && user.ADMIN?
  end 
end

State Machine Transition by JS

I want to show friend status and action in the home page. The friendship status includes:

stranger
friend
pending (request sent)
waiting (request received)
rejected (request rejected)
declined (declined request)

The action includes

stranger: -> request friendship
friend: -> unfriend
pending: -> withdraw
waiting: -> accept; -> reject
rejected
declined: -> accept

I list all states and actions in the home page, and show the state only according to current friendship status

<% h = [:waiting, :declined].include?(status.to_sym) ? {inviter_id: user.id} : {invitee_id: user.id} %>
<% btn_params =  {params: h, remote: true, class: "#{lh_btn_cls} btn-outline-primary btn-sm"} %>
<div class='fsm'  id='fsm-stranger' style='<%=status.to_sym==:stranger ? fmt_show_style : fmt_hide_style%>' >
  <div class="d-inline-block">
    <%= fa_friends_icon %> <%= t('models.friendship.statuses.stranger') %>
  </div>
  <div class="d-inline-block">
    <%= button_to t('models.friendship.operations.request'), activity_request_friendship_path(format: :json), btn_params.merge({form: {class: "fsm-switch", "curr-state": "fsm-stranger", "next-state": "fsm-pending"}}) %>
  </div>
</div>
<div class='fsm'  id='fsm-pending' style='<%=status.to_sym==:pending ? fmt_show_style : fmt_hide_style%>' >
  <div class="d-inline-block">
    <%= fa_friends_icon %> <%= t('models.friendship.statuses.pending') %>
  </div>
  <div class="d-inline-block">
    <%= button_to t('models.friendship.operations.withdraw'), activity_withdraw_friendship_path(format: :json), btn_params.merge({form: {class: "fsm-switch", "curr-state": "fsm-pending", "next-state": "fsm-stranger"}}) %>
  </div>
</div>
<div class='fsm'  id='fsm-friend' style='<%=status.to_sym==:friend ? fmt_show_style : fmt_hide_style%>' >
  <div class="d-inline-block">
    <%= fa_friends_icon %> <%= t('models.friendship.statuses.friend') %>
  </div>
  <div class="d-inline-block">
    <%= button_to t('models.friendship.operations.unfriend'), activity_unfriend_path(format: :json), btn_params.merge({form: {class: "fsm-switch", "curr-state": "fsm-friend", "next-state": "fsm-stranger"}}) %>
  </div>
</div>
<div class='fsm'  id='fsm-rejected' style='<%=status.to_sym==:rejected ? fmt_show_style : fmt_hide_style%>' >
  <%= fa_friends_icon %> <%= t('models.friendship.statuses.rejected') %>
</div>

<div class='fsm'  id='fsm-waiting' style='<%=status.to_sym==:waiting ? fmt_show_style : fmt_hide_style%>' >
  <div class="d-inline-block">
    <%= fa_friends_icon %> <%= t('models.friendship.statuses.waiting') %>
  </div>
  <div class="d-inline-block">
    <%= button_to t('models.friendship.operations.accept'), activity_accept_friendship_path(format: :json), btn_params.merge({form: {class: "fsm-switch", "curr-state": "fsm-waiting", "next-state": "fsm-friend"}}) %>
  </div>
  <div class="d-inline-block">
    <%= button_to t('models.friendship.operations.reject'), activity_reject_friendship_path(format: :json), btn_params.merge({form: {class: "fsm-switch", "curr-state": "fsm-waiting", "next-state": "fsm-declined"}}) %>
  </div>
</div>
<div class='fsm'  id='fsm-declined' style='<%=status.to_sym==:declined ? fmt_show_style : fmt_hide_style%>' >
  <div class="d-inline-block">
    <%= fa_friends_icon %> <%= t('models.friendship.statuses.declined') %>
  </div>
  <div class="d-inline-block">
    <%= button_to t('models.friendship.operations.accept'), activity_accept_friendship_path(format: :json), btn_params.merge({form: {class: "fsm-switch", "curr-state": "fsm-declined", "next-state": "fsm-friend"}}) %>
  </div>
</div>

The Javascript code:

// button-to with fsm-switch. After success, show  ID specified by "next-state"
// finite-state-machine switch
$(document).on("turbolinks:load", function() {
  $('.fsm-switch').on('ajax:success', function (e) {
    console.log("FSM switch after AJAX success")
    let cid = $(this).attr('curr-state');
    let nid = $(this).attr('next-state');
    console.log(cid);
    console.log(nid);
    $("#"+cid).toggle()
    $("#"+nid).toggle()
  });
});

Bootstrap Tooltips

Tooltips vs popover
- Popovers require Tooltips to be included.
- popovers have an option to display both a title and content, while tooltips only have an option to display a title.
- Tooltips are typically only visible on hover, Popovers are typically dismissable, whether by click on other parts of the page or second clicking the popover target (depending on implementation)
- Although it should be noted due to accessibility problems, potential SEO issues, and lack of discovery of the tooltip/popover, neither are recommended unless you absolutely need them.
Install
- check package.json, make sure 'bootstrap' and 'popper' are installed

Usages

Add to js

// Tooltips
$(document).on("turbolinks:load", function() {
  $('[data-toggle="tooltip"]').tooltip();
});

In the views, add

  data-toggle="tooltip" data-placement="left" title="Tooltip on left"
  // Or define a helper 
  def fmt_tooltip(title,position="top")
     {'data-toggle': 'tooltip', 'data-placement': position, title: title}
  end

Rails Load More (2)

Rails Load More

I want to improve it by using multiple tabs in the same page.

improve Javascript to pass both record ID and section ID

// Improvement: multiple in the same page. The HTML layout must be
//   <div id="unique_id">
//     <div class="container">
//       <div class="record" date-id=object_id>
//       </div>
//       <div class="record" date-id=object_id>
//       </div>
//     </div>
//     <div class="load-more-container">
//       <img class="loading-gif"></img>
//       <a class="load-more">load more </a>
//     </div>
//   </div>
$(document).on("turbolinks:load", function() {
// when the load more link is clicked
$('a.load-more').click(function (e) {
console.log("Load-more clicked")
// prevent the default click action
e.preventDefault();
// hide load more link
$(this).siblings('.load-more').hide();
// show loading gif
$(this).siblings('.loading-gif').show();
// Section
var section = $(this).parent().parent()
var section = section.attr('id')
console.log(`Section ID: ${section}`)
// Container
var cobj = $(this).parent().siblings(".container") // container object
// get the last id and save it in a variable 'last-id'
var last_id = cobj.find('.record').last().attr('data-id');
console.log(`Last ID: ${last_id}`)
// make an ajax call passing along our last user id
$.ajax({
  // make a get request to the server
  type: "GET",
  // get the url from the href attribute of our link
  url: $(this).attr('href'),
  // send the last id to our rails app
  data: {
    record: last_id,
    section: section
  },
  // the response will be a script
  dataType: "script",
  // upon success
  success: function (data,status,xhr) {
    console.log("AJAX done")
    // hide the loading gif. TODO: how about mutliple?
    $('.loading-gif').hide();
    // show our load more link
    $('.load-more').show();
  }
});
});
});

Use Record ID and Section ID in controller to get new records

@limit = params[:limit] || 20;
@record = params[:record]; @section=params[:section] # operation, also section ID
cond = {user: current_user};
cond[:id] = (0..@record.to_i-1) if @record
if @section
  # List
  cond[:operation] = @section
  @activities = Activity.where(cond).limit(@limit)
else
  # Hash of activities
  @activities = {}
  Activity.operations.each do |opt, value|
    cond[:operation] = opt
    @activities[opt] = Activity.where(cond).limit(@limit)
  end
end
respond_to do |format|
 format.html
 format.js
end

Append result to specified section in js.erb

<% if @activities.empty? %>
$('#<%=@section%> .load-more-container').hide()
<% else %>
$('#<%=@section%> .container').append('<%= escape_javascript(render(partial: "home/activity",collection: @activities)) %>')
<% end %>

Set multiple tabs by using Bootstrap

<ul class="nav nav-tabs nav-pills" role="tablist">
<% Activity.operations.each_with_index do |opt,idx| %>
<% opt = opt[0]%>
<% cls = idx==0 ? "active" : "" %>
<% select = (idx==0)  %>
<li class="nav-item">
  <a class="nav-link <%=cls%>" id="<%=opt%>-tab" href="#<%=opt%>" data-toggle="tab" role="tab" aria-controls="<%=opt%>" aria-selected="<%= select %>"><%=t("models.activity.operations.#{opt}")%></a>
</li>
<% end %>
</ul>
<div class="tab-content mt-2">
<% Activity.operations.each_with_index do |opt,idx| %>
<% opt = opt[0] %>
<% cls = (idx==0) ? "active" : "" %>
<div class="tab-pane fade show <%=cls%>" id="<%=opt%>" role="tabpanel" aria-labelledby="<%=opt%>-tab">
  <div class="container row">
    <%= render partial: "home/activity", collection: @activities[opt] %>
  </div>
  <div class="load-more-container text-center">
    <%= image_tag "ajax-loader.gif", style: "display:none;", class: "loading-gif" %>
    <%= link_to t('views.load_more'), "#", class: "load-more"%>
  </div>
</div>
<% end %>
</div>

Rails Load More

I want to show user activity history which could be huge in AJAX way.

Basically I follow this guide, with improvement from this guide

views/home/activities.html.erb

<div class="container">
  <%= render partial: "home/activity", collection: @activities %>
</div>
<div class="load-more-container">
  <%= image_tag "ajax-loader.gif", style: "display:none;", class: "loading-gif" %>
  <%= link_to "Load More", "#", class: "load-more"%>
</div>

Please note
1. the partial is under views/home/ instead of views/activities by default. So we need to specify the path, instead of using <%= render @activities%> directly.
2. don't add remote: true in the link_to tag, otherwise, it will fetch twice, one with id, the other one without, leading to duplicate result.
3. download the ajax-loader.gif to assets/images

model/activity.rb

    default_scope { order('id DESC') }

I use ID instead of created_at because we do not have index for created_id. Usually, the ID order should be same with created_at, with some corner case exceptions.

views/home/_activity.html.erb

<div class="record" data-id="<%= activity.id %>">
  <%= activity.id %> | <%= activity.operation %> | <%= activity.table.name %>  | <%= activity.record_id %> | <%= activity.updated_at %>
</div>

Please not that you must specify the class and data-id attribute, which are use by the Javascript below.

javascript/packs/utils.js

$(document).on("turbolinks:load", function() {
  // when the load more link is clicked
  $('a.load-more').click(function (e) {
    console.log("Load-more clicked")
    // prevent the default click action
    e.preventDefault();
    // hide load more link
    $('.load-more').hide();
    // show loading gif
    $('.loading-gif').show();
    // get the last id and save it in a variable 'last-id'
    var last_id = $('.record').last().attr('data-id');
    console.log(`Last ID: ${last_id}`)
    // make an ajax call passing along our last user id
    $.ajax({
      // make a get request to the server
      type: "GET",
      // get the url from the href attribute of our link
      url: $(this).attr('href'),
      // send the last id to our rails app
      data: {
        id: last_id
      },
      // the response will be a script
      dataType: "script",
      // upon success
      success: function () {
        // hide the loading gif
        $('.loading-gif').hide();
        // show our load more link
        $('.load-more').show();
      }
    });
  });
});

controllers/home_controller.rb

  def activities
    if params[:id]
      @activities = Activity.where(user: current_user, id: (0..params[:id].to_i-1)).limit(5)
    else
      @activities = Activity.where(user: current_user).limit(5)
    end
    respond_to do |format|
     format.html
     format.js
    end
  end

Please note that the class variable solution here does not work, reloading the page will not reset the class variable, leading to empty page.

views/home/activities.js.erb

<% if @activities.empty? %>
  $('.load-more-container').hide()
<% else %>
  $('.container').append('<%= escape_javascript(render(partial: "home/activity",collection: @activities)) %>')
<% end %>

Please note that we use the solution here to disable the link once all loaded. It depends on the class container and load-more-container set in views/home/activities.html.erb

render collection

loop method

<% users.each do |user| %>
<%= render user %>
<% end %>

render collection directly
```
<= render @users %>
```

view in other directory

<= render (partial: 'home/user', collection: @users) %>

Rails JavaScript

Working with JavaScript in Rails

UJS (Unobtrusive JavaScript): 主要的两个原则
- HTML JS 分离 (separation of functionality (the behavior layer) from a Web page's structure/content and presentation)
- 锦上添花，没JS也能用 (progressive enhancement to support user agents that may not support certain JavaScript functionality and users that have disabled JavaScript)
Rails内嵌JS
- 通过 data-* 属性关联
- local: false | remote: true -> data-remote='true'
- data-url , data-params, data-method, data-type
- data: {confirm: "Are your sure?"} -> data-confirm
- data: {disable_with: "Saving..."} -> data-disable-with

Rails-ujs event handlers

Rails 5.1 introduced rails-ujs and dropped jQuery as a dependency.
Unlike the version with jQuery, all custom events return only one parameter: event. In this parameter, there is an additional attribute detail which contains an array of extra parameters.

document.body.addEventListener("ajax:success", (event) => {
  const [data, status, xhr] = event.detail;
});

Event list:

Event name	Extra parameters (event.detail)	Fired
ajax:before		Before the whole ajax business.
ajax:beforeSend	[xhr, options]	Before the request is sent.
ajax:send	[xhr]	When the request is sent.
ajax:stopped		When the request is stopped.
ajax:success	[response, status, xhr]	After completion, if the response was a success.
ajax:error	[response, status, xhr]	After completion, if the response was an error.
ajax:complete	[xhr, status]	After the request has been completed, no matter the outcome.

You can stop execution of the Ajax request by running event.preventDefault() from the handlers methods ajax:before or ajax:beforeSend.Note, you should use return false to prevent an event for jquery-ujs and event.preventDefault() for rails-ujs.
Turbolinks: Turbolinks attaches a click handler to all tags on the page. Turbolinks will make an Ajax request for the page, parse the response, and replace the entire of the page with the of the response.

If you want to disable Turbolinks for certain links, add a data-turbolinks=false attribute to the tag

<a href="..." data-turbolinks="false">No turbolinks here</a>.

Page change events: load -> turbolinks:load

document.addEventListener("turbolinks:load", () => {
  alert("page has loaded!");
});

Server side

return JSON
1. format.json
2. JS generate HTML based on JSON data
return HTML
1. format.js
2. return HTML directly

    // foo.js.erb
    var users = document.querySelector("#users");
    users.insertAdjacentHTML("beforeend", "<%= j render(@user) %>");

How to Use AJAX With Ruby on Rails

Client make a AJAX request

  // JS style
  $.get( "/vegetables", function(data) {
    alert("Vegetables are good for you!");
  });
  // Rails style
  Rails.ajax({
    url: "/books",
    type: "get",
    data: "",
    success: function(data) {},
    error: function(data) {}
  })

Server side

Solutions
1. Solution 1: SJR (Server-Generated Javascript). Use js.erb to generate HTML, nothing to do in client.
2. Solution 2: use JSON but the response is the new HTML to use.
3. Solution 3: user JSON to return data only. Javascript update HTML using that data. e.g. React. (Rails负责生成数据，Client生成HTML)
Solution 1

// Javascript view example:
Rails.$('.random-number')[0].innerHTML = ("<%= j (render partial: 'random') %>")
// jQuery example:
$('.random-number').html("<%= j (render partial: 'random') %>")
//  `j` is an alias for `escape_javascript`

Solution 2

# controller
render json: { html: render_to_string(partial: 'random') }
# client JS
Rails.ajax({
  url: "/books",
  type: "get",
  success: function(data) { Rails.$(".random-number")[0].innerHTML = data.html; }
})

Others

Rails - display results of index and show actions via ajax
Traditional way of performing AJAX operation in Rails
Ajax Call for load more button in Rails
Hide Load More buttons when all items have been rendered in Ruby on Rails

AJAX events

Failed to get data in JS, found this question

For AJAX returns, jQuery returns events likes

$(document).ready ->
  $("#new_message").on("ajax:success", (e, data, status, xhr) ->
    console.log(xhr);
  ).on "ajax:error", (e, xhr, status, error) ->
    console.log(xhr);

However, as shown in the Rails Guide, Rails-ujs returns only one parameter event with all other in detail attribute. So the code should be like

document.body.addEventListener("ajax:success", (event) => {
  const [data, status, xhr] = event.detail;
});

mutual friends

Guide
- similar solution
DB

class CreateFriendships < ActiveRecord::Migration[6.0]
  def change
    create_table :friendships do |t|
      t.references :inviter, null: false, foreign_key: {to_table: "users"}
      t.references :invitee, null: false, foreign_key: {to_table: "users"}
      t.integer :status, null: false, default: 0

      t.timestamps
    end
    add_index :friendships, :status
  end
end

Models

# app/models/friendships
class Friendship < ApplicationRecord
  belongs_to :invitee, class_name: "User"
  belongs_to :inviter, class_name: "User"
  enum status: {pending: 0, accepted: 1},     _suffix: true, _prefix: :is
end
# app/models/users
  has_many :friendships_as_invitee, class_name: "Friendship", foreign_key: :invitee_id
  has_many :friendships_as_inviter, class_name: "Friendship", foreign_key: :inviter_id
  def friends
    ids1 = friendships_as_invitee.where(status: :accepted).pluck(:inviter_id)
    ids2 = friendships_as_inviter.where(status: :accepted).pluck(:invitee_id)
    User.where(id: ids1+ids2)
  end
  def all_friends
    ids1 = friendships_as_invitee.pluck(:inviter_id)
    ids2 = friendships_as_inviter.pluck(:invitee_id)
    User.where(id: ids1+ids2)
  end
  def pending_friends
    ids1 = friendships_as_invitee.where(status: :pending).pluck(:inviter_id)
    ids2 = friendships_as_inviter.where(status: :pending).pluck(:invitee_id)
    User.where(id: ids1+ids2)
  end
  def pending_inviters
    ids = friendships_as_invitee.where(status: :pending).pluck(:inviter_id)
    User.where(id: ids)
  end
  def pending_invitees
    ids = friendships_as_inviter.where(status: :pending).pluck(:invitee_id)
    User.where(id: ids)
  end

javascript_include_tag vs javascript_pack_tag

javascript_include_tag: for app/assets

<script src="https://localhost/assets/xmlhr.debug-1284139606.js"></script>

javascript_pack_tag: for webpacker

<script src="/packs/js/application-be5eb61178f8249f882f.js" data-turbolinks-track="reload"></script>

similar for stylesheet
html
- link vs script
- <link> for CSS
- <script> for JS

upload file

guide

form

<%= form_with(url: upload_table_records_path(@table), method: :POST, local: true) do |form| %>
  <div class="form-group row justify-content-center">
    <%= form.file_field :file, class: 'form-control col-6' %>
  </div>

  <div class="actions text-center">
    <%= submit_tag t("upload"), class: "btn btn-primary"%>
  </div>
<% end %>

controller

      f = params[:file]; contents = f.read;
      fpath = f.path;  # same with f.tempfile.path
      File.open(fpath, 'wb') do |file|
        file.write(contents)
        file.close
      end
      Record.from_csv(@table,fpath)

Note that params[:file] is ActionDispatch::Http::UploadedFile object
It has tempfile stored in tmp files, e.g. /tmp/RackMultipart20210118-18052-19hic1b.csv, which will be deleted when the file is closed.

include css.erb file in application.css

To use rouge, I include an erb file in application.css. This cause some problems in Rails console

First rails console failed with error cannot load such file -- rouge; the second try works.
Can't reload! Second try doesn't work either.

Solution: Not work

#config/application.rb
config.assets.precompile += ["rouge"]

Rails.application.secrets.secret_key_base is empty in production.

use Rails.application.credentials.secret_key_base

check for details
There are two ways to access secret_key_base:

Rails.application.credentials.secret_key_base
Rails.application.secrets.secret_key_base Rails 5 took the first way by default.

you can change Rails.application.credentials.secret_key_base by rails credentials:edit.

Markdown

Guide
Install redcarpet

Gemfile

  gem 'redcarpet'
  gem 'rouge' // for themes

app/helpers/markdown_helper.rb

module MarkdownHelper
 require 'redcarpet'
 require 'rouge'
 require 'rouge/plugins/redcarpet'

 class HTML < Redcarpet::Render::HTML
   include Rouge::Plugins::Redcarpet
 end

 def markdown(text)
   render_options = {
     # filer_html: true,
     hard_wrap: true,
     link_attributes: { rel: 'nofollow' },
     prettify: true
   }
   #renderer = Redcarpet::Render::HTML.new(render_options)
   renderer = HTML.new(render_options)
   extras = {
     no_intra_emphasis: true,
     tables: true, // support table
     fenced_code_blocks: true,
     autolink: true,
     disable_indented_code_blocks: true,
     strikethrough: true,
     lax_spacing: true,
     space_after_headers: true,
     superscript: true,
     underline: true,
     highlight: true,
     quote: true,
     footnotes: true,
   }

    markdown = Redcarpet::Markdown.new(renderer, extras)
    raw markdown.render(text)
  end
end

application_controller.rb

  include MarkdownHelper

usage: markdown(text)
Rouge themes
- we use GitHub

css (app/assets/stylesheets)

application.css

 *= require rouge
 *= require github_markdown

rouge.scss.erb

<%= Rouge::Themes::Github.render(scope: '.highlight') %>

~~copy table, blockquote, code format from github.css~~

github_markdown.css

   <div class="markdown-body">  // enable github_markdown.css
   <%= markdown(v) %>
   </div>

Issues:

List with code not working well, must have new line between

Rails建站指南

How to start a new Rails app

System

Install ubuntu 18.04 LTS

DB:PostgreSQL

Guide: default version is 10, we use the latest

    sudo apt-get install wget ca-certificates
    wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
    sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" >> /etc/apt/sources.list.d/pgdg.list'
    sudo apt-get install postgresql postgresql-contrib libpq-dev
    sudo -u postgres createuser db_user -s
    sudo -u postgres psql
    postgres=# \password (db_user)

By default, psql use peer neection (login by linux user, no password).
To change it, modify /etc/postgresql/9.5/main/pg_hba.conf
from:
local all all peer
to:
local all all md5
then restart by
sudo service postgresql restart

Command to login:
psql -U db_user -d postgres # must specify db

Rails

Guide

Rails

sudo apt install curl
curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list

sudo apt-get update
sudo apt-get install git-core zlib1g-dev build-essential libssl-dev libreadline-dev libyaml-dev libsqlite3-dev sqlite3 libxml2-dev libxslt1-dev libcurl4-openssl-dev software-properties-common libffi-dev nodejs yarn

cd
git clone https://github.com/rbenv/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(rbenv init -)"' >> ~/.bashrc
exec $SHELL

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build
echo 'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"' >> ~/.bashrc
exec $SHELL

rbenv install 2.6.5
rbenv global 2.6.5
ruby -v

gem install bundler
gem install rails -v 6.0.0
rbenv rehash
rails -v

Rails app

rails new my_site -d postgresql

# configure db database.yml
# add domain
add config.hosts << "yourdomain.com" to config/environments/development.rb
# config generator in application.rb
config.generators do |g|
  # Disable jbuilder as we use JR
  # g.jbuilder        false
  ## Disable empty files
  # helper files
  g.helper          false
  # assets files
  g.assets          false
end

Ngnix

Guide

    sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 561F9B9CAC40B2F7
    sudo sh -c 'echo deb https://oss-binaries.phusionpassenger.com/apt/passenger bionic main > /etc/apt/sources.list.d/passenger.list'
    sudo apt-get update
    sudo apt-get install -y nginx-extras libnginx-mod-http-passenger
    if [ ! -f /etc/nginx/modules-enabled/50-mod-http-passenger.conf ]; then sudo ln -s /usr/share/nginx/modules-available/mod-http-passenger.load /etc/nginx/modules-enabled/50-mod-http-passenger.conf ; fi
    sudo ls /etc/nginx/conf.d/mod-http-passenger.conf
    sudo vim /etc/nginx/conf.d/mod-http-passenger.conf
    # We simply want to change the passenger_ruby line to match the following:
    passenger_ruby /home/<deploy_user>/.rbenv/shims/ruby;
    sudo service nginx start

Deploy

Guide

Add the following gems to our Gemfile

gem 'capistrano', '~> 3.11'
gem 'capistrano-rails', '~> 1.4'
gem 'capistrano-passenger', '~> 0.2.0'
gem 'capistrano-rbenv', '~> 2.1', '>= 2.1.4'

Generate template

bundle
# use cap in rbenv, source ~/.bashrc if cap not found
cap install STAGES=production

Edit Capfile

Capfile:

  require 'capistrano/rails'
  require 'capistrano/passenger'
  require 'capistrano/rbenv'
  set :rbenv_type, :user
  set :rbenv_ruby, '2.6.5'

deploy.rb

  set :application, "my_site"
  set :repo_url, "/home/web/codes/rails"
  set :deploy_to, "/var/www/my_site"
  append :linked_files, 'config/database.yml', 'config/master.key'
  append :linked_dirs, 'log', 'tmp/pids', 'tmp/cache', 'tmp/sockets', 'vendor/bundle', '.bundle', 'public/system', 'public/uploads'
  set :keep_releases, 5

deploy/production.rb

  server 'yourdomain.com', user: 'web', roles: %w{app db web}

Prepare

RAILS_ENV=production rails db:create # create db
sudo mkdir /var/www/my_site
sudo chown -R web:web /var/www/my_site
cp master.key database.yml to /varw/www/my_site/shared/config
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys # Otherwise, ask for password when deploy

Nginx config: /etc/nginx/site-available/default

listen 80;
listen [::]:80;
server_name my_site.com;
passenger_enabled on;
rails_env    production;
# Because of incorrect path in /etc/nginx/conf.d/mod-http-passenger.conf, we have to set it again here. It's optional if it's right above.
#pssenger_ruby /home/web/.rbenv/shims/ruby; 
root /var/www/my_site/current/public;

Make swap, otherwise, too slow.
```
cap production deploy
```

HTTPS

Install certbot
By snapd:

    sudo snap install core; sudo snap refresh core
    sudo apt-get remove certbot
    sudo snap install --classic certbot
    sudo ln -s /snap/bin/certbot /usr/bin/certbot

By APT:

    sudo apt-get install certbot python-certbot-nginx
    sudo certbot --nginx (choose direct, disable http)

usage:

    sudo certbot renew # for renew
    sudo certbot renew --webroot-path /var/www/xxx # renew with webroot path
    sudo certbot certonly -a webroot --webroot-path=/var/www/<your site>/current/public -d www.example.com -d example.com -d api.example.com.   # multiple sub-domain
    sudo certbot certificates # expiration day
    sudo certbot delete --cert-name # remove unused domain

It seems the auto cron will renew the certification once per two months. But Ngnix should be restarted to load the new file.

Basic

Generator

Config generator in application.rb

config.generators.test_framework false
config.generators do |g|
  # Disable jbuilder as we use JR
  # g.jbuilder        false
  # Disable empty files
  # helper files
  g.helper          false
  # assets files
  g.assets          false
end

compression

guide
in config/application.rb
```
config.middleware.use Rack::Deflater
```
not working by https://gtmetrix.com/
compress js/css by Nginx
- enable gzip in /etc/nginx/nginx.conf
- this works with https://gtmetrix.com/
Leverage browser caching for Nginx
- Allow browser to cache static
- /etc/nginx/sites-available/default
- Not working for Google Analytics JS. Could be done as well, but I don't want to do this trick replies on Nginx

Javascript

jQuery: follow guide

install jquery if not yet: yarn add jquery
in config/webpack/environment.js

const webpack = require('webpack')
environment.plugins.prepend('Provide',
  new webpack.ProvidePlugin({
    $: 'jquery/src/jquery',
    jQuery: 'jquery/src/jquery'
  })
)

in app/javascript/packs/application.js

require('jquery')

check webpack-dev-server to make sure no error

support coffee files: follow guide
- rails webpacker:install:coffee
  - updated config/webpack/environment.js
  - updated config/webpacker.yml
  - updated config/webpack/loaders/coffee.js
- rm app/javascript/packs/hello_coffee.coffee
- put coffee files in app/javascript/coffee
- in application.js, add require('../coffee/application.coffee')

Bootstrap:

Guide

Install
```
yarn add bootstrap popper.js jquery
```
In app/javascript/stylesheets/application.scss
```
@import 'bootstrap/scss/bootstrap';
```

In app/javascript/packs/application.js

import 'stylesheets/application' # include scss above
import 'bootstrap/dist/js/bootstrap';

On-the-fly build for dev:
```
bin/webpack-dev-server
```

Email

Install rails g mailer admin_mailer send_passwd
Allow less secure apps to access your Gmail account: Guide

Email configuration for sending emails

config.action_mailer.raise_delivery_errors = true
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  :address              => "smtp.gmail.com",
  # NOTE: Please use 587 not 465. Details: https://github.com/rails/rails/issues/27298
  #:port                 => 465, # EOF error
  # Remember to enable less secure apps, otherwise Net::SMTPAuthenticationError
  :port                 => 587,
  :domain               => "my_site.com", # does it matter?
  :user_name            => "my_site@gmail.com",
  :password             => "my_password",
  # Plain vs Login, encry username and password together or separately.
  # Details: http://www.samlogic.net/articles/smtp-commands-reference-auth.htm
  #:authentication       => "plain",
  :authentication       => "login",
  :enable_starttls_auto => true
}

Check your email, Gmail may still block your access. You may need to use server to login your gmail account, then unlock, following the guide
- NOTE: use ssh -Y in Mac to connect server, ssh -X not work

I18n

Guide

add zh.yml file under lib/locale (default config/locales)

config in config/initializers/locale.rb

I18n.load_path += Dir[Rails.root.join('lib', 'locale', '*.{rb,yml}')]
I18n.available_locales = [:en, :zh]
I18n.default_locale = :zh

In application.rb

around_action :switch_locale
def switch_locale(&action)
  locale = params[:locale] || I18n.default_locale
  I18n.with_locale(locale, &action)
end
def default_url_options
  { locale: I18n.locale }
end

config/routes.rb, put everything in

scope "/:locale" do
  resources :books
end

Google

Google analytics

Add js to head

<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-159082166-1"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());
  gtag('config', 'UA-159082166-1');
</script>

Add js to Rails, NOTE the hack for turbolinks

<!-- Global site tag (gtag.js) - Google Analytics -->
<% if Rails.env.production? %>
  <script async src="https://www.googletagmanager.com/gtag/js?id=UA-159082166-1"></script>
  <script>
    window.dataLayer = window.dataLayer || [];
    function gtag(){dataLayer.push(arguments);}
    gtag('js', new Date());
    gtag('config', 'UA-159082166-1');
    // turbolinks
    document.addEventListener('turbolinks:load', event => {
      if (typeof gtag === 'function') {
        gtag('config', 'UA-159082166-1', {
          'page_location': event.data.url
        });
      }
    });
  </script>
<% end %>

Google recaptcha

Get API key
in Gemfile: gem "recaptcha"

Configure keys in config/initializers/recaptcha.rb

Recaptcha.configure do |config|
  config.site_key  = 'xxx'
  config.secret_key = 'xxxx'
end

Add to views: <%= recaptcha_tags %>

Check in controller

skip_verify = request.format.json?
if (skip_verify || verify_recaptcha(model: @user)) && @user.save
  // OK
else
  // ERROR
end

HTML5 date picker doesn't show on Safari

jQuery date picker problem in Safari

Safari does not include a native datepicker for its desktop version (although it does for iOS). Incidentally, neither does IE. It's very frustrating as it could save developers a lot of time if they did.
This is a useful link for tracking support for it: http://caniuse.com/#feat=input-datetime
Although there is no native datepicker for Safari (or IE) a pretty good workaround is to add a placeholder attribute to the date input. This informs Safari and IE users which format the fallback text input should be (which is yyyy-mm-dd). The placeholder doesn't display on browsers that support type=date so this workaround won't affect other browsers.
```
e.g. <input type="date" placeholder="yyyy-mm-dd" />
```

RichText(Quill)

Why Quill?

support math
internal format, not html

Question:

where local image saved?
support image url?

Problem:

can't have two editors on the same page
jquery syntax not work to find body
missing images under packs
- import 'quill/dist/quill.snow.css';
- https://medium.com/@technoblogueur/rails-6-and-webpacker-what-you-need-to-know-e3534fded7ff
limit size by bootstrap
- wrapper by another div, col-10 ok, do not use form-control
math
- need kaTex
- include js in application.html.erb directly
image with URL
- https://github.com/quilljs/quill/issues/2044
- new format: image_link
- set icons: https://github.com/quilljs/quill/issues/1099
- need to install font-awesome for icons

Guide:

Install

yarn add quill
include in application, import css as well.
view:
- add hidden_field with class 'rich-text-content',
- add a div with id 'editor', wrapped by div with 'col-10' to limit size
in js:
- copy content from div with id='editor' to input with class 'rich-text-content', thus save and upload to server
- config options and toolbar
support math
- include js in application.html.erb directly
image with URL
- https://github.com/quilljs/quill/issues/2044
- new format: image_link
- set icons: https://github.com/quilljs/quill/issues/1099
min height
- https://www.fabiofranchino.com/log/setting-a-minimun-default-height-to-quill-text-area/
```
.ql-editor{
  min-height: 200px;
}
```

Rails chart

chartkick

installation

# Add this line to your application's Gemfile:
gem "chartkick" # This is not optional. Without it, function (e.g. line_chart) won't work even if js is ready. 
# For Rails 6 / Webpacker, run:
yarn add chartkick chart.js
# And in app/javascript/packs/application.js, add:
require("chartkick")
require("chart.js")

chart library

Google chart

Load JS <%= javascript_include_tag "https://www.gstatic.com/charts/loader.js" %>
Get an API Key
1. To use google geo_chart, need a API key. (Seems OK for timeline chart).
2. get a key
3. AIzaSyCo0AKH9n0-vu92BsU9TwUDKjpmi6c8HZU

Set it

<script type="text/javascript">
google.charts.load('current', {
'packages':['geochart'],
'mapsApiKey': 'AIzaSyCo0AKH9n0-vu92BsU9TwUDKjpmi6c8HZU'
});
</script>

NOTE: I tried to set it in config/initializer/chartkick.rb

Chartkick.options = {
language: "en",
mapsApiKey: "AIzaSyCo0AKH9n0-vu92BsU9TwUDKjpmi6c8HZU", // NOT WORK
height: "400px", // SEEMS WORK
colors: ["#b00", "#666"]
}
Chartkick.configure({language: "de", mapsApiKey: "..."}) // ERROR to load, no configure function.

Link to current page with plus/merged with a param

Solution

link_to "Page", params.merge(:c => "e")

Error: Rails Unable to convert unpermitted parameters to hash

solution

#If you know which parameters should be allowed in the link, you can call permit with those listed.
params.permit(:param_1, :param_2).merge(:sort => column, :direction => direction, :page => nil)
# OR
params.merge(:sort => column, :direction => direction, :page => nil).permit(:param_1, :param_2, :sort, :direction, :page)
# Risk solution
params.to_unsafe_h.merge