flowerwrong (花错)

感觉现在 ruby-china 的样式包括通知比之前丑了

flowerwrong — Mon, 09 May 2016 09:04:26 +0800

:sad:

Association 中 SQL Order or Where 导致的 N+1 query 问题

flowerwrong — Sat, 21 Nov 2015 21:01:16 +0800

N + 1 query

models

class Cat < ActiveRecord::Base
  has_many :articles
end

class Article < ActiveRecord::Base
  default_scope { where(is_publish: 1) }
  scope :view_counts_order, -> { order(view_counts: :desc) }

  belongs_to :cat
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :article # , counter_cache: :article_comments_count
end

controller

# 问题控制器
Cat.includes(articles: :article_comments]).all.each do |cat|
  cat.articles.view_counts_order.each do |article|
    p article.comments.size
  end
end

# 不加order没 N + 1 query问题
Cat.includes(articles: :article_comments]).all.each do |cat|
  cat.articles.each do |article|
    p article.comments.size
  end
end

问题

如何减少 cat.articles.view_counts_order 产生的多余 sql？同理，如果 articles 后面加 where 查询也会导致多余 sql。

多余 sql

  Article Load (0.1ms)  SELECT `articles`.* FROM `articles` WHERE `articles`.`is_publish` = 1 AND `articles`.`cat_id` = 6  ORDER BY `articles`.`view_counts` DESC
   (0.1ms)  SELECT COUNT(*) FROM `comments` WHERE `comments`.`article_id` = 200
0
   (0.1ms)  SELECT COUNT(*) FROM `comments` WHERE `comments`.`article_id` = 191
0
   (0.1ms)  SELECT COUNT(*) FROM `comments` WHERE `comments`.`article_id` = 174
0

  Article Load (0.1ms)  SELECT `articles`.* FROM `articles` WHERE `articles`.`is_publish` = 1 AND `articles`.`cat_id` = 7  ORDER BY `articles`.`view_counts` DESC
   (0.1ms)  SELECT COUNT(*) FROM `comments` WHERE `comments`.`article_id` = 188
0
   (0.1ms)  SELECT COUNT(*) FROM `comments` WHERE `comments`.`article_id` = 185
0
   (0.1ms)  SELECT COUNT(*) FROM `comments` WHERE `comments`.`article_id` = 183
0
......
......

ruby-china 广州电信好慢

flowerwrong — Tue, 20 Oct 2015 10:32:25 +0800

大概是昨天开始，打开 ruby-china 就好慢了.

RSpec 测试 gem 集合

flowerwrong — Fri, 08 May 2015 12:21:56 +0800

最近看了使用 RSpec 测试 Rails 程序，实践了一番。分享下测试 gem 的集合

group :development, :test do
  gem 'awesome_print', require: false
  gem 'brakeman', require: false
  gem 'rails_best_practices', require: false
  gem 'rubocop', require: false
  gem 'better_errors'

  gem 'guard-rspec', require: false  # 自动化测试
  # gem 'spring-commands-rspec'  # 加速测试
  # gem 'email_spec'  # email测试
  # gem 'timecop'  # 时间冻结，rails4.1后activesupport有提供
  gem 'simplecov', require: false  # 测试覆盖率

  # for test
  gem 'rspec-rails'  # rspec
  gem 'factory_girl_rails'  # 测试数据
  gem 'database_cleaner'  # 清理测试数据库
end

group :development do
  # 部署
  gem 'capistrano', '~> 3.4.0'
  gem 'capistrano-rvm'
  gem 'capistrano-rails'
  gem 'capistrano-bundler'
end

group :test do
  gem 'shoulda'  # 测试model，非常省代码
  gem 'capybara'  # 功能/feature测试
  gem 'poltergeist'  # capybara phantomjs driver
  gem 'selenium-webdriver'  # capybara selenium driver 打开firefox进行测试，速度慢
  gem 'capybara-screenshot'  # 测试截图
  gem 'show_me_the_cookies'  # 主要是在功能测试过程中操作cookie，例如显示cookie
  gem 'launchy'  # 启动浏览器
  gem 'ffaker'  # 生成假数据，faker重构版本
end

Rails 集群部署问题

flowerwrong — Fri, 24 Apr 2015 19:58:40 +0800

找了一圈，rails 集群部署大多给的是单机的worker模式，然后nginx upstream代理。这样的部署没有 session 复制问题。但是集群部署的就会遇到 session 复制等等问题。如何解决呢？另外如果多地区部署 (小的比如国内各个城市，大到各国) 的时候会遇到其他什么问题呢？以及如何解决？求指教。

动态方法和幽灵方法的简单 benchmark

flowerwrong — Mon, 09 Mar 2015 23:08:06 +0800

英文地址：Performance Benchmark On Ruby's Dynamic Method

module 里面 class << self 的作用? 然后怎么扩展 class

flowerwrong — Tue, 20 Jan 2015 11:47:19 +0800

以下代码展示了如何从一个模块扩展一个类的实例方法 (include) 和类方法 (extend), 如何从一个模块扩展模块方法 (extend). 但遇到一个奇怪的问题，当在模块中使用 class << self 后该模块不能被其他类或者模块引用 (无论是include or extend) 详见module D, class S, class Y, 这是为什么？

module D
  class << self
    def say_hello_of_d
      puts 'D say hello'
    end
  end
end

module E
  def say_hello_of_e
    puts 'E say hello'
  end
end

module F
  extend E
end

module G
  include E
end

class H
  extend E
end

class S
  include E
end

class Y
  include D
end

D.say_hello_of_d # D say hello
# E.say_hello_of_e # undefined method `say_hello_of_e' for E:Module
F.say_hello_of_e # E say hello
# G.say_hello_of_e # undefined method `say_hello_of_e' for G:Module
H.say_hello_of_e # E say hello
S.new.say_hello_of_e # E say hello
# Y.new.say_hello_of_d #  undefined method `say_hello_of_d' for #<Y:0x000000013082b0>
Y.say_hello_of_d # undefined method `say_hello_of_d' for Y:Class

http://stackoverflow.com/questions/10039039/why-self-method-of-module-cannot-become-a-singleton-method-of-class https://www.ruby-forum.com/topic/4418176 http://blog.rubybestpractices.com/posts/gregory/041-issue-10.5-uses-for-modules.html http://www.techques.com/question/1-2353498/Is-extend-self-the-same-as-module_function? http://ruby-doc.com/docs/ProgrammingRuby/#Module.module_function

从一维数组怎样构建基于他取模的二位数组

flowerwrong — Fri, 16 Jan 2015 00:53:49 +0800

比如说

arr = [1,2,3,4,5,6,7,8,9,10]

# 得到如下数组
arr_per_four = [
  [1,2,3,4],
  [5,6,7,8],
  [9,10]
]

# 或者如下
arr_per_three = [
  [1,2,3],
  [4,5,6],
  [7,8,9],
  [10]
]

请问怎么最简单？

rake db:seed 和 rake assets:precompile 在远程服务器上要花费很长的时间

flowerwrong — Wed, 10 Dec 2014 15:23:45 +0800

之前用 ckeditor ，使用capistrano 3部署到远程服务器的时候每次都卡在rake assets:precompile，不知道有什么解决办法没有？
我到 ssh 到远程服务器后执行RAILS_ENV=production rake db:seed, 也会话费很长很长的时间，通常也是直接卡顿。下面我在本地进行rake db:seed的时间和远程的时间，有什么解决办法吗？

# local
$ rake db:seed
========================================
start seeds
33.115783543
end seeds
========================================

========================================
# ssh to server
start seeds
378.131025
end seeds
========================================

seeds.rb

puts '==' * 20
puts 'start seeds'

time_start = Time.now


cats = [
  {name: "白酒", title: "白酒", content: "白酒", secret_field: "secret_field"},
  {name: "红酒", title: "红酒", content: "红酒", secret_field: "secret_field"},
  {name: "葡萄酒", title: "葡萄酒", content: "葡萄酒", secret_field: "secret_field"},
  {name: "其他", title: "其他", content: "其他", secret_field: "secret_field"}
]

cats.each do |c|
  Cat.create! c
end

1.upto(50).each do |i|
  if i == 1
    u = User.new(username: 'admin', email: 'admin@gmail.com',
                 password: '12345678', password_confirmation: '12345678')
    u.save
    u.confirm!
    u.add_role :admin
    Profile.create(:user_id => u.id, :mobile => "135604744#{u.id}", :tel => "5555#{u.id}", :province => '广东省', :city => '广州市', :region => 'xxx', :address => 'xxx', :fax => "55555")
  elsif Array(2..10).include?(i)
    u = User.new(:username => "provider#{i}", :email => "provider#{i}@gmail.com", :password => "12345678", :password_confirmation => "12345678")
    u.save
    u.confirm!
    u.add_role :provider
    Profile.create(:user_id => u.id, :mobile => "135604744#{u.id}", :tel => "5555#{u.id}", :province => '广东省', :city => '广州市', :region => 'xxx', :address => 'xxx', :fax => "55555")
  else
    u = User.new(:username => "customer#{i}", :email => "customer#{i}@gmail.com", :password => "12345678", :password_confirmation => "12345678")
    u.save
    u.confirm!
    u.add_role :customer
    Profile.create(:supplier_id => rand(10), :user_id => u.id, :mobile => "135604744#{u.id}", :tel => "5555#{u.id}", :province => '广东省', :city => '广州市', :region => 'xxx', :address => 'xxx', :fax => '55555')
  end
end

time_end = Time.now
time = time_end - time_start
puts time.to_s
puts 'end seeds'
puts '==' * 20

小团队 (10 人下) 的 git flow

flowerwrong — Thu, 04 Dec 2014 10:25:15 +0800

大家推荐下小团队 (在 10 人以下) 的 git 协作工作流，以产品开发/迭代为主。

git branch -b my_name # 私有分支
git commit
git checkout master
git pull
git merge my_name
git push origin master

比如说除了master分支外，一般都会有一个dev分支，featuren分支等，当几个人协作一个feature分支的时候，应该如何处理？

分享一下我的 vim 配置

flowerwrong — Mon, 01 Dec 2014 11:25:43 +0800

FlowerWrong's Vim config

I use vundle to manage my plugins. Test on ubuntu 14.04

github

https://github.com/FlowerWrong/fw-vim

Thx https://github.com/humiaozuzu/dot-vimrc

screenshorts

Plugin list

https://github.com/FlowerWrong/mblog/blob/master/categories/vim/vim_plugins.md

Enabled

" let Vundle manage Vundle, required
Plugin 'gmarik/Vundle.vim'

" Keep Plugin commands between vundle#begin/end.

" nerdtree
Plugin 'scrooloose/nerdtree'

" colorscheme
Plugin 'tomasr/molokai'
" Plugin 'altercation/vim-colors-solarized'

" syntastic
" Plugin 'scrooloose/syntastic'

" neocomplcache
Plugin 'Shougo/neocomplcache'

" supertab
Plugin 'ervandew/supertab'

" tagbar
Plugin 'majutsushi/tagbar'

" ctrlp
Plugin 'kien/ctrlp.vim'

" markdown, js, ruby and rails
" Plugin 'tpope/vim-markdown'
" Plugin 'pangloss/vim-javascript'
" Plugin 'vim-ruby/vim-ruby'
" Plugin 'tpope/vim-rails'

" rainbow_parentheses 括号匹配高亮
" vim-trailing-whitespace 去除多余空格
" vim-indent-guides 可视化缩进
" vim-powerline 美化状态栏
" vim-easymotion 快速移动
" python-syntax py语法高亮

I only enabled some basic plugins, if you want to enable what's you like, just remove the " or add them with Plugin 'github_rpo'.

" let Vundle manage Vundle, required
Plugin 'gmarik/Vundle.vim'

" nerdtree
Plugin 'scrooloose/nerdtree'

" colorscheme
Plugin 'tomasr/molokai'

" neocomplcache
Plugin 'Shougo/neocomplcache'

" supertab
Plugin 'ervandew/supertab'

" tagbar
Plugin 'majutsushi/tagbar'

" ctrlp
Plugin 'kien/ctrlp.vim'

Installation

Backup your old vim configuration files: mv ~/.vim ~/.vim.backup mv ~/.vimrc ~/.vimrc.backup
Clone and install this repo: git clone git@github.com:FlowerWrong/fw-vim.git ~/.vim ln -s ~/.vim/vimrc ~/.vimrc
Setup Vundle: git clone https://github.com/gmarik/Vundle.vim.git ~/.vim/bundle/Vundle.vim
Install plugins. Launch vim(ignore the errors) and then run: :PluginList :PluginInstall Enjoy!

大学生刚毕业，大公司还是小公司

flowerwrong — Mon, 24 Nov 2014 13:33:42 +0800

专访第一企信CTO胡修彪：刚毕业的程序猿尽量不要去大公司 原文： http://www.csdn.net/article/2014-11-07/2822538

大公司可以学到什么是小公司所不具有的，小公司有什么是大公司所没有的？

请教代码重构

flowerwrong — Fri, 14 Nov 2014 20:38:12 +0800

请教如下代码如何重构，ruby 代码被我写成了 php

注意

不是简单的拆分成多个函数避免一个方法内容超过 10 行代码, 理想情况下, 大多数方法内容应该少于5行。空行不算进 LOC 里，if 嵌套里面得逻辑是层层递进的。

def create
  @msg = Msg.new(msg_params)
  article_ids = params[:article_ids]
  weixin_ids = params[:weixin_ids]

  if article_ids.length > 1
    @msg.is_multi = 1
  else
    @msg.is_multi = 0
  end

  if @msg.save
    article_ids.each do |a_id|
      MsgArticle.create({msg_id: @msg.id, article_id: a_id})
    end
    weixin_arr = []
    weixin_ids.each do |w_id|
      sleep 2
      weixin = Weixin.find w_id
      arr = [weixin.username, weixin.password]
      weixin_arr.push arr
      wx_ext = WxExt::WeiXin.new arr[0], arr[1]
      flag = wx_ext.init
      if flag
        puts "===" * 20
        articles = @msg.articles

        upload_msg_params = {
            AppMsgId: '',
            ajax: 1,
            count: article_ids.length,
            f: 'json',
            lang: 'zh_CN',
            random: rand,
            token: wx_ext.token,
            vid: ''
        }

        articles.each_with_index do |a, i|
          sleep 2
          puts "==start#{i}" * 5

          file_path = a.img.current_path
          file = File.new(file_path, 'rb')
          file_hash = wx_ext.upload_file(file, File.basename(file_path))

          if file_path["base_resp"]["ret"].to_s == '0'
            file_id = file_hash["content"]

            puts "=file_id=" * 5
            puts file_id

            article_param = {
                "author#{i}".to_sym => "#{a.author}",
                "title#{i}".to_sym => "#{a.title}",
                "sourceurl#{i}".to_sym => "#{a.sourceurl}",
                "fileid#{i}".to_sym => file_id,
                "digest#{i}".to_sym => "#{a.summary}",
                "content#{i}".to_sym => "#{a.content}",
                "show_cover_pic#{i}".to_sym => 1
            }
            upload_msg_params = upload_msg_params.merge article_param
          else
            flash[:notice] = '图文消息创建失败'
            return
          end
        end
        upload_msg_hash = wx_ext.upload_multi_msg(upload_msg_params)

        if upload_msg_hash["ret"].to_s == '0'
          puts "=upload_msg_hash_all=" * 2
          puts upload_msg_hash

          msg_list_hash = wx_ext.get_app_msg_list

          if msg_list_hash["base_resp"]["ret"].to_s == '0'
            puts "=msg_list_hash=" * 3
            puts msg_list_hash
            app_msg_id = msg_list_hash["app_msg_info"]["item"][0]["app_id"]
            puts "=app_msg_id=" * 3
            puts app_msg_id

            brondcast_msg_params = {
                ajax: 1,
                appmsgid: app_msg_id, # 图文appid
                cardlimit: 1, # 发送限制条数
                city: '',
                country: '',
                province: '',
                f: 'json',
                groupid: '-1',
                imgcode: '',
                lang: 'zh_CN',
                operation_seq: wx_ext.operation_seq, #
                random: rand,
                sex: 0,
                synctxweibo: 0,
                token: wx_ext.token,
                type: 10
            }
            brondcast_msg_hash = wx_ext.broadcast_msg(brondcast_msg_params)
            if brondcast_msg_hash["ret"].to_s == '0'
              puts "brondcast_msg_hash" * 3
              puts brondcast_msg_hash

              WeixinMsg.create({weixin_id: w_id, msg_id: @msg.id, publish_time: Time.now, is_sent: 1})

              flash[:notice] = '图文消息创建成功'
            else
              flash[:notice] = '图文消息创建失败'
              return
            end
          else
            flash[:notice] = '图文消息创建失败'
            return
          end
        else
          flash[:notice] = '图文消息创建失败'
          return
        end
      else
        puts "==" * 20
        puts "weixin.init failed"
        flash[:notice] = '图文消息创建失败'
        return
      end
    end
  end

  respond_with(@msg)
end

ruby 中一次性定时任务的 gem,可以自由添加

flowerwrong — Thu, 13 Nov 2014 20:45:41 +0800

求推荐一个定时任务的 gem，一次性的 (这个可选),whenever 和 clockwork 就 pass 掉了. 可以自由添加定时任务，这是最主要的. 举个例子: 皮皮微博------创建之后定时，然后到那个时候就发送

curl 或者 ruby 等等语言怎么模拟 flash 上传图片

flowerwrong — Mon, 10 Nov 2014 16:23:38 +0800

我的需求是模拟 flash 上传图片，位置是微信公众平台素材管理封面图片上传那里，其他一些论坛的图片估计也有用 flash 的. 怎么模拟登陆他？语言不限以 http://www.hdfu.net/demo.html 为例

怎样使用 websocket 建立 one to one 的聊天,类似 ruby-china 的推送

flowerwrong — Mon, 03 Nov 2014 10:43:51 +0800

我最近在学习 websocket-rails (https://github.com/websocket-rails/websocket-rails), 可以用来建立多人聊天室，但是不知道怎么建立 one to one 的聊天，类似 qq 的私人聊天，我没有找到相关的 api. 请指点下，谢谢。

socket.io 我也看了下，他有提供private message这个 event，可以监听from和to.

ruby-china 的通知机制也类似，推送到个人。于是我参考了 ruby-china 的代码，发现是用的 faye-rails (https://github.com/jamesotron/faye-rails).

主要逻辑如下：

服务器：

# https://github.com/ruby-china/ruby-china/blob/master/app/models/notification/base.rb#L20
# coding: utf-8
class Notification::Base
  store_in collection: 'notifications'

  field :read, default: false
  belongs_to :user

  index read: 1
  index user_id: 1, read: 1

  scope :unread, -> { where(read: false) }

  after_create :realtime_push_to_client
  after_update :realtime_push_to_client

  def realtime_push_to_client
    if self.user
      hash = self.notify_hash
      hash[:count] = self.user.notifications.unread.count
      FayeClient.send("/notifications_count/#{self.user.temp_access_token}", hash) # 注意self.user.temp_access_token 和 FayeClient
    end
  end
end

# https://github.com/ruby-china/ruby-china/blob/55a3b35d9bd3db028221a4b6470a2f4e04c802dd/app/models/faye_client.rb
# faye_client.rb
require 'net/http'
class FayeClient
  def self.send(channel, params)
    Thread.new {
      params[:token] = Setting.faye_token
      message = {channel: channel, data: params}
      uri = URI.parse(Setting.faye_server)
      Net::HTTP.post_form(uri, message: message.to_json)
    }
  end
end

# user model
def temp_access_token
  Rails.cache.fetch("user-#{self.id}-temp_access_token-#{Time.now.strftime("%Y%m%d")}") do
    SecureRandom.hex
  end
end

客户端：

initNotificationSubscribe : () ->
  return if not App.access_token?
  faye = new Faye.Client(App.faye_client_url)
  faye.subscribe "/notifications_count/#{App.access_token}", (json) ->
    span = $("#user_notifications_count span")
    new_title = document.title.replace(/^\(\d+\) /,'')
    if json.count > 0
      span.addClass("badge-error")
      new_title = "(#{json.count}) #{new_title}"
      url = App.fixUrlDash("#{App.root_url}#{json.content_path}")
      console.log url
      $.notifier.notify("",json.title,json.content,url)
    else
      span.removeClass("badge-error")
    span.text(json.count)
    document.title = new_title
  true

具体来说通过 token 来区分和维护多个 channel, 即每一个用户和 server 之间酒有一个 channel, 不过 faye-rails 不是走的 websocket. 见官网Faye is a publish-subscribe messaging system based on the Bayeux protocol. 但是官方的架构有说：

# http://faye.jcoglan.com/architecture.html
    Persistent connections using WebSocket
    Long-polling via HTTP POST
    Cross Origin Resource Sharing
    Callback-polling via JSON-P

这也是我疑惑不解的地方。可能作者加了 websocket 部分的实现。

Since version 0.5, Faye has supported WebSockets as a network transport for sending messages to the browser. The code that handles this is decoupled from the rest of the library and can be used to make your own WebSocket applications.

These classes are available as a stand-alone library, faye-websocket

[已解决] 上传公钥到远程服务器后，误删除了本地的 ssh 配置，无法远程服务器

flowerwrong — Mon, 06 Oct 2014 18:31:33 +0800

我为了登陆方便，在远程服务器上配置了 ssh 公钥，但是我重装系统后本地的 ssh 配置没有备份，导致远程服务器时出现如下错误：

ssh username@ip
Permission denied (publickey).

怎么解决？

网易彩票的提现是怎么做的，案例还有支付宝提现和微信电子钱包提现功能

flowerwrong — Mon, 29 Sep 2014 13:56:31 +0800

网易彩票的提现是怎么做的？类似的还有微信电子钱包和支付宝。一个网上商城里面用户有提成后需要有提现的功能。也就是如果用户的电子钱包里面有 1000RMB，那么他可以提现到各种银行卡。有没有搞过这方面的朋友，详细介绍下。谢谢。

使用 Vagrant 搭建统一开发环境

flowerwrong — Sun, 28 Sep 2014 00:55:52 +0800

http://flowerwrong.iteye.com/blog/2123258

ruby 模块中的::前缀表示什么

flowerwrong — Sat, 27 Sep 2014 00:19:52 +0800

require File.expand_path('../websocket', __FILE__) unless defined?(Faye::WebSocket) #可以把路径转换成绝对路径

module Faye
  class EventSource

    include WebSocket::API::EventTarget
    attr_reader :env, :url, :ready_state

    DEFAULT_RETRY = 5

    def initialize(env, options = {})
      WebSocket.ensure_reactor_running
      super()

      @env    = env
      @ping   = options[:ping]
      @retry  = (options[:retry] || DEFAULT_RETRY).to_f
      @url    = EventSource.determine_url(env)
      @stream = Stream.new(self)

      @ready_state = WebSocket::API::CONNECTING

      headers = ::WebSocket::Driver::Headers.new
      if options[:headers]
        options[:headers].each { |k,v| headers[k] = v }
      end

      if callback = @env['async.callback']
        callback.call([101, {}, @stream])
      end

      @stream.write("HTTP/1.1 200 OK\r\n" +
                    "Content-Type: text/event-stream\r\n" +
                    "Cache-Control: no-cache, no-store\r\n" +
                    "Connection: close\r\n" +
                    headers.to_s +
                    "\r\n" +
                    "retry: #{ (@retry * 1000).floor }\r\n\r\n")

      EventMachine.next_tick { open }

      if @ping
        @ping_timer = EventMachine.add_periodic_timer(@ping) { ping }
      end
    end
  end
end

这里的headers = ::WebSocket::Driver::Headers.new中的::表示什么？他和headers = WebSocket::Driver::Headers.new这样写有什么区别？谢谢