runup (runup)

AI 工具分享｜AI 音乐生成器

runup — Mon, 29 Dec 2025 07:35:10 +0800

AI 音乐生成器，有免费试用机会

买一套基于 Rails 的电商系统

runup — Sat, 01 Dec 2018 19:14:36 +0800

朋友这边需要可以立马能用的电商网站，麻烦我这里帮忙，我定制开发的能力不够，也来不及，具体要求如下：

1.必须基于rails的实体物品购买电商网站。
2.必须结合了支付宝和微信的支付功能。
3.必须系统具备完整的测试，且有具体的线上运行项目。
4.提供源码和部署方案。
6.功能参考一般的电商平台

devise 中使用邮件确认，邮件链接返回隐私设置错误

runup — Wed, 28 Nov 2018 23:43:07 +0800

已经解决，host 的地址写错了，应该是

host = "note-book-diary.herokuapp.com"

使用了 devise 中的 confirmable 模块，部署到了 heroku 中，邮件采用 heroku 中 sendgrid，具体的配置信息如下：

#config/environments/production.rb
config.force_ssl = true

config.action_mailer.raise_delivery_errors = true
config.action_mailer.delivery_method = :smtp

host = "note-book-diary.heroku.com"
config.action_mailer.default_url_options = { protocol: "https", host: host }
ActionMailer::Base.smtp_settings = {
address: "smtp.sendgrid.net",
port: 587,
authentication: "plain",
user_name: "xx",
password: "xx",
domain: "heroku.com",
enable_starttls_auto: true
}

访问https://note-book-diary.heroku.com/的时候不会出现任何问题，包括注册和登录页面，注册之后能收到邮件，但是邮件中的确认链接点击之后显示如下错误

NET::ERR_CERT_COMMON_NAME_INVALID

指出我的链接不是私密链接，网站使用的是 HSTS，我试着关闭 HSTS，出现也是同样的问题，chrome 和 safari 中都是返回这个结果。

config.ssl_options = { hsts: false }

Heroku 安装 libssl1.0-dev

runup — Tue, 06 Nov 2018 18:51:56 +0800

将系统部署在 heroku 上之后，发现少了一库 libssl1.0-dev，试着在 heroku 中进行安装，最终未果，下面是试过的几种方法

#heroku run shell
#apt install libssl1.0-dev
Reading package lists... Done
Building dependency tree
Reading state information... Done
W: Not using locking for read only lock file /var/lib/dpkg/lock-frontend
W: Not using locking for read only lock file /var/lib/dpkg/lock
E: Unable to locate package libssl1.0-dev
E: Couldn't find any package by glob 'libssl1.0-dev'
E: Couldn't find any package by regex 'libssl1.0-dev'

#sudo apt install libssl1.0-dev
#显示没有sudo这个命令，就是heroku中不能执行sudo

#apt update 
List directory /var/lib/apt/lists/partial is missing  #新建这个文件夹也不行

Rails 项目中路由跳转错误

runup — Sat, 04 Nov 2017 17:10:40 +0800

错误描述：需要在项目中建立一个简单的搜索，待搜索模型为 topics，代码描述如下：

#_search.html.erb
<form class="form-inline">
  <%= form_tag search_topics_path, method: :get do %>
    <%= text_field_tag :search %>
    <%= submit_tag "搜索" %>
  <% end %>
</form>

#config/routes.rb
resources :topics  do
  get :search, on: :collection
end·

#topics_controller.rb
class TopicsController < ApplicationController
  def search
    search = params[:search].present? ? params[:search] : nil
    @topics = if search
      Topic.where("title LIKE ?", "%#{search}%").order("created_at desc").page(params[:page])
    else
      Topic.all.order("created_at desc").page(params[:page])
    end
    debugger
  end
end

将_search.html.erb 放置在 welcomes/index 这个页面中，点击如上的搜索按钮，回到的是 welcomes 的 index 中，但是我想要讲参数送到到 topics 中 search 中，哪里出现了问题？

想了解 require ” xx “, 或者 load "xx"真正的查找路径。

runup — Wed, 13 Sep 2017 21:23:41 +0800

一直对这个问题比较疑惑，根据 ruby api 的介绍，如果”xx“是绝对路径，则从绝对路径中查找，如果是相对路径，则会去$LOAD_PATH 中查找。我在自己的本地文件建立文件夹 test,test 文件夹的中存在两个文件，分别是 redflag.rb 文件和 test_events.rb 文件，文件内容分别如下：

#redflag.rb
def event(name)
  puts "ALTER: #{name}" if yield
end
Dir.glob("*events.rb").each{ |file| load file}

#test_events.rb
event "an event that always happens" do
  true
end
event "an event that never happens" do
  false
end

#终端执行文件，ruby reflag.rb

ALTER: an event that always happens

如上代码叙述，正确 load 了文件，并且执行了相关的代码。

test 文件夹的目录为：

/Users/jayzen/workshop/dsl

puts $LOAD_PATH 的结果为：

/Users/jayzen/.rvm/gems/ruby-2.4.0@global/gems/did_you_mean-1.1.0/lib
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/site_ruby/2.4.0
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/site_ruby/2.4.0/x86_64-darwin16
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/site_ruby
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/vendor_ruby/2.4.0
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/vendor_ruby/2.4.0/x86_64-darwin16
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/vendor_ruby
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0
/Users/jayzen/.rvm/rubies/ruby-2.4.0/lib/ruby/2.4.0/x86_64-darwin16

从上面可知，load 的文件是相对目录，但是$LOAD_PATH 中并没有包括 test 的文件夹路径，那么 load 的真正加载路径是什么？

Rails upload file error about “No such file or directory @ rb_sysopen”

runup — Wed, 28 Jun 2017 21:56:44 +0800

参考 rails5 的 guides，下面的代码出现 Rails upload file error about“No such file or directory @ rb_sysopen,/Users/jayzen/workshop/upload_demo/public/uploads/demo.pdf”。

def upload
  uploaded_io = params[:tag][:attachment]
  File.open(Rails.root.join('public', 'uploads', uploaded_io.original_filename), 'wb') do |file|
  file.write(uploaded_io.read)
end

我对代码中 Rails.root.join 的参数个数做了修改，只是去掉“uploads”参数，代码如下，下面的代码按照预期运行，并且上传文件成功。

def upload
  uploaded_io = params[:tag][:attachment]
  File.open(Rails.root.join('public', uploaded_io.original_filename), 'wb') do |file|
  file.write(uploaded_io.read)
end

问题：当 Rails.root.join 中的参数个数小于等于 2 时候，能够正常运行，但是参数个数大于 2 时，则会出现如上的问题，为何？

其他辅助代码

#支架 
rails g scaffold tag name

#model中设置虚拟属性
class Tag < ActiveRecord
  attr_accessor :attachment
end

#controller中设置attachment白名单
params.require(:tag).permit(:name, :attachment)

#controller中添加upload方法
class TagsController < ApplicationController
  def create
    @tag = Tag.new(tag_params)
    if @tag.save
      upload
     ......
  end

  private
    def upload
    ....
    end
end

环境：mac, ruby2.4.0, rails5.1.2

database.yml 读取环境变量出错

runup — Mon, 31 Oct 2016 21:14:00 +0800

问题描述：在本机设置环境变量 PASSWORD=root，在 database.yml 中书写如下：

default: &default
  adapter: mysql2
  encoding: utf8
  pool: 5
  username: root
  password: ['PASSWORD']
  socket: /tmp/mysql.sock

rails db:create 报错如下：

Mysql2::Error: Access denied for user 'root'@'localhost' (using password: NO)

我使用的版本是 rails5.0.0.1, 本机是 OS X，数据库是 mysql5.7。其中环境变量的设置方式：刚开始的时候是在.bash_profile 中设置 export PASSWORD=root，但是发现在终端中输入 env 没有出现 PASSWORD 的值，参考了装了 ohmyzsh，为啥.bash_profile 就不执行了...那改环境变量应该去哪呢？,因为安装了 zsh，并且是直接 zsh 启动，因此在按照该链接的方式，在.bash_profile 中设置 export PASSWORD=root，同时在.zshrc 中执行 source .bash_profile 语句，终端中输入 env，显示出来 PASSWORD=root，但是 database 文件没有读取出 ['PASSWORD'] 的值，为何？

另外： 1、排除的数据库出错的可能性，我的数据库密码是 root, 在 database.yml 文件中进行硬编码，password: root，rails db:create 是成功的。 2、['PASSWORD'] 的值在 rails 中也能够读取成功，可以通过在 controller 中将 ['PASSWORD'] 赋值给实例变量，并且将其呈现在 view 中。 3、尝试了 dotenv，出现上面同样的问题。

解决：

password: ['PASSWORD'] #错误写法
password: <%= ENV["PASSWORD"] %> #正确写法

不知为何自己一直执着于错误写法。

carrierwave 和 mini_magic 图片上传和处理问题

runup — Mon, 05 Sep 2016 15:05:23 +0800

问题描述：对于尺寸小 (500*500) 的图片能够正常显示，但是对于尺寸大 (1000*1000) 的图片上传成功，但是显示不出来。controller 设置如下。

class PictureUploader < CarrierWave::Uploader::Base

  # Include RMagick or MiniMagick support:
  # include CarrierWave::RMagick
  include CarrierWave::MiniMagick

  # Choose what kind of storage to use for this uploader:
  storage :file
  # storage :fog

  # Override the directory where uploaded files will be stored.
  # This is a sensible default for uploaders that are meant to be mounted:
  def store_dir
    "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  # Provide a default URL as a default if there hasn't been a file uploaded:
  # def default_url
  #   # For Rails 3.1+ asset pipeline compatibility:
  #   # ActionController::Base.helpers.asset_path("fallback/" + [version_name, "default.png"].compact.join('_'))
  #
  #   "/images/fallback/" + [version_name, "default.png"].compact.join('_')
  # end

  # Process files as they are uploaded:
  # process :scale => [200, 300]
  #
  # def scale(width, height)
  #   # do something
  # end

  # Create different versions of your uploaded files:
  # version :thumb do
  #   process :resize_to_fit => [50, 50]
  # end

  # Add a white list of extensions which are allowed to be uploaded.
  # For images you might use something like this:
  # def extension_white_list
  #   %w(jpg jpeg gif png)
  # end

  # Override the filename of the uploaded files:
  # Avoid using model.id or version_name here, see uploader/store.rb for details.
  # def filename
  #   "something.jpg" if original_filename
  # end

end

注：使用 process :resize_to_fit=>[1200,1200],也无法完成显示大图片的功能。解决：查看 chrome 的 network，发现是图片加载失败，错误如下：

net::ERR_BLOCKED_BY_CLIENT

显示被客户端拦截，我的 chrome 装了 adblock 插件，我把http://localhost:3000加入到白名单中，就可以显示图片了。

Puma 部署 Cannot assign requested address - bind (2) for "::1" port 3000

runup — Fri, 29 Jul 2016 09:34:34 +0800

在 Ubuntu14.04 部署系统，参考文章,使用 rvm 安装，ruby2.3.0，rails5.0.0，启动项目 rails s 出现如下问题：

/home/deploy/.rvm/gems/ruby-2.3.0/gems/puma-3.6.0/lib/puma/binder.rb:266:in `initialize': Cannot assign requested address - bind(2) for "::1" port 3000 (Errno::EADDRNOTAVAIL)

google 之后，最匹配的问题是Cannot assign requested address - bind(2) (Errno::EADDRNOTAVAIL),但是解决不了目前的问题，求指导。注：端口没有被占用。

关于文件权限问题

runup — Wed, 20 Jul 2016 19:43:47 +0800

在看 the linux command，里面提到的设置文件的默认权限 umask 在 ubuntu 默认情况下

umask #0002，即文件为 -rw-rw-r--

按照我对文章的理解，默认情况下新建立的文件，文件所有者具有 r,w 权限，但是没有 x 权限。因此在不改变 umask 值的情况下，进行如下操作：

touch demo.rb  #demo.rb中内容为puts "hello world"
ls -l demo.rb  #-rw-rw-r--

终端下执行文件，此时用户为文件所有者

ruby demo.rb  # "hello world"

问题：既然文件所有者不具备“x”,即执行权限，那么我在终端下为何能运行文件成功，还是说我漏了一些知识点？

关于 Nokogiri 的安装依赖 libxml2-2.9.4 报错的问题

runup — Fri, 10 Jun 2016 19:59:11 +0800

在自己的 os x 系统上一直运行正常，包括正常使用 nokogiri 这个 gem，今天在本地建立新项目，bundle install 报 nokogiri 安装异常。单独 gem install nokogiri，报下面的错误：

Building native extensions.  This could take a while...
ERROR:  Error installing nokogiri:
    ERROR: Failed to build gem native extension.

    current directory: /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8/ext/nokogiri
/Users/jayzen/.rvm/rubies/ruby-2.3.0/bin/ruby -r ./siteconf20160610-32051-16q0bpc.rb extconf.rb
Using pkg-config version 1.1.7
checking if the C compiler accepts ... yes
checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... no
Building nokogiri using packaged libraries.
Using mini_portile version 2.1.0
checking for iconv.h... yes
checking for gzdopen() in -lz... yes
checking for iconv using --with-opt-* flags... yes
************************************************************************
IMPORTANT NOTICE:

Building Nokogiri with a packaged version of libxml2-2.9.4.

Team Nokogiri will keep on doing their best to provide security
updates in a timely manner, but if this is a concern for you and want
to use the system library instead; abort this installation process and
reinstall nokogiri as follows:

    gem install nokogiri -- --use-system-libraries
        [--with-xml2-config=/path/to/xml2-config]
        [--with-xslt-config=/path/to/xslt-config]

If you are using Bundler, tell it to use the option:

    bundle config build.nokogiri --use-system-libraries
    bundle install

Note, however, that nokogiri is not fully compatible with arbitrary
versions of libxml2 provided by OS/package vendors.
************************************************************************
Extracting libxml2-2.9.4.tar.gz into tmp/x86_64-apple-darwin15.2.0/ports/libxml2/2.9.4... OK
Running 'configure' for libxml2 2.9.4... OK
Running 'compile' for libxml2 2.9.4... ERROR, review '/Users/jayzen/.rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8/ext/nokogiri/tmp/x86_64-apple-darwin15.2.0/ports/libxml2/2.9.4/compile.log' to see what happened. Last lines are:
========================================================================
    unsigned short* in = (unsigned short*) inb;
                         ^~~~~~~~~~~~~~~~~~~~~
encoding.c:815:27: warning: cast from 'unsigned char *' to 'unsigned short *' increases required alignment from 1 to 2 [-Wcast-align]
    unsigned short* out = (unsigned short*) outb;
                          ^~~~~~~~~~~~~~~~~~~~~~
4 warnings generated.
  CC       error.lo
  CC       parserInternals.lo
  CC       parser.lo
  CC       tree.lo
  CC       hash.lo
  CC       list.lo
  CC       xmlIO.lo
xmlIO.c:1450:52: error: use of undeclared identifier 'LZMA_OK'
    ret =  (__libxml2_xzclose((xzFile) context) == LZMA_OK ) ? 0 : -1;
                                                   ^
1 error generated.
make[2]: *** [xmlIO.lo] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
========================================================================
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --with-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/Users/jayzen/.rvm/rubies/ruby-2.3.0/bin/$(RUBY_BASE_NAME)
    --help
    --clean
    --use-system-libraries
    --enable-static
    --disable-static
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --enable-cross-build
    --disable-cross-build
/Users/jayzen/.rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:366:in `block in execute': Failed to complete compile task (RuntimeError)
    from /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `chdir'
    from /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:337:in `execute'
    from /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:111:in `compile'
    from /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/mini_portile2-2.1.0/lib/mini_portile2/mini_portile.rb:150:in `cook'
    from extconf.rb:364:in `block (2 levels) in process_recipe'
    from extconf.rb:257:in `block in chdir_for_build'
    from extconf.rb:256:in `chdir'
    from extconf.rb:256:in `chdir_for_build'
    from extconf.rb:363:in `block in process_recipe'
    from extconf.rb:262:in `tap'
    from extconf.rb:262:in `process_recipe'
    from extconf.rb:555:in `<main>'

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Users/jayzen/.rvm/gems/ruby-2.3.0/extensions/x86_64-darwin-15/2.3.0/nokogiri-1.6.8/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8 for inspection.
Results logged to /Users/jayzen/.rvm/gems/ruby-2.3.0/extensions/x86_64-darwin-15/2.3.0/nokogiri-1.6.8/gem_make.out

按照提示写如下代码：gem install nokogiri -- --use-system-libraries，出现如下错误：

Building native extensions with: '--use-system-libraries'
This could take a while...
ERROR:  Error installing nokogiri:
    ERROR: Failed to build gem native extension.

    current directory: /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8/ext/nokogiri
/Users/jayzen/.rvm/rubies/ruby-2.3.0/bin/ruby -r ./siteconf20160610-36324-vvy8wk.rb extconf.rb --use-system-libraries
Using pkg-config version 1.1.7
checking if the C compiler accepts ... yes
checking if the C compiler accepts -Wno-error=unused-command-line-argument-hard-error-in-future... no
Building nokogiri using system libraries.
ERROR: cannot discover where libxml2 is located on your system. please make sure `pkg-config` is installed.
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --with-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/Users/jayzen/.rvm/rubies/ruby-2.3.0/bin/$(RUBY_BASE_NAME)
    --help
    --clean
    --use-system-libraries
    --with-zlib-dir
    --without-zlib-dir
    --with-zlib-include
    --without-zlib-include=${zlib-dir}/include
    --with-zlib-lib
    --without-zlib-lib=${zlib-dir}/lib
    --with-xml2-dir
    --without-xml2-dir
    --with-xml2-include
    --without-xml2-include=${xml2-dir}/include
    --with-xml2-lib
    --without-xml2-lib=${xml2-dir}/lib
    --with-libxml-2.0-config
    --without-libxml-2.0-config
    --with-pkg-config
    --without-pkg-config
    --with-xslt-dir
    --without-xslt-dir
    --with-xslt-include
    --without-xslt-include=${xslt-dir}/include
    --with-xslt-lib
    --without-xslt-lib=${xslt-dir}/lib
    --with-libxslt-config
    --without-libxslt-config
    --with-exslt-dir
    --without-exslt-dir
    --with-exslt-include
    --without-exslt-include=${exslt-dir}/include
    --with-exslt-lib
    --without-exslt-lib=${exslt-dir}/lib
    --with-libexslt-config
    --without-libexslt-config

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Users/jayzen/.rvm/gems/ruby-2.3.0/extensions/x86_64-darwin-15/2.3.0/nokogiri-1.6.8/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /Users/jayzen/.rvm/gems/ruby-2.3.0/gems/nokogiri-1.6.8 for inspection.
Results logged to /Users/jayzen/.rvm/gems/ruby-2.3.0/extensions/x86_64-darwin-15/2.3.0/nokogiri-1.6.8/gem_make.out

使用 brew 安装 pkg-config libxml2 libxslt，卸载，重新安装均无效，社区中相关的提问的解决方案采取无效，折腾了一天，在其他平台上也没有找到合适的解决方案，求问？

目前已经解决，解决方法参考7#楼意见,终端执行 xcode-select --install

邮件配置信息设置

runup — Sun, 05 Jun 2016 15:20:37 +0800

config.action_mailer.smtp_settings = {                                   
  address: "smtp.gmail.com",                                             
  port: 587,                                                             
  user_name: "<username>",                                           
  password: "<password>",                                                 
  authentication: "plain",                                               
  enable_starttls_auto: true }

看到railscast china邮件中密码是在其他地方设置的

:user_name            => 'poshboytl',
:password              =>  ENV['GMAIL_PASS'],

这里的 ENV['GMAIL_PASS'] 如何使用？

关于 included 方法的问题

runup — Tue, 31 May 2016 17:03:31 +0800

代码如下：

module ModuleDemo
  def self.included(mod)
    puts "#{self} is included in #{mod}"
  end

  def self.append_features(mod)
    puts "#{mod} append_features by #{self}"
  end
end

class ClassDemo
  include ModuleDemo
end

代码输出 #
ClassDemo append_features by ModuleDemo
ModuleDemo is included in ClassDemo

问题 1：included 是 hook methods，也是 Module 的私有实例方法，按照元编程的思想，私有实例变量不能被显示调用，是否与这里的 self.included 相悖。问题 2：hook methods 方法被重写的时候，一般都是 self.included 形式，这样子有什么讲究？为什么不能是如下的形式：

module ModuleDemo
  #当然include的时候是无效的
  def included(mod)
    puts "puts something"
  end
end

问题 3：included 方法在 api 中文档说明为：Callback invoked whenever the receiver is included in another module or class. This should be used in preference to Module.append_features. if your code wants to perform some action when a module is included in another. 其中英文 in preference to 应该是优先于的意思，我的理解是 included 优先于 append_features 执行，但是如上代码的执行情况，刚好相反，哪里出了问题？问题 4：api 文档中只是给出了 included 方法作为 hook methods 被重写的情形，但是对于直接使用 included 未提及。比如下面的这段代码，included 的作用是什么？,included 的一般用法是什么？

module HairColors 
  extend ActiveSupport::Concern 
  included do 
    mattr_accessor :hair_colors 
  end 
end 

class Person 
  include HairColors 
end 

Person.hair_colors = [:brown, :black, :blonde, :red] 
Person.hair_colors # => [:brown, :black, :blonde, :red] 
Person.new.hair_colors # => [:brown, :black, :blonde, :red] 
HairColors.hair_colors # => undefined method `hair_colors' for HairColors:Module

Rails API 问题

runup — Mon, 30 May 2016 19:23:08 +0800

自己在本地实现 rails api 中的实例，但是报错，api 中的实例如下所示：

module HairColors
  mattr_accessor :hair_colors
end

class Person
  include HairColors
end

Person.hair_colors = [:brown, :black, :blonde, :red]
Person.hair_colors     # => [:brown, :black, :blonde, :red]
Person.new.hair_colors # => [:brown, :black, :blonde, :red]

自己本地进行实现：

require 'active_support'

module HairColors
  mattr_accessor :hair_colors
end

class Person
  include HairColors
end

Person.hair_colors = [:brown, :black, :blonde, :red]  #报错 undefined method `hair_colors=' for Person:Class (NoMethodError)
Person.hair_colors     # => [:brown, :black, :blonde, :red]
Person.new.hair_colors # => [:brown, :black, :blonde, :red]

自己的实现与 api 中的实现结果不符，为何？

元编程代码的解释

runup — Wed, 27 Apr 2016 20:43:27 +0800

摘自元编程第二版 101 页，第二版。完整代码如下：

@setups = [proc{puts "one"}, proc{puts "two"}]

def each_setup(&block)
  @setups.each do |setup|
    block.call setup
  end
end

each_setup do |setup|
  setup.call
end

如何理解：

each_setup do |setup|
  setup.call
end

中的 setup 和

def each_setup(&block)
  @setups.each do |setup|
    block.call setup
  end
end

中的&block 的关系？

对这段代码产生迷糊是因为本身对块的理解不够，下面根据楼下的意见进行解释：下面的两段代码是等价的：

each_setup do |setup|
  setup.call
end

each_setup { |setup| setup.call }

参数&block 其实就是 { |setup| setup.call }，那么 block 就是 proc { |setup| setup.call } 那么上面的 each_setup 的代码可以改成如下形式：

def each_setup(&block)
  @setups.each do |setup|
    proc{|setup| setup.call}.call setup
  end
end

一段 Ruby 代码解释

runup — Thu, 21 Apr 2016 22:39:27 +0800

看 ruby 元编程第二版，有一段代码理解了很久看不懂，现在抛出了，求帮忙解释。p57

module Hashie
  class Mash < Hashie::Hash
    def method_missing(method_name, *args, &blk)
      return self.[](method_name, &blk) if key?(method_name)
      match = method_name.to_s.match(/(.*?)([?=!]?)$/)
      case match[2]
      when "="
        self[match[1]] = args.first
        #...
      else
        default(method_name, *args, &blk)
      end
    end
  end
end

其中两句不理解：

self.[](method_name, &blk) #[]方法是什么意思，api中没有找到
(/(.*?)([?=!]?)$/)  #(.*?)和([?=!]?)如何理解？

我自己查了蛮多资料，找不到解释的入口，求帮忙指点。

Rails 参数传递问题

runup — Sat, 12 Mar 2016 20:32:52 +0800

参考episode 57:create model through text field，自己进行实现，这段视频要实现的是在 product 中添加 tag。但是自己在处理的过程中总是会出现 category_id=nil，就是说 view 中的 new_category_name 传不到 model 中。

自己的代码已经上传到github

详细代码如下：

rails g scaffold category name:string
rails g scaffold product name:string content:text category:references

#model中
class Product < ActiveRecord::Base
  belongs_to :category
  attr_accessor :new_category_name
  before_save :create_category_from_name

  def create_category_from_name
    create_category(name: new_category_name) unless new_category_name.blank?
  end
end

#controller中
def create
  @product = Product.new(product_params)

  respond_to do |format|
    if @product.save
      format.html { redirect_to @product, notice: 'Product was successfully created.' }
      format.json { render :show, status: :created, location: @product }
   else
      format.html { render :new }
      format.json { render json: @product.errors, status: :unprocessable_entity }
  end
end

#view中
<div class="field">
  <%= f.collection_select(:category_id, Category.all, :id, :name, prompt:     "请选择")%>
  <%= f.text_field :new_category_name %>
</div>

根据各位的指点，通过在 strong parameter 添加相关参数解决了这个问题，同时在实现另外一个 episode 的时候又遇到了问题，问题如下所示：

参考的是17 HABTM Checkboxes (revised)，自己进行了实现，这是我提交到 github 中的代码

场景是为一个 model 添加多个可选 tag

在上一篇的论述中，是因为没有将需要传递的参数添加 strong parameter 中，因次参数被过滤。这次考虑了强参，但是因为遇到了不熟悉的 api，因此试了几次，都没有成功，代码如下：

rails g scaffold product name:string content:text
rails g scaffold category name:string
rails g scaffold categorization product_id:integer category_id:integer 
#model
class Product < ActiveRecord::Base
  has_many :categorizations
  has_many :categories, through: :categorizations
end

class Category < ActiveRecord::Base
  has_many :categorizations
  has_many :products, through: :categorizations
end

class Categorization < ActiveRecord::Base
  belongs_to :product
  belongs_to :category
end

#controller
def product_params
  #不能确定使用category_id是否合适
  params.require(:product).permit(:name, :content, :category_id)
end

#view
<div class = "field">
  <%= hidden_field_tag "product[category_ids][]", nil %>
  <% Category.all.each do |category| %>
  <%= check_box_tag "product[category_ids][]", category.id, @product.category_ids.include?(category.id) %>
  <%= category.name %></br>
  <% end %>
</div>

puts 使用问题

runup — Sat, 05 Mar 2016 10:08:58 +0800

我自己在做一段测验，遇到下面的一个 puts 用法问题，代码如下：

def demo
  puts "this is the demo"
end

if false || demo
  puts "succ"
end

上面的代码的执行结果为如下：

#=> this is the demo

修改上面的代码，去除第一方法中的 puts 方法：

def demo
   "this is the demo"
end

if false || demo
  puts "succ"
end