//在rails6 app分支
10238  rails action_mailbox:install
//会生成一个app/mailboxes/application_mailbox.rb//同时生成3个数据库table
10240  rails g scaffold User email name
10241  rails g scaffold Discussion title
10242  rails g scaffold Comment user:references discussion:references body:text
10243  rails db:migrate10245  rails g mailbox Replies

class ApplicationMailbox < ActionMailbox::Base# routing /something/i => :somewhererouting /reply\+.+@reply.github.com/i => :repliesrouting :all => :replies
end

mailbox集成了mail这个model。一个Ruby Mail Library.https://github.com/mikel/mail/提供了生成，转化，发送的一系列方法。

在gemfile.lock中可见：

actionmailbox (6.0.0.rc1)
  ...
  mail (>= 2.7.1)

class RepliesMailbox < ApplicationMailboxMATCHER = /reply-(.+)@reply.example.com/i# mail => Mail object# inbound_email => ActionMailbox::InboundEmail record#before_processing :ensure_userdef processreturn if user.nil?discussion.comments.create(user: user,# decoded方法返回对象的值（格式是string）,即返回的是body,不是subject
      body: mail.decoded)enddef user@user ||= User.find_by(email: mail.from)enddef discussion@discussion ||= Discussion.find(discussion_id)end# recipients是mail的方法，find{}进行匹配找到第一个符合的data。# recipients可以用to方法代替。# recipient是一个string, 使用[Regexp, 1]得到捕捉到的字符。具体见正则表达式的捕捉()def discussion_idrecipient = mail.recipients.find{|r| MATCHER.match?(r) }recipient[MATCHER, 1]endprivatedef ensure_userif user.nil?bounce_with UserMailer.missing(inbound_email)end
end

class ApplicationMailbox < ActionMailbox::Base# routing /something/i => :somewhere# routing /reply\+.+@reply.github.com/i => :replies# routing :all => :repliesrouting RepliesMailbox::MATCHER => :replies
end

...
<h4>Comments</h4>
<div>　<% @discussions.comments.each do |comment| %><strong><%= comment.user.name%></strong> commented:<br/><%= simple_format comment.body%>  <% end %>
</div>

Date: Fri, 24 May 2019 11:30:37 +0800
From: 1@1.com
To: reply-1@reply.example.com
Message-ID: <5ce7655da43ed_c653feae01b5b9c714c@chentianweideiMac.local.mail>
In-Reply-To:
Subject: congratulations
Mime-Version: 1.0
Content-Type: text/plain;charset=UTF-8
Content-Transfer-Encoding: 7bithello boy!