使用 Emacs 与 mu4e 管理邮件

在 Linux 下面其实有很多可以使用的邮件客户端，如 KDE 项目中的 Kmail、Gnome 项目中的 Evolution 和 Mozilla 家族的 Thunderbird。这些客户端都只是简单地试用过，正好最近将开发编辑器和写作环境从 Neovim 迁到了 Emacs。作为一个操作系统，不能管理邮件怎么说的过去。可以利用 Emacs 的界面进行邮件管理，可以用 Org-mode 进行邮件写作，甚至可以用 elisp 写一些插件，岂不美哉？趁最近放假赶紧折腾一下。

1. 邮件同步

查看其他的博客，发现同步博客最常用的协议是 IMAP。Linux 下支持 IMAP 协议并且下载下来的目录结构是 MailDir 结构的工具主要有两个，offlineimap 和 isync。

1.1. offlineimap 配置

offlineimap 是一个由 Python 写成的 IMAP 同步工具，主要的缺点是依赖 Python2 的库，并且同步速度不如 isync，因此仅作记录。

1.1.1. 安装

在 Archlinux 中，可以直接从 community 仓库中安装。

sudo pacman -S offlineimap

1.1.2. 配置

安装完成，要进行配置，需要创建一个 ~/.offlineimaprc 文件进行配置。详细的配置过程如下：

[general]
# 此处列出所有要同步的账户名，与下方 [Account] 节中的名字要一致
accounts = Netease, QQ
maxsyncaccounts = 3

[Account Netease]
# 绑定仓库，与下方的 [Repository] 节中的名字一致
localrepository = NeteaseLocal
remoterepository = NeteaseRemote

[Repository NeteaseLocal]
type = Maildir
# 指定本地保存的路径
localfolders = /data/cycoe/Documents/mail/myneteasemail@163.com

[Repository NeteaseRemote]
type = IMAP
# 远程 imap 主机
remotehost = imap.163.com
# 邮箱地址
remoteuser = myneteasemail@163.com
# 邮箱密码
remotepass = ********
ssl = yes
# *非常重要* 否则提示确实 CA 证书
sslcacertfile = /etc/ssl/certs/ca-certificates.crt
maxconnections = 1
# 是否从服务器上删除邮件
realdelete = no

[Account QQ]
localrepository = QQLocal
remoterepository = QQRemote

[Repository QQLocal]
type = Maildir
localfolders = /data/cycoe/Documents/mail/myqqmail@qq.com

[Repository QQRemote]
type = IMAP
remotehost = imap.qq.com
remoteuser = myqqmail@qq.com
remotepass = ***********
ssl = yes
sslcacertfile = /etc/ssl/certs/ca-certificates.crt
maxconnections = 1
realdelete = no

至此，通过 offlineimap -a Netease 就可以同步指定的账户。

1.2. isync 配置

isync 是一个由 C++ 写成的 IMAP 同步工具，经测试同步速度要比 offlineimap 更快，但是同步出来的邮件数量比 offlineimap 更多不知道是怎么回事，目前主要使用这个。

1.2.1. 安装

在 Archlinux 中，可以直接从 community 仓库中安装。

sudo pacman -S isync

1.2.2. 配置

isync 的配置方式与 offlineimap 类似，将如下配置放在 '~/.mbsyncrc' 中，并运行 `mbsync Netease` 即可更新 Netease 频道，mbsync 以频道的概念管理多个邮箱，可以通过类似以下多个配置实现多邮箱管理。

IMAPAccount Netease
# Address to connect to
Host imap.163.com
User myneteasemail@163.com
Pass **********
# To store the password in an encrypted file use PassCmd instead of Pass
# PassCmd "gpg2 -q --for-your-eyes-only --no-tty -d ~/.mailpass.gpg"
#
# Use SSL
SSLType IMAPS
# The following line should work. If get certificate errors, uncomment the two following lines and read the "Troubleshooting" section.
CertificateFile /etc/ssl/certs/ca-certificates.crt
#CertificateFile ~/.cert/imap.gmail.com.pem
#CertificateFile ~/.cert/Equifax_Secure_CA.pem

IMAPStore Netease-remote
Account Netease

MaildirStore Netease-local
Subfolders Verbatim
# The trailing "/" is important
Path /data/cycoe/Documents/mail/myneteasemail@163.com/
Inbox /data/cycoe/Documents/mail/myneteasemail@163.com/INBOX

Channel Netease
Master :Netease-remote:
Slave :Netease-local:
# Exclude everything under the internal [Gmail] folder, except the interesting folders
Patterns * ![myneteasemail@163.com]* "[myneteasemail@163.com]/INBOX"
# Or include everything
#Patterns *
# Automatically create missing mailboxes, both locally and on the server
Create Both
# Save the synchronization state files in the relevant directory
SyncState *


IMAPAccount QQ
# Address to connect to
Host imap.qq.com
User myqqmail@qq.com
Pass **********
# To store the password in an encrypted file use PassCmd instead of Pass
# PassCmd "gpg2 -q --for-your-eyes-only --no-tty -d ~/.mailpass.gpg"
#
# Use SSL
SSLType IMAPS
# The following line should work. If get certificate errors, uncomment the two following lines and read the "Troubleshooting" section.
CertificateFile /etc/ssl/certs/ca-certificates.crt
#CertificateFile ~/.cert/imap.gmail.com.pem
#CertificateFile ~/.cert/Equifax_Secure_CA.pem

IMAPStore QQ-remote
Account QQ

MaildirStore QQ-local
Subfolders Verbatim
# The trailing "/" is important
Path /data/cycoe/Documents/mail/myqqmail@qq.com/
Inbox /data/cycoe/Documents/mail/myqqmail@qq.com/INBOX

Channel QQ
Master :QQ-remote:
Slave :QQ-local:
# Exclude everything under the internal [Gmail] folder, except the interesting folders
Patterns * ![myqqmail@qq.com]* "[myqqmail@qq.com]/INBOX"
# Or include everything
#Patterns *
# Automatically create missing mailboxes, both locally and on the server
Create Both
# Save the synchronization state files in the relevant directory
SyncState *

1.3. Unsafe login

使用第三方 IMAP 服务同步 163 邮箱时，会提示 Unsafe login 错误，可以通过网易邮箱设置解决。

2. mu 邮件管理器

2.1. 安装

# 克隆 mu 仓库
git clone git://github.com/djcb/mu.git
# 生成配置
./autogen.sh
# 配置编译设置
./configure
# 编译安装
make -j 4 && sudo make install

2.2. 配置 mu

# 初始化 mu 监测的邮箱文件夹
mu init -m /data/cycoe/Documents/mail/
# 建立邮件索引
mu index

3. mu4e 多账户设置

mu4e (mu for emacs) 是 mu 在 emacs 中实现的一个邮件管理模块。后端调用 mu 进行邮件的检索和管理。在 ~/.config/emacs/lisp/ 目录下建立 init-mu4e.el 文件，并加入如下配置。mu4e 目前原生支持的功能是 context（上下文切换），因此使用上下文切换来模拟多账户管理。每次切换账户时，自动设置对应账户的变量。其中最重要的一处为 context 中的 match-fun 设置。该设置能够保证在同时删除或者归档不同 maildir 下的邮件时，邮件能够被移动到对应的 maildir 中。

(setq mu4e-contexts
      `( ,(make-mu4e-context
           :name "netease"
           :match-func (lambda (msg)
                         (when msg
                           (string-match-p "myneteasemail@163.com" (mu4e-message-field msg :maildir)))))))

完整配置如下：

;; the exact path may different -- check it
(add-to-list 'load-path "/usr/local/share/emacs/site-lisp/mu4e")

;; require the mu4e main package
(require 'mu4e)
;; use smtpmail to sent mail
(require 'smtpmail)
;; convert org content in mu4e to html
(require 'org-mime)
;; use org-mode in mu4e-message-mode
(require 'org-mu4e)

;; set default values about mu4e
(setq
 ;; auto update maildir with isync and index it
 mu4e-update-interval 300
 ;; don't do a full cleanup check
 mu4e-index-cleanup nil
 ;; don't consider up-to-date dirs
 mu4e-index-lazy-check t
 ;; show images in message mode
 mu4e-view-show-images t
 ;; set the default download dir for attachment
 mu4e-attachment-dir "/data/cycoe/downloads"
 ;; prefer html view
 mu4e-view-prefer-html t
 ;; don't save message to sent messages, gmail/imap takes care of this
 ;; (see the documentation for `mu4e-sent-messages-behavior' if you have
 ;; additional non-gmail addresses and want assign them different
 ;; behavior.)
 mu4e-sent-messages-behavior 'delete
 )

;; set default values for sending mails
(setq
 ;; user agent when send mail
 mail-user-agent 'mu4e-user-agent
 ;; 设置邮件发送方法为 smtpmail
 message-send-mail-function 'smtpmail-send-it
 ;; 根据 from 邮件头使用正确的账户上下文发送 email.
 message-sendmail-envelope-from 'header
 ;; 设置邮箱认证加密方式
 smtpmail-stream-type 'ssl
 ;; don't keep message buffers around
 message-kill-buffer-on-exit t
 )

;; some information about me
(setq
 user-full-name  "Cycoe Joo"
 ;; set a mail address list using when reply a message
 mu4e-user-mail-address-list '("myneteasemail@163.com"
                               "myqqmail@qq.com")
 mu4e-compose-signature
 (concat
  "Cycoe\n"
  "BLOG https://cycoe.cc\n")
 )

;; 该函数基于当前所在的 maildir 来判定所账户上下文。
;; (defun mu4e-message-maildir-matches (msg rx)
;;   (when rx
;;     (if (listp rx)
;;         ;; If rx is a list, try each one for a match
;;         (or (mu4e-message-maildir-matches msg (car rx))
;;             (mu4e-message-maildir-matches msg (cdr rx)))
;;       ;; Not a list, check rx
;;       (string-match rx (mu4e-message-field msg :maildir)))))

;; 设置 mu4e 上下文
(setq mu4e-contexts
      `( ,(make-mu4e-context
           :name "Netease"
           :enter-func (lambda ()
                         (mu4e-message "Entering Netease context")
                         ;; update index after switch context, otherwise the
                         ;; counting is not updated
                         (mu4e-update-index))
           :leave-func (lambda () (mu4e-message "Leaving Netease context"))
           ;; we match based on the contact-fields of the message
           :match-func (lambda (msg)
                         (when msg
                           (string-match-p "myneteasemail@163.com" (mu4e-message-field msg :maildir))))

           :vars '((user-mail-address             . "myneteasemail@163.com")
                   (mu4e-sent-folder              . "/myneteasemail@163.com/Sent")
                   (mu4e-drafts-folder            . "/myneteasemail@163.com/Drafts")
                   (mu4e-trash-folder             . "/myneteasemail@163.com/Trash")
                   (mu4e-refile-folder            . "/myneteasemail@163.com/Refile")
                   (smtpmail-smtp-user            . "myneteasemail@163.com")
                   (smtpmail-default-smtp-server  . "smtp.163.com")
                   (smtpmail-smtp-server          . "smtp.163.com")
                   (smtpmail-smtp-service         . 994)
                   (mu4e-get-mail-command         . "mbsync Netease")
                   (mu4e-maildir-shortcuts . (("/myneteasemail@163.com/INBOX"   . ?i)
                                              ("/myneteasemail@163.com/Sent"    . ?s)
                                              ("/myneteasemail@163.com/Refile"  . ?r)
                                              ("/myneteasemail@163.com/Trash"   . ?t)
                                              ("/myneteasemail@163.com/Drafts"  . ?d)))
                   (mu4e-bookmarks . ( ("maildir:/myneteasemail@163.com/INBOX AND flag:unread AND NOT flag:trashed"   "Unread messages"        ?u)
                                       ("maildir:/myneteasemail@163.com/INBOX AND date:today..now"                    "Today's messages"       ?t)
                                       ("maildir:/myneteasemail@163.com/INBOX AND date:7d..now"                       "Last 7 days"            ?w)
                                       ("maildir:/myneteasemail@163.com/INBOX AND date:1d..now"                       "Last 1 days"            ?o)
                                       ("maildir:/myneteasemail@163.com/INBOX"                                        "Inbox"                  ?i)
                                       ("maildir:/myneteasemail@163.com/Sent"                                         "Sent"                   ?s)
                                       ("maildir:/myneteasemail@163.com/Refile"                                       "Refile"                 ?r)
                                       ("maildir:/myneteasemail@163.com/Trash"                                        "Trash"                  ?t)
                                       ("maildir:/myneteasemail@163.com/Drafts"                                       "Drafts"                 ?d)
                                       ("maildir:/myneteasemail@163.com/INBOX AND mime:image/*"                       "Messages with images"   ?p)))
                   ))

         ,(make-mu4e-context
           :name "QQ"
           :enter-func (lambda ()
                         (mu4e-message "Switch to the QQ context")
                         (mu4e-update-index))
           :match-func (lambda (msg)
                         (when msg
                           (string-match-p "myqqmail@qq.com" (mu4e-message-field msg :maildir))))

           :vars '((user-mail-address             . "myqqmail@qq.com")
                   (mu4e-sent-folder              . "/myqqmail@qq.com/Sent")
                   (mu4e-drafts-folder            . "/myqqmail@qq.com/Drafts")
                   (mu4e-trash-folder             . "/myqqmail@qq.com/Trash")
                   (mu4e-refile-folder            . "/myqqmail@qq.com/Refile")
                   (smtpmail-smtp-user            . "myqqmail@qq.com")
                   (smtpmail-default-smtp-server  . "smtp.qq.com")
                   (smtpmail-smtp-server          . "smtp.qq.com")
                   (smtpmail-smtp-service         . 465)
                   (mu4e-get-mail-command         . "mbsync QQ")
                   (mu4e-maildir-shortcuts . (("/myqqmail@qq.com/INBOX"   . ?i)
                                              ("/myqqmail@qq.com/Sent"    . ?s)
                                              ("/myqqmail@qq.com/Refile"  . ?r)
                                              ("/myqqmail@qq.com/Trash"   . ?t)
                                              ("/myqqmail@qq.com/Drafts"  . ?d)))
                   (mu4e-bookmarks . ( ("maildir:/myqqmail@qq.com/INBOX AND flag:unread AND NOT flag:trashed"   "Unread messages"        ?u)
                                       ("maildir:/myqqmail@qq.com/INBOX AND date:today..now"                    "Today's messages"       ?t)
                                       ("maildir:/myqqmail@qq.com/INBOX AND date:7d..now"                       "Last 7 days"            ?w)
                                       ("maildir:/myqqmail@qq.com/INBOX AND date:1d..now"                       "Last 1 days"            ?o)
                                       ("maildir:/myqqmail@qq.com/INBOX"                                        "Inbox"                  ?i)
                                       ("maildir:/myqqmail@qq.com/Sent"                                         "Sent"                   ?s)
                                       ("maildir:/myqqmail@qq.com/Refile"                                       "Refile"                 ?r)
                                       ("maildir:/myqqmail@qq.com/Trash"                                        "Trash"                  ?t)
                                       ("maildir:/myqqmail@qq.com/Drafts"                                       "Drafts"                 ?d)
                                       ("maildir:/myqqmail@qq.com/INBOX AND mime:image/*"                       "Messages with images"   ?p)))
                   ))))

;; start with the first (default) context;
;; default is to ask-if-none (ask when there's no context yet, and none match)
(setq mu4e-context-policy 'pick-first)

(provide 'init-mu4e)

4. 配置 smtp 发送邮件

emcas 可以使用 smtpmail 发送邮件，会自动读取 ~/.authinfo 文件中的账户和密码，因此需要在该文件中配置 smtp 相关信息。

machine smtp.163.com login myneteasemail@163.com password xxxxxxxxxx
machine smtp.qq.com login myqqmail@qq.com password xxxxxxxxxx

5. 使用 Org mode 编辑新邮件

使用 Emacs 管理邮件的一大优势就是可以借助强大的 Org-mode 来写邮件，并自动导出为 HTML 邮件。生成的邮件为 multipart 的邮件，也就是说同时有 plain 部分和 HTML 部分可选。但在实际使用中，=(org-mime-htmlize)= 确实能够将邮件转化为 multipart 邮件，但是不知道为什么最后发送出去的邮件只有一个部分。要实现该功能需要在 ~/.config/emacs/lisp/init-mu4e.el 中加入如下配置。

;; convert org content in mu4e to html and send
(require 'org-mime)
;; convert org content in mu4e to html and send
(require 'org-mu4e)

;; auto enable the org-mu4e-compose-org-mode when enter the mu4e-compose-mode
(add-hook 'mu4e-compose-mode-hook
          (defun do-compose-stuff ()
            (org-mu4e-compose-org-mode)))

(defun htmlize-and-send ()
  "When in an org-mu4e-compose-org-mode message, htmlize and send it."
  (interactive)
  (when (member 'org~mu4e-mime-switch-headers-or-body post-command-hook)
    (org-mime-htmlize)
    (message-send-and-exit)))

(add-hook 'org-ctrl-c-ctrl-c-hook 'htmlize-and-send t)

6. 将邮件加入 TODO 列表中

如果想要将某封邮件加入代办事项用于记录，可以将如下代码加入 init-mu4e.el 中

;; store link to message if in header view, not to header query
(setq org-mu4e-link-query-in-headers-mode nil)
;; use org-capture to add a new todo
(setq org-capture-templates
      '(("t" "todo" entry (file+headline "/data/cycoe/Documents/Orgs/TODO.org" "Tasks")
         "* TODO [#A] %?\nSCHEDULED: %(org-insert-time-stamp (org-read-date nil t \"+0d\"))\n%a\n")))

至此，在 mu4e 的 header view 或者是 message view 中，输入 org-capture 即可自动将邮件作为代办事项加入到 /data/cycoe/Documents/Orgs/TODO.org 中。