bin/automailer.py

   1 #!/usr/bin/python3
   2 """
   3 Standalone/module to simplify composing emails.
   4
   5 The purpose of this module is to make it easier to convert machine-ready
   6 emails into actually composing emails.
   7 """
   8
   9 import os.path
  10 import subprocess
  11 import sys
  12 import tempfile
  13 import time
  14 from argparse import ArgumentDefaultsHelpFormatter, ArgumentParser
  15 from email import policy
  16 from email.parser import Parser
  17 from functools import lru_cache
  18 from pathlib import Path
  19
  20 from xdg.BaseDirectory import xdg_config_home
  21
  22 LONG_HELP = """
  23 ## Configuration
  24
  25 To configure automailer, put config files in ~/.config/tails/automailer/*.toml
  26
  27 Supported options are:
  28  - mailer: must be a string. supported values are
  29    - "print"
  30    - "thunderbird"
  31    - "notmuch"
  32  - thunderbird_cmd: must be a list of strings. default value is ["thunderbird"].
  33 """
  34
  35
  36 @lru_cache(maxsize=1)
  37 def read_config() -> dict:
  38     config_files = sorted((Path(xdg_config_home) / "tails/automailer/").glob("*.toml"))
  39     if not config_files:
  40         return {}
  41     try:
  42         import toml
  43     except ImportError:
  44         print(
  45             "Warning: could not import `toml`. Your configuration will be ignored",
  46             file=sys.stderr,
  47         )
  48         return {}
  49
  50     data = {}
  51     for fpath in config_files:
  52         with open(fpath) as fp:
  53             data.update(toml.load(fp))
  54     return data
  55
  56
  57 def parse(body: str):
  58     header, body = body.split("\n\n", maxsplit=1)
  59     msg = Parser(policy=policy.default).parsestr(header)
  60     return msg, body
  61
  62
  63 def get_attachments(msg) -> list[str]:
  64     attachments: list[str] = []
  65
  66     if "x-attach" in msg:
  67         for attachment_list in msg.get_all("x-attach"):
  68             for fpath in (f.strip() for f in attachment_list.split(",")):
  69                 if not fpath:
  70                     continue
  71                 if not os.path.exists(fpath):
  72                     print(f"Skipping attachemt '{fpath}': not found", file=sys.stderr)
  73                     continue
  74                 attachments.append(fpath)
  75
  76     return attachments
  77
  78
  79 def markdown_to_html(body: str) -> str:
  80     # Having import inside a function is a simple way of having optional dependencies
  81     import markdown
  82
  83     return markdown.markdown(body)
  84
  85
  86 def mailer_thunderbird(body: str):
  87     msg, body = parse(body)
  88     spec = []
  89     html = msg.get("Content-Type", "text/plain") == "text/html"
  90     for key in ["to", "cc", "subject"]:
  91         if key in msg:
  92             spec.append(f"{key}='{msg[key]}'")
  93     attachments = get_attachments(msg)
  94     if attachments:
  95         spec.append("attachment='%s'" % ",".join(attachments))
  96
  97     if html:
  98         body = markdown_to_html(body)
  99
 100     thunderbird_cmd = read_config().get("thunderbird_cmd", ["thunderbird"])
 101     with tempfile.TemporaryDirectory() as tmpdir:
 102         fpath = Path(tmpdir) / "email.eml"
 103         with fpath.open("w") as fp:
 104             fp.write(body)
 105         spec.append("format=%s" % ("html" if html else "text"))
 106         spec.append(f"message={fpath}")
 107         cmdline = [*thunderbird_cmd, "-compose", ",".join(spec)]
 108         subprocess.check_output(cmdline)  # noqa: S603
 109
 110         # this is a workaround to the fact that Thunderbird will terminate *before* reading the file
 111         # we don't really know how long does it take, but let's assume 2s are enough
 112         time.sleep(2)
 113
 114
 115 def mailer_notmuch(body: str):
 116     msg, body = parse(body)
 117     cmdline = ["notmuch-emacs-mua", "--client", "--create-frame"]
 118
 119     for key in ["to", "cc", "subject"]:
 120         if key in msg:
 121             cmdline.append(f"--{key}={msg[key]}")
 122     attachments = get_attachments(msg)
 123     if attachments:
 124         body = (
 125             "\n".join(
 126                 [
 127                     f'<#part filename="{attachment}" disposition=attachment><#/part>'
 128                     for attachment in attachments
 129                 ]
 130             )
 131             + "\n\n"
 132             + body
 133         )
 134
 135     with tempfile.TemporaryDirectory() as tmpdir:
 136         fpath = Path(tmpdir) / "email.eml"
 137         with fpath.open("w") as fp:
 138             fp.write(body)
 139         cmdline.append(f"--body={fpath}")
 140
 141         subprocess.check_output(cmdline)  # noqa: S603
 142
 143
 144 def mailer(mailer: str, body: str):
 145     if mailer == "thunderbird":
 146         return mailer_thunderbird(body)
 147     if mailer == "notmuch":
 148         return mailer_notmuch(body)
 149     if not mailer or mailer == "print":
 150         print(body)
 151     else:
 152         print(f"Unsupported mailer: '{mailer}'")
 153
 154
 155 def add_parser_mailer(parser: ArgumentParser, config: dict):
 156     mail_options = parser.add_argument_group("mail options")
 157     mail_options.add_argument(
 158         "--mailer",
 159         default=config.get("mailer", "print"),
 160         choices=["print", "thunderbird", "notmuch"],
 161         help="Your favorite MUA",
 162     )
 163
 164
 165 def get_parser():
 166     config = read_config()
 167     argparser = ArgumentParser(formatter_class=ArgumentDefaultsHelpFormatter)
 168     argparser.add_argument("--long-help", action="store_true", default=False)
 169     add_parser_mailer(argparser, config)
 170     return argparser
 171
 172
 173 if __name__ == "__main__":
 174     parser = get_parser()
 175     args = parser.parse_args()
 176     if args.long_help:
 177         print(LONG_HELP)
 178         sys.exit(0)
 179     body = sys.stdin.read()
 180     mailer(args.mailer, body)