.config/neomutt/buildmimetree.py

   1 #!/usr/bin/python3
   2 #
   3 # NeoMutt helper script to create multipart/* emails with Markdown → HTML
   4 # alternative conversion, and handling of inline images, using NeoMutt's
   5 # ability to manually craft MIME trees, but automating this process.
   6 #
   7 # Configuration:
   8 #   neomuttrc (needs to be a single line):
   9 #     macro compose B "\
  10 #       <enter-command> source '$my_confdir/buildmimetree.py setup|'<enter>\
  11 #       <enter-command> sourc e \$my_mdwn_postprocess_cmd_file<enter>\
  12 #     " "Convert message into a modern MIME tree with inline images"
  13 #
  14 #     (Yes, we need to call source twice, as mutt only starts to process output
  15 #     from a source command when the command exits, and since we need to react
  16 #     to the output, we need to be invoked again, using a $my_ variable to pass
  17 #     information)
  18 #
  19 # Requirements:
  20 #   - python3
  21 #   - python3-markdown
  22 # Optional:
  23 #   - pytest
  24 #   - Pynliner
  25 #   - Pygments, if installed, then syntax highlighting is enabled
  26 #
  27 # Latest version:
  28 #   https://git.madduck.net/etc/neomutt.git/blob_plain/HEAD:/.config/neomutt/buildmimetree.py
  29 #
  30 # Copyright © 2023 martin f. krafft <madduck@madduck.net>
  31 # Released under the GPL-2+ licence, just like Mutt itself.
  32 #
  33
  34 import sys
  35 import pathlib
  36 import markdown
  37 import tempfile
  38 import argparse
  39 from collections import namedtuple
  40
  41
  42 def parse_cli_args(*args, **kwargs):
  43     parser = argparse.ArgumentParser(
  44         description=(
  45             "NeoMutt helper to turn text/markdown email parts "
  46             "into full-fledged MIME trees"
  47         )
  48     )
  49     parser.epilog = (
  50         "Copyright © 2022 martin f. krafft <madduck@madduck.net>.\n"
  51         "Released under the MIT licence"
  52     )
  53
  54     subp = parser.add_subparsers(help="Sub-command parsers", dest="mode")
  55     parser_setup = subp.add_parser("setup", help="Setup phase")
  56     parser_massage = subp.add_parser("massage", help="Massaging phase")
  57
  58     parser_setup.add_argument(
  59         "--debug-commands",
  60         action="store_true",
  61         help="Turn on debug logging of commands generated to stderr",
  62     )
  63
  64     parser_setup.add_argument(
  65         "--extension",
  66         "-x",
  67         metavar="EXTENSION",
  68         dest="extensions",
  69         nargs="?",
  70         default=[],
  71         action="append",
  72         help="Markdown extension to add to the list of extensions use",
  73     )
  74
  75     parser_setup.add_argument(
  76         "--send-message",
  77         action="store_true",
  78         help="Generate command(s) to send the message after processing",
  79     )
  80
  81     parser_massage.add_argument(
  82         "--debug-commands",
  83         action="store_true",
  84         help="Turn on debug logging of commands generated to stderr",
  85     )
  86
  87     parser_massage.add_argument(
  88         "--debug-walk",
  89         action="store_true",
  90         help="Turn on debugging to stderr of the MIME tree walk",
  91     )
  92
  93     parser_massage.add_argument(
  94         "--extensions",
  95         metavar="EXTENSIONS",
  96         type=str,
  97         default="",
  98         help="Markdown extension to use (comma-separated list)",
  99     )
 100
 101     parser_massage.add_argument(
 102         "--write-commands-to",
 103         metavar="PATH",
 104         dest="cmdpath",
 105         help="Temporary file path to write commands to",
 106     )
 107
 108     parser_massage.add_argument(
 109         "MAILDRAFT",
 110         nargs="?",
 111         help="If provided, the script is invoked as editor on the mail draft",
 112     )
 113
 114     return parser.parse_args(*args, **kwargs)
 115
 116
 117 # [ PARTS GENERATION ] ########################################################
 118
 119
 120 class Part(
 121     namedtuple(
 122         "Part",
 123         ["type", "subtype", "path", "desc", "cid", "orig"],
 124         defaults=[None, None, False],
 125     )
 126 ):
 127     def __str__(self):
 128         ret = f"<{self.type}/{self.subtype}>"
 129         if self.cid:
 130             ret = f"{ret} cid:{self.cid}"
 131         if self.orig:
 132             ret = f"{ret} ORIGINAL"
 133         return ret
 134
 135
 136 class Multipart(
 137     namedtuple("Multipart", ["subtype", "children", "desc"], defaults=[None])
 138 ):
 139     def __str__(self):
 140         return f"<multipart/{self.subtype}> children={len(self.children)}"
 141
 142
 143
 144 def convert_markdown_to_html(
 145     origtext, draftpath, *, filewriter_fn=None, extensions=None
 146 ):
 147     mdwn = markdown.Markdown(extensions=extensions)
 148
 149     if not filewriter_fn:
 150
 151         def filewriter_fn(path, content, mode="w", **kwargs):
 152             with open(path, mode, **kwargs) as out_f:
 153                 out_f.write(content)
 154
 155     filewriter_fn(draftpath, origtext, encoding="utf-8")
 156     textpart = Part(
 157         "text", "plain", draftpath, "Plain-text version", orig=True
 158     )
 159
 160     htmltext = mdwn.convert(origtext)
 161
 162     htmlpath = draftpath.with_suffix(".html")
 163     filewriter_fn(
 164         htmlpath, htmltext, encoding="utf-8", errors="xmlcharrefreplace"
 165     )
 166     htmlpart = Part("text", "html", htmlpath, "HTML version")
 167
 168     logopart = Part(
 169         "image",
 170         "png",
 171         "/usr/share/doc/neomutt/logo/neomutt-256.png",
 172         "Logo",
 173         "neomutt-256.png",
 174     )
 175
 176     return Multipart(
 177         "relative",
 178         [
 179             Multipart(
 180                 "alternative",
 181                 [textpart, htmlpart],
 182                 "Group of alternative content",
 183             ),
 184             logopart,
 185         ],
 186         "Group of related content",
 187     )
 188
 189
 190 class MIMETreeDFWalker:
 191     def __init__(self, *, visitor_fn=None, debug=False):
 192         self._visitor_fn = visitor_fn
 193         self._debug = debug
 194
 195     def walk(self, root, *, visitor_fn=None):
 196         """
 197         Recursive function to implement a depth-dirst walk of the MIME-tree
 198         rooted at `root`.
 199         """
 200
 201         if isinstance(root, list):
 202             root = Multipart("mixed", children=root)
 203
 204         self._walk(
 205             root,
 206             stack=[],
 207             visitor_fn=visitor_fn or self._visitor_fn,
 208         )
 209
 210     def _walk(self, node, *, stack, visitor_fn):
 211         # Let's start by enumerating the parts at the current level. At the
 212         # root level, stack will be the empty list, and we expect a multipart/*
 213         # container at this level. Later, e.g. within a mutlipart/alternative
 214         # container, the subtree will just be the alternative parts, while the
 215         # top of the stack will be the multipart/alternative container, which
 216         # we will process after the following loop.
 217
 218         lead = f"{'| '*len(stack)}|-"
 219         if isinstance(node, Multipart):
 220             self.debugprint(
 221                 f"{lead}{node} parents={[s.subtype for s in stack]}"
 222             )
 223
 224             # Depth-first, so push the current container onto the stack,
 225             # then descend …
 226             stack.append(node)
 227             self.debugprint("| " * (len(stack) + 1))
 228             for child in node.children:
 229                 self._walk(
 230                     child,
 231                     stack=stack,
 232                     visitor_fn=visitor_fn,
 233                 )
 234             self.debugprint("| " * len(stack))
 235             assert stack.pop() == node
 236
 237         else:
 238             self.debugprint(f"{lead}{node}")
 239
 240         if visitor_fn:
 241             visitor_fn(node, stack, debugprint=self.debugprint)
 242
 243     def debugprint(self, s, **kwargs):
 244         if self._debug:
 245             print(s, file=sys.stderr, **kwargs)
 246
 247
 248 # [ RUN MODES ] ###############################################################
 249
 250
 251 class MuttCommands:
 252     """
 253     Stupid class to interface writing out Mutt commands. This is quite a hack
 254     to deal with the fact that Mutt runs "push" commands in reverse order, so
 255     all of a sudden, things become very complicated when mixing with "real"
 256     commands.
 257
 258     Hence we keep two sets of commands, and one set of pushes. Commands are
 259     added to the first until a push is added, after which commands are added to
 260     the second set of commands.
 261
 262     On flush(), the first set is printed, followed by the pushes in reverse,
 263     and then the second set is printed. All 3 sets are then cleared.
 264     """
 265
 266     def __init__(self, out_f=sys.stdout, *, debug=False):
 267         self._cmd1, self._push, self._cmd2 = [], [], []
 268         self._out_f = out_f
 269         self._debug = debug
 270
 271     def cmd(self, s):
 272         self.debugprint(s)
 273         if self._push:
 274             self._cmd2.append(s)
 275         else:
 276             self._cmd1.append(s)
 277
 278     def push(self, s):
 279         s = s.replace('"', '"')
 280         s = f'push "{s}"'
 281         self.debugprint(s)
 282         self._push.insert(0, s)
 283
 284     def flush(self):
 285         print(
 286             "\n".join(self._cmd1 + self._push + self._cmd2), file=self._out_f
 287         )
 288         self._cmd1, self._push, self._cmd2 = [], [], []
 289
 290     def debugprint(self, s, **kwargs):
 291         if self._debug:
 292             print(s, file=sys.stderr, **kwargs)
 293
 294
 295 def do_setup(
 296     extensions=None, *, out_f=sys.stdout, temppath=None, debug_commands=False
 297 ):
 298     extensions = extensions or []
 299     temppath = temppath or pathlib.Path(
 300         tempfile.mkstemp(prefix="muttmdwn-")[1]
 301     )
 302     cmds = MuttCommands(out_f, debug=debug_commands)
 303
 304     editor = f"{sys.argv[0]} massage --write-commands-to {temppath}"
 305     if extensions:
 306         editor = f'{editor} --extensions {",".join(extensions)}'
 307     if debug_commands:
 308         editor = f'{editor} --debug-commands'
 309
 310     cmds.cmd('set my_editor="$editor"')
 311     cmds.cmd('set my_edit_headers="$edit_headers"')
 312     cmds.cmd(f'set editor="{editor}"')
 313     cmds.cmd("unset edit_headers")
 314     cmds.cmd(f"set my_mdwn_postprocess_cmd_file={temppath}")
 315     cmds.push("<first-entry><edit-file>")
 316     cmds.flush()
 317
 318
 319 def do_massage(
 320     maildraft,
 321     cmd_f,
 322     *,
 323     extensions=None,
 324     converter=convert_markdown_to_html,
 325     debug_commands=False,
 326     debug_walk=False,
 327 ):
 328     # Here's the big picture: we're being invoked as the editor on the email
 329     # draft, and whatever commands we write to the file given as cmdpath will
 330     # be run by the second source command in the macro definition.
 331
 332     # Let's start by cleaning up what the setup did (see above), i.e. we
 333     # restore the $editor and $edit_headers variables, and also unset the
 334     # variable used to identify the command file we're currently writing
 335     # to.
 336     cmds = MuttCommands(cmd_f, debug=debug_commands)
 337     cmds.cmd('set editor="$my_editor"')
 338     cmds.cmd('set edit_headers="$my_edit_headers"')
 339     cmds.cmd("unset my_editor")
 340     cmds.cmd("unset my_edit_headers")
 341
 342     # let's flush those commands, as there'll be a lot of pushes from now
 343     # on, which need to be run in reverse order
 344     cmds.flush()
 345
 346     extensions = extensions.split(",") if extensions else []
 347     with open(maildraft, "r") as draft_f:
 348         tree = converter(
 349             draft_f.read(), pathlib.Path(maildraft), extensions=extensions
 350         )
 351
 352     mimetree = MIMETreeDFWalker(debug=debug_walk)
 353
 354     def visitor_fn(item, stack, *, debugprint=None):
 355         """
 356         Visitor function called for every node (part) of the MIME tree,
 357         depth-first, and responsible for telling NeoMutt how to assemble
 358         the tree.
 359         """
 360         if isinstance(item, Part):
 361             # We've hit a leaf-node, i.e. an alternative or a related part
 362             # with actual content.
 363
 364             # Let's add the part
 365             if item.orig:
 366                 # The original source already exists in the NeoMutt tree, but
 367                 # the underlying file may have been modified, so we need to
 368                 # update the encoding, but that's it:
 369                 cmds.push("<update-encoding>")
 370             else:
 371                 # … whereas all other parts need to be added, and they're all
 372                 # considered to be temporary and inline:
 373                 cmds.push(f"<attach-file>{item.path}<enter>")
 374                 cmds.push("<toggle-unlink><toggle-disposition>")
 375
 376             # If the item (including the original) comes with additional
 377             # information, then we might just as well update the NeoMutt
 378             # tree now:
 379             if item.cid:
 380                 cmds.push(f"<edit-content-id>\\Ca\\Ck{item.cid}<enter>")
 381
 382         elif isinstance(item, Multipart):
 383             # This node has children, but we already visited them (see
 384             # above), and so they have been tagged in NeoMutt's compose
 385             # window. Now it's just a matter of telling NeoMutt to do the
 386             # appropriate grouping:
 387             if item.subtype == "alternative":
 388                 cmds.push("<group-alternatives>")
 389             elif item.subtype == "relative":
 390                 cmds.push("<group-related>")
 391             elif item.subtype == "multilingual":
 392                 cmds.push("<group-multilingual>")
 393
 394         else:
 395             # We should never get here
 396             assert not "is valid part"
 397
 398         # If the item has a description, we might just as well add it
 399         if item.desc:
 400             cmds.push(f"<edit-description>\\Ca\\Ck{item.desc}<enter>")
 401
 402         # Finally, if we're at non-root level, tag the new container,
 403         # as it might itself be part of a container, to be processed
 404         # one level up:
 405         if stack:
 406             cmds.push("<tag-entry>")
 407
 408     # -----------------
 409     # End of visitor_fn
 410
 411     # Let's walk the tree and visit every node with our fancy visitor
 412     # function
 413     mimetree.walk(tree, visitor_fn=visitor_fn)
 414
 415     # Finally, cleanup. Since we're responsible for removing the temporary
 416     # file, how's this for a little hack?
 417     try:
 418         filename = cmd_f.name
 419     except AttributeError:
 420         filename = "pytest_internal_file"
 421     cmds.cmd(f"source 'rm -f {filename}|'")
 422     cmds.cmd("unset my_mdwn_postprocess_cmd_file")
 423     cmds.flush()
 424
 425
 426 # [ CLI ENTRY ] ###############################################################
 427
 428 if __name__ == "__main__":
 429     args = parse_cli_args()
 430
 431     if args.mode == "setup":
 432         if args.send_message:
 433             raise NotImplementedError()
 434
 435         do_setup(args.extensions, debug_commands=args.debug_commands)
 436
 437     elif args.mode == "massage":
 438         with open(args.cmdpath, "w") as cmd_f:
 439             do_massage(
 440                 args.MAILDRAFT,
 441                 cmd_f,
 442                 extensions=args.extensions,
 443                 debug_commands=args.debug_commands,
 444                 debug_walk=args.debug_walk,
 445             )
 446
 447
 448 # [ TESTS ] ###################################################################
 449
 450 try:
 451     import pytest
 452
 453     class Tests:
 454         @pytest.fixture
 455         def const1(self):
 456             return "CONSTANT STRING 1"
 457
 458         @pytest.fixture
 459         def const2(self):
 460             return "CONSTANT STRING 2"
 461
 462         # NOTE: tests using the capsys fixture must specify sys.stdout to the
 463         # functions they call, else old stdout is used and not captured
 464
 465         def test_MuttCommands_cmd(self, const1, const2, capsys):
 466             "Assert order of commands"
 467             cmds = MuttCommands(out_f=sys.stdout)
 468             cmds.cmd(const1)
 469             cmds.cmd(const2)
 470             cmds.flush()
 471             captured = capsys.readouterr()
 472             assert captured.out == "\n".join((const1, const2, ""))
 473
 474         def test_MuttCommands_push(self, const1, const2, capsys):
 475             "Assert reverse order of pushes"
 476             cmds = MuttCommands(out_f=sys.stdout)
 477             cmds.push(const1)
 478             cmds.push(const2)
 479             cmds.flush()
 480             captured = capsys.readouterr()
 481             assert (
 482                 captured.out
 483                 == ('"\npush "'.join(("", const2, const1, "")))[2:-6]
 484             )
 485
 486         def test_MuttCommands_cmd_push_mixed(self, const1, const2, capsys):
 487             "Assert reverse order of pushes"
 488             cmds = MuttCommands(out_f=sys.stdout)
 489             lines = ["000", "001", "010", "011", "100", "101", "110", "111"]
 490             for i in range(2):
 491                 cmds.cmd(lines[4 * i + 0])
 492                 cmds.cmd(lines[4 * i + 1])
 493                 cmds.push(lines[4 * i + 2])
 494                 cmds.push(lines[4 * i + 3])
 495             cmds.flush()
 496
 497             captured = capsys.readouterr()
 498             lines_out = captured.out.splitlines()
 499             assert lines[0] in lines_out[0]
 500             assert lines[1] in lines_out[1]
 501             assert lines[7] in lines_out[2]
 502             assert lines[6] in lines_out[3]
 503             assert lines[3] in lines_out[4]
 504             assert lines[2] in lines_out[5]
 505             assert lines[4] in lines_out[6]
 506             assert lines[5] in lines_out[7]
 507
 508         @pytest.fixture
 509         def basic_mime_tree(self):
 510             return Multipart(
 511                 "relative",
 512                 children=[
 513                     Multipart(
 514                         "alternative",
 515                         children=[
 516                             Part(
 517                                 "text",
 518                                 "plain",
 519                                 "part.txt",
 520                                 desc="Plain",
 521                                 orig=True,
 522                             ),
 523                             Part("text", "html", "part.html", desc="HTML"),
 524                         ],
 525                         desc="Alternative",
 526                     ),
 527                     Part(
 528                         "text", "png", "logo.png", cid="logo.png", desc="Logo"
 529                     ),
 530                 ],
 531                 desc="Related",
 532             )
 533
 534         def test_MIMETreeDFWalker_depth_first_walk(self, basic_mime_tree):
 535             mimetree = MIMETreeDFWalker()
 536
 537             items = []
 538
 539             def visitor_fn(item, stack, debugprint):
 540                 items.append((item, len(stack)))
 541
 542             mimetree.walk(basic_mime_tree, visitor_fn=visitor_fn)
 543             assert len(items) == 5
 544             assert items[0][0].subtype == "plain"
 545             assert items[0][1] == 2
 546             assert items[1][0].subtype == "html"
 547             assert items[1][1] == 2
 548             assert items[2][0].subtype == "alternative"
 549             assert items[2][1] == 1
 550             assert items[3][0].subtype == "png"
 551             assert items[3][1] == 1
 552             assert items[4][0].subtype == "relative"
 553             assert items[4][1] == 0
 554
 555         def test_MIMETreeDFWalker_list_to_mixed(self, basic_mime_tree):
 556             mimetree = MIMETreeDFWalker()
 557             items = []
 558
 559             def visitor_fn(item, stack, debugprint):
 560                 items.append(item)
 561
 562             mimetree.walk([basic_mime_tree], visitor_fn=visitor_fn)
 563             assert items[-1].subtype == "mixed"
 564
 565         def test_MIMETreeDFWalker_visitor_in_constructor(
 566             self, basic_mime_tree
 567         ):
 568             items = []
 569
 570             def visitor_fn(item, stack, debugprint):
 571                 items.append(item)
 572
 573             mimetree = MIMETreeDFWalker(visitor_fn=visitor_fn)
 574             mimetree.walk(basic_mime_tree)
 575             assert len(items) == 5
 576
 577         def test_do_setup_no_extensions(self, const1, capsys):
 578             "Assert basics about the setup command output"
 579             do_setup(temppath=const1, out_f=sys.stdout)
 580             captout = capsys.readouterr()
 581             lines = captout.out.splitlines()
 582             assert lines[2].endswith(f'{const1}"')
 583             assert lines[4].endswith(const1)
 584             assert "first-entry" in lines[-1]
 585             assert "edit-file" in lines[-1]
 586
 587         def test_do_setup_extensions(self, const1, const2, capsys):
 588             "Assert that extensions are passed to editor"
 589             do_setup(
 590                 temppath=const1, extensions=[const2, const1], out_f=sys.stdout
 591             )
 592             captout = capsys.readouterr()
 593             lines = captout.out.splitlines()
 594             # assert comma-separated list of extensions passed
 595             assert lines[2].endswith(f'{const2},{const1}"')
 596             assert lines[4].endswith(const1)
 597
 598         def test_do_massage_basic(self, const1, capsys):
 599             def converter(maildraft, extensions):
 600                 return Part("text", "plain", "/dev/null", orig=True)
 601
 602             do_massage(maildraft=const1, cmd_f=sys.stdout, converter=converter)
 603             captured = capsys.readouterr()
 604             assert (
 605                 captured.out.strip()
 606                 == """\
 607             set editor="$my_editor"
 608             set edit_headers="$my_edit_headers"
 609             unset my_editor
 610             unset my_edit_headers
 611             source 'rm -f pytest_internal_file|'
 612             unset my_mdwn_postprocess_cmd_file
 613             """.replace(
 614                     "            ", ""
 615                 ).strip()
 616             )
 617
 618         def test_do_massage_fulltree(self, const1, basic_mime_tree, capsys):
 619             def converter(maildraft, extensions):
 620                 return basic_mime_tree
 621
 622             do_massage(maildraft=const1, cmd_f=sys.stdout, converter=converter)
 623             captured = capsys.readouterr()
 624             lines = captured.out.splitlines()[4:][::-1]
 625             assert "Related" in lines.pop()
 626             assert "group-related" in lines.pop()
 627             assert "tag-entry" in lines.pop()
 628             assert "Logo" in lines.pop()
 629             assert "content-id" in lines.pop()
 630             assert "toggle-unlink" in lines.pop()
 631             assert "logo.png" in lines.pop()
 632             assert "tag-entry" in lines.pop()
 633             assert "Alternative" in lines.pop()
 634             assert "group-alternatives" in lines.pop()
 635             assert "tag-entry" in lines.pop()
 636             assert "HTML" in lines.pop()
 637             assert "toggle-unlink" in lines.pop()
 638             assert "part.html" in lines.pop()
 639             assert "tag-entry" in lines.pop()
 640             assert "Plain" in lines.pop()
 641
 642 except ImportError:
 643     pass