1MIME::Parser(3) User Contributed Perl Documentation MIME::Parser(3)
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3
4
6 MIME::Parser - experimental class for parsing MIME streams
7
9 Before reading further, you should see MIME::Tools to make sure that
10 you understand where this module fits into the grand scheme of things.
11 Go on, do it now. I'll wait.
12
13 Ready? Ok...
14
15 Basic usage examples
16 ### Create a new parser object:
17 my $parser = new MIME::Parser;
18
19 ### Tell it where to put things:
20 $parser->output_under("/tmp");
21
22 ### Parse an input filehandle:
23 $entity = $parser->parse(\*STDIN);
24
25 ### Congratulations: you now have a (possibly multipart) MIME entity!
26 $entity->dump_skeleton; # for debugging
27
28 Examples of input
29 ### Parse from filehandles:
30 $entity = $parser->parse(\*STDIN);
31 $entity = $parser->parse(IO::File->new("some command|");
32
33 ### Parse from any object that supports getline() and read():
34 $entity = $parser->parse($myHandle);
35
36 ### Parse an in-core MIME message:
37 $entity = $parser->parse_data($message);
38
39 ### Parse an MIME message in a file:
40 $entity = $parser->parse_open("/some/file.msg");
41
42 ### Parse an MIME message out of a pipeline:
43 $entity = $parser->parse_open("gunzip - < file.msg.gz |");
44
45 ### Parse already-split input (as "deliver" would give it to you):
46 $entity = $parser->parse_two("msg.head", "msg.body");
47
48 Examples of output control
49 ### Keep parsed message bodies in core (default outputs to disk):
50 $parser->output_to_core(1);
51
52 ### Output each message body to a one-per-message directory:
53 $parser->output_under("/tmp");
54
55 ### Output each message body to the same directory:
56 $parser->output_dir("/tmp");
57
58 ### Change how nameless message-component files are named:
59 $parser->output_prefix("msg");
60
61 ### Put temporary files somewhere else
62 $parser->tmp_dir("/var/tmp/mytmpdir");
63
64 Examples of error recovery
65 ### Normal mechanism:
66 eval { $entity = $parser->parse(\*STDIN) };
67 if ($@) {
68 $results = $parser->results;
69 $decapitated = $parser->last_head; ### get last top-level head
70 }
71
72 ### Ultra-tolerant mechanism:
73 $parser->ignore_errors(1);
74 $entity = eval { $parser->parse(\*STDIN) };
75 $error = ($@ || $parser->last_error);
76
77 ### Cleanup all files created by the parse:
78 eval { $entity = $parser->parse(\*STDIN) };
79 ...
80 $parser->filer->purge;
81
82 Examples of parser options
83 ### Automatically attempt to RFC 2047-decode the MIME headers?
84 $parser->decode_headers(1); ### default is false
85
86 ### Parse contained "message/rfc822" objects as nested MIME streams?
87 $parser->extract_nested_messages(0); ### default is true
88
89 ### Look for uuencode in "text" messages, and extract it?
90 $parser->extract_uuencode(1); ### default is false
91
92 ### Should we forgive normally-fatal errors?
93 $parser->ignore_errors(0); ### default is true
94
95 Miscellaneous examples
96 ### Convert a Mail::Internet object to a MIME::Entity:
97 my $data = join('', (@{$mail->header}, "\n", @{$mail->body}));
98 $entity = $parser->parse_data(\$data);
99
101 You can inherit from this class to create your own subclasses that
102 parse MIME streams into MIME::Entity objects.
103
105 Construction
106 new ARGS...
107 Class method. Create a new parser object. Once you do this, you
108 can then set up various parameters before doing the actual parsing.
109 For example:
110
111 my $parser = new MIME::Parser;
112 $parser->output_dir("/tmp");
113 $parser->output_prefix("msg1");
114 my $entity = $parser->parse(\*STDIN);
115
116 Any arguments are passed into init(). Don't override this in your
117 subclasses; override init() instead.
118
119 init ARGS...
120 Instance method. Initiallize a new MIME::Parser object. This is
121 automatically sent to a new object; you may want to override it.
122 If you override this, be sure to invoke the inherited method.
123
124 init_parse
125 Instance method. Invoked automatically whenever one of the top-
126 level parse() methods is called, to reset the parser to a "ready"
127 state.
128
129 Altering how messages are parsed
130 decode_headers [YESNO]
131 Instance method. Controls whether the parser will attempt to
132 decode all the MIME headers (as per RFC 2047) the moment it sees
133 them. This is not advisable for two very important reasons:
134
135 • It screws up the extraction of information from MIME fields.
136 If you fully decode the headers into bytes, you can
137 inadvertently transform a parseable MIME header like this:
138
139 Content-type: text/plain; filename="=?ISO-8859-1?Q?Hi=22Ho?="
140
141 into unparseable gobbledygook; in this case:
142
143 Content-type: text/plain; filename="Hi"Ho"
144
145 • It is information-lossy. An encoded string which contains both
146 Latin-1 and Cyrillic characters will be turned into a binary
147 mishmosh which simply can't be rendered.
148
149 History. This method was once the only out-of-the-box way to deal
150 with attachments whose filenames had non-ASCII characters.
151 However, since MIME-tools 5.4xx this is no longer necessary.
152
153 Parameters. If YESNO is true, decoding is done. However, you will
154 get a warning unless you use one of the special "true" values:
155
156 "I_NEED_TO_FIX_THIS"
157 Just shut up and do it. Not recommended.
158 Provided only for those who need to keep old scripts functioning.
159
160 "I_KNOW_WHAT_I_AM_DOING"
161 Just shut up and do it. Not recommended.
162 Provided for those who REALLY know what they are doing.
163
164 If YESNO is false (the default), no attempt at decoding will be
165 done. With no argument, just returns the current setting.
166 Remember: you can always decode the headers after the parsing has
167 completed (see MIME::Head::decode()), or decode the words on demand
168 (see MIME::Words).
169
170 extract_nested_messages OPTION
171 Instance method. Some MIME messages will contain a part of type
172 "message/rfc822" ,"message/partial" or "message/external-body":
173 literally, the text of an embedded mail/news/whatever message.
174 This option controls whether (and how) we parse that embedded
175 message.
176
177 If the OPTION is false, we treat such a message just as if it were
178 a "text/plain" document, without attempting to decode its contents.
179
180 If the OPTION is true (the default), the body of the
181 "message/rfc822" or "message/partial" part is parsed by this
182 parser, creating an entity object. What happens then is determined
183 by the actual OPTION:
184
185 NEST or 1
186 The default setting. The contained message becomes the sole
187 "part" of the "message/rfc822" entity (as if the containing
188 message were a special kind of "multipart" message). You can
189 recover the sub-entity by invoking the parts() method on the
190 "message/rfc822" entity.
191
192 REPLACE
193 The contained message replaces the "message/rfc822" entity, as
194 though the "message/rfc822" "container" never existed.
195
196 Warning: notice that, with this option, all the header
197 information in the "message/rfc822" header is lost. This might
198 seriously bother you if you're dealing with a top-level
199 message, and you've just lost the sender's address and the
200 subject line. ":-/".
201
202 Thanks to Andreas Koenig for suggesting this method.
203
204 extract_uuencode [YESNO]
205 Instance method. If set true, then whenever we are confronted with
206 a message whose effective content-type is "text/plain" and whose
207 encoding is 7bit/8bit/binary, we scan the encoded body to see if it
208 contains uuencoded data (generally given away by a "begin XXX"
209 line).
210
211 If it does, we explode the uuencoded message into a multipart,
212 where the text before the first "begin XXX" becomes the first part,
213 and all "begin...end" sections following become the subsequent
214 parts. The filename (if given) is accessible through the normal
215 means.
216
217 ignore_errors [YESNO]
218 Instance method. Controls whether the parser will attempt to
219 ignore normally-fatal errors, treating them as warnings and
220 continuing with the parse.
221
222 If YESNO is true (the default), many syntax errors are tolerated.
223 If YESNO is false, fatal errors throw exceptions. With no
224 argument, just returns the current setting.
225
226 decode_bodies [YESNO]
227 Instance method. Controls whether the parser should decode entity
228 bodies or not. If this is set to a false value (default is true),
229 all entity bodies will be kept as-is in the original content-
230 transfer encoding.
231
232 To prevent double encoding on the output side
233 MIME::Body->is_encoded is set, which tells MIME::Body not to encode
234 the data again, if encoded data was requested. This is in
235 particular useful, when it's important that the content must not be
236 modified, e.g. if you want to calculate OpenPGP signatures from it.
237
238 WARNING: the semantics change significantly if you parse MIME
239 messages with this option set, because MIME::Entity resp.
240 MIME::Body *always* see encoded data now, while the default
241 behaviour is working with *decoded* data (and encoding it only if
242 you request it). You need to decode the data yourself, if you want
243 to have it decoded.
244
245 So use this option only if you exactly know, what you're doing, and
246 that you're sure, that you really need it.
247
248 Parsing an input source
249 parse_data DATA
250 Instance method. Parse a MIME message that's already in core.
251 This internally creates an "in memory" filehandle on a Perl scalar
252 value using PerlIO
253
254 You may supply the DATA in any of a number of ways...
255
256 • A scalar which holds the message. A reference to this scalar
257 will be used internally.
258
259 • A ref to a scalar which holds the message. This reference will
260 be used internally.
261
262 • DEPRECATED
263
264 A ref to an array of scalars. The array is internally
265 concatenated into a temporary string, and a reference to the
266 new string is used internally.
267
268 It is much more efficient to pass in a scalar reference, so
269 please consider refactoring your code to use that interface
270 instead. If you absolutely MUST pass an array, you may be
271 better off using IO::ScalarArray in the calling code to
272 generate a filehandle, and passing that filehandle to parse()
273
274 Returns the parsed MIME::Entity on success.
275
276 parse INSTREAM
277 Instance method. Takes a MIME-stream and splits it into its
278 component entities.
279
280 The INSTREAM can be given as an IO::File, a globref filehandle
281 (like "\*STDIN"), or as any blessed object conforming to the IO::
282 interface (which minimally implements getline() and read()).
283
284 Returns the parsed MIME::Entity on success. Throws exception on
285 failure. If the message contained too many parts (as set by
286 max_parts), returns undef.
287
288 parse_open EXPR
289 Instance method. Convenience front-end onto parse(). Simply give
290 this method any expression that may be sent as the second argument
291 to open() to open a filehandle for reading.
292
293 Returns the parsed MIME::Entity on success. Throws exception on
294 failure.
295
296 parse_two HEADFILE, BODYFILE
297 Instance method. Convenience front-end onto parse_open(), intended
298 for programs running under mail-handlers like deliver, which splits
299 the incoming mail message into a header file and a body file.
300 Simply give this method the paths to the respective files.
301
302 Warning: it is assumed that, once the files are cat'ed together,
303 there will be a blank line separating the head part and the body
304 part.
305
306 Warning: new implementation slurps files into line array for
307 portability, instead of using 'cat'. May be an issue if your
308 messages are large.
309
310 Returns the parsed MIME::Entity on success. Throws exception on
311 failure.
312
313 Specifying output destination
314 Warning: in 5.212 and before, this was done by methods of MIME::Parser.
315 However, since many users have requested fine-tuned control over how
316 this is done, the logic has been split off from the parser into its own
317 class, MIME::Parser::Filer Every MIME::Parser maintains an instance of
318 a MIME::Parser::Filer subclass to manage disk output (see
319 MIME::Parser::Filer for details.)
320
321 The benefit to this is that the MIME::Parser code won't be confounded
322 with a lot of garbage related to disk output. The drawback is that the
323 way you override the default behavior will change.
324
325 For now, all the normal public-interface methods are still provided,
326 but many are only stubs which create or delegate to the underlying
327 MIME::Parser::Filer object.
328
329 filer [FILER]
330 Instance method. Get/set the FILER object used to manage the
331 output of files to disk. This will be some subclass of
332 MIME::Parser::Filer.
333
334 output_dir DIRECTORY
335 Instance method. Causes messages to be filed directly into the
336 given DIRECTORY. It does this by setting the underlying filer() to
337 a new instance of MIME::Parser::FileInto, and passing the arguments
338 into that class' new() method.
339
340 Note: Since this method replaces the underlying filer, you must
341 invoke it before doing changing any attributes of the filer, like
342 the output prefix; otherwise those changes will be lost.
343
344 output_under BASEDIR, OPTS...
345 Instance method. Causes messages to be filed directly into
346 subdirectories of the given BASEDIR, one subdirectory per message.
347 It does this by setting the underlying filer() to a new instance of
348 MIME::Parser::FileUnder, and passing the arguments into that class'
349 new() method.
350
351 Note: Since this method replaces the underlying filer, you must
352 invoke it before doing changing any attributes of the filer, like
353 the output prefix; otherwise those changes will be lost.
354
355 output_path HEAD
356 Instance method, DEPRECATED. Given a MIME head for a file to be
357 extracted, come up with a good output pathname for the extracted
358 file. Identical to the preferred form:
359
360 $parser->filer->output_path(...args...);
361
362 We just delegate this to the underlying filer() object.
363
364 output_prefix [PREFIX]
365 Instance method, DEPRECATED. Get/set the short string that all
366 filenames for extracted body-parts will begin with (assuming that
367 there is no better "recommended filename"). Identical to the
368 preferred form:
369
370 $parser->filer->output_prefix(...args...);
371
372 We just delegate this to the underlying filer() object.
373
374 evil_filename NAME
375 Instance method, DEPRECATED. Identical to the preferred form:
376
377 $parser->filer->evil_filename(...args...);
378
379 We just delegate this to the underlying filer() object.
380
381 max_parts NUM
382 Instance method. Limits the number of MIME parts we will parse.
383
384 Normally, instances of this class parse a message to the bitter
385 end. Messages with many MIME parts can cause excessive memory
386 consumption. If you invoke this method, parsing will abort with a
387 die() if a message contains more than NUM parts.
388
389 If NUM is set to -1 (the default), then no maximum limit is
390 enforced.
391
392 With no argument, returns the current setting as an integer
393
394 output_to_core YESNO
395 Instance method. Normally, instances of this class output all
396 their decoded body data to disk files (via MIME::Body::File).
397 However, you can change this behaviour by invoking this method
398 before parsing:
399
400 If YESNO is false (the default), then all body data goes to disk
401 files.
402
403 If YESNO is true, then all body data goes to in-core data
404 structures This is a little risky (what if someone emails you an
405 MPEG or a tar file, hmmm?) but people seem to want this bit of
406 noose-shaped rope, so I'm providing it. Note that setting this
407 attribute true does not mean that parser-internal temporary files
408 are avoided! Use tmp_to_core() for that.
409
410 With no argument, returns the current setting as a boolean.
411
412 tmp_recycling
413 Instance method, DEPRECATED.
414
415 This method is a no-op to preserve the pre-5.421 API.
416
417 The tmp_recycling() feature was removed in 5.421 because it had
418 never actually worked. Please update your code to stop using it.
419
420 tmp_to_core [YESNO]
421 Instance method. Should new_tmpfile() create real temp files, or
422 use fake in-core ones? Normally we allow the creation of temporary
423 disk files, since this allows us to handle huge attachments even
424 when core is limited.
425
426 If YESNO is true, we implement new_tmpfile() via in-core handles.
427 If YESNO is false (the default), we use real tmpfiles. With no
428 argument, just returns the current setting.
429
430 use_inner_files [YESNO]
431 REMOVED.
432
433 Instance method.
434
435 MIME::Parser no longer supports IO::InnerFile, but this method is
436 retained for backwards compatibility. It does nothing.
437
438 The original reasoning for IO::InnerFile was that inner files were
439 faster than "in-core" temp files. At the time, the "in-core"
440 tempfile support was implemented with IO::Scalar from the IO-
441 Stringy distribution, which used the tie() interface to wrap a
442 scalar with the appropriate IO::Handle operations. The penalty for
443 this was fairly hefty, and IO::InnerFile actually was faster.
444
445 Nowadays, MIME::Parser uses Perl's built in ability to open a
446 filehandle on an in-memory scalar variable via PerlIO.
447 Benchmarking shows that IO::InnerFile is slightly slower than using
448 in-memory temporary files, and is slightly faster than on-disk
449 temporary files. Both measurements are within a few percent of
450 each other. Since there's no real benefit, and since the
451 IO::InnerFile abuse was fairly hairy and evil ("writes" to it were
452 faked by extending the size of the inner file with the assumption
453 that the only data you'd ever ->print() to it would be the line
454 from the "outer" file, for example) it's been removed.
455
456 Specifying classes to be instantiated
457 interface ROLE,[VALUE]
458 Instance method. During parsing, the parser normally creates
459 instances of certain classes, like MIME::Entity. However, you may
460 want to create a parser subclass that uses your own experimental
461 head, entity, etc. classes (for example, your "head" class may
462 provide some additional MIME-field-oriented methods).
463
464 If so, then this is the method that your subclass should invoke
465 during init. Use it like this:
466
467 package MyParser;
468 @ISA = qw(MIME::Parser);
469 ...
470 sub init {
471 my $self = shift;
472 $self->SUPER::init(@_); ### do my parent's init
473 $self->interface(ENTITY_CLASS => 'MIME::MyEntity');
474 $self->interface(HEAD_CLASS => 'MIME::MyHead');
475 $self; ### return
476 }
477
478 With no VALUE, returns the VALUE currently associated with that
479 ROLE.
480
481 new_body_for HEAD
482 Instance method. Based on the HEAD of a part we are parsing,
483 return a new body object (any desirable subclass of MIME::Body) for
484 receiving that part's data.
485
486 If you set the "output_to_core" option to false before parsing (the
487 default), then we call output_path() and create a new
488 MIME::Body::File on that filename.
489
490 If you set the "output_to_core" option to true before parsing, then
491 you get a MIME::Body::InCore instead.
492
493 If you want the parser to do something else entirely, you can
494 override this method in a subclass.
495
496 Temporary File Creation
497 tmp_dir DIRECTORY
498 Instance method. Causes any temporary files created by this parser
499 to be created in the given DIRECTORY.
500
501 If called without arguments, returns current value.
502
503 The default value is undef, which will cause new_tmpfile() to use
504 the system default temporary directory.
505
506 new_tmpfile
507 Instance method. Return an IO handle to be used to hold temporary
508 data during a parse.
509
510 The default uses MIME::Tools::tmpopen() to create a new temporary
511 file, unless tmp_to_core() dictates otherwise, but you can override
512 this. You shouldn't need to.
513
514 The location for temporary files can be changed on a per-parser
515 basis with tmp_dir().
516
517 If you do override this, make certain that the object you return is
518 set for binmode(), and is able to handle the following methods:
519
520 read(BUF, NBYTES)
521 getline()
522 getlines()
523 print(@ARGS)
524 flush()
525 seek(0, 0)
526
527 Fatal exception if the stream could not be established.
528
529 Parse results and error recovery
530 last_error
531 Instance method. Return the error (if any) that we ignored in the
532 last parse.
533
534 last_head
535 Instance method. Return the top-level MIME header of the last
536 stream we attempted to parse. This is useful for replying to
537 people who sent us bad MIME messages.
538
539 ### Parse an input stream:
540 eval { $entity = $parser->parse(\*STDIN) };
541 if (!$entity) { ### parse failed!
542 my $decapitated = $parser->last_head;
543 ...
544 }
545
546 results
547 Instance method. Return an object containing lots of info from the
548 last entity parsed. This will be an instance of class
549 MIME::Parser::Results.
550
552 Maximizing speed
553 Optimum input mechanisms:
554
555 parse() YES (if you give it a globref or a
556 subclass of IO::File)
557 parse_open() YES
558 parse_data() NO (see below)
559 parse_two() NO (see below)
560
561 Optimum settings:
562
563 decode_headers() *** (no real difference; 0 is slightly faster)
564 extract_nested_messages() 0 (may be slightly faster, but in
565 general you want it set to 1)
566 output_to_core() 0 (will be MUCH faster)
567 tmp_to_core() 0 (will be MUCH faster)
568
569 Native I/O is much faster than object-oriented I/O. It's much faster
570 to use <$foo> than $foo->getline. For backwards compatibility, this
571 module must continue to use object-oriented I/O in most places, but if
572 you use parse() with a "real" filehandle (string, globref, or subclass
573 of IO::File) then MIME::Parser is able to perform some crucial
574 optimizations.
575
576 The parse_two() call is very inefficient. Currently this is just a
577 front-end onto parse_data(). If your OS supports it, you're far better
578 off doing something like:
579
580 $parser->parse_open("/bin/cat msg.head msg.body |");
581
582 Minimizing memory
583 Optimum input mechanisms:
584
585 parse() YES
586 parse_open() YES
587 parse_data() NO (in-core I/O will burn core)
588 parse_two() NO (in-core I/O will burn core)
589
590 Optimum settings:
591
592 decode_headers() *** (no real difference)
593 extract_nested_messages() *** (no real difference)
594 output_to_core() 0 (will use MUCH less memory)
595 tmp_to_core is 1)
596 tmp_to_core() 0 (will use MUCH less memory)
597
598 Maximizing tolerance of bad MIME
599 Optimum input mechanisms:
600
601 parse() *** (doesn't matter)
602 parse_open() *** (doesn't matter)
603 parse_data() *** (doesn't matter)
604 parse_two() *** (doesn't matter)
605
606 Optimum settings:
607
608 decode_headers() 0 (sidesteps problem of bad hdr encodings)
609 extract_nested_messages() 0 (sidesteps problems of bad nested messages,
610 but often you want it set to 1 anyway).
611 output_to_core() *** (doesn't matter)
612 tmp_to_core() *** (doesn't matter)
613
614 Avoiding disk-based temporary files
615 Optimum input mechanisms:
616
617 parse() YES (if you give it a seekable handle)
618 parse_open() YES (becomes a seekable handle)
619 parse_data() NO (unless you set tmp_to_core(1))
620 parse_two() NO (unless you set tmp_to_core(1))
621
622 Optimum settings:
623
624 decode_headers() *** (doesn't matter)
625 extract_nested_messages() *** (doesn't matter)
626 output_to_core() *** (doesn't matter)
627 tmp_to_core() 1
628
629 You can veto tmpfiles entirely. You can set tmp_to_core() true: this
630 will always use in-core I/O for the buffering (warning: this will slow
631 down the parsing of messages with large attachments).
632
633 Final resort. You can always override new_tmpfile() in a subclass.
634
636 Multipart messages are always read line-by-line
637 Multipart document parts are read line-by-line, so that the
638 encapsulation boundaries may easily be detected. However, bad MIME
639 composition agents (for example, naive CGI scripts) might return
640 multipart documents where the parts are, say, unencoded bitmap
641 files... and, consequently, where such "lines" might be
642 veeeeeeeeery long indeed.
643
644 A better solution for this case would be to set up some form of
645 state machine for input processing. This will be left for future
646 versions.
647
648 Multipart parts read into temp files before decoding
649 In my original implementation, the MIME::Decoder classes had to be
650 aware of encapsulation boundaries in multipart MIME documents.
651 While this decode-while-parsing approach obviated the need for
652 temporary files, it resulted in inflexible and complex decoder
653 implementations.
654
655 The revised implementation uses a temporary file (a la tmpfile())
656 during parsing to hold the encoded portion of the current MIME
657 document or part. This file is deleted automatically after the
658 current part is decoded and the data is written to the "body
659 stream" object; you'll never see it, and should never need to worry
660 about it.
661
662 Some folks have asked for the ability to bypass this temp-file
663 mechanism, I suppose because they assume it would slow down their
664 application. I considered accommodating this wish, but the temp-
665 file approach solves a lot of thorny problems in parsing, and it
666 also protects against hidden bugs in user applications (what if
667 you've directed the encoded part into a scalar, and someone
668 unexpectedly sends you a 6 MB tar file?). Finally, I'm just not
669 convinced that the temp-file use adds significant overhead.
670
671 Fuzzing of CRLF and newline on input
672 RFC 2045 dictates that MIME streams have lines terminated by CRLF
673 ("\r\n"). However, it is extremely likely that folks will want to
674 parse MIME streams where each line ends in the local newline
675 character "\n" instead.
676
677 An attempt has been made to allow the parser to handle both CRLF
678 and newline-terminated input.
679
680 Fuzzing of CRLF and newline on output
681 The "7bit" and "8bit" decoders will decode both a "\n" and a "\r\n"
682 end-of-line sequence into a "\n".
683
684 The "binary" decoder (default if no encoding specified) still
685 outputs stuff verbatim... so a MIME message with CRLFs and no
686 explicit encoding will be output as a text file that, on many
687 systems, will have an annoying ^M at the end of each line... but
688 this is as it should be.
689
690 Inability to handle multipart boundaries that contain newlines
691 First, let's get something straight: this is an evil, EVIL
692 practice, and is incompatible with RFC 2046... hence, it's not
693 valid MIME.
694
695 If your mailer creates multipart boundary strings that contain
696 newlines when they appear in the message body, give it two weeks
697 notice and find another one. If your mail robot receives MIME mail
698 like this, regard it as syntactically incorrect MIME, which it is.
699
700 Why do I say that? Well, in RFC 2046, the syntax of a boundary is
701 given quite clearly:
702
703 boundary := 0*69<bchars> bcharsnospace
704
705 bchars := bcharsnospace / " "
706
707 bcharsnospace := DIGIT / ALPHA / "'" / "(" / ")" / "+" /"_"
708 / "," / "-" / "." / "/" / ":" / "=" / "?"
709
710 All of which means that a valid boundary string cannot have
711 newlines in it, and any newlines in such a string in the message
712 header are expected to be solely the result of folding the string
713 (i.e., inserting to-be-removed newlines for readability and line-
714 shortening only).
715
716 Yet, there is at least one brain-damaged user agent out there that
717 composes mail like this:
718
719 MIME-Version: 1.0
720 Content-type: multipart/mixed; boundary="----ABC-
721 123----"
722 Subject: Hi... I'm a dork!
723
724 This is a multipart MIME message (yeah, right...)
725
726 ----ABC-
727 123----
728
729 Hi there!
730
731 We have got to discourage practices like this (and the recent file
732 upload idiocy where binary files that are part of a multipart MIME
733 message aren't base64-encoded) if we want MIME to stay relatively
734 simple, and MIME parsers to be relatively robust.
735
736 Thanks to Andreas Koenig for bringing a baaaaaaaaad user agent to
737 my attention.
738
740 MIME::Tools, MIME::Head, MIME::Body, MIME::Entity, MIME::Decoder
741
743 Eryq (eryq@zeegee.com), ZeeGee Software Inc (http://www.zeegee.com).
744 Dianne Skoll (dianne@skoll.ca)
745
746 All rights reserved. This program is free software; you can
747 redistribute it and/or modify it under the same terms as Perl itself.
748
749
750
751perl v5.38.0 2023-07-20 MIME::Parser(3)