summaryrefslogtreecommitdiff
path: root/doc/guile-email.texi
blob: ed43d5a7d8f9345b4a80268c2323b34e61da5e5d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
\input texinfo
@setfilename guile-email.info
@settitle guile-email

@copying
Copyright @copyright{} 2019 Arun Isaac@*

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.  A
copy of the license is included in the section entitled ``GNU Free
Documentation License''.
@end copying

@ifnottex
@node Top
@top guile-email
@end ifnottex

@menu
* Introduction:: What is guile-email?
* Parsing Email:: Parsing email
* Data Types:: Data types provided by guile-email
* Encoding and Decoding:: Encoding and decoding Base64, Quoted-Printable
  and Q-encoding
* Reading Email:: Reading emails from the mbox format
* Contributing:: Contributing

Indices

* Procedure Index::
* Type Index::

@end menu

@node Introduction
@chapter Introduction

guile-email is a collection of email utilities implemented in pure
guile.  It supports parsing MIME (Multipurpose Internet Mail Extensions)
compliant email messages as specified in RFC5322, RFC2045, RFC2046,
RF2047 and RFC2049.

@section Features

@itemize
@item Parse @uref{https://tools.ietf.org/html/rfc5322,,RFC5322} compliant email messages (currently does not support @uref{https://tools.ietf.org/html/rfc5322#section-4,,obsolete syntax})
@item Parse MIME compliant email messages as specified in @uref{https://tools.ietf.org/html/rfc2045,,RFC2045}, @uref{https://tools.ietf.org/html/rfc2046,,RFC2046}, @uref{https://tools.ietf.org/html/rfc2047,,RFC2047} and @uref{https://tools.ietf.org/html/rfc2049,,RFC2049}
@item Parse non-standard @uref{https://www.gnu.org/software/emacs/manual/html_node/emacs/Mail-Headers.html, Emacs message mode parens style addresses}
@item Encode and decode Quoted-Printable encoding, Base64 encoding and Q-encoding
@item Read emails from the @uref{https://en.wikipedia.org/wiki/Mbox, mbox format}
@end itemize

@node Parsing Email
@chapter Parsing Email

@example
(use-modules (email email))
@end example

@deftypefn {Scheme Procedure} parse-email (bytevector @var{email})
@deftypefnx {Scheme Procedure} parse-email (string @var{email})
Parse bytevector @var{email} and return result as an @code{<email>}
record.

Parse string @var{email} and return result as an @code{<email>}
record.
@end deftypefn

@deffn {Scheme Procedure} parse-email-headers headers
Parse string @var{headers} as email headers and return an association
list of header keys and values.
@end deffn

@deftypefn {Scheme Procedure} parse-email-body (string @var{headers}) (bytevector @var{body})
@deftypefnx {Scheme Procedure} parse-email-body (string @var{headers}) (string @var{body})
Parse bytevector @var{body} as email body where @var{headers} is an
association list of header keys and values as returned by
@code{parse-email-headers}. Return a list of <mime-entity> records if
the body is a multipart message. Else, return a single <mime-entity>
record.

Parse string @var{body} as email body where @var{headers} is an
association list of header keys and values as returned by
@code{parse-email-headers}. Return a list of <mime-entity> records if
the body is a multipart message. Else, return a single <mime-entity>
record.
@end deftypefn

Note that while an email can have characters encoded using different
schemes, a string is constrained to have all characters encoded using
the same scheme. Therefore, passing a string to @code{parse-email} or
@code{parse-email-body} will not always produce correct results. Hence,
this variant of @code{parse-email} and @code{parse-email-body} will be
deprecated in the future. This variant is only provided in the interest
of backward compatibility.

@node Data Types
@chapter Data Types

guile-email provides data types for representing emails and MIME
entities.

@section email data type

@deftp {Data Type} <email> headers body
This is the data type representing emails.
@end deftp

@deffn {Scheme Procedure} email? object
@deffnx {Scheme Procedure} email-headers email
@deffnx {Scheme Procedure} email-body email
Predicate and field accessors for the @code{<email>} data type.
@end deffn

@deffn {Scheme Procedure} make-email headers body
Construct an @code{<email>} object.  @var{headers} is an association
list of email headers.  @var{body} is either a string or a list of
@code{<mime-entity>} objects.
@end deffn

@section mime-entity data type

@deftp {Data Type} <mime-entity> headers body
This is the data type representing MIME entities.
@end deftp

@deffn {Scheme Procedure} mime-entity? object
@deffnx {Scheme Procedure} mime-entity-headers mime-entity
@deffnx {Scheme Procedure} mime-entity-body mime-entity
Predicate and field accessors for the @code{<mime-entity>} data type.
@end deffn

@deffn {Scheme Procedure} make-mime-entity headers body
Construct a mime-entity object.  @var{headers} is an association list of
MIME entity headers.  @var{body} is either a string or a list of
@code{<mime-entity>} objects.
@end deffn

@section email headers

The following descriptions of email headers are only a summary.  Please
see the relevant RFCs for more details.

@subsection email header types

@deftp {Email Header Type} AssociationList
An association list of key-value pairs (@pxref{Association Lists,,,
guile}).  Keys are the name of the email header, downcased and converted
to symbols.  Values are specific to the header and explained below.
@end deftp

@deftp {Email Header Type} Date
An SRFI-19 date.  @xref{SRFI-19 Date,,, guile}.
@end deftp

@deftp {Email Header Type} Address
An association list of atmost two keys - 'name' and 'address'.  The
values corresponding to these keys are explained below.

@table @code
@item name
Display name of the email address.  When the email address
does not specifiy a display name, this key will be absent.
@item address
Actual email address.
@end table
@end deftp

@deftp {Email Header Type} AddressList
A list of addresses, each of type 'Address'.
@end deftp

@deftp {Email Header Type} MessageID
A string containing an email message ID with the surrounding angle
brackets (@samp{<} and @samp{>}) removed.  Email message IDs uniquely
identify the email.
@end deftp

@deftp {Email Header Type} MessageIDList
A list of message IDs, each of type @code{MessageID}.
@end deftp

@subsection email headers

@deftypevr {Email Header} Date date
The date the email was sent on, as specified in the @dfn{Date} header.
@end deftypevr

@deftypevr {Email Header} AddressList from
The list of authors of the email, as specified in the @dfn{From} header.
@end deftypevr

@deftypevr {Email Header} Address sender
The sender of the email, as specified in the @dfn{Sender} header.
@end deftypevr

@deftypevr {Email Header} AddressList reply-to
The list of addresses the author of the email suggests replies be sent
to, as specified in the @dfn{Reply-To} header.
@end deftypevr

@deftypevr {Email Header} AddressList to
The list of primary recipients of the email, as specified in the
@dfn{To} header.
@end deftypevr

@deftypevr {Email Header} AddressList cc
The list of other recipients of the email at whom the content of the
email may not be directed, as specified in the @dfn{Cc} header.
@end deftypevr

@deftypevr {Email Header} AddressList bcc
THe list of recipients whose address is not to be revealed to other
recipients of the email, as specified in the @dfn{Bcc} header.
@end deftypevr

@deftypevr {Email Header} MessageID message-id
The message ID of the email, as specified in the @dfn{Message-ID}
header.
@end deftypevr

@deftypevr {Email Header} MessageIDList in-reply-to
The list of message IDs of emails to which this email is a reply, as
specified in the @dfn{In-Reply-To} header.
@end deftypevr

@deftypevr {Email Header} MessageIDList references
The list of message IDs specified in the @dfn{References} header.
@end deftypevr

@deftypevr {Email Header} String subject
A string identifying the topic of the email, as specified in the
@dfn{Subject} header.
@end deftypevr

@deftypevr {Email Header} String comments
A string containing additional comments on the body of the email, as
specified in the @dfn{Comments} header.
@end deftypevr

@deftypevr {Email Header} StringList keywords
A list of strings each an important word or phrase, as specified in the
@dfn{Keywords} header.
@end deftypevr

@deftypevr {Email Header} Date resent-date
The date at which the resent message was dispatched by the resender, as
specified in the @dfn{Resent-Date} header.
@end deftypevr

@deftypevr {Email Header} AddressList resent-from
The list of addresses specified in the @dfn{Resent-From} header.
@end deftypevr

@deftypevr {Email Header} Address resent-sender
The address specified in the @dfn{Resent-Sender} header.
@end deftypevr

@deftypevr {Email Header} AddressList resent-to
The list of addresses specified in the @dfn{Resent-To} header.
@end deftypevr

@deftypevr {Email Header} AddressList resent-cc
The list of addresses specified in the @dfn{Resent-Cc} header.
@end deftypevr

@deftypevr {Email Header} AddressList resent-bcc
The list of addresses specified in the @dfn{Resent-Bcc} header.
@end deftypevr

@deftypevr {Email Header} MessageID resent-message-id
The message ID specified in the @dfn{Resent-Message-ID} header.
@end deftypevr

@c TODO: Document trace fields

@deftypevr {Email Header} String mime-version
The MIME version specified in the @dfn{MIME-Version} header.
@end deftypevr

@deftypevr {Email Header} AssociationList content-type
The MIME type of the body, as specified in the @dfn{Content-Type}
header, as an association list.  The following keys always exist in the
association list.  Any additional parameters will also be listed as
key-value pairs.  Keys are names of the parameters, downcased and
converted to symbols.

@table @code
@item type
The primary type
@item subtype
The secondary type
@item charset
The charset
@end table
@end deftypevr

If no Content-Type header is present, a type of @code{text}, a subtype
of @code{plain} and a charset of ``utf-8'' is assumed as the default.
That is, the following:

@example
((type . text)
 (subtype . plain)
 (charset . "utf-8"))
@end example

@deftypevr {Email Header} AssociationList content-disposition
The content disposition type, as specified in the
@dfn{Content-Disposition} header, as an association list.  The following
keys always exist in the association list.

@table @code
@item type
@table @code
@item inline
@item attachment
@end table
@end table

Other optional keys include

@table @code
@item filename
@item creation-date
@item modification-date
@item read-date
@item size
@end table

Any additional parameters will also be listed as key-value pairs.
Keys are names of the parameters, downcased and converted to
symbols.
@end deftypevr

@deftypevr {Email Header} Symbol content-transfer-encoding
The encoding of the body of the email as specified in the
@dfn{Content-Transfer-Encoding} header.  This can be one of the
following symbols.

@table @code
@item 7bit
The message is 7-bit encoded.  This is the default if no
Content-Transfer-Encoding header is present.
@item 8bit
The message is 8-bit encoded.
@item quoted-printable
The message is encoded using Quoted-Printable encoding.
@item base64
The message is encoded using Base64 encoding.
@end table

Note that guile-email automatically decodes the email.  The user need
not read the @code{content-transfer-encoding} and invoke the appropriate
decoding procedure.  The @code{content-transfer-encoding} header is only
provided for the sake of completion.
@end deftypevr

@node Encoding and Decoding
@chapter Encoding and Decoding

guile-email supports encoding and decoding using Base64 encoding,
Quoted-Printable encoding and Q-encoding.  Note that guile-email
automatically invokes the necessary decoding procedures while parsing
email.  The following procedures are only provided in case you need to
use them in a context not automatically handled by guile-email.

Character encoding schemes such as UTF-8 encode characters as bytes.
Encoding schemes such as Quoted-Printable encoding, Base64 encoding and
Q-encoding re-encode these bytes as 7-bit text suitable for transmission
over a medium such as email that is not 8-bit clean.  Therefore, the
input to the following encoding procedures and the output from the
following decoding procedures is a bytevector.  Encoding characters to
bytes or decoding bytes to characters is not within the scope of these
procedures.  @xref{Representing Strings as Bytes,,, guile} for more
information on how to do this.

@section Base64 encoding

@example
(use-modules (email base64))
@end example

@deffn {Scheme Procedure} base64-encode bv
Encode bytevector @var{bv} using Base64 encoding and return the encoded
string.
@end deffn

@deffn {Scheme Procedure} base64-decode str
Decode Base64 encoded string @var{str} and return the decoded
bytevector.
@end deffn

@section Quoted-Printable encoding

The Quoted-Printable encoding and decoding procedures in this section
are typed functions in that they behave differently based on the types
of their arguments.

@example
(use-modules (email quoted-printable))
@end example

@deftypefn {Scheme Procedure} {} quoted-printable-encode (bytevector @var{bv})
@deftypefnx {Scheme Procedure} {} quoted-printable-encode (port @var{in})
@deftypefnx {Scheme Procedure} {} quoted-printable-encode (port @var{in}) (port @var{out})
Encode bytevector @var{bv} using Quoted-Printable encoding and return
the encoded string.

Read bytes from the bytevector input port @var{in} and return the
Quoted-Printable encoded string.

Read bytes from the bytevector input port @var{in} and write the
Quoted-Printable encoded string to output port @var{out}.
@end deftypefn

@deftypefn {Scheme Procedure} {} quoted-printable-decode (string @var{str})
@deftypefnx {Scheme Procedure} {} quoted-printable-decode (port @var{in})
@deftypefnx {Scheme Procedure} {} quoted-printable-decode (port @var{in}) (port @var{out})
Decode Quoted-Printable encoded string @var{str} and return the decoded
bytevector.

Read Quoted-Printable encoded characters from input port @var{in} and
return the decoded bytevector.

Read Quoted-Printable encoded characters from port @var{in} and write
the decoded bytevector to bytevector output port @var{out}.
@end deftypefn

@section Q-encoding

@example
(use-modules (email quoted-printable))
@end example

@deffn {Scheme Procedure} q-encoding-encode bv
Encode bytevector @var{bv} using Q-encoding and return the encoded
string.
@end deffn

@deffn {Scheme Procedure} q-encoding-decode str
Decode Q-encoding encoded string @var{str} and return the decoded
bytevector.
@end deffn

@node Reading Email
@chapter Reading Email

@deffn {Scheme Procedure} mbox->emails port
Read next email from @var{port} and return as a bytevector.  @var{port}
is an input port reading an mbox file.
@end deffn

@node Contributing
@chapter Contributing

Feedback, suggestions, feature requests, bug reports and patches are all
welcome.  Please write to the mailing list at
@email{guile-email@@systemreboot.net}.

@node Procedure Index
@chapter Procedure Index

@printindex fn

@node Type Index
@chapter Type Index

@printindex tp

@bye