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diff --git a/COPYING b/COPYING new file mode 100644 index 0000000..be3f7b2 --- /dev/null +++ b/COPYING @@ -0,0 +1,661 @@ + GNU AFFERO GENERAL PUBLIC LICENSE + Version 3, 19 November 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/> + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU Affero General Public License is a free, copyleft license for +software and other kinds of works, specifically designed to ensure +cooperation with the community in the case of network server software. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. 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Interpretation of Sections 15 and 16. + + If the disclaimer of warranty and limitation of liability provided +above cannot be given local legal effect according to their terms, +reviewing courts shall apply local law that most closely approximates +an absolute waiver of all civil liability in connection with the +Program, unless a warranty or assumption of liability accompanies a +copy of the Program in return for a fee. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. 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If not, see <https://www.gnu.org/licenses/>. + +Also add information on how to contact you by electronic and paper mail. + + If your software can interact with users remotely through a computer +network, you should also make sure that it provides a way for users to +get its source. For example, if your program is a web application, its +interface could display a "Source" link that leads users to an archive +of the code. There are many ways you could offer source, and different +solutions will be better for different programs; see section 13 for the +specific requirements. + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU AGPL, see +<https://www.gnu.org/licenses/>. diff --git a/email/base64.scm b/email/base64.scm new file mode 100644 index 0000000..6b11b3f --- /dev/null +++ b/email/base64.scm @@ -0,0 +1,255 @@ +;; -*- mode: scheme; coding: utf-8 -*- +;; +;; This module was renamed from (weinholt text base64 (1 0 20100612)) to +;; (guix base64) by Nikita Karetnikov <nikita@karetnikov.org> on +;; February 12, 2014. +;; +;; Some optimizations made by Ludovic Courtès <ludo@gnu.org>, 2015. +;; Turned into a Guile module (instead of R6RS). +;; +;; This module was imported into the source tree of guile-email by +;; Arun Isaac <arunisaac@systemreboot.net> on September 6, 2018. +;; +;; This program is free software: you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. +;; +;; This program is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. +;; +;; You should have received a copy of the GNU General Public License +;; along with this program. If not, see <http://www.gnu.org/licenses/>. +;; +;; This file incorporates work covered by the following copyright and +;; permission notice: +;; +;; Copyright © 2009, 2010 Göran Weinholt <goran@weinholt.se> +;; +;; Permission is hereby granted, free of charge, to any person obtaining a +;; copy of this software and associated documentation files (the "Software"), +;; to deal in the Software without restriction, including without limitation +;; the rights to use, copy, modify, merge, publish, distribute, sublicense, +;; and/or sell copies of the Software, and to permit persons to whom the +;; Software is furnished to do so, subject to the following conditions: +;; +;; The above copyright notice and this permission notice shall be included in +;; all copies or substantial portions of the Software. +;; +;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL +;; THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING +;; FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER +;; DEALINGS IN THE SOFTWARE. + +;; RFC 4648 Base-N Encodings + +(define-module (email base64) + #:export (base64-encode + base64-decode + base64-alphabet + base64url-alphabet + get-delimited-base64 + put-delimited-base64) + #:use-module (rnrs) + #:use-module ((srfi srfi-13) + #:select (string-index + string-prefix? string-suffix? + string-concatenate string-trim-both))) + +(define-syntax define-alias + (syntax-rules () + ((_ new old) + (define-syntax new (identifier-syntax old))))) + +;; Force the use of Guile's own primitives to avoid the overhead of its 'fx' +;; procedures. + +(define-alias fxbit-field bitwise-bit-field) +(define-alias fxarithmetic-shift ash) +(define-alias fxarithmetic-shift-left ash) +(define-alias fxand logand) +(define-alias fxior logior) +(define-alias fxxor logxor) + +(define base64-alphabet + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/") + +(define base64url-alphabet + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_") + +(define base64-encode + (case-lambda + ;; Simple interface. Returns a string containing the canonical + ;; base64 representation of the given bytevector. + ((bv) + (base64-encode bv 0 (bytevector-length bv) #f #f base64-alphabet #f)) + ((bv start) + (base64-encode bv start (bytevector-length bv) #f #f base64-alphabet #f)) + ((bv start end) + (base64-encode bv start end #f #f base64-alphabet #f)) + ((bv start end line-length) + (base64-encode bv start end line-length #f base64-alphabet #f)) + ((bv start end line-length no-padding) + (base64-encode bv start end line-length no-padding base64-alphabet #f)) + ((bv start end line-length no-padding alphabet) + (base64-encode bv start end line-length no-padding alphabet #f)) + ;; Base64 encodes the bytes [start,end[ in the given bytevector. + ;; Lines are limited to line-length characters (unless #f), + ;; which must be a multiple of four. To omit the padding + ;; characters (#\=) set no-padding to a true value. If port is + ;; #f, returns a string. + ((bv start end line-length no-padding alphabet port) + (assert (or (not line-length) (zero? (mod line-length 4)))) + (let-values (((p extract) (if port + (values port (lambda () (values))) + (open-string-output-port)))) + (letrec ((put (if line-length + (let ((chars 0)) + (lambda (p c) + (when (fx=? chars line-length) + (set! chars 0) + (put-char p #\linefeed)) + (set! chars (fx+ chars 1)) + (put-char p c))) + put-char))) + (let lp ((i start)) + (cond ((= i end)) + ((<= (+ i 3) end) + (let ((x (bytevector-uint-ref bv i (endianness big) 3))) + (put p (string-ref alphabet (fxbit-field x 18 24))) + (put p (string-ref alphabet (fxbit-field x 12 18))) + (put p (string-ref alphabet (fxbit-field x 6 12))) + (put p (string-ref alphabet (fxbit-field x 0 6))) + (lp (+ i 3)))) + ((<= (+ i 2) end) + (let ((x (fxarithmetic-shift-left (bytevector-u16-ref bv i (endianness big)) 8))) + (put p (string-ref alphabet (fxbit-field x 18 24))) + (put p (string-ref alphabet (fxbit-field x 12 18))) + (put p (string-ref alphabet (fxbit-field x 6 12))) + (unless no-padding + (put p #\=)))) + (else + (let ((x (fxarithmetic-shift-left (bytevector-u8-ref bv i) 16))) + (put p (string-ref alphabet (fxbit-field x 18 24))) + (put p (string-ref alphabet (fxbit-field x 12 18))) + (unless no-padding + (put p #\=) + (put p #\=))))))) + (extract))))) + + ;; Decodes a base64 string. The string must contain only pure + ;; unpadded base64 data. + +(define base64-decode + (case-lambda + ((str) + (base64-decode str base64-alphabet #f)) + ((str alphabet) + (base64-decode str alphabet #f)) + ((str alphabet port) + (unless (zero? (mod (string-length str) 4)) + (error 'base64-decode + "input string must be a multiple of four characters")) + (let-values (((p extract) (if port + (values port (lambda () (values))) + (open-bytevector-output-port)))) + (do ((i 0 (+ i 4))) + ((= i (string-length str)) + (extract)) + (let ((c1 (string-ref str i)) + (c2 (string-ref str (+ i 1))) + (c3 (string-ref str (+ i 2))) + (c4 (string-ref str (+ i 3)))) + ;; TODO: be more clever than string-index + (let ((i1 (string-index alphabet c1)) + (i2 (string-index alphabet c2)) + (i3 (string-index alphabet c3)) + (i4 (string-index alphabet c4))) + (cond ((and i1 i2 i3 i4) + (let ((x (fxior (fxarithmetic-shift-left i1 18) + (fxarithmetic-shift-left i2 12) + (fxarithmetic-shift-left i3 6) + i4))) + (put-u8 p (fxbit-field x 16 24)) + (put-u8 p (fxbit-field x 8 16)) + (put-u8 p (fxbit-field x 0 8)))) + ((and i1 i2 i3 (char=? c4 #\=) + (= i (- (string-length str) 4))) + (let ((x (fxior (fxarithmetic-shift-left i1 18) + (fxarithmetic-shift-left i2 12) + (fxarithmetic-shift-left i3 6)))) + (put-u8 p (fxbit-field x 16 24)) + (put-u8 p (fxbit-field x 8 16)))) + ((and i1 i2 (char=? c3 #\=) (char=? c4 #\=) + (= i (- (string-length str) 4))) + (let ((x (fxior (fxarithmetic-shift-left i1 18) + (fxarithmetic-shift-left i2 12)))) + (put-u8 p (fxbit-field x 16 24)))) + (else + (error 'base64-decode "invalid input" + (list c1 c2 c3 c4))))))))))) + +(define (get-line-comp f port) + (if (port-eof? port) + (eof-object) + (f (get-line port)))) + + ;; Reads the common -----BEGIN/END type----- delimited format from + ;; the given port. Returns two values: a string with the type and a + ;; bytevector containing the base64 decoded data. The second value + ;; is the eof object if there is an eof before the BEGIN delimiter. + +(define (get-delimited-base64 port) + (define (get-first-data-line port) + ;; Some MIME data has header fields in the same format as mail + ;; or http. These are ignored. + (let ((line (get-line-comp string-trim-both port))) + (cond ((eof-object? line) line) + ((string-index line #\:) + (let lp () ;read until empty line + (let ((line (get-line-comp string-trim-both port))) + (if (string=? line "") + (get-line-comp string-trim-both port) + (lp))))) + (else line)))) + (let ((line (get-line-comp string-trim-both port))) + (cond ((eof-object? line) + (values "" (eof-object))) + ((string=? line "") + (get-delimited-base64 port)) + ((and (string-prefix? "-----BEGIN " line) + (string-suffix? "-----" line)) + (let* ((type (substring line 11 (- (string-length line) 5))) + (endline (string-append "-----END " type "-----"))) + (let-values (((outp extract) (open-bytevector-output-port))) + (let lp ((line (get-first-data-line port))) + (cond ((eof-object? line) + (error 'get-delimited-base64 + "unexpected end of file")) + ((string-prefix? "-" line) + (unless (string=? line endline) + (error 'get-delimited-base64 + "bad end delimiter" type line)) + (values type (extract))) + (else + (unless (and (= (string-length line) 5) + (string-prefix? "=" line)) ;Skip Radix-64 checksum + (base64-decode line base64-alphabet outp)) + (lp (get-line-comp string-trim-both port)))))))) + (else ;skip garbage (like in openssl x509 -in foo -text output). + (get-delimited-base64 port))))) + +(define put-delimited-base64 + (case-lambda + ((port type bv line-length) + (display (string-append "-----BEGIN " type "-----\n") port) + (base64-encode bv 0 (bytevector-length bv) + line-length #f base64-alphabet port) + (display (string-append "\n-----END " type "-----\n") port)) + ((port type bv) + (put-delimited-base64 port type bv 76)))) diff --git a/email/email.scm b/email/email.scm new file mode 100644 index 0000000..ccda3ac --- /dev/null +++ b/email/email.scm @@ -0,0 +1,804 @@ +;;; guile-email --- Guile email parser +;;; Copyright © 2018 Arun Isaac <arunisaac@systemreboot.net> +;;; +;;; This file is part of guile-email. +;;; +;;; guile-email is free software; you can redistribute it and/or modify +;;; it under the terms of the GNU Affero General Public License as +;;; published by the Free Software Foundation; either version 3 of the +;;; License, or (at your option) any later version. +;;; +;;; guile-email is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +;;; Affero General Public License for more details. +;;; +;;; You should have received a copy of the GNU Affero General Public +;;; License along with guile-email. If not, see +;;; <http://www.gnu.org/licenses/>. + +(define-module (email email) + #:use-module (ice-9 iconv) + #:use-module (ice-9 match) + #:use-module (ice-9 peg) + #:use-module (ice-9 regex) + #:use-module (rnrs io simple) + #:use-module (srfi srfi-1) + #:use-module (srfi srfi-2) + #:use-module (srfi srfi-9) + #:use-module (srfi srfi-11) + #:use-module (srfi srfi-19) + #:use-module (srfi srfi-26) + #:use-module (sxml transform) + #:use-module (email base64) + #:use-module (email quoted-printable) + #:use-module ((email utils) + #:select (get-line-with-delimiter + read-objects read-while + acons* alist-delete*)) + #:export (<email> + make-email + email? + email-headers + email-body + <mime-entity> + make-mime-entity + mime-entity? + mime-entity-headers + mime-entity-body + email->headers+body + parse-email + parse-email-headers + parse-email-body + parse-email-address + interpret-address + mbox->emails)) + +(define (flatten-and-filter terms tree) + (filter list? (keyword-flatten terms tree))) + +(define-record-type <email> + (make-email headers body) + email? + (headers email-headers) + (body email-body)) + +(define-record-type <mime-entity> + (make-mime-entity headers body) + mime-entity? + (headers mime-entity-headers) + (body mime-entity-body)) + +(define string->lcase-symbol + (compose string->symbol string-downcase)) + +;;; PEG parser implementing the ABNF grammar specified in RFC5322 +;;; (Internet Message Format), RFC6854 (Update to Internet Message +;;; Format to Allow Group Syntax in the "From:" and "Sender:" Header +;;; Fields) + +;;; Obsolete syntax has not been implemented. + +;;; Core ABNF rules from RFC5234 + +(define-peg-pattern alpha body + (or (range #\A #\Z) (range #\a #\z))) + +;; Though line endings should be crlf (\r\n), we also tolerate bare +;; line feeds (\n) +(define-peg-pattern crlf none + (or "\r\n" "\n")) + +(define-peg-pattern digit body + (range #\0 #\9)) + +(define-peg-pattern dquote body + "\"") + +;; Printable ASCII characters and UTF-8 characters > \x7f (RFC6532) +(define-peg-pattern vchar body + (and (not-followed-by (or (range #\Nul #\Space) + "\x7f")) + peg-any)) + +(define-peg-pattern wsp body + (or " " "\t")) + +(define-peg-pattern lwsp body + (* (or wsp (and crlf wsp)))) + +(define-syntax-rule (define-printable-ascii-character-pattern name . exceptions) + (define-peg-pattern name body + (and (not-followed-by (or . exceptions)) + vchar))) + +;;; Quoted characters + +(define-peg-pattern quoted-pair body + (and (ignore "\\") (or vchar wsp))) + +;;; Folding white space and comments + +(define-peg-pattern fws body + (and (? (and (* wsp) crlf)) (+ wsp))) + +(define-printable-ascii-character-pattern ctext "(" ")" "\\") + +(define-peg-pattern comment none + (and "(" (* (and (? fws) ccontent)) ")")) + +(define-peg-pattern ccontent body + (or ctext quoted-pair comment)) + +(define-peg-pattern cfws body + (or (and (+ (and (? fws) comment)) (? fws)) fws)) + +;;; Atom + +(define-printable-ascii-character-pattern atext + "\"" "(" ")" "," "." ":" ";" "<" ">" "@" "[" "\\" "]") + +(define-peg-pattern atom body + (and (? cfws) (+ atext) (? cfws))) + +(define-peg-pattern dot-atom-text body + (and (+ atext) (* (and "." (+ atext))))) + +(define-peg-pattern dot-atom body + (and (? cfws) dot-atom-text (? cfws))) + +;;; Quoted strings + +(define-printable-ascii-character-pattern qtext "\\" "\"") + +(define-peg-pattern qcontent body + (or qtext quoted-pair)) + +;; TODO: Remove workaround guile peg bug for ignore +(define-peg-pattern quoted-string body + (and (? cfws) (ignore (and dquote)) + (* (and (? fws) qcontent)) + (? fws) + (ignore (and dquote)) (? cfws))) + +;;; Miscellaneous tokens + +(define-peg-pattern word body + (or atom quoted-string)) + +(define-peg-pattern phrase body + (+ word)) + +;; ABNF modified to ignore leading whitespace +;; ABNF modified to allow for blank lines in folded field +(define-peg-pattern unstructured body + (and (ignore (? fws)) + (* (and (? fws) (? vchar))) + (ignore (* wsp)))) + +;;; Date and time specification + +(define-peg-pattern day-name body + (or "Mon" "Tue" "Wed" "Thu" "Fri" "Sat" "Sun")) + +(define-peg-pattern day-of-week all + (and (ignore (? fws)) day-name)) + +;; TODO: Remove workaround guile peg bug for ignore +(define-peg-pattern day all + (and (ignore (? fws)) digit (? digit) (ignore (and fws)))) + +(define-peg-pattern month all + (or "Jan" "Feb" "Mar" "Apr" "May" "Jun" + "Jul" "Aug" "Sep" "Oct" "Nov" "Dec")) + +;; TODO: Remove workaround guile peg bug for ignore +(define-peg-pattern year all + (and (ignore (and fws)) digit digit digit digit (ignore (and fws)))) + +(define-peg-pattern date all + (and day month year)) + +(define-peg-pattern hours all + (and digit digit)) + +(define-peg-pattern minutes all + (and digit digit)) + +(define-peg-pattern seconds all + (and digit digit)) + +(define-peg-pattern time-of-day all + (and hours (ignore ":") minutes (? (and (ignore ":") seconds)))) + +;; zone-sign, zone-hours and zone-minutes do not exist in the ABNF +;; specified in RFC5322. But, we have it here since it eases parsing +;; the zone and converting it to a number of seconds as required by +;; the make-date procedure of SRFI-19. +(define-peg-pattern zone-sign all + (or "+" "-")) + +(define-peg-pattern zone-hours all + (and digit digit)) + +(define-peg-pattern zone-minutes all + (and digit digit)) + +;; TODO: Remove workaround guile peg bug for ignore +(define-peg-pattern zone all + (and (ignore (and fws)) zone-sign zone-hours zone-minutes)) + +(define-peg-pattern time all + (and time-of-day zone)) + +(define-peg-pattern date-time all + (and (? (and day-of-week (ignore ","))) date time (? cfws))) + +;;; Address specification + +(define-peg-pattern display-name all + phrase) + +(define-peg-pattern local-part body + (or dot-atom quoted-string)) + +(define-printable-ascii-character-pattern dtext "[" "]" "\\") + +(define-peg-pattern domain-literal body + (and (? cfws) "[" (* (and (? fws) dtext)) (? fws) "]" (? cfws))) + +(define-peg-pattern domain body + (or dot-atom domain-literal)) + +(define-peg-pattern addr-spec body + (and local-part "@" domain)) + +(define-peg-pattern angle-addr all + (and (ignore (? cfws)) + (ignore"<") addr-spec (ignore">") + (ignore (? cfws)))) + +(define-peg-pattern name-addr body + (and (? display-name) angle-addr)) + +(define-peg-pattern mailbox all + (or name-addr addr-spec)) + +(define-peg-pattern mailbox-list all + (and mailbox (* (and (ignore ",") mailbox)))) + +(define-peg-pattern group all + (and display-name (ignore ":") + (? group-list) (ignore ";") (? cfws))) + +(define-peg-pattern group-list all + (or mailbox-list cfws)) + +(define-peg-pattern address body + (or mailbox group)) + +(define-peg-pattern address-list all + (and address (* (and (ignore ",") address)))) + +;;; Fields + +(define-syntax-rule (define-field-pattern name header pattern) + (define-peg-pattern name all + (and (ignore (string-ci header)) (ignore ":") pattern crlf))) + +;;; Origination date field + +(define-field-pattern orig-date "Date" date-time) + +;;; Originator fields + +(define-field-pattern from "From" (or mailbox-list address-list)) +(define-field-pattern sender "Sender" (or mailbox address)) +(define-field-pattern reply-to "Reply-To" address-list) + +;; Destination address fields + +(define-field-pattern to "To" address-list) +(define-field-pattern cc "Cc" address-list) +(define-field-pattern bcc "Bcc" (? (or address-list cfws))) + +;;; Identification fields + +(define-peg-pattern no-fold-literal body + (and "[" (* dtext) "]")) + +(define-peg-pattern id-left body + dot-atom-text) + +(define-peg-pattern id-right body + (or dot-atom-text no-fold-literal)) + +(define-peg-pattern msg-id all + (and (ignore (? cfws)) (ignore "<") + id-left "@" id-right + (ignore ">") (ignore (? cfws)))) + +(define-field-pattern message-id "Message-ID" msg-id) +(define-field-pattern in-reply-to "In-Reply-To" (+ msg-id)) +(define-field-pattern references "References" (+ msg-id)) + +;;; Informational fields + +(define-field-pattern subject "Subject" unstructured) +(define-field-pattern comments "Comments" unstructured) +(define-field-pattern keywords "Keywords" (and phrase (* (and "," phrase)))) + +;;; Resent fields + +(define-field-pattern resent-date "Resent-Date" date-time) +(define-field-pattern resent-from "Resent-From" (or mailbox-list address-list)) +(define-field-pattern resent-sender "Resent-Sender" (or mailbox address)) +(define-field-pattern resent-to "Resent-To" address-list) +(define-field-pattern resent-cc "Resent-Cc" address-list) +(define-field-pattern resent-bcc "Resent-Bcc" (? (or address-list cfws))) +(define-field-pattern resent-msg-id "Resent-Message-ID" msg-id) + +;;; Trace fields + +;; word is given last priority in the ordered choice +(define-peg-pattern received-token body + (or angle-addr addr-spec domain word)) + +;; TODO: Do not discard the internal structure of received +(define-field-pattern received "Received" + (and (* received-token) (ignore ";") date-time)) + +(define-peg-pattern path body + (or angle-addr (and (? cfws) (ignore "<") (? cfws) (ignore ">") (? cfws)))) + +(define-field-pattern return "Return-Path" path) + +(define-peg-pattern trace all + (and (? return) (+ received))) + +;;; Optional fields + +(define-printable-ascii-character-pattern ftext ":") + +(define-peg-pattern field-name all + (+ ftext)) + +(define-peg-pattern optional-field all + (and field-name (ignore ":") unstructured crlf)) + +;;; MIME version + +;; I have prepended optional cfws to account for leading whitespace. +(define-field-pattern mime-version "MIME-Version" + (and (ignore (? cfws)) (+ digit) "." (+ digit))) + +;;; Content type + +;; TODO: What is <"> in RFC2045? +(define-peg-pattern tspecials body + (or "(" ")" "<" ">" "@" + "," ";" ":" "\\" + "/" "[" "]" "?" "=")) + +;; TODO: What is a CTL in RFC2045? +(define-peg-pattern token body + (+ (and (not-followed-by (or " " crlf tspecials)) + peg-any))) + +;; TODO: Implement iana-token, ietf-token and x-token +(define-peg-pattern iana-token body + token) + +(define-peg-pattern ietf-token body + token) + +(define-peg-pattern x-token body + token) + +(define-peg-pattern extension-token body + (or ietf-token x-token)) + +(define-peg-pattern discrete-type body + (or "text" "image" "audio" "video" + "application" extension-token)) + +(define-peg-pattern composite-type body + (or "message" "multipart" extension-token)) + +(define-peg-pattern type all + (or discrete-type composite-type)) + +(define-peg-pattern subtype all + (or extension-token iana-token)) + +(define-peg-pattern attribute all + token) + +;; quoted-string is given higher precedence +(define-peg-pattern value all + (or quoted-string token)) + +(define-peg-pattern parameter all + (and attribute (ignore "=") value)) + +;; I have prepended optional cfws to account for leading whitespace. +(define-field-pattern content "Content-Type" + (and (ignore (? cfws)) type (ignore "/") subtype + (* (and (ignore ";") (ignore (? cfws)) parameter)))) + +;;; Content Disposition as defined in RFC2183 + +(define-peg-pattern disposition-type body + (or "inline" "attachment" extension-token)) + +(define-peg-pattern quoted-date-time all + quoted-string) + +(define-syntax-rule (define-parameter-pattern name header pattern) + (define-peg-pattern name all + (and (ignore header) (ignore "=") pattern))) + +(define-parameter-pattern filename-parm "filename" value) +(define-parameter-pattern creation-date-parm "creation-date" quoted-date-time) +(define-parameter-pattern modification-date-parm "modification-date" quoted-date-time) +(define-parameter-pattern read-date-parm "read-date" quoted-date-time) +(define-parameter-pattern size-parm "size" (+ digit)) + +(define-peg-pattern disposition-parm body + (or filename-parm creation-date-parm modification-date-parm + read-date-parm size-parm parameter)) + +;; I have prepended optional cfws to account for leading whitespace. +(define-field-pattern disposition "Content-Disposition" + (and (ignore (? cfws)) disposition-type + (* (and (ignore ";") (ignore (? cfws)) disposition-parm)))) + +;;; Content transfer encoding + +(define-peg-pattern mechanism body + (or "7bit" "8bit" "binary" + "quoted-printable" "base64" + ietf-token x-token)) + +(define-field-pattern encoding "Content-Transfer-Encoding" + (and (ignore (? cfws)) mechanism)) + +;;; Fields + +;; The ABNF specified for fields in RFC5322 does not make sense. With +;; it, all headers are eaten up by optional-field. So, as a temporary +;; workaround, I am going with the following much simpler (but +;; possibly incorrect) ABNF. + +;; TODO: Try to understand and implement the actual ABNF specified by +;; RFC5322. +(define-peg-pattern fields all + (* (or trace + resent-date + resent-from + resent-sender + resent-to + resent-cc + resent-bcc + resent-msg-id + orig-date + from + sender + reply-to + to + cc + bcc + message-id + in-reply-to + references + subject + comments + keywords + mime-version + content + disposition + encoding + optional-field))) + +(define-peg-pattern mime-extension-field-name all + (and "Content-" (+ ftext))) + +(define-peg-pattern mime-extension-field all + (and mime-extension-field-name (ignore ":") unstructured crlf)) + +(define-peg-pattern mime-entity-fields all + (* (or content + disposition + encoding + mime-extension-field + optional-field))) + +(define (decode-mime-encoded-word word) + (regexp-substitute/global + #f "=\\?([^?]*)\\?([^?]*)\\?([^?]*)\\?=" word + 'pre (lambda (match-record) + (let ((charset (match:substring match-record 1)) + (encoding (string->lcase-symbol (match:substring match-record 2))) + (encoded-text (match:substring match-record 3))) + (bytevector->string + ((case encoding + ((b) base64-decode) + ((q) q-encoding-decode) + (else (error "Encoding of MIME word unknown" word))) + encoded-text) + charset))) + 'post)) + +(define (body->mime-entities body boundary) + "Split BODY into a list of mime entities separated by BOUNDARY (as +explained in RFC2045), and return that list." + (define (read-till-boundary port) + (read-while port get-line-with-delimiter + (negate (cut string-prefix? (string-append "--" boundary) <>)))) + + (define (read-mime-entity port) + (if (string-prefix? (string-append "--" boundary "--") + (get-line-with-delimiter port)) + (eof-object) + (read-till-boundary port))) + + (call-with-input-string body + (lambda (port) + (read-till-boundary port) + (read-objects read-mime-entity port)))) + +(define (email->headers+body email) + "Split EMAIL into headers and body. Return as multiple values." + (call-with-input-string email + (lambda (port) + (let ((headers (read-while port get-line-with-delimiter + (lambda (line) + (not (or (string= line "\n") + (string= line "\r\n"))))))) + (get-line-with-delimiter port) + (values headers + (read-while port get-line-with-delimiter identity)))))) + +(define (post-process-content-transfer-encoding _ value) + (list 'content-transfer-encoding (string->lcase-symbol value))) + +(define post-process-content-type + (match-lambda* + (`(content (type ,type) + (subtype ,subtype) + . ,parameters) + (let ((type (string->lcase-symbol type)) + (subtype (string->lcase-symbol subtype))) + `(content-type + ,(acons* 'type type + 'subtype subtype + (let ((parameters + (map (match-lambda + (`(parameter (attribute ,attribute) + (value ,value)) + (cons (string->lcase-symbol attribute) value))) + (flatten-and-filter '(parameter) parameters)))) + (if (and (eq? type 'text) + (not (assoc-ref parameters 'charset))) + ;; UTF-8 is specified as the default charset in RFC6657 + (acons 'charset "utf-8" parameters) + parameters)))))))) + +(define post-process-content-disposition + (match-lambda* + (`(disposition ,type . ,parameters) + `(content-disposition + ,(acons 'type (string->lcase-symbol type) + (map (match-lambda + (('filename-parm ('value filename)) + (cons 'filename (basename filename))) + (((? (lambda (date-parm) + (member date-parm '(creation-date-parm modification-date-parm read-date-parm))) + date-parm) value) + ;; TODO: Convert to SRFI-19 datetime + (cons date-parm value)) + (('size-parm value) + (cons 'size (string->number value))) + (`(parameter (attribute ,attribute) + (value ,value)) + (cons (string->lcase-symbol attribute) value))) + (flatten-and-filter + '(filename-parm creation-date-parm modification-date-parm + read-date-parm size-parm parameter) + parameters))))))) + +(define post-process-optional-field + (match-lambda* + (`(optional-field + (field-name ,field-name) + ,field-value) + (list (string->lcase-symbol field-name) + field-value)) + (`(optional-field (field-name ,field-name)) + (list field-name "")))) + +(define* (macro-process-address-list _ . addresses) + (flatten-and-filter '(address mailbox) addresses)) + +(define (parse-email-address address) + "Parse ADDRESS as an email address and return an association list +with keys being the symbols name and address, and values being the +display-name and addr-spec respectively. display-name and addr-spec +are as defined in RFC5322. + +For example, +(parse-email-address \"Foo <foo@example.org>\") +=> ((name \"Foo\") (address \"foo@example.org\")) +(parse-email-address \"foo@example.org\") +=> ((address \"foo@example.org\"))" + (cond + ((string-match "([^<]*)<([^>]*)>" address) + => (lambda (match-record) + (let ((name (string-trim-both (match:substring match-record 1))) + (address (match:substring match-record 2))) + (if (string-null? name) + `((address . ,address)) + `((name . ,name) + (address . ,address)))))) + (else `((address . ,address))))) + +(define interpret-address + (match-lambda + ((('name . name) + ('address . address)) + (format #f "~a <~a>" name address)) + ((('address . address)) address))) + +(define (parse-email-body headers body) + "Parse BODY as email body where HEADERS is an association list of +header keys and values as returned by parse-email-headers. Return a +list of <mime-entity> records if the body is a multipart +message. Else, return a single <mime-entity> record." + (let ((content-type (assoc-ref headers 'content-type))) + (case (assoc-ref content-type 'type) + ((multipart) + (map parse-mime-entity + (body->mime-entities body (assoc-ref content-type 'boundary)))) + ((text) + (string-trim-both + (decode-body body (assoc-ref headers 'content-transfer-encoding) + (assoc-ref content-type 'charset)))) + (else (decode-body body (assoc-ref headers 'content-transfer-encoding)))))) + +(define (add-default-headers headers) + ;; Default Content-Type and Content-Transfer-Encoding headers as + ;; specified in RFC2045 + (let ((default-headers + (acons* 'content-type '((type . text) + (subtype . plain) + ;; UTF-8 is specified as the default + ;; charset in RFC6657 + (charset . "utf-8")) + 'content-transfer-encoding '#{7bit}#))) + (append (alist-delete* (append (if (assoc-ref headers 'content-type) + (list 'content-type) (list)) + (if (assoc-ref headers 'content-transfer-encoding) + (list 'content-transfer-encoding) (list))) + default-headers) + headers))) + +(define (parse-mime-entity text) + (let-values (((headers body) (email->headers+body text))) + (let ((headers + (pre-post-order + (peg:tree + (match-pattern mime-entity-fields text)) + `((content . ,post-process-content-type) + (encoding . ,post-process-content-transfer-encoding) + (disposition . ,post-process-content-disposition) + (optional-field . ,post-process-optional-field) + (mime-entity-fields . ,(lambda (_ . mime-entity-fields) + (add-default-headers + (map (match-lambda + ((mime-entity-field value) + (cons mime-entity-field value)) + ((mime-entity-field . values) + (cons mime-entity-field values))) + mime-entity-fields)))) + (*text* . ,(lambda (_ text) text)) + (*default* . ,(lambda tree tree)))))) + (make-mime-entity headers (parse-email-body headers body))))) + +(define (parse-email email) + "Parse string EMAIL and return result as a <email> record." + (let-values (((headers body) (email->headers+body email))) + (let ((headers-alist (parse-email-headers headers))) + (make-email headers-alist (parse-email-body headers-alist body))))) + +(define (parse-email-headers headers) + "Parse string HEADERS as email headers and return an association +list of header keys and values." + (define (extract-value _ value) value) + + (pre-post-order + (peg:tree + (match-pattern fields headers)) + `((date-time . ,(lambda node + (match-let + ((`((day ,day) (month ,month) (year ,year) + (hours ,hours) (minutes ,minutes) (seconds ,seconds) + (zone-sign ,zone-sign) (zone-hours ,zone-hours) (zone-minutes ,zone-minutes)) + (flatten-and-filter + '(day month year hours minutes seconds + zone-sign zone-hours zone-minutes) + node))) + (make-date 0 + (string->number seconds) + (string->number minutes) + (string->number hours) + (string->number day) + (1+ (list-index + (cut equal? <> month) + (list "Jan" "Feb" "Mar" "Apr" "May" "Jun" + "Jul" "Aug" "Sep" "Oct" "Nov" "Dec"))) + (string->number year) + (* (case (string->symbol zone-sign) + ((+) 1) + ((-) -1)) + (+ (* 60 60 (string->number zone-hours)) + (* 60 (string->number zone-minutes)))))))) + (orig-date . ,(lambda (_ date) (list 'date date))) + (angle-addr . ,extract-value) + (mailbox . ,(match-lambda* + (`(mailbox (display-name ,name) ,address) + `((name . ,(decode-mime-encoded-word + (string-trim-both name))) + (address . ,address))) + (`(mailbox ,address) + `((address . ,(string-trim-both address)))) + (_ (error "Failed to parse mailbox")))) + (address-list *macro* . ,macro-process-address-list) + (mailbox-list *macro* . ,macro-process-address-list) + (optional-field . ,post-process-optional-field) + (msg-id . ,(match-lambda* (`(msg-id ,msg-id) msg-id))) + (content . ,post-process-content-type) + (encoding . ,post-process-content-transfer-encoding) + (disposition . ,post-process-content-disposition) + (fields . ,(lambda (_ . fields) + (add-default-headers + (filter-map (match-lambda + (('trace . _) #f) + ((field value) + (cons field value)) + ((field . values) + (cons field values)) + (_ #f)) + fields)))) + (*text* . ,extract-value) + (*default* . ,(lambda tree tree))))) + +(define* (decode-body body encoding #:optional charset) + (let ((octets + (case encoding + ((base64) + (base64-decode + (string-filter + (char-set-union + (ucs-range->char-set (char->integer #\a) (1+ (char->integer #\z))) + (ucs-range->char-set (char->integer #\A) (1+ (char->integer #\Z))) + (ucs-range->char-set (char->integer #\0) (1+ (char->integer #\9))) + (char-set #\+ #\/ #\=)) + body))) + ((quoted-printable) (quoted-printable-decode body)) + ((#{7bit}# #{8bit}# binary) body) + (else (error "Body decoding failed. Unknown encoding" encoding))))) + (if charset + (case encoding + ((base64 quoted-printable) (bytevector->string octets charset)) + ((#{7bit}# #{8bit}# binary) octets)) + octets))) + +(define (read-next-email-in-mbox port) + ;; Read and discard From_ line + (get-line-with-delimiter port) + ;; Read the actual email + (read-while port get-line-with-delimiter + (negate (cut string-prefix? "From " <>)))) + +(define (mbox->emails port) + (read-objects read-next-email-in-mbox port)) diff --git a/email/quoted-printable.scm b/email/quoted-printable.scm new file mode 100644 index 0000000..f6e3605 --- /dev/null +++ b/email/quoted-printable.scm @@ -0,0 +1,57 @@ +;;; guile-email --- Guile email parser +;;; Copyright © 2018 Arun Isaac <arunisaac@systemreboot.net> +;;; +;;; This file is part of guile-email. +;;; +;;; guile-email is free software; you can redistribute it and/or modify +;;; it under the terms of the GNU Affero General Public License as +;;; published by the Free Software Foundation; either version 3 of the +;;; License, or (at your option) any later version. +;;; +;;; guile-email is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +;;; Affero General Public License for more details. +;;; +;;; You should have received a copy of the GNU Affero General Public +;;; License along with guile-email. If not, see +;;; <http://www.gnu.org/licenses/>. + +(define-module (email quoted-printable) + #:use-module (rnrs) + #:use-module (ice-9 match) + #:export (quoted-printable-decode + q-encoding-decode)) + +;; TODO: Error out on invalid quoted-printable input +(define quoted-printable-decode + (match-lambda* + (((? string? str)) + (call-with-input-string str quoted-printable-decode)) + (((? port? in)) + (let-values (((out get-bytevector) + (open-bytevector-output-port))) + (quoted-printable-decode in out) + (get-bytevector))) + (((? port? in) (? port? out)) + (let ((c (read-char in))) + (cond + ((eof-object? c) + out) + ((char=? c #\=) + ;; TODO: Support "\r\n" line ending + (let ((c1 (read-char in))) + (unless (char=? c1 #\Newline) + (let ((c2 (read-char in))) + (put-u8 out (string->number (string c1 c2) 16))))) + (quoted-printable-decode in out)) + (#t + (put-u8 out (char->integer c)) + (quoted-printable-decode in out))))))) + +(define (q-encoding-decode str) + (quoted-printable-decode + (string-map + (lambda (c) + (if (char=? c #\_) #\Space c)) + str))) diff --git a/email/utils.scm b/email/utils.scm new file mode 100644 index 0000000..7d51ebb --- /dev/null +++ b/email/utils.scm @@ -0,0 +1,95 @@ +;;; guile-email --- Guile email parser +;;; Copyright © 2018 Arun Isaac <arunisaac@systemreboot.net> +;;; +;;; This file is part of guile-email. +;;; +;;; guile-email is free software; you can redistribute it and/or modify +;;; it under the terms of the GNU Affero General Public License as +;;; published by the Free Software Foundation; either version 3 of the +;;; License, or (at your option) any later version. +;;; +;;; guile-email is distributed in the hope that it will be useful, but +;;; WITHOUT ANY WARRANTY; without even the implied warranty of +;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +;;; Affero General Public License for more details. +;;; +;;; You should have received a copy of the GNU Affero General Public +;;; License along with guile-email. If not, see +;;; <http://www.gnu.org/licenses/>. + +(define-module (email utils) + #:use-module (ice-9 match) + #:use-module (ice-9 peg codegen) + #:use-module (ice-9 textual-ports) + #:use-module (rnrs io simple) + #:export (get-line-with-delimiter + read-objects + read-while + acons* + alist-delete*)) + +(define (read-objects read-proc port) + "Read all objects using READ-PROC from PORT and return them as a +list." + (let ((x (read-proc port))) + (if (eof-object? x) + (list) + (cons x (read-objects read-proc port))))) + +(define* (read-while port read-proc pred) + "Read from PORT using READ-PROC while PRED returns #t. READ-PROC is +invoked with the input port as argument. PRED is invoked with each +string returned by READ-PROC as argument." + (define (read-while-loop output) + (let ((x (read-proc port))) + (cond + ((eof-object? x) x) + ((pred x) + (put-string output x) + (read-while-loop output)) + (#t (unget-string port x))))) + + (let ((str (call-with-output-string read-while-loop))) + (if (string-null? str) (eof-object) str))) + +(define (get-line-with-delimiter port) + "Read a line from PORT and return it as a string including the +delimiting linefeed character." + (let ((line (get-line port))) + (if (eof-object? line) + line + (string-append line "\n")))) + +(define acons* + (match-lambda* + ((key value) + (acons key value (list))) + ((key value . rest) + (acons key value (apply acons* rest))) + ((alist) alist))) + +(define (alist-delete* keys alist) + "Return a list containing all elements of ALIST whose keys are not a +member of KEYS." + (filter (match-lambda + ((key . _) + (not (member key keys)))) + alist)) + +(define (cg-string-ci pat accum) + (syntax-case pat () + ((pat-str-syntax) (string? (syntax->datum #'pat-str-syntax)) + (let ((pat-str (syntax->datum #'pat-str-syntax))) + (let ((plen (string-length pat-str))) + #`(lambda (str len pos) + (let ((end (+ pos #,plen))) + (and (<= end len) + (string-ci= str #,pat-str pos end) + #,(case accum + ((all) #`(list end (list 'cg-string #,pat-str))) + ((name) #`(list end 'cg-string)) + ((body) #`(list end #,pat-str)) + ((none) #`(list end '())) + (else (error "bad accum" accum))))))))))) + +(add-peg-compiler! 'string-ci cg-string-ci) |