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Diffstat (limited to 'third_party/lisp/mime4cl/mime.lisp')
| -rw-r--r-- | third_party/lisp/mime4cl/mime.lisp | 1049 |
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diff --git a/third_party/lisp/mime4cl/mime.lisp b/third_party/lisp/mime4cl/mime.lisp new file mode 100644 index 000000000000..3cdac4b26b6f --- /dev/null +++ b/third_party/lisp/mime4cl/mime.lisp @@ -0,0 +1,1049 @@ +;;; mime4cl.lisp --- MIME primitives for Common Lisp + +;;; Copyright (C) 2005-2008, 2010 by Walter C. Pelissero +;;; Copyright (C) 2021-2023 by the TVL Authors + +;;; Author: Walter C. Pelissero <walter@pelissero.de> +;;; Project: mime4cl + +;;; This library is free software; you can redistribute it and/or +;;; modify it under the terms of the GNU Lesser General Public License +;;; as published by the Free Software Foundation; either version 2.1 +;;; of the License, or (at your option) any later version. +;;; This library 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 +;;; Lesser General Public License for more details. +;;; You should have received a copy of the GNU Lesser General Public +;;; License along with this library; if not, write to the Free +;;; Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +;;; 02111-1307 USA + +(in-package :mime4cl) + +(defclass mime-part () + ((subtype + :type (or string null) + :initarg :subtype + :accessor mime-subtype + ;; some mime types don't require a subtype + :initform nil) + (type-parameters + :type list + :initarg :type-parameters + :initform '() + :accessor mime-type-parameters) + (version + :type (or string null) + :initarg :mime-version + :initform "1.0" + :accessor mime-version) + (id + :initform nil + :initarg :id + :reader mime-id) + (description + :initform nil + :initarg :description + :accessor mime-description) + (encoding + :initform :7bit + :initarg :encoding + :reader mime-encoding + :documentation + "It's supposed to be either: + :7BIT, :8BIT, :BINARY, :QUOTED-PRINTABLE, :BASE64, a + X-token or an ietf-token (whatever that means).") + (disposition + :type (or string null) + :initarg :disposition + :initform nil + :accessor mime-disposition) + (disposition-parameters + :type list + :initarg :disposition-parameters + :initform '() + :accessor mime-disposition-parameters)) + (:documentation + "Abstract base class for all types of MIME parts.")) + +(defclass mime-bodily-part (mime-part) + ((body + :initarg :body + :accessor mime-body)) + (:documentation + "Abstract base class for MIME parts with a body.")) + +(defclass mime-unknown-part (mime-bodily-part) + ((type + :initarg :type + :reader mime-type + :documentation + "The original type string from the MIME header.")) + (:documentation + "MIME part unknown to this library. Accepted but not handled.")) + +(defclass mime-text (mime-bodily-part) ()) + +;; This turns out to be handy when making methods specialised +;; non-textual attachments. +(defclass mime-binary (mime-bodily-part) ()) + +(defclass mime-image (mime-binary) ()) + +(defclass mime-audio (mime-binary) ()) + +(defclass mime-video (mime-binary) ()) + +(defclass mime-application (mime-binary) ()) + +(defclass mime-multipart (mime-part) + ((parts :initarg :parts + :accessor mime-parts))) + +(defclass mime-message (mime-part) + ((headers :initarg :headers + :initform '() + :type list + :accessor mime-message-headers) + (real-message :initarg :body + :accessor mime-body))) + +(defun mime-part-p (object) + (typep object 'mime-part)) + +(defmethod initialize-instance ((part mime-multipart) &key &allow-other-keys) + (call-next-method) + ;; The initialization argument of the PARTS slot of a mime-multipart + ;; is expected to be a list of mime-parts. Thus, we implicitly + ;; create the mime parts using the arguments found in this list. + (with-slots (parts) part + (when (slot-boundp part 'parts) + (setf parts + (mapcar #'(lambda (subpart) + (if (mime-part-p subpart) + subpart + (apply #'make-instance subpart))) + parts))))) + +(defmethod initialize-instance ((part mime-message) &key &allow-other-keys) + (call-next-method) + ;; Allow a list of mime parts to be specified as body of a + ;; mime-message. In that case we implicitly create a mime-multipart + ;; and assign to the body slot. + (with-slots (real-message) part + (when (and (slot-boundp part 'real-message) + (consp real-message)) + (setf real-message + (make-instance 'mime-multipart :parts real-message))))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defun alist= (alist1 alist2 &key (test #'eql)) + (null + (set-difference alist1 alist2 + :test #'(lambda (x y) + (and (funcall test (car x) (car y)) + (funcall test (cdr x) (cdr y))))))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric mime= (mime1 mime2) + (:documentation + "Return true if MIME1 and MIME2 have equivalent structure and identical bodies (as for EQ).")) + +(defmethod mime= ((part1 mime-part) (part2 mime-part)) + (macrolet ((null-or (compare x y) + `(or (and (not ,x) + (not ,y)) + (and ,x ,y + (,compare ,x ,y)))) + (cmp-slot (compare reader) + `(null-or ,compare (,reader part1) (,reader part2)))) + (and (eq (class-of part1) (class-of part2)) + (cmp-slot string-equal mime-subtype) + (alist= (mime-type-parameters part1) + (mime-type-parameters part2) + :test #'string-equal) + (cmp-slot string= mime-id) + (cmp-slot string= mime-description) + (cmp-slot eq mime-encoding) + (cmp-slot equal mime-disposition) + (alist= (mime-disposition-parameters part1) + (mime-disposition-parameters part2) + :test #'string-equal)))) + +(defmethod mime= ((part1 mime-multipart) (part2 mime-multipart)) + (and (call-next-method) + (every #'mime= (mime-parts part1) (mime-parts part2)))) + +(defmethod mime= ((part1 mime-message) (part2 mime-message)) + (and (call-next-method) + (alist= (mime-message-headers part1) (mime-message-headers part2) + :test #'string=) + (mime= (mime-body part1) (mime-body part2)))) + +(defun mime-body-stream (mime-part) + (make-input-adapter (mime-body mime-part))) + +(defun mime-body-length (mime-part) + (let ((body (mime-body mime-part))) + ;; here the stream type is missing on purpose, because we may not + ;; be able to size the length of a stream + (etypecase body + (string + (length body)) + (vector + (length body)) + (pathname + (file-size body)) + (file-portion + (with-open-stream (in (open-decoded-file-portion body)) + (loop + for byte = (read-byte in nil) + while byte + count byte)))))) + +(defmacro with-input-from-mime-body-stream ((stream part) &body forms) + `(with-open-stream (,stream (mime-body-stream ,part)) + ,@forms)) + +(defmethod mime= ((part1 mime-bodily-part) (part2 mime-bodily-part)) + (and (call-next-method) + (with-input-from-mime-body-stream (in1 part1) + (with-input-from-mime-body-stream (in2 part2) + (loop + for b1 = (read-byte in1 nil) + for b2 = (read-byte in2 nil) + always (eq b1 b2) + while (and b1 b2)))))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric get-mime-type-parameter (part name) + (:documentation + "Return the MIME type parameter associated to NAME of PART.")) + +(defgeneric (setf get-mime-type-parameter) (value part name) + (:documentation + "Set the MIME type parameter associated to NAME of PART.")) + +(defmethod get-mime-type-parameter ((part mime-part) name) + (cdr (assoc name (mime-type-parameters part) :test #'string-equal))) + +(defmethod (setf get-mime-type-parameter) (value part name) + (aif (assoc name (mime-type-parameters part) :test #'string-equal) + (setf (cdr it) value) + (push (cons name value) + (mime-type-parameters part))) + value) + +(defgeneric get-mime-disposition-parameter (part name) + (:documentation + "Return the MIME disposition parameter associated to NAME of PART.")) + +(defmethod get-mime-disposition-parameter ((part mime-part) name) + (cdr (assoc name (mime-disposition-parameters part) :test #'string-equal))) + +(defmethod (setf get-mime-disposition-parameter) (value part name) + (aif (assoc name (mime-disposition-parameters part) :test #'string-equal) + (setf (cdr it) value) + (push (cons name value) + (mime-disposition-parameters part)))) + +(defmethod mime-part-file-name ((part mime-part)) + "Return the filename associated to mime PART or NIL if the mime +part doesn't have a file name." + (or (get-mime-disposition-parameter part :filename) + (get-mime-type-parameter part :name))) + +(defmethod (setf mime-part-file-name) (value (part mime-part)) + "Set the filename associated to mime PART." + (setf (get-mime-disposition-parameter part :filename) value + (get-mime-type-parameter part :name) value)) + +(defun mime-text-charset (part) + (get-mime-type-parameter part :charset)) + +(defun split-header-parts (string) + "Split parts of a MIME headers. These are divided by +semi-colons not within strings or comments." + (labels ((skip-comment (pos) + (loop + while (< pos (length string)) + do (case (elt string pos) + (#\( (setf pos (skip-comment (1+ pos)))) + (#\\ (incf pos 2)) + (#\) (return (1+ pos))) + (otherwise (incf pos))) + finally (return pos))) + (skip-string (pos) + (loop + while (< pos (length string)) + do (case (elt string pos) + (#\\ (incf pos 2)) + (#\" (return (1+ pos))) + (otherwise (incf pos))) + finally (return pos)))) + (loop + with start = 0 and i = 0 and parts = '() + while (< i (length string)) + do (case (elt string i) + (#\; (push (subseq string start i) parts) + (setf start (incf i))) + (#\" (setf i (skip-string i))) + (#\( (setf i (skip-comment (1+ i)))) + (otherwise (incf i))) + finally (return (mapcar #'string-trim-whitespace (nreverse (cons (subseq string start) parts))))))) + +(defun parse-parameter (string) + "Given a string like \"foo=bar\" return a pair (\"foo\" . +\"bar\"). Return NIL if string is not parsable." + ;; TODO(sterni): when-let + (let ((equal-position (position #\= string))) + (when equal-position + (let ((key (subseq string 0 equal-position))) + (if (= equal-position (1- (length string))) + (cons key "") + (let ((value (string-trim-whitespace (subseq string (1+ equal-position))))) + (cons key + (if (and (> (length value) 1) + (char= #\" (elt value 0))) + ;; the syntax of a RFC822 string is more or + ;; less the same as the Lisp one: use the Lisp + ;; reader + (or (ignore-errors (read-from-string value)) + (subseq value 1)) + (let ((end (or (position-if #'whitespace-p value) + (length value)))) + (subseq value 0 end)))))))))) + +(defun parse-content-type (string) + "Parse string as a Content-Type MIME header and return a list +of three elements. The first is the type, the second is the +subtype and the third is an alist of parameters and their values. +Example: (\"text\" \"plain\" ((\"charset\" . \"us-ascii\")...))." + (let* ((parts (split-header-parts string)) + (content-type-string (car parts)) + (slash (position #\/ content-type-string))) + ;; You'd be amazed to know how many MUA can't produce an RFC + ;; compliant message. + (when slash + (let ((type (subseq content-type-string 0 slash)) + (subtype (subseq content-type-string (1+ slash)))) + (list type subtype (remove nil (mapcar #'parse-parameter (cdr parts)))))))) + +(defun parse-content-disposition (string) + "Parse string as a Content-Disposition MIME header and return a +list. The first element is the layout, the other elements are +the optional parameters alist. +Example: (\"inline\" (\"filename\" . \"doggy.jpg\"))." + (let ((parts (split-header-parts string))) + (cons (car parts) (mapcan #'(lambda (parameter-string) + (awhen (parse-parameter parameter-string) + (list it))) + (cdr parts))))) + +(defun parse-RFC822-header (string) + "Parse STRING which should be a valid RFC822 message header and +return two values: a string of the header name and a string of +the header value." + (let ((colon (position #\: string))) + (when colon + (values (string-trim-whitespace (subseq string 0 colon)) + (string-trim-whitespace (subseq string (1+ colon))))))) + + +(defvar *default-type* '("text" "plain" (("charset" . "us-ascii"))) + "Internal special variable that contains the default MIME type at +any given time of the parsing phase. There are MIME container parts +that may change this.") + +(defvar *mime-types* + '((:text mime-text) + (:image mime-image) + (:audio mime-audio) + (:video mime-video) + (:application mime-application) + (:multipart mime-multipart) + (:message mime-message))) + +(defgeneric mime-part-size (part) + (:documentation + "Return the size in bytes of the body of a MIME part.")) + +(defgeneric print-mime-part (part stream) + (:documentation + "Output to STREAM one of the possible human-readable representation +of mime PART. Binary parts are omitted. This function can be used to +quote messages, for instance.")) + +(defun do-multipart-parts (body-stream part-boundary contents-function end-part-function) + "Read through BODY-STREAM. Call CONTENTS-FUNCTION at +each (non-boundary) line or END-PART-FUNCTION at each PART-BOUNDARY." + (let* ((boundary (s+ "--" part-boundary)) + (boundary-length (length boundary))) + (labels ((output-line (line) + (funcall contents-function line)) + (end-part () + (funcall end-part-function)) + (last-part () + (end-part) + (return-from do-multipart-parts)) + (process-line (line) + (cond ((not (string-starts-with boundary line)) + ;; normal line + (output-line line)) + ((and (= (length (string-trim-whitespace line)) + (+ 2 boundary-length)) + (string= "--" line :start2 boundary-length)) + ;; end of the last part + (last-part)) + ;; according to RFC2046 "the boundary may be followed + ;; by zero or more characters of linear whitespace" + ((= (length (string-trim-whitespace line)) boundary-length) + ;; beginning of the next part + (end-part)) + (t + ;; the line boundary is followed by some + ;; garbage; we treat it as a normal line + (output-line line))))) + (loop + for line = (read-line body-stream nil) + ;; we should never reach the end of a proper multipart MIME + ;; stream, but we don't want to be fooled by corrupted ones, + ;; so we check for EOF + unless line + do (last-part) + do (process-line line))))) + +(defun index-multipart-parts (body-stream part-boundary) + "Read from BODY-STREAM and return the file offset of the MIME parts +separated by PART-BOUNDARY." + (let ((parts '()) + (start 0) + (len 0) + (beginning-of-part-p t)) + (flet ((sum-chars (line) + (incf len (length line)) + ;; account for the #\newline + (if beginning-of-part-p + (setf beginning-of-part-p nil) + (incf len))) + (end-part () + (setf beginning-of-part-p t) + (push (cons start (+ start len)) parts) + (setf start (file-position body-stream) + len 0))) + (do-multipart-parts body-stream part-boundary #'sum-chars #'end-part) + ;; the first part is all the stuff up to the first boundary; + ;; just junk + (cdr (nreverse parts))))) + +(defgeneric encode-mime-part (part stream)) +(defgeneric encode-mime-body (part stream)) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defun write-mime-header (part stream) + (when (mime-version part) + (format stream "~&MIME-Version: ~A~%" (mime-version part))) + (format stream "~&Content-Type: ~A~:{; ~A=~S~}~%" (mime-type-string part) + (mapcar #'(lambda (pair) + (list (car pair) (cdr pair))) + (mime-type-parameters part))) + (awhen (mime-encoding part) + (format stream "Content-Transfer-Encoding: ~A~%" it)) + (awhen (mime-description part) + (format stream "Content-Description: ~A~%" it)) + (when (mime-disposition part) + (format stream "Content-Disposition: ~A~:{; ~A=~S~}~%" + (mime-disposition part) + (mapcar #'(lambda (pair) + (list (car pair) (cdr pair))) + (mime-disposition-parameters part)))) + (awhen (mime-id part) + (format stream "Content-ID: ~A~%" it)) + (terpri stream)) + +(defmethod encode-mime-part ((part mime-part) stream) + (write-mime-header part stream) + (encode-mime-body part stream)) + +(defmethod encode-mime-part ((part mime-message) stream) + ;; tricky: we have to mix the MIME headers with the message headers + (dolist (h (mime-message-headers part)) + (unless (stringp (car h)) + (setf (car h) + (string-capitalize (car h)))) + (unless (or (string-starts-with "content-" (car h) #'string-equal) + (string-equal "mime-version" (car h))) + (format stream "~A: ~A~%" + (car h) (cdr h)))) + (encode-mime-part (mime-body part) stream)) + +(defmethod encode-mime-part ((part mime-multipart) stream) + ;; choose a boundary if not already set + (let* ((original-boundary (get-mime-type-parameter part :boundary)) + (boundary (choose-boundary (mime-parts part) original-boundary))) + (unless (and original-boundary + (string= boundary original-boundary)) + (setf (get-mime-type-parameter part :boundary) boundary)) + (call-next-method))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defmethod encode-mime-body ((part mime-part) stream) + (with-input-from-mime-body-stream (in part) + (encode-stream in stream (mime-encoding part)))) + +(defmethod encode-mime-body ((part mime-message) stream) + (encode-mime-body (mime-body part) stream)) + +(defmethod encode-mime-body ((part mime-multipart) stream) + (let ((boundary (or (get-mime-type-parameter part :boundary) + (setf (get-mime-type-parameter part :boundary) + (choose-boundary (mime-parts part)))))) + (dolist (p (mime-parts part)) + (format stream "~%--~A~%" boundary) + (encode-mime-part p stream)) + (format stream "~%--~A--~%" boundary))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defun time-RFC822-string (&optional (epoch (get-universal-time))) + "Return a string describing the current time according to +the RFC822." + (multiple-value-bind (ss mm hh day month year week-day dst tz) (decode-universal-time epoch) + (declare (ignore dst)) + (format nil "~A, ~A ~A ~2,'0D ~2,'0D:~2,'0D:~2,'0D ~:[-~;+~]~2,'0D~2,'0D" + (subseq (week-day->string week-day) 0 3) + day (subseq (month->string month) 0 3) (mod year 100) hh mm ss + (plusp tz) (abs (truncate tz)) (mod (* 60 tz) 60)))) + +(defun parse-RFC822-date (date-string) + "Parse a RFC822 compliant date string and return an universal +time." + ;; if we can't parse it, just return NIL + (ignore-errors + ;; skip the optional DoW + (awhen (position #\, date-string) + (setf date-string (subseq date-string (1+ it)))) + (destructuring-bind (day month year time &optional tz &rest rubbish) + (split-at '(#\space #\tab) date-string) + (declare (ignore rubbish)) + (destructuring-bind (hh mm &optional ss) (split-string-at-char time #\:) + (encode-universal-time + (if ss + (read-from-string ss) + 0) + (read-from-string mm) + (read-from-string hh) + (read-from-string day) + (1+ (position month + '("Jan" "Feb" "Mar" "Apr" "May" "Jun" + "Jul" "Aug" "Sep" "Oct" "Nov" "Dec") + :test #'string-equal)) + (read-from-string year) + (when (and tz (or (char= #\+ (elt tz 0)) + (char= #\- (elt tz 0)))) + (/ (read-from-string tz) 100))))))) + +(defun read-RFC822-headers (stream &optional required-headers) + "Read RFC822 compliant headers from STREAM and return them in a +alist of keyword and string pairs. REQUIRED-HEADERS is a list of +header names we are interested in; if NIL return all headers +found in STREAM." + ;; the skip-header variable is to avoid the mistake of appending a + ;; continuation line of a header we don't want to a header we want + (loop + with headers = '() and skip-header = nil + for line = (let ((line (read-line stream nil))) + ;; skip the Unix "From " header if present + (if (string-starts-with "From " line) + (read-line stream nil) + line)) + then (read-line stream nil) + while (and line + (not (zerop (length line)))) + do (if (whitespace-p (elt line 0)) + (unless (or skip-header + (null headers)) + (setf (cdar headers) (s+ (cdar headers) '(#\newline) line))) + (multiple-value-bind (name value) (parse-RFC822-header line) + ;; the line contained rubbish instead of an header: we + ;; play nice and return as we were at the end of the + ;; headers + (unless name + (return (nreverse headers))) + (if (or (null required-headers) + (member name required-headers :test #'string-equal)) + (progn + (push (cons name value) headers) + (setf skip-header nil)) + (setf skip-header t)))) + finally (return (nreverse headers)))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric mime-message (thing) + (:documentation + "Convert THING to a MIME-MESSAGE object.")) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defun mime-message-header-values (name message &key decode) + "Return all values of the header with NAME in MESSAGE, optionally decoding + it according to RFC2047 if :DECODE is T." + (loop ;; A header may occur multiple times + for header in (mime-message-headers message) + ;; MIME Headers should be case insensitive + ;; https://stackoverflow.com/a/6143644 + when (string-equal (car header) name) + collect (if decode + (decode-RFC2047 (cdr header)) + (cdr header)))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defvar *lazy-mime-decode* t + "If true don't decode mime bodies in memory.") + +(defgeneric decode-mime-body (part input-stream)) + +(defmethod decode-mime-body ((part mime-part) (stream flexi-stream)) + (let ((base (flexi-stream-root-stream stream))) + (if *lazy-mime-decode* + (setf (mime-body part) + (make-file-portion :data (etypecase base + (vector-stream + (flexi-streams::vector-stream-vector base)) + (file-stream + (pathname base))) + :encoding (mime-encoding part) + :start (flexi-stream-position stream) + :end (flexi-stream-bound stream))) + (call-next-method)))) + +(defmethod decode-mime-body ((part mime-part) (stream file-stream)) + (if *lazy-mime-decode* + (setf (mime-body part) + (make-file-portion :data (pathname stream) + :encoding (mime-encoding part) + :start (file-position stream))) + (call-next-method))) + +(defmethod decode-mime-body ((part mime-part) (stream vector-stream)) + (if *lazy-mime-decode* + (setf (mime-body part) + (make-file-portion :data (flexi-streams::vector-stream-vector stream) + :encoding (mime-encoding part) + :start (flexi-streams::vector-stream-index stream))) + (call-next-method))) + +(defmethod decode-mime-body ((part mime-part) stream) + (setf (mime-body part) + (decode-stream-to-sequence stream (mime-encoding part)))) + +(defmethod decode-mime-body ((part mime-multipart) stream) + "Decode STREAM according to PART characteristics and return a +list of MIME parts." + (save-file-excursion (stream) + (let ((offsets (index-multipart-parts stream (get-mime-type-parameter part :boundary)))) + (setf (mime-parts part) + (mapcar #'(lambda (p) + (destructuring-bind (start . end) p + (let ((*default-type* (if (eq :digest (mime-subtype part)) + '("message" "rfc822" ()) + '("text" "plain" (("charset" . "us-ascii"))))) + (in (make-positioned-flexi-input-stream stream + :position start + :bound end + :ignore-close t))) + (read-mime-part in)))) + offsets))))) + +(defmethod decode-mime-body ((part mime-message) stream) + "Read from STREAM the body of PART. Return the decoded MIME +body." + (setf (mime-body part) + (read-mime-message stream))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defvar +known-encodings+ '(:7BIT :8BIT :BINARY :QUOTED-PRINTABLE :BASE64) + "List of known content encodings.") + +(defun keywordify-encoding (string) + "Return a keyword for a content transfer encoding string. +Return STRING itself if STRING is an unkown encoding." + (aif (member string +known-encodings+ :test #'string-equal) + (car it) + string)) + +(defun header (name headers) + (let ((elt (assoc name headers :test #'string-equal))) + (values (cdr elt) (car elt)))) + +(defun (setf header) (value name headers) + (let ((entry (assoc name headers :test #'string-equal))) + (unless entry + (error "missing header ~A can't be set" name)) + (setf (cdr entry) value))) + +(defun make-mime-part (headers stream) + "Create a MIME-PART object based on HEADERS and a body which +has to be read from STREAM. If the mime part type can't be +guessed from the headers, use the *DEFAULT-TYPE*." + (flet ((hdr (what) + (header what headers))) + (destructuring-bind (type subtype parms) + (or + (aand (hdr :content-type) + (parse-content-type it)) + *default-type*) + (let* ((class (or (cadr (assoc type *mime-types* :test #'string-equal)) + 'mime-unknown-part)) + (disp (aif (hdr :content-disposition) + (parse-content-disposition it) + (values nil nil))) + (part (make-instance class + :type (hdr :content-type) + :subtype subtype + :type-parameters parms + :disposition (car disp) + :disposition-parameters (cdr disp) + :mime-version (hdr :mime-version) + :encoding (keywordify-encoding + (hdr :content-transfer-encoding)) + :description (hdr :content-description) + :id (hdr :content-id) + :allow-other-keys t))) + (decode-mime-body part stream) + part)))) + +(defun read-mime-part (stream) + "Read mime part from STREAM. Return a MIME-PART object." + (let ((headers (read-rfc822-headers stream + '(:mime-version :content-transfer-encoding :content-type + :content-disposition :content-description :content-id)))) + (make-mime-part headers stream))) + +(defun read-mime-message (stream) + "Main function to read a MIME message from a stream. It +returns a MIME-MESSAGE object." + (let ((headers (read-rfc822-headers stream)) + (*default-type* '("text" "plain" (("charset" . "us-ascii"))))) + (flet ((hdr (what) + (header what headers))) + (destructuring-bind (type subtype parms) + (or (aand (hdr :content-type) + (parse-content-type it)) + *default-type*) + (declare (ignore type subtype)) + (make-instance 'mime-message + :headers headers + ;; this is just for easy access + :type-parameters parms + :body (make-mime-part headers stream)))))) + +(defmethod mime-message ((msg mime-message)) + msg) + +(defmethod mime-message ((msg string)) + (mime-message (flexi-streams:string-to-octets msg))) + +(defmethod mime-message ((msg vector)) + (with-input-from-sequence (in msg) + (mime-message in))) + +(defmethod mime-message ((msg pathname)) + (with-open-file (in msg :element-type '(unsigned-byte 8)) + (mime-message in))) + +(defmethod mime-message ((msg flexi-stream)) + (read-mime-message msg)) + +(defmethod mime-message ((msg stream)) + (read-mime-message (make-flexi-stream msg))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric mime-part (object) + (:documentation + "Promote object, if necessary, to MIME-PART.")) + +(defmethod mime-part ((object string)) + (make-instance 'mime-text :subtype "plain" :body object)) + +(defmethod mime-part ((object pathname)) + (make-instance 'mime-application + :subtype "octect-stream" + :content-transfer-encoding :base64 + :body (read-file object :element-type '(unsigned-byte 8)))) + +(defmethod mime-part ((object mime-part)) + object) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defmethod make-encoded-body-stream ((part mime-bodily-part)) + (let ((body (mime-body part))) + (make-instance (case (mime-encoding part) + (:base64 + 'base64-encoder-input-stream) + (:quoted-printable + 'quoted-printable-encoder-input-stream) + (otherwise + '8bit-encoder-input-stream)) + :underlying-stream + (make-input-adapter body)))) + +(defun choose-boundary (parts &optional default) + (labels ((match-in-parts (boundary parts) + (loop + for p in parts + thereis (typecase p + (mime-multipart + (match-in-parts boundary (mime-parts p))) + (mime-bodily-part + (match-in-body p boundary))))) + (match-in-body (part boundary) + (with-open-stream (in (make-encoded-body-stream part)) + (loop + for line = (read-line in nil) + while line + when (string= line boundary) + return t + finally (return nil))))) + (do ((boundary (if default + (format nil "--~A" default) + #1=(format nil "--~{~36R~}" + (loop + for i from 0 below 20 + collect (random 36)))) + #1#)) + ((not (match-in-parts boundary parts)) (subseq boundary 2))))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +;; fall back method +(defmethod mime-part-size ((part mime-part)) + (let ((body (mime-body part))) + (typecase body + (pathname + (file-size body)) + (string + (length body)) + (vector + (length body)) + (t nil)))) + +(defmethod mime-part-size ((part mime-multipart)) + (loop + for p in (mime-parts part) + for size = (mime-part-size p) + unless size + return nil + sum size)) + +(defmethod mime-part-size ((part mime-message)) + (mime-part-size (mime-body part))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defmethod print-mime-part ((part mime-multipart) (out stream)) + (case (mime-subtype part) + (:alternative + ;; try to choose something simple to print or the first thing + (let ((parts (mime-parts part))) + (print-mime-part (or (find-if #'(lambda (part) + (and (eq (class-of part) (find-class 'mime-text)) + (eq (mime-subtype part) :plain))) + parts) + (car parts)) out))) + (otherwise + (dolist (subpart (mime-parts part)) + (print-mime-part subpart out))))) + +;; This is WRONG. Here we don't use any special character encoding +;; because we don't know which one we should use. Messages written in +;; anything but ASCII will likely be unreadable -wcp11/10/07. +(defmethod print-mime-part ((part mime-text) (out stream)) + (let ((body (mime-body part))) + (etypecase body + (string + (write-string body out)) + (vector + (loop + for byte across body + do (write-char (code-char byte) out))) + (pathname + (with-open-file (in body) + (loop + for c = (read-char in nil) + while c + do (write-char c out))))))) + +(defmethod print-mime-part ((part mime-message) (out stream)) + (flet ((hdr (name) + (multiple-value-bind (value tag) + (header name (mime-message-headers part)) + (cons tag value)))) + (dolist (h (mapcar #'hdr '("from" "subject" "to" "date" "x-march-archive-id"))) + (when h + (format out "~&~A: ~A" (car h) (cdr h)))) + (format out "~2%") + (print-mime-part (mime-body part) out))) + +(defmethod print-mime-part ((part mime-part) (out stream)) + (format out "~&[ ~A subtype=~A ~@[description=~S ~]~@[size=~A~] ]~%" + (type-of part) (mime-subtype part) (mime-description part) (mime-part-size part))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric find-mime-part-by-path (mime path) + (:documentation + "Return a subpart of MIME identified by PATH, which is a list of +integers. For example '(2 3 1) is the first part of the third of the +second in MIME.")) + +(defmethod find-mime-part-by-path ((part mime-part) path) + (if (null path) + part + (error "~S doesn't have subparts" part))) + +(defmethod find-mime-part-by-path ((part mime-message) path) + (if (null path) + part + (if (= 1 (car path)) + (find-mime-part-by-path (mime-body part) (cdr path)) + (error "~S may have just one subpart, but part ~D was requested (parts are enumerated base 1)." + part (car path))))) + +(defmethod find-mime-part-by-path ((part mime-multipart) path) + (if (null path) + part + (let ((parts (mime-parts part)) + (part-number (car path))) + (if (<= 1 part-number (length parts)) + (find-mime-part-by-path (nth (1- (car path)) (mime-parts part)) (cdr path)) + (error "~S has just ~D subparts, but part ~D was requested (parts are enumerated base 1)." + part (length parts) part-number))))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric find-mime-part-by-id (part id) + (:documentation + "Return a subpart of PAR, whose Content-ID is the same as ID, which +is a string.")) + +(defmethod find-mime-part-by-id ((part mime-part) id) + (when (string= id (mime-id part)) + part)) + +(defmethod find-mime-part-by-id ((part mime-message) id) + (find-mime-part-by-id (mime-body part) id)) + +(defmethod find-mime-part-by-id ((part mime-multipart) id) + (or (call-next-method) + (some #'(lambda (p) + (find-mime-part-by-id p id)) + (mime-parts part)))) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric find-mime-text-part (msg) + (:documentation + "Return message if it is a text message or first text part. + If no suitable text part is found, return NIL.")) + +(defmethod find-mime-text-part ((part mime-text)) + part) ; found our target + +(defmethod find-mime-text-part ((msg mime-message)) + ;; mime-body is either a mime-part or mime-multipart + (find-mime-text-part (mime-body msg))) + +(defmethod find-mime-text-part ((parts mime-multipart)) + ;; multipart messages may have a body, otherwise we + ;; search for the first text part + (or (call-next-method) + (find-if #'find-mime-text-part (mime-parts parts)))) + +(defmethod find-mime-text-part ((part mime-part)) + nil) ; default case + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric mime-type-string (mime-part) + (:documentation + "Return the string describing the MIME part.")) + +(defmethod mime-type-string ((part mime-unknown-part)) + (mime-type part)) + +(defmethod mime-type-string ((part mime-text)) + (format nil "text/~A" (mime-subtype part))) + +(defmethod mime-type-string ((part mime-image)) + (format nil "image/~A" (mime-subtype part))) + +(defmethod mime-type-string ((part mime-audio)) + (format nil "audio/~A" (mime-subtype part))) + +(defmethod mime-type-string ((part mime-video)) + (format nil "video/~A" (mime-subtype part))) + +(defmethod mime-type-string ((part mime-application)) + (format nil "application/~A" (mime-subtype part))) + +(defmethod mime-type-string ((part mime-multipart)) + (format nil "multipart/~A" (mime-subtype part))) + +(defmethod mime-type-string ((part mime-message)) + (format nil "message/~A" (mime-subtype part))) + +(defmethod mime-type-string ((part mime-unknown-part)) + (mime-type part)) + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +(defgeneric map-parts (function mime-part) + (:documentation + "Recursively map FUNCTION to MIME-PART or its components.")) + +;; Here we wrongly assume that we'll never want to replace messages +;; and multiparts altogether. If you need to do so you have to write +;; your own mapping functions. + +(defmethod map-parts ((function function) (part mime-part)) + (funcall function part)) + +(defmethod map-parts ((function function) (part mime-message)) + (setf (mime-body part) (map-parts function (mime-body part))) + part) + +(defmethod map-parts ((function function) (part mime-multipart)) + (setf (mime-parts part) (mapcar #'(lambda (p) + (map-parts function p)) + (mime-parts part))) + part) + +;; apply-on-parts is like map-parts but doesn't modify the parts (at least +;; not implicitly) + +(defgeneric apply-on-parts (function part)) + +(defmethod apply-on-parts ((function function) (part mime-part)) + (funcall function part)) + +(defmethod apply-on-parts ((function function) (part mime-multipart)) + (dolist (p (mime-parts part)) + (apply-on-parts function p))) + +(defmethod apply-on-parts ((function function) (part mime-message)) + (apply-on-parts function (mime-body part))) + +(defmacro do-parts ((var mime-part) &body body) + `(apply-on-parts #'(lambda (,var) ,@body) ,mime-part)) |