;;; address.lisp --- e-mail address parser
;;; Copyright (C) 2007, 2008, 2009 by Walter C. Pelissero
;;; Copyright (C) 2022 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
;;; Although not MIME specific, this parser is often useful together
;;; with the MIME primitives. It should be able to parse the address
;;; syntax described in RFC2822 excluding the obsolete syntax (see
;;; RFC822). Have a look at the test suite to get an idea of what
;;; kind of addresses it can parse.
(in-package :mime4cl)
(defstruct (mailbox (:conc-name mbx-))
description
user
host
domain)
(defstruct (mailbox-group (:conc-name mbxg-))
name
mailboxes)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun write-mailbox-domain-name (addr &optional (stream *standard-output*))
(when (eq :internet (mbx-domain addr))
(write-char #\[ stream))
(write-string (mbx-host addr) stream)
(when (eq :internet (mbx-domain addr))
(write-char #\] stream))
(when (stringp (mbx-domain addr))
(write-char #\. stream)
(write-string (mbx-domain addr) stream)))
(defun write-mailbox-address (addr &optional (stream *standard-output*))
(write-string (mbx-user addr) stream)
(when (mbx-host addr)
(write-char #\@ stream)
(write-mailbox-domain-name addr stream)))
(defmethod mbx-domain-name ((MBX mailbox))
"Return the complete domain name string of MBX, in the form
\"host.domain\"."
(with-output-to-string (out)
(write-mailbox-domain-name mbx out)))
(defmethod mbx-address ((mbx mailbox))
"Return the e-mail address string of MBX, in the form
\"user@host.domain\"."
(with-output-to-string (out)
(write-mailbox-address mbx out)))
(defun write-mailbox (addr &optional (stream *standard-output*))
(awhen (mbx-description addr)
(write it :stream stream :readably t)
(write-string " <" stream))
(write-mailbox-address addr stream)
(awhen (mbx-description addr)
(write-char #\> stream)))
(defun write-mailbox-group (grp &optional (stream *standard-output*))
(write-string (mbxg-name grp) stream)
(write-string ": " stream)
(loop
for mailboxes on (mbxg-mailboxes grp)
for mailbox = (car mailboxes)
do (write-mailbox mailbox stream)
unless (endp (cdr mailboxes))
do (write-string ", " stream))
(write-char #\; stream))
(defmethod print-object ((mbx mailbox) stream)
(if (or *print-readably* *print-escape*)
(call-next-method)
(write-mailbox mbx stream)))
(defmethod print-object ((grp mailbox-group) stream)
(if (or *print-readably* *print-escape*)
(call-next-method)
(write-mailbox-group grp stream)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun parser-make-mailbox (description address-list)
(make-mailbox :description description
:user (car address-list)
:host (cadr address-list)
:domain (when (cddr address-list)
(string-concat (cddr address-list) "."))))
(defun populate-grammar ()
(defrule address-list
:= (+ address ","))
(defrule address
:= mailbox
:= group)
(defrule mailbox
:= display-name? angle-addr comment?
:reduce (parser-make-mailbox (or display-name comment) angle-addr)
:= addr-spec comment?
:reduce (parser-make-mailbox comment addr-spec))
(defrule angle-addr
:= "<" addr-spec ">")
(defrule group
:= display-name ":" mailbox-list ";"
:reduce (make-mailbox-group :name display-name :mailboxes mailbox-list))
(defrule display-name
:= phrase
:reduce (string-concat phrase " "))
(defrule phrase
:= word+)
(defrule word
:= atext
:= string)
(defrule mailbox-list
:= (+ mailbox ","))
(defrule addr-spec
:= local-part "@" domain :reduce (cons local-part domain))
(defrule local-part
:= dot-atom :reduce (string-concat dot-atom ".")
:= string)
(defrule domain
:= dot-atom
:= domain-literal :reduce (list domain-literal :internet))
;; actually, according to the RFC, dot-atoms don't allow spaces in
;; between but these rules do
(defrule dot-atom
:= (+ atom "."))
(defrule atom
:= atext+
:reduce (apply #'concatenate 'string atext)))
(deflazy define-grammar
(let ((*package* #.*package*)
(*compile-print* (when npg::*debug* t)))
(reset-grammar)
(format t "~&creating e-mail address grammar...~%")
(populate-grammar)
(let ((grammar (npg:generate-grammar #'string=)))
(reset-grammar)
(npg:print-grammar-figures grammar)
grammar)))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; The lexical analyser
(defstruct cursor
stream
(position 0))
(defun read-delimited-string (stream end-char &key nesting-start-char (escape-char #\\))
(labels ((collect ()
(with-output-to-string (out)
(loop
for c = (read-char stream nil)
while (and c (not (char= c end-char)))
do (cond ((char= c escape-char)
(awhen (read-char stream nil)
(write-char it out)))
((and nesting-start-char
(char= c nesting-start-char))
(write-char nesting-start-char out)
(write-string (collect) out)
(write-char end-char out))
(t (write-char c out)))))))
(collect)))
(defun read-string (cursor)
(make-token :type 'string
:value (read-delimited-string (cursor-stream cursor) #\")
:position (incf (cursor-position cursor))))
(defun read-domain-literal (cursor)
(make-token :type 'domain-literal
:value (read-delimited-string (cursor-stream cursor) #\])
:position (incf (cursor-position cursor))))
(defun read-comment (cursor)
(make-token :type 'comment
:value (read-delimited-string (cursor-stream cursor) #\) :nesting-start-char #\()
:position (incf (cursor-position cursor))))
(declaim (inline atom-component-p))
(defun atom-component-p (c)
(declare (type character c))
(not (find c " ()\"[]@.<>:;,")))
(defun read-atext (first-character cursor)
(be string (with-output-to-string (out)
(write-char first-character out)
(loop
for c = (read-char (cursor-stream cursor) nil)
while (and c (atom-component-p c))
do (write-char c out)
finally (when c
(unread-char c (cursor-stream cursor)))))
(make-token :type 'atext
:value string
:position (incf (cursor-position cursor)))))
(defmethod read-next-tokens ((cursor cursor))
(flet ((make-keyword (c)
(make-token :type 'keyword
:value (string c)
:position (incf (cursor-position cursor)))))
(be in (cursor-stream cursor)
(loop
for c = (read-char in nil)
while c
unless (whitespace-p c)
return (list
(cond ((char= #\( c)
(read-comment cursor))
((char= #\" c)
(read-string cursor))
((char= #\[ c)
(read-domain-literal cursor))
((find c "@.<>:;,")
(make-keyword c))
(t
;; anything else is considered a text atom even
;; though it's just a single character
(read-atext c cursor))))))))
(defun analyse-string (string)
"Return the list of tokens produced by a lexical analysis of
STRING. These are the tokens that would be seen by the parser."
(with-input-from-string (stream string)
(be cursor (make-cursor :stream stream)
(loop
for tokens = (read-next-tokens cursor)
until (endp tokens)
append tokens))))
(defun mailboxes-only (list-of-mailboxes-and-groups)
"Return a flat list of MAILBOX-ADDRESSes from
LIST-OF-MAILBOXES-AND-GROUPS, which is the kind of list returned
by PARSE-ADDRESSES. This turns out to be useful when your
program is not interested in mailbox groups and expects the user
addresses only."
(mapcan #'(lambda (mbx)
(if (typep mbx 'mailbox-group)
(mbxg-mailboxes mbx)
(list mbx)))
list-of-mailboxes-and-groups))
(defun parse-addresses (string &key no-groups)
"Parse STRING and return a list of MAILBOX-ADDRESSes or
MAILBOX-GROUPs. If STRING is unparsable return NIL. If
NO-GROUPS is true, return a flat list of mailboxes throwing away
the group containers, if any."
(be grammar (force define-grammar)
(with-input-from-string (stream string)
(be* cursor (make-cursor :stream stream)
mailboxes (ignore-errors ; ignore parsing errors
(parse grammar 'address-list cursor))
(if no-groups
(mailboxes-only mailboxes)
mailboxes)))))
(defun debug-addresses (string)
"More or less like PARSE-ADDRESSES, but don't ignore parsing errors."
(be grammar (force define-grammar)
(with-input-from-string (stream string)
(be cursor (make-cursor :stream stream)
(parse grammar 'address-list cursor)))))
