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diff --git a/lisp/net/html2text.el b/lisp/net/html2text.el new file mode 100644 index 00000000000..2b1c2057bb4 --- /dev/null +++ b/lisp/net/html2text.el @@ -0,0 +1,461 @@ +;;; html2text.el --- a simple html to plain text converter -*- coding: utf-8 -*- + +;; Copyright (C) 2002-2016 Free Software Foundation, Inc. + +;; Author: Joakim Hove <hove@phys.ntnu.no> + +;; This file is part of GNU Emacs. + +;; GNU Emacs 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. + +;; GNU Emacs 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 GNU Emacs. If not, see <http://www.gnu.org/licenses/>. + +;;; Commentary: + +;; These functions provide a simple way to wash/clean html infected +;; mails. Definitely do not work in all cases, but some improvement +;; in readability is generally obtained. Formatting is only done in +;; the buffer, so the next time you enter the article it will be +;; "re-htmlized". +;; +;; The main function is `html2text'. + +;;; Code: + +;; +;; <Global variables> +;; + +(eval-when-compile + (require 'cl)) + +(defvar html2text-format-single-element-list '(("hr" . html2text-clean-hr))) + +(defvar html2text-replace-list + '(("´" . "`") + ("&" . "&") + ("'" . "'") + ("¦" . "|") + ("¢" . "c") + ("ˆ" . "^") + ("©" . "(C)") + ("¤" . "(#)") + ("°" . "degree") + ("÷" . "/") + ("€" . "e") + ("½" . "1/2") + (">" . ">") + ("¿" . "?") + ("«" . "<<") + ("&ldquo" . "\"") + ("‹" . "(") + ("‘" . "`") + ("<" . "<") + ("—" . "--") + (" " . " ") + ("–" . "-") + ("‰" . "%%") + ("±" . "+-") + ("£" . "£") + (""" . "\"") + ("»" . ">>") + ("&rdquo" . "\"") + ("®" . "(R)") + ("›" . ")") + ("’" . "'") + ("§" . "§") + ("¹" . "^1") + ("²" . "^2") + ("³" . "^3") + ("˜" . "~")) + "The map of entity to text. + +This is an alist were each element is a dotted pair consisting of an +old string, and a replacement string. This replacement is done by the +function `html2text-substitute' which basically performs a +`replace-string' operation for every element in the list. This is +completely verbatim - without any use of REGEXP.") + +(defvar html2text-remove-tag-list + '("html" "body" "p" "img" "dir" "head" "div" "br" "font" "title" "meta") + "A list of removable tags. + +This is a list of tags which should be removed, without any +formatting. Note that tags in the list are presented *without* +any \"<\" or \">\". All occurrences of a tag appearing in this +list are removed, irrespective of whether it is a closing or +opening tag, or if the tag has additional attributes. The +deletion is done by the function `html2text-remove-tags'. + +For instance the text: + +\"Here comes something <font size\"+3\" face=\"Helvetica\"> big </font>.\" + +will be reduced to: + +\"Here comes something big.\" + +If this list contains the element \"font\".") + +(defvar html2text-format-tag-list + '(("b" . html2text-clean-bold) + ("strong" . html2text-clean-bold) + ("u" . html2text-clean-underline) + ("i" . html2text-clean-italic) + ("em" . html2text-clean-italic) + ("blockquote" . html2text-clean-blockquote) + ("a" . html2text-clean-anchor) + ("ul" . html2text-clean-ul) + ("ol" . html2text-clean-ol) + ("dl" . html2text-clean-dl) + ("center" . html2text-clean-center)) + "An alist of tags and processing functions. + +This is an alist where each dotted pair consists of a tag, and then +the name of a function to be called when this tag is found. The +function is called with the arguments p1, p2, p3 and p4. These are +demonstrated below: + +\"<b> This is bold text </b>\" + ^ ^ ^ ^ + | | | | +p1 p2 p3 p4 + +Then the called function will typically format the text somewhat and +remove the tags.") + +(defvar html2text-remove-tag-list2 '("li" "dt" "dd" "meta") + "Another list of removable tags. + +This is a list of tags which are removed similarly to the list +`html2text-remove-tag-list' - but these tags are retained for the +formatting, and then moved afterward.") + +;; +;; </Global variables> +;; + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +;; +;; <Utility functions> +;; + + +(defun html2text-replace-string (from-string to-string min max) + "Replace FROM-STRING with TO-STRING in region from MIN to MAX." + (goto-char min) + (let ((delta (- (string-width to-string) (string-width from-string))) + (change 0)) + (while (search-forward from-string max t) + (replace-match to-string) + (setq change (+ change delta))) + change)) + +;; +;; </Utility functions> +;; + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +;; +;; <Functions related to attributes> i.e. <font size=+3> +;; + +(defun html2text-attr-value (list attribute) + "Get value of ATTRIBUTE from LIST." + (nth 1 (assoc attribute list))) + +(defun html2text-get-attr (p1 p2) + (goto-char p1) + (re-search-forward "\\s-+" p2 t) + (let (attr-list) + (while (re-search-forward "[-a-z0-9._]+" p2 t) + (setq attr-list + (cons + (list (match-string 0) + (when (looking-at "\\s-*=") + (goto-char (match-end 0)) + (skip-chars-forward "[:space:]") + (when (or (looking-at "\"[^\"]*\"\\|'[^']*'") + (looking-at "[-a-z0-9._:]+")) + (goto-char (match-end 0)) + (match-string 0)))) + attr-list))) + attr-list)) + +;; +;; </Functions related to attributes> +;; + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +;; +;; <Functions to be called to format a tag-pair> +;; +(defun html2text-clean-list-items (p1 p2 list-type) + (goto-char p1) + (let ((item-nr 0) + (items 0)) + (while (search-forward "<li>" p2 t) + (setq items (1+ items))) + (goto-char p1) + (while (< item-nr items) + (setq item-nr (1+ item-nr)) + (search-forward "<li>" (point-max) t) + (cond + ((string= list-type "ul") (insert " o ")) + ((string= list-type "ol") (insert (format " %s: " item-nr))) + (t (insert " x ")))))) + +(defun html2text-clean-dtdd (p1 p2) + (goto-char p1) + (let ((items 0) + (item-nr 0)) + (while (search-forward "<dt>" p2 t) + (setq items (1+ items))) + (goto-char p1) + (while (< item-nr items) + (setq item-nr (1+ item-nr)) + (re-search-forward "<dt>\\([ ]*\\)" (point-max) t) + (when (match-string 1) + (delete-region (point) (- (point) (string-width (match-string 1))))) + (let ((def-p1 (point)) + (def-p2 0)) + (re-search-forward "\\([ ]*\\)\\(</dt>\\|<dd>\\)" (point-max) t) + (if (match-string 1) + (progn + (let* ((mw1 (string-width (match-string 1))) + (mw2 (string-width (match-string 2))) + (mw (+ mw1 mw2))) + (goto-char (- (point) mw)) + (delete-region (point) (+ (point) mw1)) + (setq def-p2 (point)))) + (setq def-p2 (- (point) (string-width (match-string 2))))) + (put-text-property def-p1 def-p2 'face 'bold))))) + +(defun html2text-delete-tags (p1 p2 p3 p4) + (delete-region p1 p2) + (delete-region (- p3 (- p2 p1)) (- p4 (- p2 p1)))) + +(defun html2text-delete-single-tag (p1 p2) + (delete-region p1 p2)) + +(defun html2text-clean-hr (p1 p2) + (html2text-delete-single-tag p1 p2) + (goto-char p1) + (newline 1) + (insert (make-string fill-column ?-))) + +(defun html2text-clean-ul (p1 p2 p3 p4) + (html2text-delete-tags p1 p2 p3 p4) + (html2text-clean-list-items p1 (- p3 (- p1 p2)) "ul")) + +(defun html2text-clean-ol (p1 p2 p3 p4) + (html2text-delete-tags p1 p2 p3 p4) + (html2text-clean-list-items p1 (- p3 (- p1 p2)) "ol")) + +(defun html2text-clean-dl (p1 p2 p3 p4) + (html2text-delete-tags p1 p2 p3 p4) + (html2text-clean-dtdd p1 (- p3 (- p1 p2)))) + +(defun html2text-clean-center (p1 p2 p3 p4) + (html2text-delete-tags p1 p2 p3 p4) + (center-region p1 (- p3 (- p2 p1)))) + +(defun html2text-clean-bold (p1 p2 p3 p4) + (put-text-property p2 p3 'face 'bold) + (html2text-delete-tags p1 p2 p3 p4)) + +(defun html2text-clean-title (p1 p2 p3 p4) + (put-text-property p2 p3 'face 'bold) + (html2text-delete-tags p1 p2 p3 p4)) + +(defun html2text-clean-underline (p1 p2 p3 p4) + (put-text-property p2 p3 'face 'underline) + (html2text-delete-tags p1 p2 p3 p4)) + +(defun html2text-clean-italic (p1 p2 p3 p4) + (put-text-property p2 p3 'face 'italic) + (html2text-delete-tags p1 p2 p3 p4)) + +(defun html2text-clean-font (p1 p2 p3 p4) + (html2text-delete-tags p1 p2 p3 p4)) + +(defun html2text-clean-blockquote (p1 p2 p3 p4) + (html2text-delete-tags p1 p2 p3 p4)) + +(defun html2text-clean-anchor (p1 p2 p3 p4) + ;; If someone can explain how to make the URL clickable I will surely + ;; improve upon this. + ;; Maybe `goto-addr.el' can be used here. + (let* ((attr-list (html2text-get-attr p1 p2)) + (href (html2text-attr-value attr-list "href"))) + (delete-region p1 p4) + (when href + (goto-char p1) + (insert (if (string-match "\\`['\"].*['\"]\\'" href) + (substring href 1 -1) href)) + (put-text-property p1 (point) 'face 'bold)))) + +;; +;; </Functions to be called to format a tag-pair> +;; + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +;; +;; <Functions to be called to fix up paragraphs> +;; + +(defun html2text-fix-paragraph (p1 p2) + (goto-char p1) + (let ((refill-start) + (refill-stop)) + (when (re-search-forward "<br>$" p2 t) + (goto-char p1) + (when (re-search-forward ".+[^<][^b][^r][^>]$" p2 t) + (beginning-of-line) + (setq refill-start (point)) + (goto-char p2) + (re-search-backward ".+[^<][^b][^r][^>]$" refill-start t) + (forward-line 1) + (end-of-line) + ;; refill-stop should ideally be adjusted to + ;; accommodate the "<br>" strings which are removed + ;; between refill-start and refill-stop. Can simply + ;; be returned from my-replace-string + (setq refill-stop (+ (point) + (html2text-replace-string + "<br>" "" + refill-start (point)))) + ;; (message "Point = %s refill-stop = %s" (point) refill-stop) + ;; (sleep-for 4) + (fill-region refill-start refill-stop)))) + (html2text-replace-string "<br>" "" p1 p2)) + +;; +;; This one is interactive ... +;; +(defun html2text-fix-paragraphs () + "This _tries_ to fix up the paragraphs - this is done in quite a ad-hook +fashion, quite close to pure guess-work. It does work in some cases though." + (interactive) + (goto-char (point-min)) + (while (re-search-forward "^<br>$" nil t) + (delete-region (match-beginning 0) (match-end 0))) + ;; Removing lonely <br> on a single line, if they are left intact we + ;; don't have any paragraphs at all. + (goto-char (point-min)) + (while (not (eobp)) + (let ((p1 (point))) + (forward-paragraph 1) + ;;(message "Kaller fix med p1=%s p2=%s " p1 (1- (point))) (sleep-for 5) + (html2text-fix-paragraph p1 (1- (point))) + (goto-char p1) + (when (not (eobp)) + (forward-paragraph 1))))) + +;; +;; </Functions to be called to fix up paragraphs> +;; + +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; + +;; +;; <Interactive functions> +;; + +(defun html2text-remove-tags (tag-list) + "Removes the tags listed in the list `html2text-remove-tag-list'. +See the documentation for that variable." + (interactive) + (dolist (tag tag-list) + (goto-char (point-min)) + (while (re-search-forward (format "\\(</?%s[^>]*>\\)" tag) (point-max) t) + (delete-region (match-beginning 0) (match-end 0))))) + +(defun html2text-format-tags () + "See the variable `html2text-format-tag-list' for documentation." + (interactive) + (dolist (tag-and-function html2text-format-tag-list) + (let ((tag (car tag-and-function)) + (function (cdr tag-and-function))) + (goto-char (point-min)) + (while (re-search-forward (format "\\(<%s\\( [^>]*\\)?>\\)" tag) + (point-max) t) + (let ((p1) + (p2 (point)) + (p3) (p4)) + (search-backward "<" (point-min) t) + (setq p1 (point)) + (unless (search-forward (format "</%s>" tag) (point-max) t) + (goto-char p2) + (insert (format "</%s>" tag))) + (setq p4 (point)) + (search-backward "</" (point-min) t) + (setq p3 (point)) + (funcall function p1 p2 p3 p4) + (goto-char p1)))))) + +(defun html2text-substitute () + "See the variable `html2text-replace-list' for documentation." + (interactive) + (dolist (e html2text-replace-list) + (goto-char (point-min)) + (let ((old-string (car e)) + (new-string (cdr e))) + (html2text-replace-string old-string new-string (point-min) (point-max))))) + +(defun html2text-format-single-elements () + (interactive) + (dolist (tag-and-function html2text-format-single-element-list) + (let ((tag (car tag-and-function)) + (function (cdr tag-and-function))) + (goto-char (point-min)) + (while (re-search-forward (format "\\(<%s\\( [^>]*\\)?>\\)" tag) + (point-max) t) + (let ((p1) + (p2 (point))) + (search-backward "<" (point-min) t) + (setq p1 (point)) + (funcall function p1 p2)))))) + +;; +;; Main function +;; + +;;;###autoload +(defun html2text () + "Convert HTML to plain text in the current buffer." + (interactive) + (save-excursion + (let ((case-fold-search t) + (buffer-read-only)) + (html2text-remove-tags html2text-remove-tag-list) + (html2text-format-tags) + (html2text-remove-tags html2text-remove-tag-list2) + (html2text-substitute) + (html2text-format-single-elements) + (html2text-fix-paragraphs)))) + +;; +;; </Interactive functions> +;; +(provide 'html2text) + +;;; html2text.el ends here |