Image ALT tags, conversion options, footer URLs and silent DOM.

src/Html2Text.php

@@ -19,6 +19,23 @@
 
 class Html2Text {
 
+	/**
+	 * Replaces URLs from <a> tags with a reference number (eg: "[1]") and moves the URL itself to
+	 * the end of the document. Makes the resulting text much easier to read if your HTML contains
+	 * many long URLs. The downside being the user has to scroll to the bottom of the document in
+	 * order to find (and click on) the URL. It's a trade off and a decision you can make per
+	 * document.
+	 */
+	const OPT_FOOTER_URLS = 1;
+
+	/**
+	 * If you use the OPT_FOOTER_URLS option, this variable will keep track of which indexes point
+	 * to which URLs, so they can be inserted at the end of the converted text.
+	 * @var array Associative array, where the key is a URL, and the value is an associative array
+	 *     of properties (currently "index" and "text").
+	 */
+	static $_indexedUrls = array();
+
 	/**
 	 * Tries to convert the given HTML into a plain text format - best suited for
 	 * e-mail display, etc.
@@ -30,28 +47,53 @@ class Html2Text {
 	 * </ul>
 	 *
 	 * @param string html the input HTML
+	 * @param array An array of options of the Html2Text::OPT_* variety
 	 * @return string the HTML converted, as best as possible, to text
 	 * @throws Html2TextException if the HTML could not be loaded as a {@link DOMDocument}
 	 */
-	static function convert($html) {
+	static function convert($html,$options=array()) {
+
+		// reset
+		Html2Text::$_indexedUrls = array();
+
+		// DOMDocument doesn't support empty value and throws an error
+		if (!$html) {
+			return '';
+		}
+
 		// replace &nbsp; with spaces
 		$html = str_replace("&nbsp;", " ", $html);
 
 		$html = static::fixNewlines($html);
 
 		$doc = new \DOMDocument();
-		if (!$doc->loadHTML($html)) {
+		$doc->strictErrorChecking = FALSE;
+		$doc->recover = TRUE;
+		$doc->xmlStandalone = true;
+		$prevValue = libxml_use_internal_errors(true); //prevent $doc to trhow any warnings
+		$loaded = $doc->loadHTML($html,LIBXML_NOWARNING | LIBXML_NOERROR | LIBXML_NONET);
+		libxml_use_internal_errors($prevValue); //restore original setting
+
+		if (!$loaded) {
 			throw new Html2TextException("Could not load HTML - badly formed?", $html);
 		}
 
-		$output = static::iterateOverNode($doc);
+		$output = static::iterateOverNode($doc,$options);
 
 		// remove leading and trailing spaces on each line
 		$output = preg_replace("/[ \t]*\n[ \t]*/im", "\n", $output);
 
 		// remove leading and trailing whitespace
 		$output = trim($output);
 
+		// if they want URLs at the end of the document instead of inline, append them here
+		if (in_array(static::OPT_FOOTER_URLS,$options) && Html2Text::$_indexedUrls) {
+			$output .= "\n\n------\n\n";
+			foreach (Html2Text::$_indexedUrls as $url=>$info) {
+				$output .= "[".$info['index']."] ".($info['text']?$info['text']." ":"").$url."\n";
+			}
+		}
+
 		return $output;
 	}
 
@@ -106,7 +148,7 @@ static function prevChildName($node) {
 		return $nextName;
 	}
 
-	static function iterateOverNode($node) {
+	static function iterateOverNode($node,&$options) {
 		if ($node instanceof \DOMText) {
 		  // Replace whitespace characters with a space (equivilant to \s)
 			return preg_replace("/[\\t\\n\\f\\r ]+/im", " ", $node->wholeText);
@@ -163,6 +205,10 @@ static function iterateOverNode($node) {
 				$output = "- ";
 				break;
 
+			case "img":
+				$output = $node->getAttribute("alt");
+				break;
+
 			default:
 				// print out contents of unknown tags
 				$output = "";
@@ -176,7 +222,7 @@ static function iterateOverNode($node) {
 			for ($i = 0; $i < $node->childNodes->length; $i++) {
 				$n = $node->childNodes->item($i);
 
-				$text = static::iterateOverNode($n);
+				$text = static::iterateOverNode($n,$options);
 
 				$output .= $text;
 			}
@@ -226,6 +272,8 @@ static function iterateOverNode($node) {
 					if ($href == $output || $href == "mailto:$output" || $href == "http://$output" || $href == "https://$output") {
 						// link to the same address: just use link
 						$output;
+					} elseif (in_array(static::OPT_FOOTER_URLS,$options)) {
+						$output = $output."[".static::_indexUrl($href,$output)."]";
 					} else {
 						// replace it
 						$output = "[$output]($href)";
@@ -251,4 +299,20 @@ static function iterateOverNode($node) {
 		return $output;
 	}
 
+	/**
+	 * Accepts a URL (and optionally the link text) and returns a unique index number for that URL.
+	 * @param  string $url  The URL you want an index number for.
+	 * @param  string $text The text of the link (associated with the above URL).
+	 * @return integer      The index number that will refer to the URL passed.
+	 */
+	static function _indexUrl($url,$text=null) {
+		if (!isset(static::$_indexedUrls[$url])) {
+			static::$_indexedUrls[$url] = array(
+				'index'=>count(static::$_indexedUrls),
+				'text'=>$text,
+			);
+		}
+		return static::$_indexedUrls[$url]['index'];
+	}
+
 }