Add URl links and better hashtag support

index.php

@@ -7,6 +7,7 @@
 	*	For educational purposes only.
 	*	It produces an Actor who can be followed.
 	*	It can send messages to followers.
+	*	Those messages can have linkable URls and hashtags.
 	*	It saves logs about requests it receives and sends.
 	*	It is NOT suitable for production use.
 	*	This code is "licenced" under CRAPL v0 - https://matt.might.net/articles/crapl/
@@ -467,13 +468,22 @@ HTML;
 	}
 
 	//	Content can be plain text. But to add clickable links and hashtags, it needs to be turned into HTML.
-	//	Tags are also included separately in the message
+	//	Tags are also included separately in the note
 	function process_content( $content ) {
 		global $server;
 
+		//	Convert any URls into hyperlinks
+		$link_pattern = '/\bhttps?:\/\/\S+/iu';
+		$replacement = function ( $match ) {
+			$url = htmlspecialchars( $match[0], ENT_QUOTES, "UTF-8" );
+			return "<a href=\"$url\">$url</a>";
+		};
+		$content = preg_replace_callback( $link_pattern, $replacement, $content );	  
+
 		//	Get any hashtags
 		$hashtags = [];
-		preg_match_all( '/#(\w+)/', $content, $matches );
+		$hashtag_pattern = '/(?:^|\s)\#(\w+)/';	//	Beginning of string, or whitespace, followed by #
+		preg_match_all( $hashtag_pattern, $content, $matches );
 		foreach ($matches[1] as $match) {
 			$hashtags[] = $match;
 		}