Add hashtag support

index.php

@@ -367,6 +367,9 @@ HTML;
 		//	Get the posted content
 		$content = $_POST["content"];
 
+		//	Process the content into HTML to get hashtags etc
+		list( "HTML" => $content, "TagArray" => $tags ) = process_content( $content );
+
 		//	Current time - ISO8601
 		$timestamp = date( "c" );
 
@@ -386,7 +389,8 @@ HTML;
 			"attributedTo" => "https://{$server}/{$username}",
 			"content"      => $content,
 			"contentMap"   => ["en" => $content],
-			"to"           => ["https://www.w3.org/ns/activitystreams#Public"]
+			"to"           => ["https://www.w3.org/ns/activitystreams#Public"],
+			"tag"          => $tags
 		];
 
 		//	Construct the Message
@@ -462,6 +466,40 @@ HTML;
 		die();
 	}
 
+	//	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
+	function process_content( $content ) {
+		global $server;
+
+		//	Get any hashtags
+		$hashtags = [];
+		preg_match_all( '/#(\w+)/', $content, $matches );
+		foreach ($matches[1] as $match) {
+			$hashtags[] = $match;
+		}
+
+		//	Construct the tag value for the note object
+		$tags = [];
+		foreach ( $hashtags as $hashtag ) {
+			$tags[] = array(
+				"type" => "Hashtag",
+				"name" => "#{$hashtag}",
+			);
+		}
+
+		//	Add HTML links for hashtags into the text
+		$content = preg_replace(
+			'/(?<!\S)#([0-9\p{L}]+)/u', 
+			"<a href='https://{$server}/tag/$1'>#$1</a>", 
+			$content
+		);
+
+		//	Construct the content
+		$content = "<p>{$content}</p>";
+
+		return ["HTML" => $content, "TagArray" => $tags];
+	}
+
 //	"One to stun, two to kill, three to make sure"
 die();
 die();