add ajaxchat library - needs a lot of integration work to handle decentralisation (e.g. chatroom@website) and zotid w/permissions (e.g. ACL controlled chatrooms); we can also rip out a lot of stuff we don't need.

library/ajaxchat/chat/lib/class/AJAXChatHTTPHeader.php

@@ -0,0 +1,56 @@
+<?php
+/*
+ * @package AJAX_Chat
+ * @author Sebastian Tschan
+ * @copyright (c) Sebastian Tschan
+ * @license Modified MIT License
+ * @link https://blueimp.net/ajax/
+ */
+
+// Class to manage HTTP header
+class AJAXChatHTTPHeader {
+
+	var $_contentType;
+	var $_constant;
+	var $_noCache;
+
+	function __construct($encoding='UTF-8', $contentType=null, $noCache=true) {
+		if($contentType) {
+			$this->_contentType = $contentType.'; charset='.$encoding;
+			$this->_constant = true;
+		} else {
+			if(isset($_SERVER['HTTP_ACCEPT']) && (strpos($_SERVER['HTTP_ACCEPT'],'application/xhtml+xml') !== false)) {
+				$this->_contentType = 'application/xhtml+xml; charset='.$encoding;
+			} else {
+	 			$this->_contentType = 'text/html; charset='.$encoding;
+			}
+			$this->_constant = false;
+		}
+		$this->_noCache = $noCache;
+	}
+
+	// Method to send the HTTP header:
+	function send() {
+		// Prevent caching:
+		if($this->_noCache) {
+			header('Cache-Control: no-cache, must-revalidate');
+			header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
+		}
+		
+		// Send the content-type-header:
+		header('Content-Type: '.$this->_contentType);
+		
+		// Send vary header if content-type varies (important for proxy-caches):
+		if(!$this->_constant) {
+			header('Vary: Accept');
+		}
+	}
+    
+	// Method to return the content-type string:
+	function getContentType() {
+		// Return the content-type string:
+		return $this->_contentType;
+	}
+
+}
+?>