1 ///////////////////////////////////////////////////////////////////////////////

     2 // The FeedUpdateBroker class implements a simple RSS fetcher and parser.

     3 // Adapted from WRTKit RssReader example

     4 

     5 // Constructor.

     6 function FeedUpdateBroker() {

     7     this.httpReq = null;

     8     this.feedAddress = null;

     9     this.callback = null;

    10 	this.ignoreContent = false;

    11 	this.cancelled = false;

    12 	this.responseParser = this.handleRssResponse;

    13 	this.startFromItem = 0;

    14 	this.maxItems = 0;

    15 }

    16 

    17 // Fetches a feed from the specified URL and calls the callback when the feed

    18 // has been fetched and parsed, or if the process results in an error.

    19 FeedUpdateBroker.prototype.doFetchFeed = function(){    

    20     // create new XML HTTP request

    21     this.httpReq = new Ajax();

    22     

    23     // set callback

    24     var self = this;

    25     this.httpReq.onreadystatechange = function() { self.readyStateChanged(); };

    26 

    27     // initiate the request

    28     this.httpReq.open("GET", nocache(this.feedAddress), true);

    29     this.httpReq.send(null);

    30 }

    31 

    32 // has been fetched and parsed, or if the process results in an error.

    33 FeedUpdateBroker.prototype.fetchFeed = function(feedURL, callback) {

    34     // remember callback

    35     this.callback = callback;

    36     this.feedAddress = feedURL;

    37 	this.doFetchFeed();

    38 }

    39 

    40 // Callback for ready-state change events in the XML HTTP request.

    41 FeedUpdateBroker.prototype.readyStateChanged = function() {

    42     // complete request?

    43     if (this.httpReq.readyState == 4) {

    44         // attempt to get response status

    45         var responseStatus = null;

    46         try {

    47             responseStatus = this.httpReq.status;

    48         } catch (noStatusException) {}

    49         

    50 		// are we being prompted for login?

    51 		var text = this.httpReq.responseText;

    52 		if ( isLoginPrompt (text) ) {

    53 			var self = this;

    54 //			setTimeout(self.doFetchFeed(), 100);

    55 			login(function(){self.doFetchFeed();});

    56 			return;

    57 		}

    58 		

    59         // handle the response and call the registered callback object

    60 		var response = this.httpReq.responseXML;

    61 		if (response == null) {

    62 			// if the content type is not set correctly, we get the response as text

    63 			var xmlparser = new DOMParser();

    64 		    response = xmlparser.parseFromString(this.httpReq.responseText, "text/xml");

    65 		}

    66         this.callback.feedUpdateCompleted(this.handleResponse(responseStatus, response));

    67     }

    68 }

    69 

    70 // Handles a completed response.

    71 FeedUpdateBroker.prototype.handleResponse = function(responseStatus, xmlDoc){

    72 	if (this.responseParser == null) {

    73 		return this.handleRssResponse(responseStatus, xmlDoc);

    74 	}

    75 	else {

    76 		return this.responseParser.call(this, this, responseStatus, xmlDoc);

    77 	}	

    78 }

    79 

    80 

    81 FeedUpdateBroker.prototype.handleRssResponse = function(broker, responseStatus, xmlDoc){

    82 	if ( this.cancelled ) {

    83         return { status: "cancelled" };

    84 	}

    85     if (responseStatus == 200 && xmlDoc != null) {

    86         // node ref for iterating

    87         var node;

    88         

    89         // get last modified time - default to current time

    90         var lastModified = new Date().getTime();

    91         var channelElements = xmlDoc.getElementsByTagName("channel");

    92         if (channelElements.length > 0) {

    93             node = channelElements[0].firstChild;

    94             while (node != null) {

    95                 if (node.nodeType == Node.ELEMENT_NODE) {

    96                     if (node.nodeName == "pubDate" ||

    97                             node.nodeName == "lastBuildDate" ||

    98                             node.nodeName == "dc:date") {

    99                         lastModified = getTextOfNode(node);

   100                         break;

   101                     }

   102                 }

   103                 node = node.nextSibling;

   104             }

   105         }

   106         

   107         // init feed items array

   108         var items = [];

   109         

   110         // we got the feed XML so now we'll parse it

   111         var itemElements = xmlDoc.getElementsByTagName("item");

   112 		

   113         for (var i = this.startFromItem; i < itemElements.length; i++) {

   114 			if ( this.maxItems > 0 && this.maxItems < i ) {

   115 				break;

   116 			}

   117             // iterate through child nodes of this item and gather

   118             // all the data we need for a feed item

   119             var title = null;

   120             var date = null;

   121             var description = null;

   122             var url = null;

   123             var author = null;

   124             node = itemElements[i].firstChild;

   125             while (node != null) {

   126                 if (node.nodeType == Node.ELEMENT_NODE) {

   127                     if (node.nodeName == "title") {

   128                         // item title

   129                         title = getTextOfNode(node);

   130                     } else if (node.nodeName == "pubDate" || node.nodeName == "dc:date") {

   131                         // item publishing date

   132                         date = getTextOfNode(node);

   133                     } else if (node.nodeName == "description" && !this.ignoreContent ) {

   134                         // item description

   135                         description = getTextOfNode(node);

   136                     } else if (node.nodeName == "link") {

   137                         // link URL

   138                         url = getTextOfNode(node);

   139                     } else if (node.nodeName == "dc:creator" ) {

   140 						author = getTextOfNode(node);

   141 					}

   142                 }

   143                 node = node.nextSibling;

   144             }

   145             

   146             // create the item and add to the items array

   147             items.push({ title: title, date: date, description: description, url: url, author: author });

   148         }

   149         

   150         // update was completed successfully

   151         return { status: "ok", lastModified: lastModified, items: items };

   152     } else {

   153         // update failed

   154         return { status: "error" };

   155     }

   156 }

   157 

   158 // Returns the text of a node.

   159 function getTextOfNode(node) {

   160     var buf = "";

   161 	// iterate through all child elements and collect all text to the buffer

   162 	var child = node.firstChild;

   163 	while (child != null) {

   164 		if (child.nodeType == Node.TEXT_NODE || child.nodeType == Node.CDATA_SECTION_NODE) {

   165 			// append text to buffer

   166 			if (buf != "") {

   167 				buf += " ";

   168 			}

   169 			buf += child.nodeValue;

   170 		}

   171 		child = child.nextSibling;

   172 	}

   173 	

   174 	return buf;

   175 }

   176 

   177 FeedUpdateBroker.prototype.cancel = function() {

   178 	this.cancelled = true;

   179 	this.httpReq.abort();

   180 }