author | ivanl |
Thu, 30 Jul 2009 16:17:56 +0100 | |
changeset 16 | 6544cc5386ce |
parent 15 | 5e64ec5b1dfe |
child 18 | b73e6caf0031 |
permissions | -rw-r--r-- |
0 | 1 |
/////////////////////////////////////////////////////////////////////////////// |
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// The FeedUpdateBroker class implements a simple RSS fetcher and parser. |
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// Adapted from WRTKit RssReader example |
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// Constructor. |
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function FeedUpdateBroker() { |
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this.httpReq = null; |
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this.feedAddress = null; |
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this.callback = null; |
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this.ignoreContent = false; |
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this.cancelled = false; |
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this.responseParser = this.handleRssResponse; |
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this.startFromItem = 0; |
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this.maxItems = 0; |
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} |
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// Fetches a feed from the specified URL and calls the callback when the feed |
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// has been fetched and parsed, or if the process results in an error. |
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FeedUpdateBroker.prototype.doFetchFeed = function(){ |
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// create new XML HTTP request |
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this.httpReq = new Ajax(); |
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// set callback |
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var self = this; |
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this.httpReq.onreadystatechange = function() { self.readyStateChanged(); }; |
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// initiate the request |
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this.httpReq.open("GET", nocache(this.feedAddress), true); |
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this.httpReq.send(null); |
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} |
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// has been fetched and parsed, or if the process results in an error. |
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FeedUpdateBroker.prototype.fetchFeed = function(feedURL, callback) { |
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// remember callback |
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this.callback = callback; |
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this.feedAddress = feedURL; |
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this.doFetchFeed(); |
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} |
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// Callback for ready-state change events in the XML HTTP request. |
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FeedUpdateBroker.prototype.readyStateChanged = function() { |
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// complete request? |
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if (this.httpReq.readyState == 4) { |
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// attempt to get response status |
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var responseStatus = null; |
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try { |
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responseStatus = this.httpReq.status; |
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} catch (noStatusException) {} |
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// are we being prompted for login? |
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var text = this.httpReq.responseText; |
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if ( isLoginPrompt (text) ) { |
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var self = this; |
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setTimeout(self.doFetchFeed(), 100); |
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// login(function(){self.doFetchFeed();}); |
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return; |
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} |
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// handle the response and call the registered callback object |
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var response = this.httpReq.responseXML; |
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if (response == null) { |
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// if the content type is not set correctly, we get the response as text |
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var xmlparser = new DOMParser(); |
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response = xmlparser.parseFromString(this.httpReq.responseText, "text/xml"); |
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} |
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this.callback.feedUpdateCompleted(this.handleResponse(responseStatus, response)); |
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} |
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} |
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// Handles a completed response. |
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FeedUpdateBroker.prototype.handleResponse = function(responseStatus, xmlDoc){ |
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if (this.responseParser == null) { |
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return this.handleRssResponse(responseStatus, xmlDoc); |
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} |
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else { |
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return this.responseParser.call(this, this, responseStatus, xmlDoc); |
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} |
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} |
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FeedUpdateBroker.prototype.handleRssResponse = function(broker, responseStatus, xmlDoc){ |
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if ( this.cancelled ) { |
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return { status: "cancelled" }; |
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} |
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if (responseStatus == 200 && xmlDoc != null) { |
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// node ref for iterating |
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var node; |
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// get last modified time - default to current time |
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var lastModified = new Date().getTime(); |
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var channelElements = xmlDoc.getElementsByTagName("channel"); |
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if (channelElements.length > 0) { |
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node = channelElements[0].firstChild; |
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while (node != null) { |
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if (node.nodeType == Node.ELEMENT_NODE) { |
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if (node.nodeName == "pubDate" || |
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node.nodeName == "lastBuildDate" || |
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node.nodeName == "dc:date") { |
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lastModified = getTextOfNode(node); |
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break; |
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} |
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} |
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node = node.nextSibling; |
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} |
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} |
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// init feed items array |
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var items = []; |
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// we got the feed XML so now we'll parse it |
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var itemElements = xmlDoc.getElementsByTagName("item"); |
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for (var i = this.startFromItem; i < itemElements.length; i++) { |
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if ( this.maxItems > 0 && this.maxItems < i ) { |
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break; |
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} |
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// iterate through child nodes of this item and gather |
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// all the data we need for a feed item |
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var title = null; |
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var date = null; |
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var description = null; |
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var url = null; |
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var author = null; |
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node = itemElements[i].firstChild; |
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while (node != null) { |
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if (node.nodeType == Node.ELEMENT_NODE) { |
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if (node.nodeName == "title") { |
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// item title |
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title = getTextOfNode(node); |
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} else if (node.nodeName == "pubDate" || node.nodeName == "dc:date") { |
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// item publishing date |
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date = getTextOfNode(node); |
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} else if (node.nodeName == "description" && !this.ignoreContent ) { |
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// item description |
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description = getTextOfNode(node); |
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} else if (node.nodeName == "link") { |
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// link URL |
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url = getTextOfNode(node); |
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} else if (node.nodeName == "dc:creator" ) { |
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author = getTextOfNode(node); |
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} |
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} |
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node = node.nextSibling; |
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} |
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// create the item and add to the items array |
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items.push({ title: title, date: date, description: description, url: url, author: author }); |
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} |
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// update was completed successfully |
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return { status: "ok", lastModified: lastModified, items: items }; |
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} else { |
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// update failed |
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return { status: "error" }; |
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} |
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} |
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// Returns the text of a node. |
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function getTextOfNode(node) { |
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var buf = ""; |
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// iterate through all child elements and collect all text to the buffer |
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var child = node.firstChild; |
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while (child != null) { |
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if (child.nodeType == Node.TEXT_NODE || child.nodeType == Node.CDATA_SECTION_NODE) { |
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// append text to buffer |
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if (buf != "") { |
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buf += " "; |
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} |
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buf += child.nodeValue; |
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} |
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child = child.nextSibling; |
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} |
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4 | 173 |
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10
07ac2f6a36a9
1.0rc10 Fixes annoyances and buglets in reading forums and blog.
ivanl
parents:
6
diff
changeset
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return buf; |
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} |
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FeedUpdateBroker.prototype.cancel = function() { |
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this.cancelled = true; |
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this.httpReq.abort(); |
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} |