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October 11, 2011 17:46
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Alternate JavaScript implementation of Feed2JS using the Google Feed API
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| /** | |
| * Feed2JS using the Google Feed API | |
| * | |
| * Inspired by Feed2JS (http://feed2js.org) | |
| * | |
| * Author: Richard Davies (http://www.richarddavies.us) | |
| * | |
| * Example Usage: | |
| * <!-- Requires the Google Loader and API key from http://code.google.com/apis/loader/signup.html --> | |
| * <script src="https://www.google.com/jsapi?key=YOUR_KEY_HERE"></script> | |
| * <script src="feed2js.js" data-src="http://www.example.com/feed.xml" data-num="3" data-html="n" data-pc="y"></script> | |
| * | |
| * Attributes * = default value | |
| * data-src URL of feed | |
| * data-chan Display channel? | |
| * y* Display title and description | |
| * title Display title only | |
| * n Don't Display title or description | |
| * data-num Max number of feed items to display | |
| * 0* Display all items (max 100 items) | |
| * data-desc Display item descriptions? | |
| * y* Display description | |
| * n No description | |
| * data-html Use HTML in item description? | |
| * y* Use HTML from feed, ignoring data-desc character limit | |
| * n Use plain text description snippet (< 120 characters) | |
| * data-date Display time and date for each item | |
| * y Display date/time | |
| * n* No date/time | |
| * pc Podcast (media) enclosures (for RSS 2.0 feeds with enclosures) | |
| * y Display link to media files | |
| * n* Don't display media files | |
| * | |
| * Google Feed API Documentation | |
| * http://code.google.com/apis/ajaxfeeds/documentation/reference.html | |
| */ | |
| // Get a reference to the currently executing <script> element | |
| // Since scripts are executed sequentially the currently executing script is always the last script in the DOM so far. | |
| // (Unless executing script adds any additional script elements, as google.load() does... so put it first) | |
| var scripts = document.getElementsByTagName('script'); | |
| var thisScript = scripts[scripts.length - 1]; | |
| // If this is the first execution on the page initialize some global variables and load Google Feeds API | |
| if (typeof feed2js_idx === 'undefined') { | |
| var feed2js_idx = 0; // Global var to track current index # (for multiple feeds on a page) | |
| var feed2js_DOMready = false; // Global flag to signal when DOM has finished loading | |
| google.load('feeds', '1'); | |
| google.setOnLoadCallback(function() { | |
| feed2js_DOMready = true; | |
| }); // i.e. <body onload="..."> | |
| } | |
| (function() { | |
| var idx = feed2js_idx++; | |
| var id = 'rss-box-' + (idx+1); | |
| var attributes = new Object(); | |
| attributes.feedURL = thisScript.getAttribute('data-src'); | |
| attributes.chan = thisScript.getAttribute('data-chan') || 'y'; | |
| attributes.num = thisScript.getAttribute('data-num') || 0; | |
| attributes.desc = thisScript.getAttribute('data-desc') || 'y'; | |
| attributes.html = thisScript.getAttribute('data-html') || 'y'; | |
| attributes.date = thisScript.getAttribute('data-date') || 'n'; | |
| attributes.pc = thisScript.getAttribute('data-pc') || 'n'; | |
| if (attributes.num <= 0) | |
| attributes.num = 100; | |
| // Create container div element for feed and insert into DOM after current <script> element | |
| var container = document.createElement('div'); | |
| container.id = id; | |
| container.className = 'rss-box'; | |
| thisScript.parentNode.insertBefore(container, thisScript.nextSibling); | |
| // There is a new WHATWG proposal to add document.currentScript, but it only works in Firefox as of Oct. 2011 | |
| // document.currentScript.parentNode.insertBefore(container, document.currentScript.nextSibling); | |
| // Wait unti feed2js_DOMready is true before proceeding | |
| var intervalID = setInterval(function() { | |
| if (feed2js_DOMready) { | |
| clearInterval(intervalID); | |
| // Create a Google Feed API instance that will grab RSS feed | |
| var feed = new google.feeds.Feed(attributes.feedURL); | |
| // Set number of feed items to load | |
| feed.setNumEntries(attributes.num); | |
| // Request the feed and call the callback function with the result | |
| feed.load(function(result) { | |
| // Grab the DOM container we will put the results into | |
| var container = document.getElementById(id); | |
| if (!result.error) { | |
| // Build feed title and description | |
| if (attributes.chan == 'y' || attributes.chan == 'title') { | |
| // Feed title | |
| var title = document.createElement('div'); | |
| title.className = 'rss-title'; | |
| title.innerHTML = '<a href="{url}">{title}</a>'.supplant({ | |
| title: result.feed.title, | |
| url: result.feed.link | |
| }); | |
| // Include feed description? | |
| if (attributes.chan == 'y') | |
| title.innerHTML += '<br />{desc}'.supplant({ | |
| desc: result.feed.description | |
| }); | |
| // Output title and description | |
| container.appendChild(title); | |
| } | |
| // Build list of feed items | |
| var ul = document.createElement('ul'); | |
| ul.className = 'rss-items'; | |
| for (var i = 0; i < result.feed.entries.length; i++) { | |
| var entry = result.feed.entries[i]; | |
| var li = document.createElement('li'); | |
| li.className = 'rss-item'; | |
| li.innerHTML = '<a href="{url}">{title}</a>'.supplant({ | |
| title: entry.title, | |
| url: entry.link | |
| }); | |
| // Include item timestamp? | |
| if (attributes.date == 'y') { | |
| var entryDate = new Date(entry.publishedDate); | |
| li.innerHTML += '<br /><span class="rss-date">{date}</span>'.supplant({ | |
| date: entryDate.toLocaleString() | |
| }); | |
| } | |
| // Include item description? | |
| if (attributes.desc == 'y') | |
| li.innerHTML += '<br />{desc}'.supplant({ | |
| desc: attributes.html == 'y' ? entry.content : entry.contentSnippet | |
| }); | |
| // Include media enclosures? | |
| if (attributes.pc == 'y' && entry.mediaGroups) { | |
| var media = document.createElement('div'); | |
| media.className = 'rss-item-media'; | |
| var p = document.createElement('p'); | |
| p.innerHTML = 'Media files'; | |
| media.appendChild(p); | |
| var ul2 = document.createElement('ul'); | |
| media.appendChild(ul2); | |
| for (var prop1 in entry.mediaGroups) | |
| for (var prop2 in entry.mediaGroups[prop1].contents) { | |
| var mediaEnc = entry.mediaGroups[prop1].contents[prop2]; | |
| var li2 = document.createElement('li'); | |
| li2.innerHTML += '<a href="{url}" title="{type}">{title}</a> ({size})'.supplant({ | |
| url: mediaEnc.url, | |
| title: (function() { | |
| // Extract filename from URL | |
| var matches = mediaEnc.url.match(/([^\/]*)$/); | |
| return RegExp.$1; | |
| })(), | |
| type: mediaEnc.type, | |
| size: (function() { | |
| // Convert file size in bytes to KB or MB | |
| var fileSizeKB = mediaEnc.fileSize/1024; | |
| if (fileSizeKB < 1000) | |
| return Math.round(fileSizeKB) + ' KB'; | |
| else { | |
| var fileSizeMB = fileSizeKB/1024; | |
| return Math.round(fileSizeMB*10)/10 + ' MB'; | |
| } | |
| })() | |
| }); | |
| ul2.appendChild(li2); | |
| } | |
| li.appendChild(media); | |
| } | |
| ul.appendChild(li); | |
| } | |
| // Output list of feed items | |
| container.appendChild(ul); | |
| } else { // Error loading feed | |
| container.className += ' rss-error'; | |
| var errorHead = document.createElement('p'); | |
| errorHead.innerHTML = '<strong>ERROR: The following error occurred while loading the feed <a href="{feedURL}">{feedURL}</a>:</strong>'.supplant({ | |
| feedURL: attributes.feedURL | |
| }); | |
| var errorMsg = document.createElement('p'); | |
| errorMsg.innerHTML = '{code} {desc}'.supplant({ | |
| code: result.error.code, | |
| desc: result.error.message | |
| }); | |
| var errorHelp = document.createElement('p'); | |
| errorHelp.innerHTML = 'Please verify that the <a href="{feedURL}">feed URL</a> works in your browser and that the feed passes a <a href="{validatorURL}">validator test</a>.'.supplant({ | |
| feedURL: attributes.feedURL, | |
| validatorURL: 'http://feedvalidator.org/check.cgi?url=' + attributes.feedURL | |
| }); | |
| // Output error message | |
| container.appendChild(errorHead); | |
| container.appendChild(errorMsg); | |
| container.appendChild(errorHelp); | |
| } | |
| }); | |
| } | |
| }, 100); | |
| })(); | |
| // Supplant function allows for variable substitution inside a string | |
| // http://javascript.crockford.com/remedial.html | |
| String.prototype.supplant = function (o) { | |
| return this.replace(/{([^{}]*)}/g, | |
| function (a, b) { | |
| var r = o[b]; | |
| return typeof r === 'string' || typeof r === 'number' ? r : a; | |
| } | |
| ); | |
| }; |
This is cool, Richard. Where can I see it in action? and how would one use it?
There is an example of how to use it in the comment header in the code. You can see it in use at http://www.publicalerts.org/index.cfm?c=51183
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Feed2JS is a RSS to HTML parser. This is a (mostly complete) alternate implementation I created that uses the Google Feed API instead of the hosted service at http://feed2js.org. It has the following advantages over the hosted service: