Netvibes UWA workshop at ParisWeb 2007

Universal Widget API : How to build multiplaform widgets Xavier Borderie / netvibes http://dev.netvibes.com ParisWeb 2007 workshop Saturday, November 17th, 2007

What are widgets • Small, specialized applications (mostly) • Available through the browser: Netvibes, iGoogle, Live.com,YourMinis... • Available through an installed engine:Vista Gadgets, Apple Dashboard,Yahoo! Widgets, Opera...

Netvibes’ thinking when creating UWA • MiniAPI is doing quite well • 1000 modules since May 2006 • Positive feedbacks from the community • No de-facto standard • Each site/engine uses its own format • W3C’s speciﬁcation is still in its infancy (working draft)

What UWA promises • Works on the most popular platforms, without any change to the original ﬁle • Today: Netvibes, iGoogle, Live.com, Opera, Apple Dashboard, Windows Vista, Yahoo! Widgets • Works just like MiniAPI, in a stricter way • Easy to learn thanks to proven standards: XHTML/XML, JavaScript/Ajax, CSS

UWA basics • One static XHTML ﬁle, using well-formed XML • UTF-8 encoding • Netvibes namespace a must: xmlns:widget=“http://www.netvibes.com/ns/”

Presenting the basic skeleton • http://dev.netvibes.com/ﬁles/uwa-skeleton.html • Starting point for most of the developers, through copy/pasting • Skeleton generator is in the testing phase...

Skeleton 1 : XHTML headers • Nothing new here... • ...just don’t forget the Netvibes namespace <?xml version=\"1.0\" encoding=\"utf-8\"?> <!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Strict//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd\"> <html xmlns=\"http://www.w3.org/1999/xhtml\" xmlns:widget=\"http://www.netvibes.com/ns/\" > <head> <title>Title of the Widget</title> <link rel=\"icon\" type=\"image/png\" href=\"http://www.netvibes.com/favicon.ico\" />

Skeleton II : meta tags • Various usages • Most are optional <meta name=\"author\" content=\"John Doe\" /> <meta name=\"website\" content=\"http://exemple.org\" /> <meta name=\"description\" content=\"A descriptive description\" /> <meta name=\"keywords\" content=\"these, are, key words\" /> <meta name=\"screenshot\" content=\"http://exemple.org/widget-full.png\" /> <meta name=\"thumbnail\" content=\"http://exemple.org/widget-logo.png\" /> <meta name=\"apiVersion\" content=\"1.0\" /> <meta name=\"autoRefresh\" content=\"20\" /> <meta name=\"debugMode\" content=\"true\" />

Skeleton III : emulation ﬁles • Optional but very useful when testing in Standalone mode <link rel=\"stylesheet\" type=\"text/css\" href=\"http://www.netvibes.com/themes/uwa/style.css\" /> <script type=\"text/javascript\" src=\"http://www.netvibes.com/js/UWA/load.js.php? env=Standalone\"></script>

Skeleton IV : UWA preferences • UWA-speciﬁc tag set • Bad: doesn’t work well with the W3C XHTML validator • Good: makes for more portable preferences <widget:preferences> <preference name=\"url\" type=\"text\" label=\"URL\" defaultValue=\"http://feeds.feedburner.com/NetvibesDevBlog\" /> <preference name=\"pass\" type=\"password\" label=\"Password\" /> <preference name=\"displayImages\" type=\"boolean\" label=\"Display images?\" defaultValue=\"true\" /> <preference name=\"limit\" type=\"range\" label=\"Number of items to display\" defaultValue=\"10\" step=\"1\" min=\"1\" max=\"25\" /> <preference name=\"category\" type=\"list\" label=\"Category\" defaultValue=\"1st\" onchange=\"refresh\"> <option value=\"all\" label=\"all\" /> <option value=\"1st\" label=\"First category\" /> <option value=\"2nd\" label=\"Second category\" /> <option value=\"3rd\" label=\"Third category\" /> </preference> <preference name=\"search\" type=\"hidden\" defaultValue=\"\" /> </widget:preferences>

<widget:preferences> <preference name=\"url\" type=\"text\" label=\"URL\" defaultValue=\"http://feeds.feedburner.com/NetvibesDevBlog\" /> <preference name=\"password\" type=\"password\" label=\"Password\" /> <preference name=\"displayImages\" type=\"boolean\" label=\"Display images?\" defaultValue=\"true\" /> <preference name=\"limit\" type=\"range\" label=\"Number of items to display\" defaultValue=\"10\" step=\"1\" min=\"1\" max=\"25\" /> <preference name=\"category\" type=\"list\" label=\"Category\" defaultValue=\"1st\" onchange=\"refresh\"> <option value=\"all\" label=\"all\" /> <option value=\"1st\" label=\"First category\" /> <option value=\"2nd\" label=\"Second category\" /> <option value=\"3rd\" label=\"Third category\" /> </preference> <preference name=\"search\" type=\"hidden\" defaultValue=\"\" /> </widget:preferences>

Skeleton V : CSS and JavaScript code • Simple: just use the dedicated tags <style type=\"text/css\"> /* your CSS rules */ </style> <script type=\"text/javascript\"> var YourWidgetName = {}; YourWidgetName.data = null; YourWidgetName.display = function(responseJson) { // display code } widget.onLoad = function() { UWA.Data.getFeed(widget.getValue('url'), YourWidgetName.display); } widget.onRefresh = widget.onLoad; widget.refresh = widget.onLoad; </script>

Skeleton VI : End of ﬁle • The body can be pre-ﬁlled or completely empty: its content is free since the DOM can update it at any time • Data are loaded using JavaScript and placed in the body using the DOM </head> <body> <p>Loading...</p> </body> </html>

What about diving into some code?

Using CSS and JavaScript • Works just like in a classic HTML file: <script> and <style> • Refrain from using external files: put everything in the widget • CSS: try prefixing every rule with class named after the widget, .myWidget p { ... } • CSS: target with classes rather than ids • JS: put every method/variable in an object named after the widget, var MyWidget = {};

Practical examples: ʇxǝʇdılɟ Fireplace

Fliptext • http://nvmodules.typhon.net/maurice/ ﬂiptext/ • Entirely made with just HTML, CSS et JS - no external calls • Adapted in UWA from the original code, to be found at: http://www.ﬂiptext.org/

widget.onLoad = function() { for (i in Flip.table) { Flip.table[Flip.table[i]] = i } out = '<textarea></textarea><p><button>flip <img src=\"http://nvmodules.typhon.net/maurice/fliptext/refresh.png\" alt=\"Flip\" /> dılɟ</button></p><textarea></textarea>'; widget.setBody(out); var bt = widget.body.getElementsByTagName('button')[0]; var textareas = widget.body.getElementsByTagName('textarea'); bt.onclick = function(){ var result = Flip.flipString(textareas[0].value.toLowerCase()); textareas[1].value = result; } }

Fireplace • http://nvmodules.typhon.net/maurice/ ﬁreplace/index.html • Demonstrating the possibility to use Flash • The widget generates the HTML using JavaScript, but you can directly place the <object> tag within the widget’s body, and never use JavaScript • You can also directly submit your SWF to Ecosystem, which will wrap it in a UWA container for you

widget.onLoad = function() { var contentHtml = ''; contentHtml += '<div style=\"margin: 0 auto;text- align:center;\">'; contentHtml += '<object type=\"application/x-shockwave-flash\" data=\"http://nvmodules.typhon.net/maurice/fireplace/fire.swf\" width=\"320\" height=\"240\" class=\"flash\">'; contentHtml += '<param name=\"movie\" value=\"http:// nvmodules.typhon.net/maurice/fireplace/fire.swf\" />'; //contentHtml += '<param name=\"wmode\" value=\"opaque\" />'; contentHtml += '<embed src=\"http://nvmodules.typhon.net/ maurice/fireplace/fire.swf\" type=\"application/x-shockwave-flash\" width=\"320\" height=\"240\"></embed>'; contentHtml += '</object>'; contentHtml += '</div>'; widget.setBody(contentHtml); widget.onResize(); }

Let’s practice

Build a Zorglangue widget from the Fliptext widget • http://ndiremdjian.free.fr/pics/zorglangue.htm • Same CSS and widget.onLoad() as in Fliptext • Just place the linked page’s JavaScript in a Zorglub object.

The ﬁnal Zorglangue • http://nvmodules.typhon.net/maurice/ zorglub/ • Compare the code with Fliptext: http://nvmodules.typhon.net/maurice/ ﬁreplace/index.html

UWA’s JavaScript method and properties • Refrain from using or document window • Replace with document.getElementById(‘id’) widget.body.getElementsByClassName(‘class’)[0] • HTML elements are only extended when created using widget.createElement(). You can extend them by hand: var foo = UWA.$element (widget.body.getElementsByClassName (‘bar’)[0]; foo.setStyle(‘backgroundColor’, ‘red’);

UWA’s JavaScript method and properties • Most of the methods and properies have been moved document and window, into two UWA-speciﬁc objects: widget et UWA. • widget: usual methods found in JavaScript frameworks • UWA: mostly only used for UWA.Data, which contains the Ajax methods • See the UWA cheat-sheet :)

Ajax methods • 4 quick methods: • UWA.Data.getText(url, callback); • UWA.Data.getXml(url, callback); • UWA.Data.getJson(url, callback); • UWA.Data.getFeed(url, callback); • All are built upon the master one: • UWA.data.request(url, request);

UWA.Data.request • Allows you to make more complex queries: POST + parameters, authentication, cache handling... • UWA.Data.request(url, request) : • request = { method:’post’, proxy:’ajax’, cache:3600, parameters:’lastname=Bond&id=007’, onComplete:MyWidget.display };

Practical examples: Getting images out of a feed: FFFFOUND Handling a feed: Skyblog getText and parsing: DeMets getText and parsing: LinkedIn

Getting images out of a feed: FFFFOUND • http://nvmodules.typhon.net/maurice/uwa- ffffound/ • JS: getting the feed with getFeed(), extracting the image links (<link> from the JSON feed format), HTML code built on the ﬂy • CSS: placing the elements • JSON Feed Format: http://dev.netvibes.com/ doc/uwa_speciﬁcation/ uwa_json_feed_format

Handling RSS/Atom: Skyblog • http://nvmodules.typhon.net/maurice/ skyblog/ • Preferences: blog’s name and number of articles to display • JS: parsing the JSON feed, building the HTML code using the DOM rather than in a string • Nota: use of the limit preference • Nota: UWA.Utils.setTooltip()

getText and parsing : DeMets • http://nvmodules.typhon.net/maurice/uwa- demets/ • getText on a custom PHP script (UTF-8 conversion) • A few RegExps to remove most of the useless content • ﬁnally getting and displaying the restaurant’s menu

getText and parsing : LinkedIn • http://ﬂorent.solt.googlepages.com/linkedin- pretty.html • getText directly on the URL to be parsed • Display the chosen section (via preference), with a bit of RegExps to simplify/manipulate the content

Models and controlers • To better ﬁt in the platform’s theme/style • To ease the conception of some common applications/needs

Models • CSS classes • Data grid • E-mail list • Feed list • Rich list • Thumbnailed list

Controlers • CSS classes + JavaScript behaviors • TabView • Pager

Practical examples: getFeed and FeedList: RSSReader JSON request and Pager: Twitter getJson and TabView: TwitterKing getText parsing and TabView+Pager+...: Rugby World Cup

RSS Reader • http://www.netvibes.com/api/uwa/examples/ rssreader.html • getFeed translate any kind of feed into an internal and normalized JSON format • http://dev.netvibes.com/doc/ uwa_speciﬁcation/uwa_json_feed_format • From there on, retrieving the data in JavaScript is just a matter of knowing what’s where in the JSON feed

Twitter • http://dev.netvibes.com/ﬁles/examples/ twitter-05-auth-getpost.html • UWA.Data.request on an authenticated JSON • HTML building with the DOM and UWA méthods (setHTML, etc.)

TwitterKing • http://www.my-widget.com/ twitter_widget.html • Just like the previous Twitter widget, but overcharged with any possible API call and UWA controler :)

Rugby World Cup • http://nvmodules.typhon.net/romain/ rugbyworldcup/ • getText directly on a third-party URL • Code parsing, RegExp, recomposition of the original links, Pager, TabView... the whole shebang

Thank you! • http://dev.netvibes.com • http://dev.netvibes.com/doc/ • http://dev.netvibes.com/forum/ • http://dev.netvibes.com/blog/ • http://eco.netvibes.com • We are always hiring! :) http://dev.netvibes.com/doc/jobs

Netvibes UWA workshop at ParisWeb 2007

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