Using Google's GData API

11

Clouds and Web2.0II: Case Study and Tutorial

CTS08 Tutorial Hyatt Regency Irvine California

May 19 2008

Geoffrey Fox, Marlon PierceCommunity Grids Laboratory, School of informatics

Indiana University

http://www.infomall.org/multicore gcf@indiana.edu, http://www.infomall.org

Polar Grid: A Web 2.0 Case Study

Using Microformats, GeoRSS, REST, and KML

Slides from Yu Ma

More Detailed Information

• See Marie’s blog: http://tethealla.blogspot.com/

• We use blogs in the lab extensively as lab books.

PolarGrid Datasets• A typical processed dataset consists of:

– One plain text header file describing the overall system and metadata of the particular chunk of measurements.

– Multiple JPG images processed from the corresponding raw data.

– Collection timestamp and fundamental properties such as waveform and transmitting (TX) /receiving (RX) antenna IDs are embedded in file names.

• Images are processed by Kansas University’s Matlab-based code, GOAP

Approaches• Convert unstructured metadata description

into microformats.• Construct a relational database to enable fast

and dynamic queries.• Provide geographic annotation embedded into

web feeds that can be plotted by Google Maps and Google Earth

• Technologies: – GeoRSS: RSS syndication with geo-location – Microformats: extensions to XHTML

Microformat Conversion• Microformats capture “semantic” metadata

information in XHTML format.• Principals for converted microformats:

– Simple: capture the most basic information unit.– Reusable: capture shared features among data.– Composable: when combined, can reflect more complex

relationships among data. • Most of our microformat classes are prefixed with

“pg:” denoting the PolarGrid project namespace, except when existing generic ones such as the geo microformat are used.

How To Extend XHTML

• Use either <div> or <span> tags. • Display of these tags can be controlled with

style sheets• You can also dynamically control these with

JavaScript.• Next generation of browsers will have built-in

support for well-known microformats such as hCard.

Simple Example: Geo Format

<span class="geo"> <span class="longitude">-2.193</span> <span class="latitude">52.686</span></span>

Polar Grid Microformat Examples

• Simple descriptions:<span class="pg:radar-type">MCRDS</span>

• Measurements with unit:<span class="pg:delay">

<span class="pg:value">2.5</span><span class="pg:unit">us</span>

</span>

Microformat Examples

• Identification for cross-references:<span class="pg:waveform”>

<span class="pg:id">1</span></span>

• Commonly shared features: (e.g. both TX and RX antennas record same kind of information) <span class="pg:antenna"><span class="pg:id">0</span><span

class="pg:type">TX/RX</span><span class="pg:attenuation">0</span>

</span>

Microformat Examples

• Structured collections/Arrays:<span class="pg:antenna-array"><span

class="pg:array-size">2</span><span class="pg:antenna”><span class="pg:id">0</span><span class="pg:type">TX</span><span class="pg:attenuation">0</span></span><span

class="pg:antenna”><span class="pg:id">1</span> <span

class="pg:type">TX</span> <span class="pg:attenuation">0</span></span>

</span>

Microformat Examples

• Complex objects: (e.g. spatial and temporal information that uniquely defines a processed data chunk)<span class="pg:data-chunk"><span

class="pg:name">Start/Stop</span><span class="pg:utc-timestamp">1202755351.892651</span><span class="geo">

<span class="longitude">-2.193</span> <span class="latitude">52.686</span></span>

</span>

GeoRSS-Simple Embedded Atom Feed

<?xml version="1.0" encoding="utf-8"?><feed xmlns="http://www.w3.org/2005/Atom"

xmlns:georss="http://www.georss.org/georss"> <title>PolarGrid Expedition</title> <id>tag:pg3.ucs.indiana.edu,2008:polargrid-expedition-2008-05</id> <updated>2008-05-11T02:02:54Z</updated> <author> <name>Polar Grid</name> </author> <link type="application/atom+xml" rel="self"

href="http://pg3.ucs.indiana.edu/cgi-bin/getPolarGridFeed"/>

GeoRSS-Simple Embedded Atom Feed

<entry> <title>Data Chunk: 2008-03-11 11:55:41</title> <id>tag:pg3.ucs.indiana.edu,2008:polargrid expedition-2008-05-

262</id> <updated>2008-03-11T11:55:41Z</updated> <content type="html">

… (data chunk information described in microformats) … </content> <georss:point>77.585957 -52.448461</georss:point> <georss:point>77.580976 -52.435148</georss:point> </entry></feed>

Google RSS Feed Reader

Google Maps

Corresponding KML<?xml version="1.0" encoding="UTF-8"?><kml xmlns="http://earth.google.com/kml/2.2"><Document> <name>PolarGrid Expedition</name> <Placemark id="tag:pg3.ucs.indiana.edu,2008:polargrid-expedition-2008-05-

262”> <name>Data Chunk: 2008-03-11 11:55:41</name> <description><![CDATA[ … (data chunk information described in microformats) … ]]></description> <Point><coordinates>-52.448461,77.585957</coordinates></Point> <Point><coordinates>-52.435148,77.580976</coordinates></Point></Placemark></Document></kml>

Google Earth and KML

Web 2.0 Lessons

• Web 2.0 approaches can be applied to management of scientific information.

• With the right choices, you get a lot for free.• Microformats: simple ways to encode name-

value pairs, build up semantic descriptions.• GeoRSS: orders data by both time and space

– Works in all standard RSS/Atom readers.– Google Maps supports natively

Web 2.0 Tutorial Map

Browser +JavaScript Libraries

Browser + JavaScript Libraries

Browser +JavaScript Libraries

Blogs, Calendars, Docs, etc

Social Gadget Containers

Gadgets, Gadget Aggregators

Facebook

Facebook AppsServer-SideGdata Apps

User Layer

System Cloud Layer

AJAX, JSON, REST, RSS

SOAP, REST, RSS

Map Key• Red blocks represent browsers and things that run in them

(JavaScript).– This is the “user” level.– Client side mashups

• Green blocks represent Web servers and their applications.– This is the “developer” level.– Server-side mashups.– These can run on any hosting environment: your web server, Amazon

EC2, Google GAE, etc. • Blue blocks represent third party services.

– This is the “system cloud” layer.• Arrows represent network communications.

– Everything goes over HTTP– REST, AJAX: communication patterns. – RSS, ATOM, JSON, SOAP: message format.

Using Google’s GData API

How to Write Server-Side Mash-Ups

GData: the API to Google Services• Google provides an extensive set of online services with well-known

user interfaces.– Docs– Spreadsheet– YouTube– Blogger/Blogspot– Calendar – Picasso Photo Sharing– GMail

• These have programming interfaces as well as user interfaces.– Server side: Java, .NET, PHP, Python– Client side: JavaScript

• Client interfaces include visual components suitable for mash-ups• Server-side APIs don’t include visual components but do allow you to

make server-side mash-ups.

Server-Side Mash-Up Use Case• Imagine you have a Web service that runs a large parallel finite

element code.– Output can include images, movies, output files, metadata, etc.– Your web service manages the interaction with the queuing system

(another topic…) • With a server-side mash-up, your Web Service can

– Post status information about your jobs (“Step 521 Completed!”) on your blog.

– Post URLs pointing to your output files on your blog.– Upload your visualizations to Picasso and YouTube (and post links).– Generate RSS/Atom feeds of the above.– Post results to Google Calendar

• We’ll look at some Java examples.

Getting Started with GData • Create a Blog, make sure you can login to YouTube, etc.• You will need a clientID and associated developer key.

– Get these from http://code.google.com/apis/base/signup.html.• Get the Java code

– http://code.google.com/p/gdata-java-client/downloads/list• See any number of Google examples

– http://code.google.com/apis/base/javadevguide.html• One trick: You can get your blogger ID by examining the your Blog’s Atom

feed. – It will be in the header and look something like this:

<id>tag:blogger.com,1999:blog-19457310</id> – The blog ID to use in the code below would be 19457310 in this example.

• The full working example is here– http://communitygrids.blogspot.com/2008/03/googles-gdata-java-api.html– We will simplify for pedagogical reasons.

Posting Results to Your Blogspot BlogString userName="me@gmail.com";String password= "qwerty";String content=“…”;

GoogleService myService=new GoogleService("blogger","");

myService.setUserCredentials(userName,password);

Entry myEntry = new Entry();myEntry.setTitle(new PlainTextConstruct(title));myEntry.setContent(new PlainTextConstruct(content));

URL postUrl = new URL("http://www.blogger.com/feeds/" + blogID + "/posts/default");myService.insert(postUrl, myEntry);

Create the entry to insert

Login in

Replace these with your values

Insert the new entry using REST’s POST

Getting a YouTube FeedString feedUrl="http://gdata.youtube.com/feeds/api/videos/";String scarFace5sec="http://gdata.youtube.com/feeds/api/videos/egwB7hVIIEc";

YouTubeService service = new YouTubeService(clientID, developer_key);service.setUserCredentials(userName,password);

VideoFeed videoFeed =youTubeService.getFeed(new URL(feedUrl),VideoFeed.class);

VideoEntry videoEntry = youTubeService.getEntry(new URL(scarFace5sec),VideoEntry.class);

//Loop over feed entries and display.String feedContent=

"Title: " + videoEntry.getTitle().getPlainText()+”";feedContent+=videoEntry.getMediaGroup().

getDescription().getPlainTextContent()+”";

Posting To Google CalendarCalendarService calService=new CalendarService(clientID);calService.setUserCredentials(userName,password);URL postUrl =new URL("http://www.google.com/calendar/feeds/"+userName+"/private/full");

CalendarEventEntry myEntry = new CalendarEventEntry();myEntry.setTitle(new PlainTextConstruct(titleOfEvent));myEntry.setContent(new PlainTextConstruct(contentToPost));

DateTime startTime = new DateTime(new Date());When eventTimes = new When();eventTimes.setStartTime(startTime);myEntry.addTime(eventTimes);CalendarEventEntry insertedEntry = calendarService.insert(postUrl, myEntry);

CalendarEventEntry myEntry2 = new CalendarEventEntry();String now=(new Date()).toString();myEntry2.setContent(new PlainTextConstruct("Test post at "+now));myEntry2.setQuickAdd(true);

// Send the request and receive the response:CalendarEventEntry insertedEntry2 =calendarService.insert(postUrl, myEntry2);

Create the event time and insert

Create a new Calendar entry

Log in to the calendar service

An alternative way to post the entry

Some Other Things You Can Do with GData Server Code

• YouTube– Search movies by keyword tag, “related”, categories– Upload and download movies.– Put movies into collections

• Calendar– Retrieve events as RSS feed

• Spreadsheet– Remotely retrieve and insert or change row and cell data.– Use structured queries to retrieve data ranges.– Remotely invoke batch operations

Making FaceBook Applications

Using Facebook as a backend service.

Full Examples and More Detailed Notes

• PHP and JavaScript notes– http://communitygrids.blogspot.com/2008/02/

quick-facebook-javascript-api-notes.html

• JavaScript example: – http://communitygrids.blogspot.com/2008/02/

little-more-jsfacebook-hacking.html

Why Use FaceBook as a Portal?• Because it has 10’s of millions of users.

– The largest Web 2.0-style Web portal • Easy to create Social Networks: groups of

friends and share applications, communicate, share information, etc.– And more importantly, tools for building and

managing these networks• Can leverage many third party applications

– For example, photo albums– Of course many of them are trivial, silly

FaceBook APIs• These come in two flavors

– Embedded: make your application available through FaceBook.

• PHP APIs– Embedding: use Facebook authentication and social

network data in your application.• JavaScript API

• In both cases, you run your application on your Web server.– You application do anything you can implement.– And you can query FaceBook for social network

information, user metadata.

Using The JavaScript API• Getting Started:

– You just need a Web server to host your application.– Register as a developer– Place Facebook’s xd_receiver.htm on your web server

• Make sure the relative path used is correct. • What will happen?

– Your page will run outside of Facebook.– Anyone loading your application will be directed to Facebook to login.– User is then redirected back to your page.

• Your application can make calls back to Facebook.• And you can do anything else you want.

– So you could embed this application in a portlet, interact with a local database,

– You can build your application with .NET or Java Server Faces, etc.

HTML Page Example

<textarea style="width:500px;height:300px;" id="_traceTextBox">

</textarea><script

src="http://static.ak.facebook.com/js/api_lib/FacebookApi.debug.js" type="text/javascript">var api = new FB.ApiClient('<your_key_here>',

'/xd_receiver.htm', null);…

</script>

Interact with FaceBookapi.requireLogin(function(exception) {

api.friends_get(null,getResults);var myinfo= 'last_name,

first_name,hometown_location,work_history,pic_small';

api.users_getInfo(api.get_session().uid,myinfo,getInfo);

});

Notes on Previous Slides

• The requireLogin, friends_get, and users_getInfo are FaceBook API calls.

• The getResults and getInfo methods are callback methods that I defined.– Shown in next slide

• The myinfo data structure is taken from the Facebook XML user profile.– http://wiki.developers.facebook.com/index.php/

Users.getInfo

Developer Defined Call-Back Functions

function getResults(result,exception) {Debug.dump(api.get_session().uid,’You');Debug.dump(result,’Your Friends’);

}

function getInfo(result,exception) {Debug.dump(result,’Your info');

}

These two methods receive the output returned from Facebook by the API’s friends_get() and users_getInfo() methods. The results are dumped to the text window but you can do more interesting things.

Output Info Dumped to Text Area

you: 627774031Your friends: {Array}[Deleted]

Your Info: {Array}[0]: {Object}first_name: Marlonhometown_location: {Object}city:state:country:zip:last_name: Piercepic_small: http://profile.ak.facebook.com/profile6/1797/98/t627774031_2463.jpguid: 627774031work_history: {Object}

User’s Facebook ID and the ID numbers of his friends

User’s profile metadata. Note some fields are strings, some areArrays, and some are structured objects of strings.

Facebooks’ Query Language

• All of the FaceBook API is basically a set of wrappers around their SQL like FQL query language. So you can, if you prefer, make custom methods out of FQL query strings. var myQuery='SELECT name FROM user WHERE uid='+api.get_session().uid;

api.fql_query(myQuery, getFQLResponse);

getFQLResponse() is a developer-written callback function

Working with Facebook Groups

• To list information about groups you are a member of, use the following. – You can replace the value of uid with any UID you

know.– 18629081888 is the Group ID for the Open Grid

Forum’s uninteresting Facebook group

api.groups_get(api.get_session().uid,null,getGroups);

api.groups_getMembers(18629081888,getGroupMembers);

More Information

• The JavaScript documentation is available from here– http://wiki.developers.facebook.com/index.php/

JavaScript_Client_Library• It is pretty minimal, but it is essentially the

same as the better documented PHP API.– Replace PHP’s "." with a "_". – So PHP’s users.getInfo becomes users_getInfo(...)

in JavaScript.

Open Social API and Gadgets

What Is a Gadget?

Simple gadgets for getting a Grid proxy credential and running remote commands. Both run on my own Web server.

Gadget Definition

• This XML page is web accessible via http://156.56.104.143:8080/GTLAB/MyProxyGadget.xml

• This URL points to the actual application (written in JSF)• Google uses an HTML IFrame to load the page.• You can also use content type=“html” for more integrated

applications.– For example, you can send messages between gadgets in the

client.

<?xml version="1.0" encoding="UTF-8" ?> <Module> <ModulePrefs title="MyProxy Gadget Example" scrolling="true" height="500"/> <Content type="url" href="http://156.56.104.143:8080/GTLAB/examples/MyProxyExample.jsf"> </Content> </Module>

Gadgets and Open Social• Open Social is a consortium of Facebook’s major

competitors.– Orkut, MySpace, Hi5, LinkedIn, Friendster, etc.

• The Open Social API has two parts– JavaScript libraries for building social gadgets.

• Must run in a gadget container (server)– REST APIs for exchanging data between container servers.

• The ideas:– JS APIs let you make portable gadgets that will work in

different containers (Hi5LinkedIn) but data will be different.

– REST will let you export/import data.

Getting Started• You need a Gadget container to host your gadgets.

– LinkedIn is notably selective about the gadgets it will host.• Orkut provides a sandbox, but you have to upload your

gadgets.• Apache Shindig is an extremely simple Java-based

container.– De facto reference implementation of Open Social– Not suitable for production by a long ways.– But it will work on an air plane.

• Shindig is something of a moving target.– My February notes were obsolete…

Getting Started with Shindig• Visit the Web site for information

– http://incubator.apache.org/shindig• Check out the code with SVN

– mkdir $HOME/shindig; cd shindig– svn co http://svn.apache.org/repos/asf/incubator/shindig/trunk/

• Build and run it with Apache Maven– Run “mvn” from $HOME/shindig/– Run “mvn -Prun” from $HOME/shindig/java/server

• Point browser to http://localhost:8080/gadgets/files/container/sample1.html and look through other samples. – You can also load these HTML files using file:// if you don't want to run the

Jetty server.• Periodically check for updates and rebuild

– svn update• The READMEs have better/more up-to-date information than the website.

What Do You Get?

• Shindig actually has two major parts:– A container that can run social gadgets

• This must have access to your user and social network database.

– A gadget aggregator that displays gadgets• Runs the layout manager.• Think of this as your own iGoogle server.

• Access the gadget container – http://localhost:8080/gadgets/files/

samplecontainer/samplecontainer.html

The gadget can be displayed in your http://localhost:8080 display container.

The gadget is actually served remotely. This is the module definition.

<link rel="stylesheet" href="gadgets.css"><script type="text/javascript" src="../../js/rpc.js?c=1&debug=1"></script><script type="text/javascript" src="cookies.js"></script><script type="text/javascript" src="util.js"></script><script type="text/javascript" src="gadgets.js"></script><script type="text/javascript" src="cookiebaseduserprefstore.js"></script>

Import JS Libraries into Container Page

var my = {};

my.gadgetSpecUrls = [ 'http://www.google.com/ig/modules/horoscope.xml', 'http://www.google.com/ig/modules/aue07otr.xml', 'http://www.labpixies.com/campaigns/todo/todo.xml'];

my.LayoutManager = function() { gadgets.LayoutManager.call(this);};

my.LayoutManager.inherits(gadgets.LayoutManager);

my.LayoutManager.prototype.getGadgetChrome = function(gadget) { var chromeId = 'gadget-chrome-' + gadget.id; return chromeId ? document.getElementById(chromeId) : null;};

Create Your Layout ManagerNote gadgets are loaded from remote hostcontainers.

my.init = function() { gadgets.container.layoutManager = new my.LayoutManager();};my.renderGadgets = function() { for (var i = 0; i < my.gadgetSpecUrls.length; ++i) { var gadget = gadgets.container.createGadget( {specUrl: my.gadgetSpecUrls[i]}); gadgets.container.addGadget(gadget); gadgets.container.renderGadget(gadget); }};

Initialize and Render

<body onLoad="my.init();my.renderGadgets()"> <h2>Sample: Dynamic Height</h2> <div id="gadget-chrome-0" class="gadgets-gadget-chrome"></div> <div id="gadget-chrome-1" class="gadgets-gadget-chrome"></div> <div id="gadget-chrome-2" class="gadgets-gadget-chrome"></div></body>

HTML Display

Shows the 3 Gadgets. As we saw, this will use “flow” layout and “chrome” styling.

Hosting Your Own Social Gadget

• Place your widget code here:– $HOME/shindig/javascript/samplecontainer/examples

• After compilation, these will be located here:– ./target/gadgets/files/samplecontainer/examples.

• These will be served up from– http://localhost:8080/gadgets/files/samplecontainer/

examples/myapp.xml

• Myapp.xml is the gadget definition we saw earlier.

http://localhost:8080/gadgets/files/samplecontainer/samplecontainer.html

Hello World Gadget in Container

User and his network of friends provided by the local container. “Hello” chosen based friend’s preferred

Uses flat XML file.

Shindig social network XML “database”. Real containers would use a real database.

OpenSocial API essentially lets you retrieve this sort of data.

my.gadgetSpecUrls = [ 'http://www.google.com/ig/modules/horoscope.xml', 'http://www.google.com/ig/modules/aue07otr.xml', 'http://localhost:8080/gadgets/files/samplecontainer/examples/SocialHelloWorld.xml'];

More Information

• See http://communitygrids.blogspot.com for more detailed information.

• Email: mpierce@cs.indiana.edu