Api web 2.0
Representational state transfer
• REST is not a protocol or a format its a kind of architecture
• A service is accessed with its URI through HTTP operation like GET, POST, PUT or DELETE.
• Enough for most of web services
• Example :
http://www.inria.fr/add?var=1&var=2 3 ;)
HTTP Query with JAVA• Init the HTTP query:URL url = new URL("my_url");HttpURLConnection UrlConn = (HttpURLConnection)
url.openConnection();urlConn.setRequestMethod("GET");urlConn.setAllowUserInteraction(false);urlConn.setDoOutput(true);
• Read the answerInputStream response = urlConn.getInputStream();BufferedReader br = new BufferedReader(new InputStreamReader(response));while ((String line = o_oBufReader.readLine()) != null){
//do whatever you want}
• DiconnecturlConn.disconnect();
AJAX
• Asynchronous javascript
• HTTP query in javascript without reloading all the page
• Richer interfaces
• Example: mail notification and instant messaging in gmail.
AJAX : init the query
Var xhr;
if (window.XMLHttpRequest) { xhr = new XMLHttpRequest(); // Firefox, Safari, ...
} else if (window.ActiveXObject) {
xhr = new ActiveXObject("Microsoft.XMLHTTP"); // Internet Explorer } or
try { xhr = new ActiveXObject("Microsoft.XMLHTTP"); //try Internet Explorer
}catch(e) { xhr = new XMLHttpRequest() //firefox, safari ...
}
AJAX : send and process query
• Process function :
request.onreadystatechange = function(){ // instructions
};
• Send the query : xhr.open('GET', 'http://web2/api/method?param=value', true);xhr.send(null);
• Important: Same Origin PolicySo use a servlet as intermediary
JSON: JavaScript Object Notationhttp://www.json.org/
• JSON object:var person = { "name" : "John"
"phone" : [ {"type" : "home", "num" : "1234"}, {"type" : "mobile", "num" : "5678"} ]
}; person.name; person.phone[0].num;
• Eval function:var JSONString = "someVar = { 'color' : 'blue' }";
eval(JSONString); • Tutorial: http://www.hunlock.com/blogs/Mastering_JSON_(_JavaScript_Object_Notation_)
API flickrhttp://www.flickr.com/services/api/
• API_Key and secret:http://www.flickr.com/services/api/keys/apply/
Note : il faut un compte Yahoo pour y accèder.
• URL API: http://api.flickr.com/services/rest/?method=method_name¶m1=value1¶m2=value2...
• Paramètre souvent requis: api_key– On demande la clé en ligne, cf URL ci-dessus.
• Recherche de photos par tags:http://api.flickr.com/services/rest/?method=flickr.photos.search&tags=a_tag&api_key=your_key
Example of XML Response
• URL API: http://api.flickr.com/services/rest/?method_name¶m1=value1¶m2=value2...
• Paramètre souvent requis: api_key
• Recherche de photos par tags:http://api.flickr.com/services/rest/?method=flickr.photos.search&tags=a_tag&api_key=your_key
Don't worry: API JAVA ;)
• Dom API:DocumentBuilderFactory fabrique =
DocumentBuilderFactory.newInstance();DocumentBuilder constructeur =
fabrique.newDocumentBuilder();Document document = constructeur.parse(rdfFile);Element racine = document.getDocumentElement();NodeList photos = racine.getElementsByTagName("photo");for(int i = 0; i < photos.getLength(); i++){
photos.item(i).getAttributes() …}
• Or just forget to manipulate XML: http://sourceforge.net/projects/flickrj/
FlickrJ: API JAVAhttp://sourceforge.net/projects/flickrj/
• Init service:Flickr flickr = new Flickr(apiKey, secret, new REST());
• Different interfaces:– flickr.getPhotosInterface()– flickr.getPeopleInterface()– flickr.getContactsInterface()– flickr.getLicensesInterface()– flickr.getTagsInterface()– …
FlickrJ: examplehttp://sourceforge.net/projects/flickrj/
• Init service:Flickr flickr = new
Flickr("47422029b3aabee4aca6a5853eca74b6", "ab7f2d30639a9828", new REST());
PhotosInterface pi = flickr.getPhotosInterface();
SearchParameters sp = new SearchParameters(); String []tabTag = {« cars »}; sp.setTags(tabTag);
PhotoList photoList = pi.search(sp, 50, 1); Iterator it = photoList.iterator();
while (it.hasNext()) { Photo photo = (Photo) it.next(); out.println("<img src='" +
photo.getThumbnailUrl() + "' />"); }
JSON and flickrhttp://api.flickr.com/services/rest/?method=method_name&format=json
• URL API: Example: flickr.blogs.getList– XML response
<blogs> <blog id="73" name="Bloxus" url="http://remote.bloxus.com/" /> <blog id="74" name="Manila" url="http://test1.userland.com/" />
</blogs>
– JSON responsersp = { "stat": "ok",
"blogs": { "blog": [{ "id" : "73", "name" : "Bloxus", "url" : "..."
}{ "id" : "74", "name" : "Manila", "url" :
"..." } ] } }
• URL API: Examplefor (var i=0; i<rsp.blogs.blog.length; i++){
var blog = rsp.blogs.blog[i]...
}
Youtubehttp://code.google.com/apis/youtube
• API key and secret:http://code.google.com/apis/youtube/dashboard
• REST interface:http://www.youtube.com/api2_rest
• To request a response in JSON format, use the alt=json parameter.
• Server side API: Java, .NET, PHP, python …
• Widget and players API (client side): javascript, flash
API JAVA Youtubehttp://code.google.com/p/gdata-java-client/downloads/list
• Importimport com.google.gdata.client.youtube.YouTubeService;import com.google.gdata.util.ServiceException;
• Init serviceYouTubeService myService =
new YouTubeService("the name of my app");
• Init search query:YouTubeQuery query =
new YouTubeQuery(new URL(URL_VIDEOS_FEED));
• Appel au service:VideoFeed videoFeed =
service.query(query, VideoFeed.class); for (VideoEntry ve : videoFeed.getEntries()) { ... }
API Youtube
• Parametrize query:– search terms: query.setVideoQuery(searchTerms); – Order: RELEVANCE, VIEW_COUNT, PUBLISHED, RATING :
query.setOrderBy(YouTubeQuery.OrderBy.RELEVANCE); – Number of results: query.setMaxResults(count);– Pagination: query.setStartIndex(start); – include restricted content (excluded by default): query.setIncludeRacy(true);
• Code example
Google search: AJAX APIhttp://code.google.com/apis/ajaxsearch/documentation/
• Basis:// create a search controlvar searchControl = new google.search.SearchControl(null);
// add in a full set of searcherssearchControl.addSearcher(new google.search.LocalSearch());searchControl.addSearcher(new google.search.WebSearch());searchControl.addSearcher(new google.search.VideoSearch());searchControl.addSearcher(new google.search.BlogSearch());searchControl.addSearcher(new google.search.NewsSearch());searchControl.addSearcher(new google.search.ImageSearch());searchControl.addSearcher(new google.search.BookSearch());searchControl.addSearcher(new google.search.PatentSearch());
// tell the searcher to draw itself and tell it where to attach// Note that an element must exist within the HTML document with id "search_control"searchControl.draw(document.getElementById("search_control"));
Google search: AJAX APIhttp://code.google.com/apis/ajaxsearch/documentation/
• SearcherControl Draw Modes:– create a drawOptions object
var drawOptions = new google.search.DrawOptions();
– tell the searcher to draw itself in linear mode
drawOptions.setDrawMode(google.search.SearchControl.DRAW_MODE_LINEAR);
– tell the searcher to draw itself in linear mode
drawOptions.setDrawMode(google.search.SearchControl.DRAW_MODE_TABBED);
– decouple the "search form" from the set of search results
drawOptions.setSearchFormRoot(document.getElementById("id_dom_elem"));
– Display results :
searchControl.draw(element, drawOptions);
Google search: AJAX APIhttp://code.google.com/apis/ajaxsearch/documentation/
• Keeping a Search Result:// establish a keep callbacksearchControl.setOnKeepCallback(this, MyKeepHandler);
function MyKeepHandler(result) { // clone the result html nodevar node = result.html.cloneNode(true); // attach itvar savedResults = document.getElementById("saved_results");savedResults.appendChild(node);
}
Google maphttp://code.google.com/apis/ajaxse
arch/
http://gmaps-samples.googlecode.com/svn/trunk/demogallery.html
API Facebook
• Install facebook "Developper" application to get API_Key and secret.
• Interface restful:http://api.facebook.com/restserver.php?
v=1.0&api_key=YOUR_API_KEY&method=METHOD_NAME&sig=METHOD_OPTIONS
• FacebookML: A meta language to develop facebook apps (interpreted on facebook servers)
• FQL: Facebook Query Language• Server API: Php, java, .NET, etc;
API java pour Facebook
• Plus maintenue par facebook:
Alternatives: http://code.google.com/p/facebook-java-api
• Authentification de l'application:
Facebook fb = new Facebook(request, response, FB_API_KEY, FB_SECRET_KEY);
fb.requireLogin("") if(!face.isLogin()) return null; //can't access applicationFacebookRestClient fbrclient = fb.getFacebookRestClient();
• Id utilisateur:
fbrclient.users_getLoggedInUser();
API java pour Facebook
• Récupérer le nom et status de l'utilisateur courant (un peu compliqué, mais bon…):
//fill the list of users
ArrayList<Long> user = new ArrayList<Long>();//set of information required on usersEnumSet<ProfileField> fields =
EnumSet.of(com.facebook.api.ProfileField.NAME,com.facebook.api.ProfileField.STATUS);
users.add(fbrclient.users_getLoggedInUser()); Document d = fbrclient.users_getInfo(users, fields);String userName =
d.getElementsByTagName(com.facebook.api.ProfileField.NAME.fieldName).item(0).getTextContent();
String userName =
d.getElementsByTagName(com.facebook.api.ProfileField.NAME.fieldName).item(0).getTextContent();
API java pour Facebook
• Informations sur les amis:
Document d = fbrclient.friends_get();NodeList userIDNodes = d.getElementsByTagName("uid");Collection<Integer> friends = new ArrayList<Integer>(); for (int i = 0; i < userIDNodes.getLength(); i++) {
Node node = userIDNodes.item(i);Integer id = Integer.valueOf(node.getTextContent());friends.add(id);
}Document infos =
fbrclient.users_getInfo(users, fields);//then we can iterate on the list of friends id and get the
informationfor(Integer id : friends){
String fieldName = infos.getElementsByTagName(...).item(i).getTextContent(); //etc.
}
And more…
• All google apps: http://code.google.com/more– Open social http://code.google.com/apis/opensocial/
– Maps: http://code.google.com/apis/maps/– Etc.
• Delicious: http://delicious.com/help/api • Digg: http://apidoc.digg.com/ • Technorati: http://technorati.com/developers/api/• And most of web 2.0 platforms propose access
to their data through APIs!!!
It's your turn now !!!
Build a search engine that search on different web 2.0 services and propose differents médias:
• Photos with flickr• Video with youtube• People and social features with facebook• And whatever you want with web 2.0 APIs.
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