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 answer
InputStream response = urlConn.getInputStream();
BufferedReader br =
new BufferedReader(new InputStreamReader(response));
while ((String line = o_oBufReader.readLine()) != null){
//do whatever you want
}
• Diconnect
urlConn.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 Policy
So use a servlet as intermediary
JSON: JavaScript Object Notation
http://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 flickr
http://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/?metho
d=method_name&param1=value1&param2=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=yo
Example of XML Response
• URL API:
http://api.flickr.com/services/rest/?metho
d_name&param1=value1&param2=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=yo
ur_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 JAVA
http://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: example
http://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 flickr
http://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 response
rsp = { "stat": "ok",
"blogs": {
"blog": [{ "id" : "73", "name" : "Bloxus", "url" : "..." }
{ "id" : "74", "name" : "Manila", "url" : "..." } ]
}
}
• URL API: Example
for (var i=0; i<rsp.blogs.blog.length; i++){
var blog = rsp.blogs.blog[i]
...
}
Youtube
http://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 Youtube
http://code.google.com/p/gdata-java-client/downloads/list
• Import
import com.google.gdata.client.youtube.YouTubeService;
import com.google.gdata.util.ServiceException;
• Init service
YouTubeService 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 API
http://code.google.com/apis/ajaxsearch/documentation/
• Basis:
// create a search control
var searchControl = new google.search.SearchControl(null);
// add in a full set of searchers
searchControl.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 API
http://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 API
http://code.google.com/apis/ajaxsearch/documentation/
• Keeping a Search Result:
// establish a keep callback
searchControl.setOnKeepCallback(this, MyKeepHandler);
function MyKeepHandler(result) {
// clone the result html node
var node = result.html.cloneNode(true);
// attach it
var savedResults =
document.getElementById("saved_results");
savedResults.appendChild(node);
}
Google map
http://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 application
FacebookRestClient 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 users
EnumSet<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.fi
eldName)
.item(0).getTextContent();
String userName =
d.getElementsByTagName(com.facebook.api.ProfileField.NAME.fi
eldName)
.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
information
for(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/
•
•
•
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– 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.