This tutorial shows you
the basic of OAuth using Apache Oltu (Formely known as Apache Amber).
We have created a Java Web Application that authenticates the user to
Facebook via OAuth 2.0 and retreive the protected resources from
Facebook.
Setup
:
Run
the Project :
Check
out the project from the above URL, import into the eclipse and Run
as a Server.
Click
on the link and it will take you the Facebook page for Authentication
:
Once
you are login into Facebook, It will ask you to allow the Oauth
application to access your private data:
Once
you click on “Okay” button. It will display your profile detail
like UserId, Name etc.
Code
Description :
OAuthServlet.Java
In the Servlet initParams, We
have defined the clientId, clinetSecret and the redirectUri, You can
change it as per your Apps.
//
clientId is 'App ID '
@WebInitParam(name
= "clientId",
value = "YOUR_CLIENT_ID"),
//
clientSecret is 'App Secret'
@WebInitParam(name
= "YOUR_CLIENT_SECRET",
value = "70ba69525274876dce9697ad183a9051"),
//
This must be identical to 'Valid OAuth Redirect URI's'
The
Java Web Application act as a third-party website or termed as
“client” which operate on behalf of a user. It first sends the
request to Facebook which authenticates the user, obtain the user's
authorization(i,e Approve/Deny page) and issues an access token which
client can use while interacting with the resource server i,e
Facebook to access public profile of the user.
End
user Authorization request :
Created
the End User Authorization Request by providing end-user
authorization URI at the Authorization Server (e.g. Facebook),
application's client id and a redirect URI in order to receive the
authorization code. Apache Oltu has an enum OAuthProviderType for
authorization and token endpoints of common OAuth 2 providers like
Facebook.
OauthClientRequest
authClientRequest = OAuthClientRequest
.authorizationProvider(OAuthProviderType.FACEBOOK)
.setClientId(clientId).setRedirectURI(redirectUri)
.buildQueryMessage();
The
above code will produce an OAuth request where all the parameters are
encoded in the URL query.
response.sendRedirect(authClientRequest.getLocationUri());
Get Authorization Code
from redirect URI :
Once
the user grants permission for your client application, then the
Facebook will redirects the user to redirectUri with the code in the
request parameter.
OAuthAuthzResponse
oar = OauthAuthzResponse.oauthCodeAuthzResponse(request); code =
oar.getCode();
Exchange
OAuth code for an access token :
Apache
Oltu has two different classes to parse the access token response.
Facebook’s response is not fully compliant with the final version
of the OAuth 2 specification, but it can be parsed using the class
GitHubTokenResponse.
OauthClientRequest
authClientRequest =
OAuthClientRequest.tokenProvider(OAuthProviderType.FACEBOOK)
.setGrantType(GrantType.AUTHORIZATION_CODE)
.setClientId(clientId).setClientSecret(clientSecret)
.setRedirectURI(redirectUri).setCode(authorizationCode)
.buildBodyMessage();
//create
OAuth client that uses custom http client under the hood
oAuthClient
= new OAuthClient(new URLConnectionClient());
GitHubTokenResponse
oAuthResponse =
oAuthClient.accessToken(authClientRequest,
GitHubTokenResponse.class);
String
accessToken = oauthResponse.getAccessToken();
Get
Facebook profile data :
OAuthClientRequest
bearerClientRequest = new
OAuthBearerClientRequest("https://graph.facebook.com/me").setAccessToken(accessToken).buildQueryMessage();
OAuthResourceResponse
resourceResponse oAuthClient.resource(bearerClientRequest,
OAuth.HttpMethod.GET,
OauthResourceResponse.class);
DisplayFacebookProfile.Java
This
class will display the user profile on the UI.
Summary
:
This
application demonstrates the basic of OAuth 2.0 using Apache Oltu i,e how to authenticates the user and retreive the protected resources from
Facebook.
Resources
:
https://cwiki.apache.org/confluence/display/OLTU/OAuth+2.0+Client+Quickstart
Code download link:
https://drive.google.com/file/d/0B7WKU816EmtaSUw3UmpsWUljWk0/view?usp=sharing
