How can I use Scribe with JSF to connect to the LinkedIn API?

Question

Based upon the Scribe example on github, I'm trying to authorize my application to use LinkedIn's api.

Here is my current code that is tied to a button click:

public String generateFromLinkedIn() {
    OAuthService service = new ServiceBuilder()
         .provider(LinkedInApi.class)
         .apiKey(apiKey)
         .apiSecret(apiSecret)
         .callback("http://localhost:8080/Project/faces/linkedIn.xhtml").build();

    ExternalContext externalContext = FacesContext.getCurrentInstance()
         .getExternalContext();

    Token requestToken = service.getRequestToken();
    String authUrl = service.getAuthorizationUrl(requestToken);

    try {
        externalContext.redirect(authUrl);
    } catch (IOException ex) {
        Logger.getLogger(LinkedInController.class.getName()).log(Level.SEVERE, null, ex);
    }

    Map<String, String> parameterMap = (Map<String, String>) externalContext.getRequestParameterMap();

    Verifier v = new Verifier(parameterMap.get("oauth_verifier"));
    Token accessToken = service.getAccessToken(requestToken, v);

    OAuthRequest request = new OAuthRequest(Verb.GET, "https://api.linkedin.com/v1/people/~");

    service.signRequest(accessToken, request); 
    Response response = request.send();

    System.err.println(response.getBody());

    return "";
}

And in my .xhtml page I have:

<h:commandButton value="Generate" action="#{linkedInController.generateFromLinkedIn()}"></h:commandButton>

Everything works okay until I try to get the Verifier from the parameter map, which does not have any oauth_verifier. I tried splitting it up into multiple methods, but so far I cannot obtain the oauth_verifier from the URL parameters even though it is clearly there after returning from LinkedIn authorization dialog.

Any suggestions on how to get this verifier correctly or how to make Scribe work with JSF?

Answer 1

You seem somehow to expect that the redirected request magically returns to exactly same location in the code and continues from there. This is untrue. It are effectively 2 HTTP requests. You're basically still fiddling around in the parameter map of the current request (the one which called the generateFromLinkedIn() method).

After you call redirect() you should be returning from the method. You should move the remainder of the code into the @PostConstruct or <f:viewAction> of the backing bean tied to linkedIn.xhtml. It's the one who's called with the parameter.