Question

How can I send an invitation to use an app with Graph API? I looked at the reference, and can’t find something that fits. Any clue?

Answer 1

If you need to use restfb, as I got from your tags, you can try this:

This is a self contained junit test that retrieves the authentication token and posts an apprequest. No user generated auth_token is required but you can only send apprequests like this to users that already have authorized your app.

Dependencies are JUnit, Commons HttpClient and restfb itself.

package com.apprequesttest;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.methods.GetMethod;
import org.junit.Test;

import com.restfb.DefaultFacebookClient;
import com.restfb.Facebook;
import com.restfb.FacebookClient;
import com.restfb.Parameter;
import com.restfb.types.FacebookType;

public class AppRequestTest
{
    @Test
    public void testAppRequest() throws Exception
    {
        String appId = "YOUR_APP_ID";
        String appSecret = "YOUR_ACCESS_TOKEN";
        String tokenUrl = "https://graph.facebook.com/oauth/access_token?client_id=" + appId + "&client_secret=" + appSecret
                + "&grant_type=client_credentials";
        HttpClient client = new HttpClient();
        HttpMethod method = new GetMethod(tokenUrl);

        client.executeMethod(method);
        String rawAccessToken = new String(method.getResponseBody());

        String accessToken = rawAccessToken.split("=")[1];

        FacebookClient facebookClient = new DefaultFacebookClient(accessToken);

        String apprequestCall = "TARGET_USER_ID/apprequests";

        AppRequestResponse apprequest = facebookClient.publish(apprequestCall,
                                                               AppRequestResponse.class,
                                                               Parameter.with("message", "BANANAMSG"),
                                                               Parameter.with("data", "BANANADATA"));

        System.out.println(apprequest.request);
        System.out.println(apprequest.to);

    }

    /**
     * Couldn't find any beans that would acomodate this response on restfb so we create our own here
     * Looks like "to" is an array but this works well enough for the sake of the example 
     */
    public static class AppRequestResponse extends FacebookType
    {
        private static final long serialVersionUID = 1L;

        public AppRequestResponse()
        {
            // Empty
        }

        @Facebook
        public String request;

        @Facebook
        public String to;
    }
}