Maintaining session in android ( application stay authenticated on the server side)-ThrowExceptions

Exception or error:

I am building a login application in android in which i am hitting a url(with username and password) upto that part it works fine but after that whenever I am hitting a url(once the user is authenticated) , it return nothing(i.e. a error message like please login first). However it works fine in very similar iphone app and on browser.

I got somewhere that it is the error of phpSessionId(i.e. the session is destroyed for further request) and If we want our Android application to stay authenticated on the server side we need to fetch that id after the first connection and then send it in the headers of all our subsequent requests.

But the problem is that I am unable to get the sessionId from header of the first connection and sending it with further request along with the header.

Please give me some codes or links to complete the task properly.
Thanks.

How to solve:

Finally I solved the issue of session handling in Android.
Android cant handle the session itself(which a simple browser can) so we have to handle it explicitly.
I changed the code for http connection a bit.
Created an instance of DefaultHttpClient in the first Activity when connection established.

public static DefaultHttpClient httpClient;

For the first time connection,I did the following:

URL url=new URL(urlToHit);
LoginScreen.httpClient = new DefaultHttpClient(); //LoginScreen is the name of the current Activity

HttpPost httppost = new HttpPost(url.toString());
HttpResponse response = LoginScreen.httpClient.execute(httppost); 

xr.parse(new InputSource(url.openStream())); //SAX parsing

Now for all further connections I used the same httpClient
For example in the next activity:

URL url=new URL(urlToHit);

HttpPost httppost = new HttpPost(url.toString());
HttpResponse response = LoginScreen.httpClient.execute(httppost); 

// Log.v("response code",""+response.getStatusLine().getStatusCode());

// Get hold of the response entity
HttpEntity entity = response.getEntity();

InputStream instream = null;

if (entity != null) {
    instream = entity.getContent();
}
xr.parse(new InputSource(instream)); //SAX parsing

Hope this will help you all too to solve session issue in Android.

###

The best idea is to put all the function that your server do in on unique class which is going to be call by the tasks which want to connect. I call this class WebServiceManager. This class have exactly the same method than the server.

As you want an unique session do :

private static WebServiceManager wsm = null;

public static WebServiceManager getInstance() {
    if (wsm == null) {
        wsm = new WebServiceManager();
    }
    return wsm;
}

private final HttpClient httpClient;

private WebServiceManager() {
    httpClient=new DefaultHttpClient();
}

and then you call the method of your instance of webServiceManager to use always the same session. 🙂

###

My problem was that i login first and saved the returned session in userpreferences.
After that the POST call to set a record said

“Error ,Cannot authenticate the User”

So i added
post.setHeader("oAuth-Token", UserPreferences.ACCESS_TOKEN);
the whole thing looks like this.

HttpPost post=new HttpPost(URL );  
post.setHeader("oAuth-Token", UserPreferences.ACCESS_TOKEN);    

.
.
and It solved the problem.

###

I wrote a post about it a while back on coderwall
It uses the HttpRequestInterceptor and HttpResponseInterceptor classes which are perfect for that kind of scenario.

Here is an example:

public class HTTPClients {

private static DefaultHttpClient _defaultClient;
private static String session_id;
private static HTTPClients _me;
private HTTPClients() {

}
public static DefaultHttpClient getDefaultHttpClient(){
    if ( _defaultClient == null ) {
        _defaultClient = new DefaultHttpClient();
        _me = new HTTPClients();
        _defaultClient.addResponseInterceptor(_me.new SessionKeeper());
        _defaultClient.addRequestInterceptor(_me.new SessionAdder());
    }
    return _defaultClient;
}

private class SessionAdder implements HttpRequestInterceptor {

    @Override
    public void process(HttpRequest request, HttpContext context)
            throws HttpException, IOException {
        if ( session_id != null ) {
            request.setHeader("Cookie", session_id);
        }
    }

}

private class SessionKeeper implements HttpResponseInterceptor {

    @Override
    public void process(HttpResponse response, HttpContext context)
            throws HttpException, IOException {
        Header[] headers = response.getHeaders("Set-Cookie");
        if ( headers != null && headers.length == 1 ){
            session_id = headers[0].getValue();
        }
    }

}

}

###

Here is an another implementation using Volley library … a very useful hint from https://stackoverflow.com/a/36496607/3099185

    CustomRequest jsonObjReq = new CustomRequest(Request.Method.GET,
            url, null,  new Response.Listener<JSONObject>() {

        @Override
        public void onResponse(JSONObject response) {
                Log.d(TAG, response.toString());
        }
    }, new Response.ErrorListener(){

        @Override
        public void onErrorResponse(VolleyError error) {
            VolleyLog.d(TAG, "Error: " + error.getMessage());
            Toast.makeText(getApplicationContext(),
                    error.getMessage(), Toast.LENGTH_SHORT).show();
            // hide the progress dialog
        }
    });

Custom request class

import android.util.Log;

import com.android.volley.AuthFailureError;
import com.android.volley.Response;
import com.android.volley.toolbox.JsonObjectRequest;

import org.json.JSONObject;

import java.util.HashMap;
import java.util.Map;

public class CustomRequest extends JsonObjectRequest {
    private String session_id = "";

    public CustomRequest(int method, String url, JSONObject jsonRequest,
                                   Response.Listener listener, Response.ErrorListener errorListener) {
        super(method, url, jsonRequest, listener, errorListener);
    }

    public CustomRequest(int method, String url, JSONObject jsonRequest, String session_id,
                                   Response.Listener listener, Response.ErrorListener errorListener) {
        super(method, url, jsonRequest, listener, errorListener);
        this.session_id = session_id;
    }


    @Override
    public Map getHeaders() throws AuthFailureError {
        Map headers = new HashMap();
        Log.d(TAG, " -> session_id = " + session_id);
        if(!(session_id.equals(""))) {
            headers.put("Cookie", this.session_id);
        }
        return headers;
    }

}

Simple way of implementing volley using singleton pattern
http://arnab.ch/blog/2013/08/asynchronous-http-requests-in-android-using-volley/

Remember to initialize mRequestQueue in onCreate() to avoid unexpected null pointer exception

@Override
public void onCreate() {
    super.onCreate();

    // initialize the singleton
    sInstance = this;
        mRequestQueue = Volley.newRequestQueue(this);
}

Hope this help too … ! 🙂

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