Java Android HTTP POST login error

Question

i have a problem logging in to a website made in asp... Here is the code i am using:

public class MainActivity extends Activity {
Button bottone;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        bottone = (Button) findViewById(R.id.button1);
        if (android.os.Build.VERSION.SDK_INT > 9) {
            StrictMode.ThreadPolicy policy = 
                    new StrictMode.ThreadPolicy.Builder().permitAll().build();
            StrictMode.setThreadPolicy(policy);
            }
        bottone.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // starting new Async Task
                try {
                    login();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
    public static void login() throws IOException
    {
        String loginurl = "https://www.blurum.it/Web/", user, pass;
        user = "tester55";
        pass = "provapassword321";

        DefaultHttpClient httpClient = new DefaultHttpClient();
        HttpPost httpPost = new HttpPost(loginurl);

        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(3);
        nameValuePairs.add(new BasicNameValuePair("ctrl_LoginControl$loginView$c01$RPLogin$LoginView$Username", user));
        nameValuePairs.add(new BasicNameValuePair("ctrl_LoginControl$loginView$c01$RPLogin$LoginView$Password", pass));
        nameValuePairs.add(new BasicNameValuePair("remember", "on"));
        nameValuePairs.add(new BasicNameValuePair("ctrl_LoginControl$loginView$c01$RPLogin$LoginView$LoginButton", "Accedi"));



        httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

        // Execute HTTP Post Request 
        HttpResponse response = httpClient.execute(httpPost);
        Log.d("logggd", "response stat code " + response.getStatusLine().getStatusCode());

        if (response.getStatusLine().getStatusCode() < 400) {

            String cookie = response.getFirstHeader("Cookie")
                    .getValue();
            Log.d("logggdc", "cookie: " + cookie);

            // get the contacts page 
            HttpGet getContacts = new HttpGet("https://www.blurum.it/Web/default.aspx");
            getContacts.setHeader("Cookie", cookie);
            response = httpClient.execute(getContacts);

            InputStream ins = response.getEntity().getContent();
            BufferedReader in = new BufferedReader(new InputStreamReader(
                    ins));

            String inputLine;
            while ((inputLine = in.readLine()) != null) {
                Log.d("logggd1", " " + inputLine);
            }

            in.close();
        } else {
                Log.d("logggd2", "Response error: "
                        + response.getStatusLine().getStatusCode());
            }
        }
    }

But my application crash, so i can't find the error in the code... Here is the logcat:

    11-12 20:05:37.678: W/dalvikvm(1806): threadid=1: thread exiting with uncaught exception (group=0xb4177180)
11-12 20:05:37.688: E/AndroidRuntime(1806): FATAL EXCEPTION: main
11-12 20:05:37.688: E/AndroidRuntime(1806): java.lang.NullPointerException
11-12 20:05:37.688: E/AndroidRuntime(1806):     at com.example.testlogin.MainActivity.login(MainActivity.java:93)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at com.example.testlogin.MainActivity$1.onClick(MainActivity.java:53)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at android.view.View.performClick(View.java:3511)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at android.view.View$PerformClick.run(View.java:14105)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at android.os.Handler.handleCallback(Handler.java:605)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at android.os.Handler.dispatchMessage(Handler.java:92)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at android.os.Looper.loop(Looper.java:137)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at android.app.ActivityThread.main(ActivityThread.java:4424)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at java.lang.reflect.Method.invokeNative(Native Method)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at java.lang.reflect.Method.invoke(Method.java:511)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
11-12 20:05:37.688: E/AndroidRuntime(1806):     at dalvik.system.NativeStart.main(Native Method)
11-12 20:05:38.218: I/dalvikvm(1806): threadid=3: reacting to signal 3
11-12 20:05:38.228: I/dalvikvm(1806): Wrote stack traces to '/data/anr/traces.txt'

I extracted the posted data to the server in firefox with Tamper Data, here is a screen, the login i think is divided in 2 post, here are the screen: https://i.sstatic.net/GZiZ0.png https://i.sstatic.net/FKH3P.png

I am not sure if i have to send the first page or the second post data, can be this the error? thanks.

Answer 1

It seems response.getFirstHeader("Cookie") is returning null.

As per javadoc

Returns the first header with a specified name of this message. Header values are ignored. If there is more than one matching header in the message the first element of getHeaders(String) is returned. If there is no matching header in the message null is returned

Solution:

Do a null check before calling getValue();

Example:

String cookie = null;
if(response.getFirstHeader("Cookie") != null)
{
cookie = response.getFirstHeader("Cookie")
                    .getValue();
}

Answer 2

You can't call the below line more than once in your code block;

response.getStatusLine()

You are calling it more than once in your lines that look like this;

Log.d("logggd", "response stat code " + response.getStatusLine().getStatusCode());

And then you're calling it again on this line;

if (response.getStatusLine().getStatusCode() < 400) {

Comment out the first calling of response.getStatusLine() - that's where you're trying to log the status code. So your code should look like this;

//Log.d("logggd", "response stat code " + response.getStatusLine().getStatusCode());

You also want to try and do this somewhere there in your method called login();

    // Execute HTTP Post Request 
    HttpResponse response = httpClient.execute(httpPost);
    StatusLine statusLine = response.getStatusLine();

    Log.d("logggd", "response stat code " + statusLine.getStatusCode());


    if (statusLine.getStatusCode() < 400) {

         String cookie = null;
          if(response.getFirstHeader("Cookie") != null){
                 cookie = response.getFirstHeader("Cookie").getValue();
          }
          Log.d("logggdc", "cookie: " + cookie);

    //...etc....etc...etc