Designing Secure Authentication & Web Service Integration for Mobile App

Add necessary dependencies: In your app's build.gradle file, include the required dependencies for handling authentication and network communication.

implementation 'com.google.firebase:firebase-auth:20.0.0'
implementation 'com.squareup.okhttp3:okhttp:4.9.1'

Set up Firebase Authentication: Initialize Firebase Authentication in your app by adding the necessary configuration in your AndroidManifest.xml file, and obtain a Firebase project-specific configuration file (google-services.json) from the Firebase console.

Implement social media authentication:Use Firebase Authentication to authenticate users with their social media accounts.

// Create a GoogleSignInClient
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
        .requestIdToken(getString(R.string.default_web_client_id))
        .requestEmail()
        .build();
GoogleSignInClient mGoogleSignInClient = GoogleSignIn.getClient(this, gso);

// Start the sign-in intent
Intent signInIntent = mGoogleSignInClient.getSignInIntent();
startActivityForResult(signInIntent, RC_SIGN_IN);

Handle the authentication result:After the user selects their social media account and grants permission, handle the authentication result in the onActivityResult() method.

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == RC_SIGN_IN) {
        Task task = GoogleSignIn.getSignedInAccountFromIntent(data);
        try {
            // Get the GoogleSignInAccount
            GoogleSignInAccount account = task.getResult(ApiException.class);

            // Use the account to authenticate with your web service
            // Send the authentication token to your server for verification

        } catch (ApiException e) {
            // Handle the exception
        }
    }
}

Communicate securely with the web service:To securely communicate with the web service, you can use HTTPS and include the necessary headers, such as an authentication token, in the API calls.

// Create an OkHttpClient instance
OkHttpClient client = new OkHttpClient();

// Build the request body
RequestBody requestBody = new FormBody.Builder()
        .add("token", authToken)
        .build();

// Create the request
Request request = new Request.Builder()
        .url("https://example.com/api/user-data")
        .post(requestBody)
        .build();

// Execute the request asynchronously
client.newCall(request).enqueue(new Callback() {
    @Override
    public void onFailure(Call call, IOException e) {
        // Handle the failure
    }

    @Override
    public void onResponse(Call call, Response response) throws IOException {
        // Handle the response
    }
});

Ensure you handle errors, store and refresh authentication tokens appropriately, and implement necessary security measures to protect user data.