SDKs for Android / How to use Pay Station in combination with Firebase authentication
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SDKs for Android

How to use Pay Station in combination with Firebase authentication

If you have already implemented user authentication in your application using Firebase, you can generate a payment token on Firebase side and then pass it to the client side of the application to open the payment UI.

Using this integration option, you need to independently implement the logic for determining the user’s country and currency to pay for the purchase.

Integration flow:

  1. Create a project.
  1. Sign up to Publisher Account and create a new project. You will need the ID of the created project in further steps.

  1. Set up a catalog:
    • Create an item catalog on Xsolla side. You can add items manually or import them from Google Play or PlayFab.
    • Implement getting and displaying the catalog on the client side of the application using the Store library.

  1. Set up an item purchase:
    • Create an order with user and item data on the client side of the application using the Firebase Cloud Function.
    • Implement the opening of the payment UI on the client side of your application using the Payments library.

  1. Set up an order status tracking.

Notice

To complete the integration and start accepting real payments, you need to sign a licensing agreement with Xsolla.

You can sign the licensing agreement at any integration step, but keep in mind that the review process can take up to 3 business days.

Use the sample web application as an example to implement the combined use of Firebase authentication and Pay Station. The source code for the sample web application is available on GitHub.

Create project

Sign up to Publisher Account

Publisher Account is the main tool to configure Xsolla features, as well as to work with analytics and transactions.

The data about the company and your application specified during registration will be used to create a draft licensing agreement with Xsolla and to generate recommendations on solutions that are suitable for you. You can change the data later, but providing the correct data when you sign up will speed up the process of signing the licensing agreement.

To sign up, go to Publisher Account and create an account.

Note

The password from Publisher Account can consist of Latin letters, numerals, and special characters and must contain at least:

  • 8 characters
  • one digit
  • one capital letter
  • one lowercase letter

To ensure password security, we recommend:

  • changing your password at least once every 90 days
  • using a new password that does not match the last 4 passwords on your account
  • using a unique password that does not match passwords used anywhere else
  • not storing your password where it is easily accessible
  • using password managers to store your password

Publisher account uses two-factor authentication and sends a confirmation code with each authentication attempt.

Create project in Publisher Account

If you have multiple applications, we recommend creating a separate project for each application. Based on the data specified during project creation, Xsolla generates recommendations on solutions that are suitable for you.

To create a new project:

  1. Open Publisher Account.
  2. In the side menu, click Create project.

  1. Enter your project name in English (required).

Note
After you’ve created the project, you can add additional languages and localized project names in the Project settings section.

  1. Select one or several release platforms of your game (required).
  2. Add a link to your game. If your game doesn’t have a website yet, add a link to the source that includes information about the game (required).
  3. Select the game engine.
  4. Select the monetization options you use or plan to use.
  5. Specify if the game is already released. If the game hasn’t been released yet, specify the planned release date.
  6. Click Create project. You will see a page with the Xsolla products recommended for you.

During the integration process, you need to provide the project ID that can be found in your Publisher Account next to the project name.

Set up catalog

Create items in Publisher Account

Notice

You need to create a catalog on Xsolla side. You can add items manually or import them from Google Play or PlayFab. When importing from Google Play, you can import a maximum of 100 items at a time.

These instructions provide steps for basic setup of a virtual item. Later, you can add other items to your catalog (virtual currency, bundles, game keys), create item groups, set up promotional campaigns, regional prices, etc.

To add a virtual item with basic settings to the catalog:

  1. Open your project in Publisher Account.
  2. Click Store in the side menu.
  3. In the Virtual Items pane, click Connect.
  4. In the drop-down menu, select Create item.

  1. Set the basic settings of the item in the following fields:
    • Image (optional)
    • SKU (item unique ID)
    • Item name
    • Description (optional)

  1. Specify item price:
    1. Set the Price in real currency toggle to On.
    2. In the Default currency field, change the currency (optional) and specify the item price.
    3. If you changed the currency in the Default currency field, select the same currency in the Price in real currency field.

Note
To ensure that the API calls for getting the catalog work correctly, make sure that the default currency and the list of currencies in which prices are specified match for all items.

  1. Change the item status to Available.

  1. Click Create item.

Display catalog on client side of application

  1. Add the Store library to your project. To do this, open build.gradle and add the following line to the dependencies section:

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    implementation("com.xsolla.android:store:latest.release")
    

    1. On the client side of the application, add a UI to display the product catalog.
    2. Implement requesting for an item catalog from Xsolla servers.

    Note
    In the example, the XStore.getVirtualItems method to get a list of virtual items is used. You can also get information about catalog items using other Store library methods.

    Example (StoreActivity class of the sample web application):

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    package com.xsolla.androidsample
    
    import androidx.appcompat.app.AppCompatActivity
    import android.os.Bundle
    import android.widget.Toast
    import androidx.recyclerview.widget.LinearLayoutManager
    import androidx.recyclerview.widget.RecyclerView
    import com.xsolla.android.store.XStore
    import com.xsolla.android.store.callbacks.GetVirtualItemsCallback
    import com.xsolla.android.store.entity.response.items.VirtualItemsResponse
    import com.xsolla.androidsample.adapter.BuyItemAdapter
    
    class StoreActivity : AppCompatActivity() {
    
        private lateinit var itemsView: RecyclerView
    
        override fun onCreate(savedInstanceState: Bundle?) {
            super.onCreate(savedInstanceState)
            setContentView(R.layout.activity_store)
    
            XStore.init(<projectId>)
    
            initUI()
            loadVirtualItems()
        }
    
        private fun initUI() {
            itemsView = findViewById(R.id.buy_recycler_view)
            itemsView.layoutManager = LinearLayoutManager(this)
        }
    
        private fun loadVirtualItems() {
            val parentActivity = this
            XStore.getVirtualItems(object : GetVirtualItemsCallback {
                override fun onSuccess(response: VirtualItemsResponse) {
                    itemsView.adapter = BuyItemAdapter(parentActivity, response.items.filter { item -> item.virtualPrices.isEmpty() && !item.isFree })
                }
    
                override fun onError(throwable: Throwable?, errorMessage: String?) {
                    showNotificationMessage(errorMessage ?: throwable?.javaClass?.name ?: "Error")
                }
            })
        }
    
        private fun showNotificationMessage(message: String) {
            Toast.makeText(
                baseContext,
                message,
                Toast.LENGTH_SHORT,
            ).show()
        }
    }
    

    In the XStore.init() initialization block of the script, specify the project ID that you can find in your Publisher Account next to the project name.

    Set up item purchase

    Create order using the Cloud Functions

    To create an order with user and item data on Xsolla side, add a Cloud Function to the project that uses the Create payment token for purchase API call. This call will return a payment token, which is required to open the payment UI and make a purchase.

    Limitations:

    • You need to pass either the user country or the user’s IP address when requesting the payment token.
    • If you don’t pass the currency in the token, it is determined by the country.
    • If you pass the currency in the token, the user pays in this currency.

    Note
    You need to first create and initialize a Firebase project, and activate user authentication using Firebase. For details on these steps, refer to the following Firebase instructions:

    To add a Cloud Function to a project:

    1. Install the Firebase CLI (Command-Line Interface). To do this, run the CLI command:

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      npm install -g firebase-tools
      

      1. To link your project to the Firebase project, initialize the Firebase project by running the CLI command:

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        firebase init functions
        

        1. Follow the installer’s instructions to configure the settings:
          1. Select an existing codebase.
          2. Specify JavaScript as the language for creating Cloud Functions.
          3. Install dependencies.

        1. Open functions/index.js and modify it:

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        // The Cloud Functions for Firebase SDK to create Cloud Functions and triggers.
        const functions = require('firebase-functions/v1');
        
        const projectId = <projectId>;
        const apiKey = <apiKey>;
        
        exports.getXsollaPaymentToken = functions.https.onRequest((req, res) => {
        
          const requestBody = req.body;
            if (!requestBody) {
              res.status(400).send('Request body is missing');
              return;
            }
        
          const userId = requestBody.data.uid;
          const email = requestBody.data.email;
          const sku = requestBody.data.sku;
          const returnUrl = requestBody.data.returnUrl;
        
          const payload = {
            user: {
              id: {value: userId},
              name: {
                value: email
              },
              email: {
                value: email
              },
              country: {
                value: 'US',
                allow_modify: false
              }
            },
            purchase: {
              items: [
                {
                  sku: sku,
                  quantity: 1
                }
              ]
            },
            sandbox: true,
            settings: {
              language: 'en',
              currency: 'USD',
              return_url: returnUrl,
              ui: {
                theme: '63295aab2e47fab76f7708e3'
              }
            }
          }
        
          let url = "https://store.xsolla.com/api/v3/project/" + projectId.toString() + "/admin/payment/token";
        
          fetch(
            url,
            {
              method: "POST",
              headers: {
                'Content-Type': 'application/json',
                Authorization: 'Basic ' + btoa(`${projectId}:${apiKey}`)
              },
              body: JSON.stringify(payload)
            },
          )
          .then(xsollaRes => {
            // Handle the response data
            if (xsollaRes.ok) {
              return xsollaRes.json();
            } else {
              throw new Error(`HTTP request failed with status ${xsollaRes.status} and statusText: ${xsollaRes.statusText}`)
            }
          })
          .then(data => {
            res.send(JSON.stringify(data));
          })
          .catch(error => {
            res.send("Error = " + error);
          });
        });
        
        exports.webhookFakeResponse = functions.https.onRequest((request, response) => {
          response.status(200).send()
        })
        

        1. In the script, specify the values ​​for the variables:
          • projectId — project ID that you can find in your Publisher Account next to the project name.

          • apiKey — API key. It is shown in Publisher Account only once when it is created and must be stored on your side. You can create a new key in the following section:
            • Company settings > API keys
            • Project settings > API keys

        1. To test the Cloud Function with the emulator, run the CLI command:

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          firebase emulators:start
          

          1. After running the Cloud Function, you can call the following methods on the client side of your application:
            • getXsollaPaymentToken — returns the payment token for opening the payment interface.
            • webhookFakeResponse — sends the HTTP code 200 in response to the Payment webhook. The method doesn’t contain purchase validation logic: use it only for testing. For the full list of webhooks and general information about working with them, refer to the webhooks documentation.

          1. To call methods locally, use the https://localhost:5001/{firebase-project-id}/us-central1/getXsollaPaymentToken and https://localhost:5001/{firebase-project-id}/us-central1/webhookFakeResponse URLs, where {firebase-project-id} is the Firebase project ID (Firebase console > Project Settings > Project ID).

          1. To deploy the Cloud Function in production, run the CLI command:

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            firebase deploy --only functions
            

            1. Once deployed in production, you can call methods via the https://us-central1-{firebase-project-id}.cloudfunctions.net/getXsollaPaymentToken and https://us-central1-{firebase-project-id}.cloudfunctions.net/webhookFakeResponse URLs, where {firebase-project-id} is the Firebase project ID (Firebase console > Project Settings > Project ID). For details on running the feature in production, refer to the Firebase documentation.

            Set up launch of payment UI

            1. Add the Payments library to your project. To do this, open build.gradle and add the following line to the dependencies section:

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              implementation("com.xsolla.android:payments:latest.release")
              

              1. Open AndroidManifest.xml and add permission for internet access:

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              <uses-permission android:name="android.permission.INTERNET" />
              

              1. Add the logic for creating an order (calling the XStore.getXsollaPaymentToken method of the Cloud Function) and opening the payment UI with the received payment token (XPayments.createIntentBuilder() class).

              1. To call the getXsollaPaymentToken method, provide one of the following URLs, where {firebase-project-id} is the Firebase project ID (Firebase console > Project Settings > Project ID):
                • for local access — https://localhost:5001/{firebase-project-id}/us-central1/getXsollaPaymentToken
                • for access in the production — https://us-central1-{firebase-project-id}.cloudfunctions.net/getXsollaPaymentToken

              Example (BuyItemAdapter class of the sample web application):

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              package com.xsolla.androidsample.adapter
              
              import android.R.attr.duration
              import android.os.Handler
              import android.os.Looper
              import android.view.LayoutInflater
              import android.view.ViewGroup
              import android.widget.Toast
              import androidx.recyclerview.widget.RecyclerView
              import com.bumptech.glide.Glide
              import com.xsolla.android.payments.XPayments
              import com.xsolla.android.payments.data.AccessToken
              import com.xsolla.android.store.entity.response.items.VirtualItemsResponse
              import com.xsolla.androidsample.R
              import com.xsolla.androidsample.StoreActivity
              import org.json.JSONObject
              import java.io.BufferedReader
              import java.io.BufferedWriter
              import java.io.OutputStream
              import java.io.OutputStreamWriter
              import java.net.HttpURLConnection
              import java.net.URL
              
              
              class BuyItemAdapter(private val parentActivity: StoreActivity, private val items: List<VirtualItemsResponse.Item>) :
                  RecyclerView.Adapter<BuyItemViewHolder>() {
                  override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BuyItemViewHolder {
                      return BuyItemViewHolder( LayoutInflater.from(parent.context)
                          .inflate(R.layout.buy_item_sample, parent, false))
                  }
              
                  override fun onBindViewHolder(holder: BuyItemViewHolder, position: Int) {
                      val item = items[position]
                      Glide.with(holder.view).load(item.imageUrl).into(holder.itemImage)
                      holder.itemName.text = item.name
                      holder.itemDescription.text = item.description
                      var priceText: String
                      if(item.virtualPrices.isNotEmpty()) {
                          priceText = item.virtualPrices[0].getAmountRaw() + " " + item.virtualPrices[0].name
                      } else {
                          priceText = item.price?.getAmountRaw() + " " + item.price?.currency.toString()
                      }
              
                      holder.itemPrice.text = priceText
              
                      holder.itemButton.setOnClickListener {
                          Thread {
                              purchase(item.sku!!)
                          }.start()
                      }
                  }
              
                  private fun purchase(sku: String) {
              
                      val uid = parentActivity.intent.getStringExtra("uid")
                      val email = parentActivity.intent.getStringExtra("email")
              
                      val jsonBody = JSONObject()
                      jsonBody.put("data", JSONObject().apply {
                          put("uid", uid)
                          put("email", email)
                          put("sku", sku)
                          put("returnUrl", "app://xpayment." + parentActivity.packageName)
                      })
              
                      val connection = URL(https://localhost:5001/{firebase-project-id}/us-central1/getXsollaPaymentToken).openConnection() as HttpURLConnection
                      connection.requestMethod = "POST"
                      connection.setRequestProperty("Content-Type", "application/json")
                      connection.doOutput = true
              
                      val outputStream: OutputStream = connection.outputStream
                      val writer = BufferedWriter(OutputStreamWriter(outputStream))
                      writer.write(jsonBody.toString())
                      writer.flush()
                      writer.close()
              
                      val responseCode = connection.responseCode
              
                      if (responseCode == HttpURLConnection.HTTP_OK) {
                          val response = connection.inputStream.bufferedReader().use(BufferedReader::readText)
                          connection.disconnect()
              
                          val jsonObject = JSONObject(response)
                          val token = jsonObject.getString("token")
                          val orderId = jsonObject.getString("order_id")
              
                          val intent = XPayments.createIntentBuilder(parentActivity)
                              .accessToken(AccessToken(token))
                              .isSandbox(true)
                              .build()
                          parentActivity.startActivityForResult(intent, 1)
                      } else {
                          Handler(Looper.getMainLooper()).post {
                              showNotificationMessage("HTTP request failed with error: $responseCode")
                          }
                      }
                  }
              
                  override fun getItemCount() = items.size
              
                  private fun showNotificationMessage(message: String) {
                      Toast.makeText(
                          parentActivity,
                          message,
                          Toast.LENGTH_SHORT,
                      ).show()
                  }
              }
              

              1. Add the onActivityResult() method to process the payment result.

              Example (StoreActivity class of the sample web application):

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              override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
                      super.onActivityResult(requestCode, resultCode, data)
                      if (requestCode == 1) {
                          val (status, _) = XPayments.Result.fromResultIntent(data)
                          when (status) {
                              XPayments.Status.COMPLETED -> showNotificationMessage("Payment completed")
                              XPayments.Status.CANCELLED -> showNotificationMessage("Payment canceled")
                              XPayments.Status.UNKNOWN -> showNotificationMessage("Payment error")
                          }
                      }
                  }
              

              Set up order status tracking

              Tracking the order status is required to ensure that the payment was successful and to grant items to the user.

              Get order status on client side

              To subscribe to order status changes on the client side of your application, call the XStore.getOrderStatus method and pass the following parameters to the method:

              • listener — a listener object of the OrderStatusListener type.
              • orderId — the order ID received from the purchase via the shopping cart, one-click purchase, or purchase for virtual currency.

              For detailed information about how the method works, refer to the Track order status section.

              Get order status on server side

              Notice

              The SDK allows you to track the order status on the client side of your application. However, we recommend setting up the Payment webhook handler to receive order information in the back end of your application. This allows you to implement additional validation of completed purchases

              For the full list of webhooks and general information about working with them, refer to the webhooks documentation.

              To configure webhooks on Xsolla side:

              1. Open your project in Publisher Account.
              2. Click Project settings in the side menu and go to the Webhooks section.
              3. In the Webhook server field, enter the URL to which Xsolla will send webhooks.

              Note

              For testing, you can specify https://us-central1-{firebase-project-id}.cloudfunctions.net/webhookFakeResponse, where {firebase-project-id} is the Firebase project ID (Firebase console > Project Settings > Project ID). In this case, Firebase simulates successful processing of the webhook. For a real project, you need to add purchase validation logic.

              To test webhooks, you can also choose any dedicated site, such as webhook.site, or a platform, such as ngrok.

              1. Copy and save the value from the Secret key field. This key is generated by default and is used to sign webhooks. If you want to change it, click the update icon.
              2. Click Enable webhooks.

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              Last updated: April 5, 2024

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