Android Subscriptions Code

These codes will allow you to acknowledge and verify purchases or subscriptions. There is 1 call for each type of transaction.

1. To get started, go to console.google.cloud.com/functions

2. Click Create Function

3. Give your new function a meaningful name

androidSubscriptionHandler should be the name you use here

4. Save the trigger type

5. Copy the code below and click the blue "next" button

Copy Me

androiidSubscriptionHandler.

const functions = require("firebase-functions");
const admin = require("firebase-admin");
const googleServiceAccountKey = require("./serviceAccount.json");
admin.initializeApp({
  credential: admin.credential.cert(googleServiceAccountKey),
});
const {google} = require("googleapis");
const axios = require("axios");

exports.androidSubscriptionHandler = functions.https.onRequest((request, response) => {

  // caputre the data from the request
  const {purchaseObject, type} = request.body;
  functions.logger.info("trying to handle " + type + " for the follow purchaseObject");
  functions.logger.info(JSON.stringify(purchaseObject));
  // get the token and subscription id from the request
  const purchaseToken = purchaseObject.purchaseToken;
  const subscriptionID = purchaseObject.productId;
  // set your package id
  const packageID = "edu.fit.my.jgibb2018.pob";

  const returnTheResponse = (data) => {
    functions.logger.log("returning the response" + JSON.stringify(data));
    response.status(200).send(data);
  };

  const acknowledgeSubscription = (err, tokens) => {
    functions.logger.info(`
    Attempting to acknowledge subscription ${subscriptionID}\n
    your access token for a manual retry ${tokens.access_token}\n
    your purchase object ${JSON.stringify(purchaseObject)}\n\n
    `);

    const config = {
      method: "post",
      url: `https://androidpublisher.googleapis.com/androidpublisher/v3/applications/${packageID}/purchases/subscriptions/${subscriptionID}/tokens/${purchaseToken}:acknowledge`,
      headers: {
        "Authorization": `Bearer ${tokens.access_token}`,
      },
    };
    functions.logger.info("acknowledge config" + JSON.stringify(config));
    axios(config)
        .then(function(r) {
          returnTheResponse("Your transaction has been completed");
        })
        .catch(function(e) {
          functions.logger.warn("an error occured while acknowledging the subscription");

          functions.logger.error(JSON.stringify({error: e}));

          returnTheResponse({error: e.data, status: e.status, message: e.message});
        });
  };

  const verifySubscription = (err, tokens) => {
    functions.logger.info("verify function");
    const config = {
      method: "get",
      url: `https://androidpublisher.googleapis.com/androidpublisher/v3/applications/${packageID}/purchases/subscriptions/${subscriptionID}/tokens/${purchaseToken}`,
      headers: {
        "Authorization": `Bearer ${tokens.access_token}`,
      },
    };
    functions.logger.info(config.url);
    axios(config)
        .then(function(r) {
          functions.logger.info("verify success" + JSON.stringify(r.data));
          returnTheResponse(r.data);
        })
        .catch(function(e) {
          returnTheResponse(JSON.stringify({error: e.data, status: e.status, message: e.message}));
        });
  };

  const getAccessToken = () => {
    const jwtClient = new google.auth.JWT(
        googleServiceAccountKey.client_email,
        null,
        googleServiceAccountKey.private_key,
        ["https://www.googleapis.com/auth/androidpublisher"],
        null,
    );
    try {
      if (type == "subscriptionAcknowledge") {
        jwtClient.authorize(acknowledgeSubscription);
      } else if (type == "subscriptionVerify") {
        jwtClient.authorize(verifySubscription);
      }
    } catch (error) {
      functions.logger.error(error);
      response.status(500).send("issue getting getting auth", JSON.stringify(error));
    }
  };

  getAccessToken();
  });

6. Clear the default and paste the copied code into the code

7. Update the package.json file

copy and paste over the default text

{
  "name": "sample-http",
  "version": "0.0.1",
  "dependencies": {
     "axios": "^0.26.0",
     "googleapis": "^97.0.0",
     "firebase-functions": "^3.18.0",
     "firebase-admin": "^10.0.2"
   }
}

8. Set the name of the functions entry point

the name used here should match the name used in Step 3 above

9. Click the plus icon to create a new file and name it "serviceAccount.json"

10. Copy and paste the content of this projects service account file from your computer into this newly created file.

11. Deploy the function

12. Set function invocation privacy permissions

This allows any device with your endpoint URL the ability to verify purchases made via your app

1. Go to https://console.cloud.google.com/functions/list

2. Select the function you want to make public. (the function you just created)

3. Click the Permissions tab.

4. Click Add Principle

5. In the Add members field, type allUsers

6. Select the Cloud Function Invoker role from the Select a role drop-down menu.

7. Click Add.