Calling a Cloud Function from Android through Firebase

Question

Situation

I have created a Google Cloud Function through functions.https.onRequest, which is working nicely when I paste its URL in a browser and integ

Answer 1

It isn't possible for now but as mentioned in the other answer, you can trigger functions using an HTTP request from Android. If you do so, it's important that you protect your functions with an authentication mechanism. Here's a basic example:

'use strict';

var functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);

exports.helloWorld = functions.https.onRequest((request, response) => {
  console.log('helloWorld called');
  if (!request.headers.authorization) {
      console.error('No Firebase ID token was passed');
      response.status(403).send('Unauthorized');
      return;
  }
  admin.auth().verifyIdToken(request.headers.authorization).then(decodedIdToken => {
    console.log('ID Token correctly decoded', decodedIdToken);
    request.user = decodedIdToken;
    response.send(request.body.name +', Hello from Firebase!');
  }).catch(error => {
    console.error('Error while verifying Firebase ID token:', error);
    response.status(403).send('Unauthorized');
  });
});

To get the token in Android you should use this and then add it to your request like this:

connection = (HttpsURLConnection) url.openConnection();
...
connection.setRequestProperty("Authorization", token);