Flutter + firebase: Configure app to use local firebase emulator

Question

I have configured firebase to run locally for debugging using the emulator by following this link.

Now I want to be able to run my app connected to the localhost for debugging triggers as well. Is there a way to achieve this by configuring my flutter app to use the localhost?

My emulator is running as following:

Answer 1

My latest setup of flutter fire

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  
  await Firebase.initializeApp();

  const bool USE_EMULATOR = true;

  if (USE_EMULATOR) {
    // [Firestore | localhost:8080]
    FirebaseFirestore.instance.settings = const Settings(
      host: 'localhost:8080',
      sslEnabled: false,
      persistenceEnabled: false,
    );
    
    // [Authentication | localhost:9099]
    await FirebaseAuth.instance.useEmulator('http://localhost:9099');

    // [Storage | localhost:9199]
    await FirebaseStorage.instance.useEmulator(
      host: 'localhost',
      port: 9199,
    );
  }
}

Make sure your host and port matches from firebase emulators:start

NOTE: in main.dart now you can always provide 'localhost'

await FirebaseAuth.instance.useEmulator('http://localhost:9099');

because it will change automagically to '10.0.2.2' if it is running on android

Long story short!

for latest guide follow https://firebase.flutter.dev/docs/firestore/usage#emulator-usage

Old but, Gold. Detailed config.(Outdated)

STEP 1 [setup firestore in flutter in main.dart]

Future<void> main() async {
  
    WidgetsFlutterBinding.ensureInitialized(); <--- Important!
      
    await Firestore.instance.settings(
            host: '192.168.1.38:5002', <--- Make sure to put your local ip 
            sslEnabled: false);             it will not work if you use 'localhost:5002'
                                            Google it "how to find my local ip"
       
}

STEP 1 [setup firestore in flutter in main.dart] for newer version of firebase

Future<void> main() async {
  
    WidgetsFlutterBinding.ensureInitialized(); <--- Important!
   
    String host = Platform.isAndroid ? '10.0.2.2:5002' : 'localhost:5002';
    await FirebaseFirestore.instance.settings = Settings(
         host: host,
         sslEnabled: false,
    );  
       
}

STEP 2 [init firebase project]

firebase init

STEP 3 [config firestore emulator eg firebase.json]

"emulators": {
    "ui": {
      "enabled": true,
      "host": "localhost",
      "port": 4000
    },
    "functions": {
      "port": 5001
    },
    "firestore": {
      "host": "0.0.0.0", <------ Make sure to set it "0.0.0.0"
      "port": 5002
    },
}

STEP 4 [run emulators and flutter app]

firebase emulators:start
flutter run

Worked both on iOS simulator and Android emulators

PS: try to restart firestore emulator or/and flutter app

Done!

BONUS [import export data to firestore emulator]

when you stop firestore emulator all data in firestore will be gone. So maybe before stoping emulator if you want to continue from where you left of you can export firestore emulator data like so

firebase emulators:export../data (../data can be any path you want )

to load exported data

firebase emulators:start --import../data

you can save different states of your firestore emulator for different cases, example

firebase emulators:start --import ../initialData 
firebase emulators:start --import ../otherStateData

❤️ Note for myself use dart for firebase functions ❤️

If you want to use dart for firebase functions you can follow this https://github.com/pulyaevskiy/firebase-functions-interop

one good thing I found for myself to detect if your function is running in emulator or production you can read more here

long story short

functions/index.js

export const prepopulateFirestoreEmulator = functions.https.onRequest(
  (request, response) => {
    if (process.env.FUNCTIONS_EMULATOR && process.env.FIRESTORE_EMULATOR_HOST) {
      // TODO: prepopulate firestore emulator from 'yourproject/src/sample_data.json
      response.send('Prepopulated firestore with sample_data.json!');
    } else {
      response.send(
        "Do not populate production firestore with sample_data.json"
      );
    }
  }
);

functions/index.dart

import 'package:firebase_functions_interop/firebase_functions_interop.dart';
import 'package:node_interop/node.dart';
import 'package:node_interop/util.dart';

void devPrepopulateCollections(ExpressHttpRequest request) {
  var env =
      new Map<String, String>.from(dartify(process.env)); // <-- important part

  if (env.containsKey('FUNCTIONS_EMULATOR') &&
      env.containsKey('FIRESTORE_EMULATOR_HOST')) {
    // TODO: prepopulate firestore emulator from 'yourproject/src/sample_data.json
    request.response
      ..write("Prepopulated firestore with sample_data.json!")
      ..close();
  } else {
    request.response
      ..write("Do not populate production firestore with sample_data.json")
      ..close();
  }
}

Answer 2

After carefully going through the docs here , I got it working by configuring the host setting on the firestore instance:

import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:flutter/material.dart';
import 'package:tracker/screens/screens.dart';

void main() async {

  // This will set the app to communicate with localhost
  await Firestore.instance.settings(host: "10.0.2.2:8080", sslEnabled: false);

  runApp(AppSetupScreen());
}

Note : This will only work with emulator and not with physical device.

Answer 3

An add-on:

To make the Firebase emulators work with the physical devices

Work for both iOS and Android devices

1. Cloud functions setup:

in firebase.json

{
  // ...other configs
  "emulators": {
    "functions": {
      "port": 5001,
      "host": "0.0.0.0" // must have
    },
    "firestore": {
      "port": 8080,
      "host": "0.0.0.0" // must have
    },
  }
}

2. Your Flutter app setup:

The IP address you use for cloud functions and firestore should be the same

// The FirebaseFunctions config
// ! You need to replace the placeholder with your IP address below:
FirebaseFunctions.instance.useFunctionsEmulator(origin: 'http://<YOUR_IP_ADDRESS>:5001');

// The Firestore config
// ! You need to replace the placeholder with your IP address below:
FirebaseFirestore.instance.settings = Settings(
  host: '<YOUR_IP_ADDRESS>:8080',
  sslEnabled: false,
  persistenceEnabled: false,
);

Answer 4

for cloud_firestore: ^0.14.1+2 , instead of using FirebaseFirestore.instance.settings use this -

FirebaseFunctions.instance.useFunctionsEmulator(
    origin: "http://localhost:5001",
  );

It internally handles setting up 10.0.2.2 if the device is android.

Your main block should look like the following

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  FirebaseFunctions.instance.useFunctionsEmulator(
    origin: "http://localhost:5001",
  );
  runApp(MyApp());
}

Answer 5

Looks like i've connected ios to localhost:8080, but db works very slow and I also didn't notice any logs in a file. @UsmanZaheer, can you please tell when did it write logs and was it working fast?

Steps:

• firebase init

• add links that have been created by ini to package.json in functions;

  "firestore": { "rules": "firestore.rules", "indexes": "firestore.indexes.json" },

• firebase emulators:start

in main() write

await Firestore.instance.settings(
      host: 'http://localhost:8080',
      sslEnabled: false,
      persistenceEnabled: false,
      timestampsInSnapshotsEnabled: true
  ).catchError((e) => print(e));

Answer 6

Your main.dart should look like this:

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firestore.instance
    .settings(
       host: 'http://localhost:8080',
       sslEnabled: false,
       persistenceEnabled: false,
     )
    .catchError((e) => print(e));
  // 
  // ...
  //
  runApp(App(...));
}

in your firebase.json file

  "emulators": {
    "firestore": {
          "host": "localhost",
          "port": 8080
    },
    ...
  }

you should also set the following in your terminal:

export FIRESTORE_EMULATOR_HOST=localhost:8080

and then run

firebase emulators:start

Answer 7

Adjustment for Flutter Web

addition to the correct answer by @Sultanmyrza

Platform requires dart:io/dart:html which are mutually exclussive so to check for the platform I use kIsWeb

FirebaseFirestore __firestore;
FirebaseFirestore get _firestore {
  if (__firestore != null) {
    return __firestore;
  }
  debugPrint('isFirebaseEmulator: $isFirebaseEmulator');
  __firestore = FirebaseFirestore.instance;
  if (isFirebaseEmulator) {
    __firestore.settings = const Settings(
      host: kIsWeb ? 'localhost:8080' : '10.0.2.2:8080',
      sslEnabled: false,
    );
  }
  return __firestore;
}

Answer 8

Latest Update : To connect flutter app to your local firebase emulator suite, followthis official instruction for configuration.

Answer 9

My init function looks like so:

init_firebase.dart

Future<void> initFirebase() async {
  await Firebase.initializeApp(
    options: DefaultFirebaseOptions.currentPlatform,
  );

  if (!kReleaseMode) {
    try {
      await Future.wait([
        FirebaseAuth.instance.useAuthEmulator('localhost', 9099),
        FirebaseStorage.instance.useStorageEmulator('localhost', 9199),
      ]);

      FirebaseFunctions.instance.useFunctionsEmulator('localhost', 5001);
      FirebaseFirestore.instance.useFirestoreEmulator('localhost', 8080);
    } catch (e) {}
  }
}

By using !kReleaseMode , we don't have to have a boolean that we switch each time. It will just use emulator by default during development

By wrapping it in try-catch block we avoid some errors from hot reload