google_identity_services_web
A JS-interop layer for Google Identity's Sign In With Google SDK.
See the original JS SDK reference:
Usage
This package is the Dart JS-interop layer of the new Sign In With Google SDK. Here's the API references for both of the sub-libraries:
id.dart: Sign In With Google JavaScript API referenceoauth2.dart: Google 3P Authorization JavaScript Library for websites - API referenceloader.dart: An (optional) loader mechanism that installs the library and resolves aFuture<void>when it's ready.
Loading the SDK
There are two ways to load the JS SDK in your app.
Modify your index.html (most performant)
The most performant way is to modify your web/index.html file to insert a
script tag as recommended.
Place the script tag in the <head> of your site:
<head>
<!-- ··· -->
<!-- Include the GSI SDK below -->
<script src="https://accounts.google.com/gsi/client" async defer></script>
</head>
With the loadWebSdk function (on-demand)
An alternative way, that downloads the SDK on demand, is to use the
loadWebSdk function provided by the library. A simple location to embed
this in a Flutter Web only app can be the main.dart:
import 'package:google_identity_services_web/loader.dart' as gis;
// ···
void main() async {
await gis.loadWebSdk(); // Load the GIS SDK
// The rest of your code...
// ···
}
(Note that the above won't compile for mobile apps, so if you're developing a
cross-platform app, you'll probably need to hide the call to loadWebSdk
behind a conditional import/export.)
Using the SDK
Once the SDK has been loaded, it can be used by importing the correct library:
import 'package:google_identity_services/id.dart';for Authentication.- This will expose an
idJSObject that binds togoogle.accounts.id.
- This will expose an
import 'package:google_identity_services/oauth2.dart';for Authorization.- This will expose an
oauth2JSObject that binds togoogle.accounts.oauth2.
- This will expose an
Troubleshooting
Watch the browser's development tools JS console while using this package. Information about errors during initialization and use of the library will be displayed there.
Some common issues identified so far:
The given origin is not allowed for the given client ID
When you perform local tests or development, you must add both
http://localhostandhttp://localhost:<port_number>to the Authorized JavaScript origins box. The Referrer-Policy response header must also be set tono-referrer-when-downgradewhen using http and localhost.
Browser compatibility
The new SDK is introducing concepts that are on track for standardization to most browsers, and it might not be compatible with older browsers.
Refer to the official documentation site for the latest browser compatibility information of the underlying JS SDK:
- Sign In With Google > Supported browsers and platforms