signly_google 0.1.0

Flutter plugin-style package that performs one-shot Google Sign-In for Android and iOS and returns only the requested token.

🚀 signly_google

A modern Google Sign‑In wrapper for Flutter using the latest SDK.

✨ Simple API
🔐 Secure token flows
📱 Mobile friendly
🧠 Backend ready

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📦 What you get

Icon	Token	Purpose
🪪	idToken (JWT)	Authenticate user on backend
🔁	serverAuthCode	Exchange for refreshToken
🌐	accessToken	Call Google APIs
👤	Profile	Email, name, avatar

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🏗 GCP SETUP

🪜 Step 1: OAuth Consent Screen

📍 Google Cloud Console → APIs & Services → OAuth Consent Screen

✔ App name
✔ Support email (User support)
✔ Audience
✔ Developer email (Contact info)

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🤖 Step 2: Android OAuth Client

Type: Android
Provide: 📦 Package name
🔑 SHA‑1 fingerprint

✅ Used for handshake only
🚫 Not passed in Flutter code

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🍎 Step 3: iOS OAuth Client

Type: iOS
Provide: 📦 Bundle ID

Add in ios/Runner/Info.plist

<key>GIDClientID</key>
<string>YOUR_CLIENT_ID.apps.googleusercontent.com</string>

<key>CFBundleURLTypes</key>
<array>
  <dict>
    <key>CFBundleURLSchemes</key>
    <array>
      <string>com.googleusercontent.apps.YOUR_CLIENT_ID</string>
    </array>
  </dict>
</array>

🔁 URL scheme returns user back to app after login

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🌐 Step 4: Web OAuth Client (IMPORTANT)

Type: Web Application

🎯 This is your serverClientId

Used for: ✅ idToken audience
✅ serverAuthCode
✅ backend refresh flow

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🔐 Token meanings

🪪 idToken

JWT signed by Google
Contains user identity

🌐 accessToken

Call Google APIs
⏳ Expires automatically

🔁 serverAuthCode

One‑time code
Backend → refreshToken + accessToken

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📱 Flutter Usage

import 'package:signly_google/signly_google.dart';

final client = SignlyGoogleClient();

final result = await client.signIn(
     GoogleSignInRequest(
          clientId: ...
          serverClientId: ...
          scopes: ['email', 'profile'],
          requestedTokenType: GoogleRequestedTokenType.<token_type>,
);

Access values

result.requestedToken
result.requestedTokenType.name
result.userId
result.userData.email
result.userData.displayName
result.userData.photoUrl

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🧠 Best Practice Flow

📱 Flutter → idToken + authCode
🖥 Backend → refreshToken
♻ Backend refreshes forever

🚫 Do NOT rely only on mobile accessToken

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📄 License

MIT