feat(auth): Integrate with Google

AUTHENTICATION.md

@@ -1,6 +1,6 @@
 # Authentication Guide
 
-This project supports authentication via both username/password and GitHub OAuth. All authenticated API endpoints require a valid JWT Bearer token.
+This project supports authentication via username/password, GitHub OAuth, and Google OAuth. All authenticated API endpoints require a valid JWT Bearer token.
 
 ## 1. Username/Password Login
 
@@ -11,32 +11,39 @@ This project supports authentication via both username/password and GitHub OAuth
    - `POST /api/v1/users/login` with form data `username` and `password`.
    - The response will include `{ "access_token": "<JWT>", "token_type": "bearer" }`.
 
+
 ## 2. GitHub OAuth Login
 
 1. Go to `/api/v1/auth/github/login` in your browser.
 2. Authorize the app on GitHub.
 3. You will be redirected back and receive a JSON response with `{ "access_token": "<JWT>", "token_type": "bearer" }`.
 
-## 3. Using the Token in Swagger UI
+## 3. Google OAuth Login
+
+1. Go to `/api/v1/auth/google/login` in your browser.
+2. Authorize the app with your Google account.
+3. You will be redirected back and receive a JSON response with `{ "access_token": "<JWT>", "token_type": "bearer" }`.
+
+## 4. Using the Token in Swagger UI
 
 - Open `/docs` (Swagger UI).
 - Click the "Authorize" button.
 - **Paste only the JWT token** (do NOT include the `Bearer ` prefix).
 - Click "Authorize".
 - You can now access all authenticated endpoints.
 
-## 4. Using the Token in API Clients (e.g., Postman)
+## 5. Using the Token in API Clients (e.g., Postman)
 
 - Set the `Authorization` header:
   ```
   Authorization: <your_token>
   ```
 
-## 5. Notes
+## 6. Notes
 
 - The same JWT token format is used for both login methods.
 - If you get a credentials error, ensure you are pasting only the token (not `Bearer <token>`) in Swagger UI.
-- For GitHub login, the user is auto-registered on first login if not already present.
+- For GitHub and Google login, the user is auto-registered on first login if not already present.
 
 ---
 

app/api/routes/auth.py

@@ -4,8 +4,9 @@
 
 from app.config.database import get_db
 from app.config.github import github
+from app.config.google import google
 from app.schemas.users import Token
-from app.services.auth import login_github_user, login_user
+from app.services.auth import login_github_user, login_google_user, login_user
 
 router = APIRouter()
 
@@ -26,7 +27,22 @@ async def login_via_github(request: Request):
     return await github.authorize_redirect(request, redirect_uri)
 
 
+# Google OAuth login route
+@router.get("/google/login")
+async def login_via_google(request: Request):
+    """Initiates the Google OAuth login flow."""
+    redirect_uri = request.url_for("auth_google_callback")
+    return await google.authorize_redirect(request, redirect_uri)
+
+
 @router.get("/github/callback")
 async def auth_github_callback(request: Request, db: Session = Depends(get_db)):
     """Handles the GitHub OAuth callback and logs in or registers the user."""
     return await login_github_user(request, db)
+
+
+# Google OAuth callback route
+@router.get("/google/callback")
+async def auth_google_callback(request: Request, db: Session = Depends(get_db)):
+    """Handles the Google OAuth callback and logs in or registers the user."""
+    return await login_google_user(request, db)

app/config/google.py

@@ -0,0 +1,24 @@
+from authlib.integrations.starlette_client import OAuth
+from starlette.config import Config
+
+from app.settings import settings
+
+oauth = OAuth(
+    Config(
+        environ={
+            "GOOGLE_CLIENT_ID": settings.GOOGLE_CLIENT_ID,
+            "GOOGLE_CLIENT_SECRET": settings.GOOGLE_CLIENT_SECRET,
+        }
+    )
+)
+
+google = oauth.register(
+    name="google",
+    client_id=settings.GOOGLE_CLIENT_ID,
+    client_secret=settings.GOOGLE_CLIENT_SECRET,
+    access_token_url="https://oauth2.googleapis.com/token",
+    authorize_url="https://accounts.google.com/o/oauth2/v2/auth",
+    api_base_url="https://www.googleapis.com/oauth2/v2/",
+    client_kwargs={"scope": "openid email profile"},
+    server_metadata_url="https://accounts.google.com/.well-known/openid-configuration",
+)

app/services/auth.py

@@ -5,6 +5,7 @@
 from fastapi.responses import JSONResponse
 
 from app.config.github import github
+from app.config.google import google
 from app.models.user import User
 from app.schemas.users import AuthType, UserCreate
 from app.services.user import create_user
@@ -46,6 +47,21 @@ def create_github_user(profile, email: str, db):
     return user
 
 
+def create_google_user(profile, email: str, db):
+    """Create a new user from Google profile data."""
+    name = profile.get("name") or profile.get("email")
+    provider_id = str(profile.get("id"))
+    user_in = UserCreate(
+        email=email,
+        name=name,
+        is_active=True,
+        provider_id=provider_id,
+        auth_type=AuthType.google,
+    )
+    user = create_user(db, user_in)
+    return user
+
+
 async def login_github_user(request, db):
     """Login user via GitHub OAuth. Returns an access token if successful. Raises HTTPException if authentication fails."""
     try:
@@ -87,3 +103,31 @@ async def login_github_user(request, db):
             },
             status_code=400,
         )
+
+
+async def login_google_user(request, db):
+    """Login user via Google OAuth. Returns an access token if successful. Raises HTTPException if authentication fails."""
+    try:
+        token = await google.authorize_access_token(request)
+        resp = await google.get("userinfo", token=token)
+        profile = resp.json()
+        email = profile.get("email")
+        if not email:
+            raise HTTPException(
+                status_code=400, detail="Google account has no accessible email."
+            )
+
+        user = db.query(User).filter(User.email == email).first()
+        if not user:
+            user = create_google_user(profile, email, db)
+
+        access_token = create_access_token({"sub": str(user.id), "email": user.email})
+        return JSONResponse({"access_token": access_token, "token_type": "bearer"})
+    except OAuthError as e:
+        logging.error("OAuthError occurred during Google authentication", exc_info=e)
+        return JSONResponse(
+            {
+                "error": "An error occurred during authentication. Please try again later."
+            },
+            status_code=400,
+        )

app/settings.py

@@ -35,6 +35,10 @@ class Settings(BaseSettings):
     GITHUB_CLIENT_ID: str
     GITHUB_CLIENT_SECRET: str
 
+    # google
+    GOOGLE_CLIENT_ID: str
+    GOOGLE_CLIENT_SECRET: str
+
     class Config:
         """Configuration for the settings."""