1. OAuth2認可コードの流れ
ソーシャル ログインでは、Web アプリケーションにとって最も安全なフローである OAuth2 認証コード フローが使用されます。
User → App → Provider (Google/GitHub) → User Login → Callback → App → JWT Token
┌──────┐ ┌──────┐ ┌──────────┐
│ User │────→│ App │────→│ Provider │
│ │ │ │ │ (Google) │
│ │←────│ │←────│ │
└──────┘ └──────┘ └──────────┘
1. Click 2. Redirect 3. Login
"Login to Provider & Consent
with
Google"
5. Exchange 4. Redirect
code for back with
token auth code
2. Authlib のセットアップ
uv add authlib httpx
# app/config.py - thêm OAuth settings
class Settings(BaseSettings):
# ... existing settings
# Google OAuth2
google_client_id: str = ""
google_client_secret: str = ""
# GitHub OAuth2
github_client_id: str = ""
github_client_secret: str = ""
# OAuth callback URL
oauth_redirect_base: str = "http://localhost:8000"
3. OAuth2プロバイダーの構成
# app/core/oauth.py
from authlib.integrations.starlette_client import OAuth
from app.config import settings
oauth = OAuth()
# Google
oauth.register(
name="google",
client_id=settings.google_client_id,
client_secret=settings.google_client_secret,
server_metadata_url="https://accounts.google.com/.well-known/openid-configuration",
client_kwargs={"scope": "openid email profile"},
)
# GitHub
oauth.register(
name="github",
client_id=settings.github_client_id,
client_secret=settings.github_client_secret,
access_token_url="https://github.com/login/oauth/access_token",
authorize_url="https://github.com/login/oauth/authorize",
api_base_url="https://api.github.com/",
client_kwargs={"scope": "user:email"},
)
4. ソーシャルアカウントモデル
# app/models/social_account.py
from datetime import datetime
from sqlalchemy import String, Integer, ForeignKey, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship
from app.core.database import Base
class SocialAccount(Base):
__tablename__ = "social_accounts"
__table_args__ = (
UniqueConstraint("provider", "provider_user_id", name="uq_social_provider_user"),
)
id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
user_id: Mapped[int] = mapped_column(
ForeignKey("users.id", ondelete="CASCADE"), nullable=False
)
provider: Mapped[str] = mapped_column(String(50), nullable=False) # "google", "github"
provider_user_id: Mapped[str] = mapped_column(String(255), nullable=False)
provider_email: Mapped[str | None] = mapped_column(String(255))
access_token: Mapped[str | None] = mapped_column(String(500))
refresh_token: Mapped[str | None] = mapped_column(String(500))
created_at: Mapped[datetime] = mapped_column(default=datetime.utcnow)
# Relationship
user: Mapped["User"] = relationship(back_populates="social_accounts")
5. OAuth2 ルート
# app/api/v1/oauth.py
from fastapi import APIRouter, Depends, HTTPException, Request
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession
from starlette.responses import RedirectResponse
from app.config import settings
from app.core.database import get_db
from app.core.oauth import oauth
from app.core.security import create_access_token, create_refresh_token, hash_password
from app.models.social_account import SocialAccount
from app.models.user import User
from app.schemas.auth import TokenResponse
router = APIRouter(prefix="/oauth", tags=["OAuth2"])
# ========== Google ==========
@router.get("/google/login")
async def google_login(request: Request):
"""Redirect đến Google login page."""
redirect_uri = f"{settings.oauth_redirect_base}/api/v1/oauth/google/callback"
return await oauth.google.authorize_redirect(request, redirect_uri)
@router.get("/google/callback")
async def google_callback(
request: Request,
session: AsyncSession = Depends(get_db),
):
"""Callback sau khi Google authenticate."""
try:
token = await oauth.google.authorize_access_token(request)
except Exception:
raise HTTPException(status_code=400, detail="OAuth authentication failed")
# Lấy user info từ Google
user_info = token.get("userinfo")
if not user_info:
raise HTTPException(status_code=400, detail="Failed to get user info")
google_id = user_info["sub"]
email = user_info["email"]
name = user_info.get("name", email.split("@")[0])
# Tìm hoặc tạo user
user = await find_or_create_social_user(
session=session,
provider="google",
provider_user_id=google_id,
email=email,
name=name,
access_token=token.get("access_token"),
)
# Generate JWT tokens
access_token = create_access_token(data={"sub": str(user.id)})
refresh_token = create_refresh_token(data={"sub": str(user.id)})
# Redirect to frontend with tokens
frontend_url = f"{settings.cors_origins[0]}/auth/callback"
return RedirectResponse(
url=f"{frontend_url}?access_token={access_token}&refresh_token={refresh_token}"
)
# ========== GitHub ==========
@router.get("/github/login")
async def github_login(request: Request):
"""Redirect đến GitHub login page."""
redirect_uri = f"{settings.oauth_redirect_base}/api/v1/oauth/github/callback"
return await oauth.github.authorize_redirect(request, redirect_uri)
@router.get("/github/callback")
async def github_callback(
request: Request,
session: AsyncSession = Depends(get_db),
):
"""Callback sau khi GitHub authenticate."""
try:
token = await oauth.github.authorize_access_token(request)
except Exception:
raise HTTPException(status_code=400, detail="OAuth authentication failed")
# Lấy user info từ GitHub API
resp = await oauth.github.get("user", token=token)
user_info = resp.json()
# Lấy email (GitHub có thể không trả email public)
if not user_info.get("email"):
email_resp = await oauth.github.get("user/emails", token=token)
emails = email_resp.json()
primary_email = next(
(e["email"] for e in emails if e["primary"] and e["verified"]),
None,
)
user_info["email"] = primary_email
if not user_info.get("email"):
raise HTTPException(status_code=400, detail="Email not available from GitHub")
user = await find_or_create_social_user(
session=session,
provider="github",
provider_user_id=str(user_info["id"]),
email=user_info["email"],
name=user_info.get("name") or user_info["login"],
access_token=token.get("access_token"),
)
access_token = create_access_token(data={"sub": str(user.id)})
refresh_token = create_refresh_token(data={"sub": str(user.id)})
frontend_url = f"{settings.cors_origins[0]}/auth/callback"
return RedirectResponse(
url=f"{frontend_url}?access_token={access_token}&refresh_token={refresh_token}"
)
# ========== Helper ==========
async def find_or_create_social_user(
session: AsyncSession,
provider: str,
provider_user_id: str,
email: str,
name: str,
access_token: str | None = None,
) -> User:
"""Tìm user từ social account hoặc tạo mới."""
import secrets
# 1. Tìm social account đã liên kết
result = await session.execute(
select(SocialAccount)
.where(
SocialAccount.provider == provider,
SocialAccount.provider_user_id == provider_user_id,
)
)
social = result.scalar_one_or_none()
if social:
# Cập nhật access token
social.access_token = access_token
await session.flush()
# Lấy user
result = await session.execute(
select(User).where(User.id == social.user_id)
)
return result.scalar_one()
# 2. Tìm user bằng email
result = await session.execute(
select(User).where(User.email == email)
)
user = result.scalar_one_or_none()
if not user:
# 3. Tạo user mới
user = User(
name=name,
email=email,
hashed_password=hash_password(secrets.token_urlsafe(32)),
is_active=True,
)
session.add(user)
await session.flush()
# 4. Tạo social account link
social = SocialAccount(
user_id=user.id,
provider=provider,
provider_user_id=provider_user_id,
provider_email=email,
access_token=access_token,
)
session.add(social)
await session.flush()
return user
6. セッションミドルウェア（OAuth状態用）
# app/main.py
from starlette.middleware.sessions import SessionMiddleware
# OAuth cần session để lưu state
app.add_middleware(
SessionMiddleware,
secret_key=settings.secret_key.get_secret_value(),
same_site="lax",
https_only=settings.environment == "production",
)
概要
この記事では、ソーシャル ログインが実装されています。
- OAuth2認可コードフロー: フローは Web アプリにとって安全です
- Googleログイン: OpenID Connect with Google
- GitHub ログイン: GitHub API を使用した OAuth2
- アカウントリンク: ソーシャルアカウントを既存のユーザーとリンクします
- 自動登録：初回ソーシャルログイン時に自動的にアカウントを作成します
次の記事では、ミドルウェア、イベント、およびライフスパンの管理について説明します。