framework of google login

auth.py

@@ -0,0 +1,59 @@
+import httpx
+from fastapi import APIRouter, Request
+from fastapi.responses import RedirectResponse
+import os
+
+router = APIRouter()
+
+GOOGLE_CLIENT_ID = os.getenv("GOOGLE_CLIENT_ID")
+GOOGLE_CLIENT_SECRET = os.getenv("GOOGLE_CLIENT_SECRET")
+
+REDIRECT_URI = "http://localhost:8000/auth/callback"
+
+GOOGLE_AUTH_URL = "https://accounts.google.com/o/oauth2/v2/auth"
+GOOGLE_TOKEN_URL = "https://oauth2.googleapis.com/token"
+GOOGLE_USERINFO_URL = "https://www.googleapis.com/oauth2/v2/userinfo"
+
+
+@router.get("/login/google")
+def login_google():
+    url = (
+        f"{GOOGLE_AUTH_URL}"
+        f"?client_id={GOOGLE_CLIENT_ID}"
+        f"&redirect_uri={REDIRECT_URI}"
+        f"&response_type=code"
+        f"&scope=openid email profile"
+    )
+    return RedirectResponse(url)
+
+
+@router.get("/auth/callback")
+async def auth_callback(code: str):
+    async with httpx.AsyncClient() as client:
+        # 1. 用 code 换 token
+        token_res = await client.post(
+            GOOGLE_TOKEN_URL,
+            data={
+                "code": code,
+                "client_id": GOOGLE_CLIENT_ID,
+                "client_secret": GOOGLE_CLIENT_SECRET,
+                "redirect_uri": REDIRECT_URI,
+                "grant_type": "authorization_code",
+            },
+        )
+        token_json = token_res.json()
+        access_token = token_json["access_token"]
+
+        # 2. 获取用户信息
+        user_res = await client.get(
+            GOOGLE_USERINFO_URL,
+            headers={"Authorization": f"Bearer {access_token}"},
+        )
+        user_info = user_res.json()
+
+    # 这里你可以写入数据库
+    return {
+        "email": user_info["email"],
+        "name": user_info["name"],
+        "picture": user_info["picture"],
+    }