使用Python InstalledAppFlow调用Google Blogger API时出现OAuth 400错误（缺失redirect_uri）

你遇到的问题核心在于云端环境（Colab/Replit）与Desktop类型OAuth凭证的默认重定向逻辑不兼容，再加上你使用的google-auth-oauthlib 1.2.2版本可能存在自动读取重定向URI的bug，导致生成的授权URL缺失必填的redirect_uri参数。

直接修复代码 #

在调用authorization_url时显式指定redirect_uri为urn:ietf:wg:oauth:2.0:oob（这是Desktop凭证对应的"授权码手动输入"模式的标准URI）：

import os
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.discovery import build

CLIENT_SECRET_FILE = 'credentials.json' 
SCOPES = ['https://www.googleapis.com/auth/blogger']

print("--- Starting Minimal Authentication Test ---")

try:
    flow = InstalledAppFlow.from_client_secrets_file(CLIENT_SECRET_FILE, SCOPES)
    # 显式指定重定向URI
    auth_url, _ = flow.authorization_url(prompt='consent', redirect_uri='urn:ietf:wg:oauth:2.0:oob')
    
    print("\nPlease visit this URL to authorize:")
    print(auth_url)
    
    code = input('\nEnter the authorization code here: ')
    flow.fetch_token(code=code)
    creds = flow.credentials
    
    print("\nSUCCESS! Authentication credentials obtained.")

except Exception as e:
    print(f"\n--- AN ERROR OCCURRED ---")
    print(e)

额外验证步骤 #

1. 再次确认credentials.json的格式，确保redirect_uris数组包含目标URI，结构如下：

{
  "installed": {
    "client_id": "YOUR_CLIENT_ID",
    "client_secret": "YOUR_CLIENT_SECRET",
    "redirect_uris": ["urn:ietf:wg:oauth:2.0:oob", "http://localhost"],
    "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    "token_uri": "https://oauth2.googleapis.com/token"
  }
}

2. 若问题仍存在，尝试升级google-auth-oauthlib到最新版本：

pip install --upgrade google-auth-oauthlib

适配Colab的更优方案 #

Colab提供了内置的认证工具，无需手动处理授权码流程，更适配云端环境：

from google.colab import auth
from googleapiclient.discovery import build

# 执行内置认证流程
auth.authenticate_user()

# 直接构建Blogger服务
service = build('blogger', 'v3', credentials=None)

内容的提问来源于stack exchange，提问作者Carl Shop