OAuth报错：Tuple object is not callable及认证参数修改问题排查

背景 #

原本基于client_credentials授权模式的代码可以正常运行：

f = open('creds.json')
creds = json.load(f)

def get_access_token(url, client_id, client_secret):
    response = requests.post(
        url,
        data={"grant_type": "client_credentials", "scope": "api://xyz.default"},
        auth=(client_id, client_secret),
    )
    return response.json()["access_token"]

new_token = get_access_token(creds["auth_url"],client_id=creds["client_id"], client_secret=creds["client_secret"])
headers = {"loggedInUsername": "Test, User","Content-Type":"application/json",'Authorization': f"Bearer {new_token}"}

改为password授权模式后，Postman中参数配置可正常请求，但Python代码在pytest中抛出'Tuple object is not callable'错误：

def get_access_token(url, client_id, username, password):
    response = requests.post(
        url,
        data={"grant_type": "password", "scope": "api://xyz.default"},
        auth=(client_id, username, password),
    )
    return response.json()["access_token"]

new_token = get_access_token(creds["auth_url"],client_id=creds["client_id"], username=creds["username"], password=creds["password"])
headers = {"loggedInUsername": "Test, User","Content-Type":"application/json",'Authorization': f"Bearer {new_token}"}

原因分析 #

错误确实是因为auth参数传了三元组导致的：

• requests库的auth参数仅接受二元组（对应HTTP Basic Auth的用户名和密码），或者一个实现了__call__方法的认证对象。
• 当你传入三元组(client_id, username, password)时，requests会尝试将这个元组当作可调用对象去执行，而元组本身没有可调用的方法，因此抛出'Tuple object is not callable'错误。
• 另外，OAuth2的password授权模式并不需要用auth参数传递凭证，而是要把client_id、username、password都放在请求体的data参数中。

修正后的代码 #

f = open('creds.json')
creds = json.load(f)

def get_access_token(url, client_id, username, password):
    response = requests.post(
        url,
        data={
            "grant_type": "password",
            "scope": "api://xyz.default",
            "client_id": client_id,
            "username": username,
            "password": password
        }
    )
    return response.json()["access_token"]

new_token = get_access_token(
    creds["auth_url"],
    client_id=creds["client_id"],
    username=creds["username"],
    password=creds["password"]
)
headers = {
    "loggedInUsername": "Test, User",
    "Content-Type": "application/json",
    "Authorization": f"Bearer {new_token}"
}

内容的提问来源于stack exchange，提问作者JD2775