为何Python中request()函数报参数错误，疑似被识别为字典get()？

问题描述 #

requests库本身使用正常，但自定义的Business类函数中出现报错，报错提示TypeError: request() takes 2 positional arguments but 5 were given。

原代码 #

import requests
from requests import request


class Business:
    def __init__(self, url, api_key):
        self.url = url
        self.api_key = api_key

    def send_valid_request(self, category, location):
        headers = {'Authorization': 'Bearer ' + api_key}
        params = {'term': category, 'location': location}
        response = request('GET', url, params, None, headers)
#                     ^^
# 错误位置           ^^

        businesses = response.json()['businesses']
        return businesses

    def see_original_name(self, business_name, category, location):
        businesses = self.send_valid_request(category, location)
        ...


category = input(f'Choose the business category: ')
location = input(f'Choose your business location: ')

url = '...'
api_key = '...'

business = Business(url, api_key)


while True:
    question = input(
       'What do you want to know? (choose: name search(NS)/general search(GS)) ')
    if question == 'NS':
        while True:
            business_name = input('Buisness name: ')
            business.see_original_name(business_name, category, location)
      ... 

报错信息 #

Traceback (most recent call last):

  File ".../mainapp.py", line ..., in <module>
    business.see_original_name(business_name, category, location)

  File ".../mainapp.py", line 20, in see_original_name
    businesses = self.send_valid_request(category, location)

  File ".../mainapp.py", line 15, in send_valid_request
    response = request('GET', url, params, None, headers)

TypeError: request() takes 2 positional arguments but 5 were given

错误原因及修正方案 #

1. 实例属性未正确引用 #

方法内直接使用api_key和url是错误的，这两个是类实例的属性，必须通过self.api_key和self.url访问，否则会触发未定义变量的错误。

2. request()函数参数传递错误 #

requests库的request()函数签名为request(method, url, **kwargs)，只有前两个参数（请求方法、URL）是位置参数，其余参数（params、headers等）都需要通过关键字参数传递，不能直接作为位置参数传入。你传入的params、None、headers都被当成了位置参数，导致参数数量超出预期。

修正后的关键代码 #

def send_valid_request(self, category, location):
    # 正确引用实例属性
    headers = {'Authorization': 'Bearer ' + self.api_key}
    params = {'term': category, 'location': location}
    # 使用关键字参数传递params和headers，默认值为None的参数可省略
    response = request('GET', self.url, params=params, headers=headers)
    businesses = response.json()['businesses']
    return businesses

补充说明 #

你之前的猜测错误，这个问题和字典的get()函数无关，纯粹是requests库的request()函数参数使用方式错误。

内容的提问来源于stack exchange，提问作者Code7G