Requests库简介

Requests是Python中最受欢迎的HTTP库，以简洁、人性化的API设计著称。相比Python内置的urllib库，Requests提供了更简洁的API和更强大的功能。

主要特点：

• 简单易用的API
• 自动内容解码
• 支持HTTP连接保持和连接池
• 国际化域名和URL
• 支持文件分块上传
• 完善的SSL/TLS验证

安装Requests库

使用pip命令安装：

pip install requests

发送GET请求

GET请求用于从服务器获取数据：

import requests

# 基本GET请求
response = requests.get('https://api.example.com/data')

# 带参数的GET请求
params = {'key1': 'value1', 'key2': 'value2'}
response = requests.get('https://api.example.com/data', params=params)

# 打印响应内容
print(response.text)

处理GET响应

# 检查请求是否成功
if response.status_code == 200:
    print("请求成功!")
    
# 获取响应内容的不同格式
print("文本格式:", response.text)
print("JSON格式:", response.json())
print("二进制内容:", response.content)
print("响应头:", response.headers)

发送POST请求

POST请求用于向服务器提交数据：

import requests

# 发送JSON数据
payload = {'username': 'admin', 'password': 'secret'}
response = requests.post('https://api.example.com/login', json=payload)

# 发送表单数据
form_data = {'key1': 'value1', 'key2': 'value2'}
response = requests.post('https://api.example.com/submit', data=form_data)

# 上传文件
files = {'file': open('report.xlsx', 'rb')}
response = requests.post('https://api.example.com/upload', files=files)

处理HTTP响应

response = requests.get('https://api.example.com')
if response.status_code == 200:
    print("Success!")
elif response.status_code == 404:
    print("Not Found!")

response = requests.get('https://api.example.com/data.json')
data = response.json()
print(data['key'])

print("Content Type:", response.headers['Content-Type'])
print("Server:", response.headers.get('Server', 'Unknown'))

高级用法

设置请求头

headers = {
    'User-Agent': 'MyApp/1.0',
    'Authorization': 'Bearer YOUR_ACCESS_TOKEN',
    'Accept': 'application/json'
}

response = requests.get('https://api.example.com', headers=headers)

超时设置

# 设置连接超时和读取超时
try:
    response = requests.get('https://api.example.com', timeout=(3.05, 27))
except requests.exceptions.Timeout:
    print("请求超时!")

会话保持

# 使用Session对象保持会话和cookies
with requests.Session() as session:
    session.headers.update({'User-Agent': 'MyApp/1.0'})
    
    # 登录
    session.post('https://api.example.com/login', data={'user': 'admin', 'pass': 'secret'})
    
    # 后续请求会保持会话状态
    response = session.get('https://api.example.com/dashboard')

错误处理

try:
    response = requests.get('https://api.example.com', timeout=5)
    response.raise_for_status()  # 如果状态码不是200，将抛出HTTPError异常
except requests.exceptions.HTTPError as errh:
    print("HTTP错误:", errh)
except requests.exceptions.ConnectionError as errc:
    print("连接错误:", errc)
except requests.exceptions.Timeout as errt:
    print("超时错误:", errt)
except requests.exceptions.RequestException as err:
    print("请求异常:", err)

掌握Requests库，高效处理HTTP请求

Requests库简化了Python中的HTTP请求处理，是每个Python开发者必备的工具