#coding: utf-8
import socket
import ssl
def parsed_url(url):
"""
解析 url 返回 (protocol host port path)
"""
# 判断协议是 http 还是 https
protocol = 'http'
if url[:7] == 'http://':
u = url.split('://')[1]
elif url[:8] == 'https://':
u = url.split('://')[1]
protocol = 'https'
else:
u = url
# 检查默认 path
i = u.find('/')
if i == -1:
host = u
path = '/'
else:
host = u[:i]
path = u[i:]
# 不同协议对应不同的默认端口
port_dict = {
'http': 80,
'https': 443,
}
port = port_dict[protocol]
# 不为默认端口的情况
if ':' in host:
h = host.split(':')
host = h[0]
port = int(h[1])
# 输出结果,协议,主机,端口,路径
return protocol, host, port, path
def socket_by_protocol(protocol):
"""
根据协议返回一个 socket 实例
"""
if protocol == 'http':
s = socket.socket()
else:
s = ssl.wrap_socket(socket.socket())
return s
def response_by_socket(s):
"""
参数是一个 socket 实例
返回这个 socket 读取的所有数据
"""
response = b''
buffer_size = 1024
# 循环保证数据全部接收
while True:
r = s.recv(buffer_size)
if len(r) == 0:
break
response += r
return response
def parsed_response(r):
"""
把 response 解析出 状态码 headers(为字典) body 返回
"""
header, body = r.split('\r\n\r\n', 1)
h = header.split('\r\n')
status_code = h[0].split()[1]
status_code = int(status_code)
header = {}
for line in h[1:]:
k, v = line.split(': ')
# header 内部有一些状态信息
header[k] = v
return status_code, header, body
def get(url):
"""
用 GET 请求 url 并返回响应
"""
protocol, host, port, path = parsed_url(url)
print('get {} {} {} {}'.format(protocol, host, port, path))
s = socket_by_protocol(protocol)
s.connect((host, port))
request = 'GET {} HTTP/1.1\r\nHost: {}\r\nCookie:user=assafasdfsadf\r\nConnection:close\r\n\r\n'.format(path, host)
encoding = 'utf-8'
s.send(request.encode(encoding))
response = response_by_socket(s)
print('get response, ', response)
r = response.decode(encoding)
status_code, headers, body = parsed_response(r)
if status_code in [301, 302]:
url = headers['Location']
return get(url)
return status_code, headers, body
def main():
"""
运行主函数
"""
url = 'http://movie.douban.com/top250'
status_code, headers, body = get(url)
print('main status_code', status_code)
print('main headers ({})'.format(headers))
print('main body', body)
# 以下为测试函数
def test_parsed_url():
"""
测试函数检验 parsed_url 函数是否正确
"""
http = 'http'
https = 'https'
host = 'g.cn'
path = '/'
test_items = [
('http://g.cn', (http, host, 80, path)),
('http://g.cn/', (http, host, 80, path)),
('http://g.cn:90', (http, host, 90, path)),
('http://g.cn:90/', (http, host, 90, path)),
('https://g.cn', (https, host, 443, path)),
('https://g.cn:233/', (https, host, 233, path)),
]
for t in test_items:
url, expected = t
u = parsed_url(url)
e = "parsed_url ERROR, ({}) ({}) ({})".format(url, u, expected)
assert u == expected, e
def test_parsed_response():
"""
测试是否能正确解析响应
"""
# \ 表示连接多行字符串
response = 'HTTP/1.1 301 Moved Permanently\r\n' \
'Content-Type: text/html\r\n' \
'Location: https://movie.douban.com/top250\r\n' \
'Content-Length: 178\r\n\r\n' \
'test body'
status_code, header, body = parsed_response(response)
assert status_code == 301
assert len(list(header.keys())) == 3
assert body == 'test body'
def test_get():
"""
测试是否能正确处理 HTTP 和 HTTPS
"""
urls = [
'http://movie.douban.com/top250',
'https://movie.douban.com/top250',
]
# 这里就直接调用了 get 如果出错就会挂, 测试得比较简单
for u in urls:
get(u)
def test():
"""
用于测试的主函数
"""
test_parsed_url()
test_get()
test_parsed_response()
if __name__ == '__main__':
test()
main()
以上程序中所用到的知识点如下:
# https 请求的默认端口是 443 # https 的 socket 连接需要 import ssl # 使用 s = ssl.wrap_socket(socket.socket()) 来初始化
# 默认端口的区别
# http 的默认端口为 80 # https 的默认端口为 443
# 创建 socket 实例的区别
# http : s = socket.socket() # https : s = ssl.wrap_socket(socket.socket())
用法:assert 布尔表达式, 异常字符串 # 如果断言成功,布尔表达式为真,则通过测试 # 布尔表达式为假,中断程序,并输出异常字符串
# 301, 302 都为重定向状态码 # 重定向状态会在 HTTP 头的 Location 部分告诉你应该转向的 URL # 即 若遇到重定向状态码,就请求新地址并且返回