Python 仅获取响应头, 不获取实体的实例
脚本专栏 发布日期：2024/10/13 浏览次数：1
正在浏览：Python 仅获取响应头, 不获取实体的实例
Python Just get Response Headers, not get content.
1. Use HEAD method
> import requests
> res = requests.head("http://www.baidu.com/")
> req.head("https://www.baidu.com/").headers
{'Content-Encoding': 'gzip', 'Server': 'bfe/1.0.8.18', 'Last-Modified': 'Mon, 13 Jun 2016 02:50:08 GMT', 'Connection': 'Keep-Alive', 'Pragma': 'no-cache', 'Cache-Control': 'private, no-cache, no-store, proxy-revalidate, no-transform', 'Date': 'Fri, 13 Oct 2017 04:36:20 GMT', 'Content-Type': 'text/html'}
> res.ok
True
> res.content
''
# 但是会遇到一些问题, 比如, 服务器不支持 HEAD, 或者拒绝 HEAD.
# 如下情况就被拒绝
#
> res = req.head("https://www.douban.com/subject/1/")
> res
<Response [403]>
> res.ok
False
> res.content
''
> res.headers
{'Content-Encoding': 'gzip', 'Keep-Alive': 'timeout=30', 'Server': 'dae', 'Connection': 'keep-alive', 'Date': 'Fri, 13 Oct 2017 04:39:00 GMT', 'Content-Type': 'text/html'}
不是很通用, 因为有些服务器不支持.
2. Use urllib
import urllib
> res = urllib.urlopen("http://127.0.0.1:8000/git.exe")
> res.url
'http://127.0.0.1:8000/git.exe'
> res.headers.headers
['Server: SimpleHTTP/0.6 Python/2.7.10\r\n', 'Date: Fri, 13 Oct 2017 06:06:37 GMT\r\n', 'Content-type: application/x-msdownload\r\n', 'Content-Length: 7569408\r\n', 'Last-Modified: Fri, 16 Dec 2016 07:09:32 GMT\r\n']
> len(r.read())
7569408
# urllib 只有在调用 read/readline/readlines 的时候才会从 web 服务器读取数据.
# 源码可以在 urllib/httplib 中找到.
# urllib.py
def urlopen(url, ...):
opener = FancyURLopener()
return opener.open(url)
class FancyURLopener(URLopener).open():
getattr(self, name)(url)
class URLopener.open_http():
errcode, errmsg, headers = h.getreply()
if(200 <= errcode < 300):
return addinfourl(fp, headers, "http:" + url, errcode)
else:
if data is None:
return self.http_error(url, fp, errcode, errmsg, headers)
else:
return self.http_error(url, fp, errcode, errmsg, headers, data)
class URLopener.http_error():
return method(url, fp, errcode, errmsg, headers)
class FancyURLopener.http_error_default():
return addinfourl(fp, headers, "http:" + url, errcode)
class addinfourl(addbase):
# 代码中并没有对 fp 做任何操作,包括读写.
class addbase.__init __():
self.fp = fp
self.read = self.fp.read
self.readline = self.fp.readline
if hasattr(self.fp, "readlines"): self.readlines = self.fp.readlines
self.fileno = self.fp.fileno
# ... ...
可以看到, urllib.open 最终返回了 addbase, addbase 中没有对 socket 做任务处理, 不会有任何读写. 之后显示调用 read/readline/readlines, 才会从 web 服务器读取数据.
图 1. 初始化网络.
图 2. urlopen() 之后
图 3. read() 之后
3. Use socket
看过 urllib 之后, 可以使用 socket 写一个方法, 只获取 header.
import socket
import ssl
_timeout = 10
socket.setdefaulttimeout(_timeout)
def get_header(host, port=80, uri="/", method="GET", user_ssl=False):
# 这里可以再扩充一下, 支持 headers
conn = None
header = """%s %s HTTP/1.1\r\nHost: %s\r\nConnection: close\r\nUser-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36\r\n\r\n""" % (
method, uri, host)
if user_ssl:
ssl_context = ssl.SSLContext(ssl.PROTOCOL_TLSv1)
_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
conn = ssl_context.wrap_socket(_socket, server_hostname=host)
conn.connect((host, port))
conn.send(header)
else:
conn = socket.create_connection((host, port), _timeout)
conn.sendall(header)
text = ""
while True:
if "\r\n\r\n" in text:
break
buff = conn.recv(10)
text += buff
# print buff
conn.close()
return text.split("\r\n\r\n")[0]
if __name__ == '__main__':
print get_header("www.douban.com", uri="/subject/27076001/")
print
print get_header("www.douban.com", uri="/subject/27076001/", port=443, user_ssl=True)
"external nofollow" target="_blank" href="https://stackoverflow.com/questions/32062925/python-socket-server-handle-https-request"><< Python socket server handle HTTPS request (https://stackoverflow.com/questions/32062925/python-socket-server-handle-https-request)以上这篇Python 仅获取响应头, 不获取实体的实例就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持。