Question

我正在使用python的urllib2库向特定主机发出几个http请求。每次发出请求时，都会创建一个新的tcp和http连接，这需要花费大量时间。有没有办法使用urllib2保持tcp / http连接活着？

Answer 1

如果切换到httplib，您将可以更好地控制基础连接。

例如：

import httplib

conn = httplib.HTTPConnection(url)

conn.request('GET', '/foo')
r1 = conn.getresponse()
r1.read()

conn.request('GET', '/bar')
r2 = conn.getresponse()
r2.read()

conn.close()

这将在相同的底层TCP连接上发送2个HTTP GET。

Answer 2

我过去使用过第三方urllib3库效果很好。它旨在通过汇集连接以便重用来补充urllib2。

来自the wiki的修改示例：

>>> from urllib3 import HTTPConnectionPool
>>> # Create a connection pool for a specific host
... http_pool = HTTPConnectionPool('www.google.com')
>>> # simple GET request, for example
... r = http_pool.urlopen('GET', '/')
>>> print r.status, len(r.data)
200 28050
>>> r = http_pool.urlopen('GET', '/search?q=hello+world')
>>> print r.status, len(r.data)
200 79124

Answer 3

如果你需要比普通的httplib更自动的东西，这可能有所帮助，虽然它不是线程安全的。

try:
    from http.client import HTTPConnection, HTTPSConnection
except ImportError:
    from httplib import HTTPConnection, HTTPSConnection
import select
connections = {}


def request(method, url, body=None, headers={}, **kwargs):
    scheme, _, host, path = url.split('/', 3)
    h = connections.get((scheme, host))
    if h and select.select([h.sock], [], [], 0)[0]:
        h.close()
        h = None
    if not h:
        Connection = HTTPConnection if scheme == 'http:' else HTTPSConnection
        h = connections[(scheme, host)] = Connection(host, **kwargs)
    h.request(method, '/' + path, body, headers)
    return h.getresponse()


def urlopen(url, data=None, *args, **kwargs):
    resp = request('POST' if data else 'GET', url, data, *args, **kwargs)
    assert resp.status < 400, (resp.status, resp.reason, resp.read())
    return resp

如何在执行多个请求时加速Python的urllib2

3 个答案: