urllib2 未检索整个 HTTP 响应

Question

我很困惑为什么我无法使用 urllib2 从 FriendFeed 下载一些 JSON 响应的全部内容。

>>> import urllib2
>>> stream = urllib2.urlopen('http://friendfeed.com/api/room/the-life-scientists/profile?format=json')
>>> stream.headers['content-length']
'168928'
>>> data = stream.read()
>>> len(data)
61058
>>> # We can see here that I did not retrieve the full JSON
... # given that the stream doesn't end with a closing }
... 
>>> data[-40:]
'ce2-003048343a40","name":"Vincent Racani'

如何使用 urllib2 检索完整响应？

Answer 1

获取所有数据的最佳方式：

fp = urllib2.urlopen("http://www.example.com/index.cfm")

response = ""
while 1:
    data = fp.read()
    if not data:         # This might need to be    if data == "":   -- can't remember
        break
    response += data

print response

原因是，鉴于套接字的性质，.read() 不能保证返回整个响应。我以为这在文档中讨论过（可能是urllib），但我找不到。

Answer 2

使用tcpdump（或类似的东西）来监控实际的网络交互 - 然后您可以分析为什么某些客户端库会损坏站点。确保通过编写测试脚本来重复多次，以便查看问题是否一致：

import urllib2
url = 'http://friendfeed.com/api/room/friendfeed-feedback/profile?format=json'
stream = urllib2.urlopen(url)
expected = int(stream.headers['content-length'])
data = stream.read()
datalen = len(data)
print expected, datalen, expected == datalen

该网站一直为我工作，所以我无法给出发现失败的例子:)

Answer 3

继续调用 stream.read() 直到它完成...

while data = stream.read() :
    ... do stuff with data

Answer 4

readlines() 

也可以