当我尝试从Python打开http://www.comicbookdb.com/browse.php(在我的浏览器中工作正常)时,我得到一个空响应:
>>> import urllib.request
>>> content = urllib.request.urlopen('http://www.comicbookdb.com/browse.PHP')
>>> print(content.read())
b''
设置User-agent时也会发生同样的情况:
>>> opener = urllib.request.build_opener()
>>> opener.addheaders = [('User-agent','Mozilla/5.0')]
>>> content = opener.open('http://www.comicbookdb.com/browse.PHP')
>>> print(content.read())
b''
或者当我使用httplib2时:
>>> import httplib2
>>> h = httplib2.Http('.cache')
>>> response,content = h.request('http://www.comicbookdb.com/browse.PHP')
>>> print(content)
b''
>>> print(response)
{'cache-control': 'no-store,no-cache,must-revalidate,post-check=0,pre-check=0','content-location': 'http://www.comicbookdb.com/browse.PHP','expires': 'Thu,19 Nov 1981 08:52:00 GMT','content-length': '0','set-cookie': 'PHPSESSID=590f5997a91712b7134c2cb3291304a8; path=/','date': 'Wed,25 Dec 2013 15:12:30 GMT','server': 'Apache','pragma': 'no-cache','content-type': 'text/html','status': '200'}
或者当我尝试使用cURL下载它时:
C:\>curl -v http://www.comicbookdb.com/browse.PHP
* About to connect() to www.comicbookdb.com port 80
* Trying 208.76.81.137... * connected
* Connected to www.comicbookdb.com (208.76.81.137) port 80
> GET /browse.PHP HTTP/1.1
User-Agent: curl/7.13.1 (i586-pc-mingw32msvc) libcurl/7.13.1 zlib/1.2.2
Host: www.comicbookdb.com
Pragma: no-cache
Accept: */*
< HTTP/1.1 200 OK
< Date: Wed,25 Dec 2013 15:20:06 GMT
< Server: Apache
< Expires: Thu,19 Nov 1981 08:52:00 GMT
< Cache-Control: no-store,pre-check=0
< Pragma: no-cache
< Set-Cookie: PHPSESSID=0a46f2d390639da7eb223ad47380b394; path=/
< Content-Length: 0
< Content-Type: text/html
* Connection #0 to host www.comicbookdb.com left intact
* Closing connection #0
在浏览器中打开URL或使用Wget下载它似乎工作正常,但是:
C:\>wget http://www.comicbookdb.com/browse.PHP
--16:16:26-- http://www.comicbookdb.com/browse.PHP
=> `browse.PHP'
Resolving www.comicbookdb.com... 208.76.81.137
Connecting to www.comicbookdb.com[208.76.81.137]:80... connected.
HTTP request sent,awaiting response... 200 OK
Length: unspecified [text/html]
[ <=> ] 40,687 48.75K/s
16:16:27 (48.75 KB/s) - `browse.PHP' saved [40687]
与从同一服务器下载不同的文件一样:
>>> content = urllib.request.urlopen('http://www.comicbookdb.com/index.PHP')
>>> print(content.read(100))
b'
那么为什么其他URL不起作用呢?
最佳答案
似乎服务器需要一个Connection:keep-alive标头,例如,curl(我希望其他失败的客户端)也不会默认添加.
使用curl,您可以使用此命令,该命令将显示非空响应:
curl -v -H 'Connection: keep-alive' http://www.comicbookdb.com/browse.PHP
使用Python,您可以使用以下代码:
import httplib2
h = httplib2.Http('.cache')
response,content = h.request('http://www.comicbookdb.com/browse.PHP',headers={'Connection':'keep-alive'})
print(content)
print(response)