Question

现在，这是不确定的。 Gzip，图像，有时它不起作用。

如何修改此下载功能以便它可以处理任何内容？（无论是gzip还是任何标题？）

如果是gzip，如何自动“检测”？我不想总是传递真/假，就像我现在做的那样。

def download(source_url, g = False, correct_url = True):
    try:
        socket.setdefaulttimeout(10)
        agents = ['Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)','Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 5.1)','Microsoft Internet Explorer/4.0b1 (Windows 95)','Opera/8.00 (Windows NT 5.1; U; en)']
        ree = urllib2.Request(source_url)
        ree.add_header('User-Agent',random.choice(agents))
        ree.add_header('Accept-encoding', 'gzip')
        opener = urllib2.build_opener()
        h = opener.open(ree).read()
        if g:
            compressedstream = StringIO(h)
            gzipper = gzip.GzipFile(fileobj=compressedstream)
            data = gzipper.read()
            return data
        else:
            return h
    except Exception, e:
        return ""

Answer 1

检查Content-Encoding标题：

import urllib2
import socket
import random
import StringIO
import gzip

def download(source_url):
    try:
        socket.setdefaulttimeout(10)
        agents = ['Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)','Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 5.1)','Microsoft Internet Explorer/4.0b1 (Windows 95)','Opera/8.00 (Windows NT 5.1; U; en)']
        ree = urllib2.Request(source_url)
        ree.add_header('User-Agent',random.choice(agents))
        ree.add_header('Accept-encoding', 'gzip')
        opener = urllib2.build_opener()
        response = opener.open(ree)
        encoding=response.headers.getheader('Content-Encoding')
        content = response.read()
        if encoding and 'gzip' in encoding:
            compressedstream = StringIO.StringIO(content)
            gzipper = gzip.GzipFile(fileobj=compressedstream)
            data = gzipper.read()
            return data
        else:
            return content
    except urllib2.URLError as e:
        return ""

data=download('http://api.stackoverflow.com/1.0/questions/3708418?type=jsontext')
print(data)

如果您正在处理的服务器没有将内容编码报告为gzip，那么您可以通过try首先进行更积极的攻击：

def download(source_url):
    try:
        socket.setdefaulttimeout(10)
        agents = ['Mozilla/4.0 (compatible; MSIE 5.5; Windows NT 5.0)','Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 5.1)','Microsoft Internet Explorer/4.0b1 (Windows 95)','Opera/8.00 (Windows NT 5.1; U; en)']
        ree = urllib2.Request(source_url)
        ree.add_header('User-Agent',random.choice(agents))
        ree.add_header('Accept-encoding', 'gzip')
        opener = urllib2.build_opener()
        response = opener.open(ree)
        content = response.read()
        compressedstream = StringIO.StringIO(content)
        gzipper = gzip.GzipFile(fileobj=compressedstream)
        try:
            data = gzipper.read()
        except IOError:
            data = content
        return data        
    except urllib2.URLError as e:
        return ""

Answer 2

要检测您下载的数据类型，您应该替换h = opener.open(ree).read()的{{1}}。

现在你有了响应对象。您可以使用h.headers（类似dict）对象来分析标头。特别是你会对标题'content-type'和'content-encoding'感兴趣。您可以确定分析它的内容。

h = opener.open(ree)

Answer 3

import urllib2
import StringIO
import gzip

req = urllib2.Request('http:/foo/')
h = urllib2.urlopen(req)
data = resp.read()
if 'gzip' in resp.headers['Content-Encoding']:
    compressedstream = StringIO(h)
    gzipper = gzip.GzipFile(fileobj=compressedstream)
    data = gzipper.read()

# etc...

如何在Python中修改此下载功能？

3 个答案: