标签:inf top html ogr 打开 table 运行 begin completed
一 pycurl介绍
pycurl模块为libcurl库提供了一个python接口。libcurl是一个开源免费且方便快捷的基于客户端的url传输库,支持FTP,HTTP,HTTPS,IMAP,IMAPS,LDAP,LDAPS,POP3,POP3S,RTMP,RTSP,SCP等等。libcurl还支持SSL认证,HTTP POST,HTTP PUT,FTP UPLOADING等等。和urllib模块类似,pycurl模块也可以用来获取一个url的对象。pycurl使用了大部分libcurl提供的函数,使得pycurl具有以下特性:
快速 libcurl本身就很快速,pycurl就是对libcurl进行了一次封装,所以pycurl同样很快速。
支持多种协议,SSL,认证和代理选项。pycurl支持大部分libcurl的回调函数。
multi 和 share 接口支持
可以和应用的I/O整合
二 pycurl使用案例
1.安装pycurl
CentOS6 下使用pip install pycurl安装
可以使用ipython来调试
2.获取一个url响应结果
import pycurl from StringIO import StringIO buffer=StringIO() c=pycurl.Curl() c.setopt(c.URL,‘http://pycurl.io/‘) c.setopt(c.WRITEFUNCTION,buffer.write) c.perform() c.close() body=buffer.getvalue() print(body)
pycurl本身不会存储url的响应结果,因此,需要设置一个buffer,让pycurl将结果写入到这个buffer中
想要获取调试信息,可以设置
c.setopt(c.VERBOSE, True)
等同于 curl -v
3.审查响应头
在实际案例中,我们想要根据服务端的编码格式来解码响应结果
import pycurl
import re
try:
from io import BytesIO
except ImportError:
from StringIO import StringIO as BytesIO
headers={}
def header_function(header_line):
# HTTP standard specifies that headers are encoded in iso-8859-1.
# On Python 2, decoding step can be skipped.
# On Python 3, decoding step is required.
header_line=header_line.decode(‘iso-8859-1‘)
# Header lines include the first status line (HTTP/1.x ...).
# We are going to ignore all lines that don‘t have a colon in them.
# This will botch headers that are split on multiple lines...
if ‘:‘ not in header_line:
return
# Break the header line into header name and value.
name, value = header_line.split(‘:‘, 1)
# Remove whitespace that may be present.
# Header lines include the trailing newline, and there may be whitespace
# around the colon.
name = name.strip()
value = value.strip()
# Header names are case insensitive.
# Lowercase name here.
name = name.lower()
# Now we can actually record the header name and value.
headers[name] = value
buffer=BytesIO()
c=pycurl.Curl()
c.setopt(c.URL,‘http://pycurl.io‘)
c.setopt(c.WRITEFUNCTION,buffer.write)
#set our header function
c.setopt(c.HEADERFUNCTION,header_function)
c.perform()
c.close()
# Figure out what encoding was sent with the response, if any.
# Check against lowercased header name.
encoding=None
if ‘content-type‘ in headers:
content_type=headers[‘content-type‘].lower()
match=re.search(‘charset=(\S+)‘, content_type)
if match:
encoding=match.group(1)
print(‘Decoding using %s‘ % encoding)
if encoding is None:
# Default encoding for HTML is iso-8859-1.
# Other content types may have different default encoding,
# or in case of binary data, may have no encoding at all.
encoding=‘iso-8859-1‘
print(‘Assuming encoding is %s‘ % encoding)
body=buffer.getvalue()
# Decode using the encoding we figured out.
print(body.decode(encoding))
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4.将响应结果写入到文件
import pycurl with open(‘out.html‘,‘wb‘) as f: c=pycurl.Curl() c.setopt(c.URL,‘http://pycurl.io/‘) c.setopt(c.WRITEDATA,f) c.perform() c.close()
这里最重要的部分就是以二进制模式打开文件,这样响应结果可以以字节码写入到文件中,不需要编码和解码。
5.跟踪url跳转
libcurl和pycurl默认不跟踪url跳转。
import pycurl c=pycurl.Curl() #Redirects to https://www.python.org/. c.setopt(c.URL,‘http://www.python.org/‘) #Follow redirect c.setopt(c.FOLLOWLOCATION,True) c.perform() c.close()
6.审查响应
import pycurl
try:
from io import BytesIO
except ImportError:
from StringIO import StringIO as BytesIO
buffer=BytesIO()
c=pycurl.Curl()
c.setopt(c.URL,‘http://www.python.org/‘)
c.setopt(c.WRITEFUNCTION,buffer.write)
c.perform()
#Last used URL
print(‘Effective_url: %s‘ %c.getinfo(c.EFFECTIVE_URL))
#HTTP response code
print(‘Response_code: %d‘ %c.getinfo(c.RESPONSE_CODE))
#Total time of previous transfer
print(‘Total_time: %f‘ %c.getinfo(c.TOTAL_TIME))
#Time from start until name resolving completed
print(‘Namelookup_time: %f‘ %c.getinfo(c.NAMELOOKUP_TIME))
#Time from start until remote host or proxy completed
print(‘Connect_time: %f‘ %c.getinfo(c.CONNECT_TIME))
#Time from start until SLL/SSH handshake completed
print(‘SSL/SSH_time: %f‘ %c.getinfo(c.APPCONNECT_TIME))
#Time from start until just before the transfer begins
print(‘Pretransfer_time: %f‘ %c.getinfo(c.PRETRANSFER_TIME))
#Time from start until just when the first byte is received
print(‘Starttransfer_time: %f‘ %c.getinfo(c.STARTTRANSFER_TIME))
#Time taken for all redirect steps before the final transfer
print(‘Redirect_time: %f‘ %c.getinfo(c.REDIRECT_TIME))
#Total number of redirects that were followed
print(‘Redirect_count: %d‘ %c.getinfo(c.REDIRECT_COUNT))
#URL a redirect would take you to,had you enabled redirects
print(‘Redirect_url: %s‘ %c.getinfo(c.REDIRECT_URL))
#Number of bytes uploaded
print(‘Size_upload: %d‘ %c.getinfo(c.SIZE_UPLOAD))
#Average upload speed
print(‘Speed_upload: %f‘ %c.getinfo(c.SPEED_UPLOAD))
#Number of bytes downloaded
print(‘Size_download: %d‘ %c.getinfo(c.SIZE_DOWNLOAD))
#Average download speed
print(‘Speed_download: %f‘ %c.getinfo(c.SPEED_DOWNLOAD))
#getinfo must be called before close
c.close()
# python response_info.py Effective_url: http://www.python.org/ Response_code: 301 Total_time: 0.105395 Namelookup_time: 0.051208 Connect_time: 0.078317 SSL/SSH_time: 0.000000 Pretransfer_time: 0.078322 Starttransfer_time: 0.105297 Redirect_time: 0.000000 Redirect_count: 0 Redirect_url: https://www.python.org/ Size_upload: 0 Speed_upload: 0.000000 Size_download: 0 Speed_download: 0.000000
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7.发送表单数据
发送表单数据使用POSTFIELDS参数
import pycurl
try:
#python 3
from urllib.parse import urlencode
except ImportError:
from urllib import urlencode
c=pycurl.Curl()
c.setopt(c.URL,‘http://pycurl.io/tests/testpostvars.php‘)
post_data={‘field‘:‘value‘}
#Form data must be provided already urlencoded
postfields=urlencode(post_data)
# Sets request method to POST,
# Content-Type header to application/x-www-form-urlencoded
# and data to send in request body.
c.setopt(c.POSTFIELDS, postfields)
c.perform()
c.close()
8.文件上传
上传文件使用HTTPPOST参数,上传一个物理文件,使用FORM_FILE
import pycurl
c = pycurl.Curl()
c.setopt(c.URL, ‘http://pycurl.io/tests/testfileupload.php‘)
c.setopt(c.HTTPPOST, [
(‘fileupload‘, (
# upload the contents of this file
c.FORM_FILE, __file__,
)),
])
c.perform()
c.close()
为上传的文件设置不同的文件名和内容类型
import pycurl
c = pycurl.Curl()
c.setopt(c.URL, ‘http://pycurl.io/tests/testfileupload.php‘)
c.setopt(c.HTTPPOST, [
(‘fileupload‘, (
# upload the contents of this file
c.FORM_FILE, __file__,
# specify a different file name for the upload
c.FORM_FILENAME, ‘helloworld.py‘,
# specify a different content type
c.FORM_CONTENTTYPE, ‘application/x-python‘,
)),
])
c.perform()
c.close()
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如果文件数据在内存中,使用BUFFER/BUFFERPTR
import pycurl
c = pycurl.Curl()
c.setopt(c.URL, ‘http://pycurl.io/tests/testfileupload.php‘)
c.setopt(c.HTTPPOST, [
(‘fileupload‘, (
c.FORM_BUFFER, ‘readme.txt‘,
c.FORM_BUFFERPTR, ‘This is a fancy readme file‘,
)),
])
c.perform()
c.close()
9.处理FTP协议
import pycurl c = pycurl.Curl() c.setopt(c.URL, ‘ftp://ftp.sunet.se/‘) c.setopt(c.FTP_USE_EPSV, 1) c.setopt(c.QUOTE, [‘cwd pub‘, ‘type i‘]) c.perform() c.close()
10.Sharing Data
import pycurl
import threading
print >>sys.stderr, ‘Testing‘, pycurl.version
class Test(threading.Thread):
def __init__(self, share):
threading.Thread.__init__(self)
self.curl = pycurl.Curl()
self.curl.setopt(pycurl.URL, ‘http://curl.haxx.se‘)
self.curl.setopt(pycurl.SHARE, share)
def run(self):
self.curl.perform()
self.curl.close()
s = pycurl.CurlShare()
s.setopt(pycurl.SH_SHARE, pycurl.LOCK_DATA_COOKIE)
s.setopt(pycurl.SH_SHARE, pycurl.LOCK_DATA_DNS)
t1 = Test(s)
t2 = Test(s)
t1.start()
t2.start()
del s
11.使用multi接口
libcurl的easy接口是一个同步的,高效的,上手快的用于文件传输的接口。multi接口是一个异步的接口,它可以使用一个或者多个线程进行多路传输。
multi接口比easy接口多了以下几个功能:
提供一个pull接口。使用libcurl的应用决定哪里何时询问libcurl去接收或者发送数据
在同一个线程中启动多路同步传输而不必使应用程序变得更复杂
使得应用程序同时等待在应用程序本身的文件描述符和libcurl文件描述符上的动作变得简单许多
使得基于事件处理和扩展的传输可以达到上千个并行连接
例1
import pycurl
m = pycurl.CurlMulti()
m.handles = []
c1 = pycurl.Curl()
c2 = pycurl.Curl()
c1.setopt(c1.URL, ‘http://curl.haxx.se‘)
c2.setopt(c2.URL, ‘http://cnn.com‘)
c2.setopt(c2.FOLLOWLOCATION, 1)
m.add_handle(c1)
m.add_handle(c2)
m.handles.append(c1)
m.handles.append(c2)
num_handles = len(m.handles)
while num_handles:
while 1:
ret, num_handles = m.perform()
if ret != pycurl.E_CALL_MULTI_PERFORM:
break
m.select(1.0)
m.remove_handle(c2)
m.remove_handle(c1)
del m.handles
m.close()
c1.close()
c2.close()
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例2
import os, sys
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
import pycurl
urls = (
"http://curl.haxx.se",
"http://www.python.org",
"http://pycurl.sourceforge.net",
"http://pycurl.sourceforge.net/tests/403_FORBIDDEN", # that actually exists ;-)
"http://pycurl.sourceforge.net/tests/404_NOT_FOUND",
)
# Read list of URIs from file specified on commandline
try:
urls = open(sys.argv[1], "rb").readlines()
except IndexError:
# No file was specified
pass
# init
m = pycurl.CurlMulti()
m.handles = []
for url in urls:
c = pycurl.Curl()
# save info in standard Python attributes
c.url = url.strip()
c.body = StringIO()
c.http_code = -1
m.handles.append(c)
# pycurl API calls
c.setopt(c.URL, c.url)
c.setopt(c.WRITEFUNCTION, c.body.write)
c.setopt(c.FOLLOWLOCATION,True)
m.add_handle(c)
# get data
num_handles = len(m.handles)
while num_handles:
while 1:
ret, num_handles = m.perform()
print ret,num_handles
if ret != pycurl.E_CALL_MULTI_PERFORM:
break
# currently no more I/O is pending, could do something in the meantime
# (display a progress bar, etc.)
m.select(1.0)
# close handles
for c in m.handles:
# save info in standard Python attributes
c.http_code = c.getinfo(c.HTTP_CODE)
# pycurl API calls
m.remove_handle(c)
c.close()
m.close()
# print result
for c in m.handles:
data = c.body.getvalue()
if 0:
print "**********", c.url, "**********"
print data
else:
print "%-53s http_code %3d, %6d bytes" % (c.url, c.http_code, len(data))
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例3
import os, sys
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
import pycurl
urls = (
"http://curl.haxx.se",
"http://www.python.org",
"http://pycurl.sourceforge.net",
"http://pycurl.sourceforge.net/THIS_HANDLE_IS_CLOSED",
)
# init
m = pycurl.CurlMulti()
m.handles = []
for url in urls:
c = pycurl.Curl()
# save info in standard Python attributes
c.url = url
c.body = StringIO()
c.http_code = -1
c.debug = 0
m.handles.append(c)
# pycurl API calls
c.setopt(c.URL, c.url)
c.setopt(c.WRITEFUNCTION, c.body.write)
c.setopt(c.FOLLOWLOCATION,True)
m.add_handle(c)
# debug - close a handle
if 1:
c = m.handles[3]
c.debug = 1
c.close()
# get data
num_handles = len(m.handles)
while num_handles:
while 1:
ret, num_handles = m.perform()
if ret != pycurl.E_CALL_MULTI_PERFORM:
break
# currently no more I/O is pending, could do something in the meantime
# (display a progress bar, etc.)
m.select(1.0)
# close handles
for c in m.handles:
# save info in standard Python attributes
try:
c.http_code = c.getinfo(c.HTTP_CODE)
except pycurl.error:
# handle already closed - see debug above
assert c.debug
c.http_code = -1
# pycurl API calls
if 0:
m.remove_handle(c)
c.close()
elif 0:
# in the C API this is the wrong calling order, but pycurl
# handles this automatically
c.close()
m.remove_handle(c)
else:
# actually, remove_handle is called automatically on close
c.close()
m.close()
# print result
for c in m.handles:
data = c.body.getvalue()
if 0:
print "**********", c.url, "**********"
else:
print "%-53s http_code %3d, %6d bytes" % (c.url, c.http_code, len(data))
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可以使用multi接口来缩短访问很多url的时间
假设一个文件中包含了很多个url,现在要通过脚本去访问每个url判断返回码是不是200
文件中共有87个url
方法一 使用python的for语句顺序访问每个url
import os,sys
import pycurl
from StringIO import StringIO
try:
if sys.argv[1]=="-":
urls=sys.stdin.readlines()
else:
urls=open(sys.argv[1],‘rb‘).readlines()
#print urls
except:
print "Usage: %s check_urls.txt <file with urls to check>" %sys.argv[0]
raise SystemExit
class Curl:
def __init__(self,url):
self.url=url
self.body=StringIO()
self.http_code=0
self._curl=pycurl.Curl()
self._curl.setopt(pycurl.URL,self.url)
self._curl.setopt(pycurl.WRITEFUNCTION,self.body.write)
self._curl.setopt(pycurl.FOLLOWLOCATION,True)
self._curl.setopt(pycurl.NOSIGNAL,1)
def perform(self):
self._curl.perform()
def close(self):
self.http_code=self._curl.getinfo(pycurl.HTTP_CODE)
self._curl.close()
for url in urls:
url=url.strip()
if not url or url[0] == ‘#‘:
continue
c=Curl(url)
c.perform()
c.close()
print url, c.http_code
real 2m46.134s user 0m0.134s sys 0m0.185s
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方法二 使用pycurl的CurlMulti()函数
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from StringIO import StringIOimport pycurl# We should ignore SIGPIPE when using pycurl.NOSIGNAL - see# the libcurl tutorial for more info.try: import signal from signal import SIGPIPE,SIG_ING signal.signal(signal.SIGPIPE,signal.SIG_IGN)except ImportError: pass# need a given txt file contains urlstry: if sys.argv[1]=="-": urls=sys.stdin.readlines() else: urls=open(sys.argv[1],‘rb‘).readlines() #print urlsexcept: print "Usage: %s check_urls.txt <file with urls to check>" %sys.argv[0] raise SystemExitclass Curl: def __init__(self,url): self.url=url self.body=StringIO() self.http_code=0 self._curl=pycurl.Curl() self._curl.setopt(pycurl.URL,self.url) self._curl.setopt(pycurl.FOLLOWLOCATION,True) self._curl.setopt(pycurl.WRITEFUNCTION,self.body.write) self._curl.setopt(pycurl.NOSIGNAL,1) self._curl.debug=0 def perform(self): self._curl.perform() def close(self): try: self.http_code=self._curl.getinfo(pycurl.HTTP_CODE) except pycurl.error: assert c.debug self.http_code=0 self._curl.close()def print_result(items): for c in items: data=c.body.getvalue() if 0: print "***************",c.url,"******************" print data elif 1: print "%-60s %3d %6d" %(c.url,c.http_code,len(data))def test_multi(): handles=[] m=pycurl.CurlMulti() for url in urls: url=url.strip() if not url or url[0] == ‘#‘: continue c=Curl(url) m.add_handle(c._curl) handles.append(c) while 1: ret,num_handles=m.perform() if ret!= pycurl.E_CALL_MULTI_PERFORM: break while num_handles: m.select(5.0) while 1: ret,num_handles=m.perform() if ret!= pycurl.E_CALL_MULTI_PERFORM: break for c in handles: c.close() m.close() print_result(handles)if 1: test_multi() |
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real 2m46.049suser 0m0.082ssys 0m0.132s |
在pycurl作者给的案例中,使用CurlMulti()接口处理多个url速度是最快的,但是当url数量多时速度并不快,而且有部分url还不能获取正确的返回值
方法三 使用python的多线程模块
python由于有GIL全局解释器锁的存在,python提供的threading模块不能充分利用多线程的优势,在多核CPU服务器上,统一时刻实际上只有一个线程在运行,其他线程都处于锁定状态。所以python的threading模块不适合用于处理CPU密集型任务,相反,threading线程数据量越多,速度越慢。但是对于I/O密集型或者网络密集型任务,还是可以使用threading模块
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import os,sys,timeimport threadingimport Queuetry: from cStringIO import StringIOexcept ImportError: from StringIO import StringIOimport pycurl# We should ignore SIGPIPE when using pycurl.NOSIGNAL - see# the libcurl tutorial for more info.try: import signal from signal import SIGPIPE,SIG_ING signal.signal(signal.SIGPIPE,signal.SIG_IGN)except ImportError: pass# need a given txt file contains urlstry: if sys.argv[1]=="-": urls=sys.stdin.readlines() else: urls=open(sys.argv[1],‘rb‘).readlines() #print urlsexcept: print "Usage: %s check_urls.txt <file with urls to check>" %sys.argv[0] raise SystemExit class Curl: def __init__(self,url): self.url=url self.body=StringIO() self.http_code=0 self._curl=pycurl.Curl() self._curl.setopt(pycurl.URL,self.url) self._curl.setopt(pycurl.FOLLOWLOCATION,True) self._curl.setopt(pycurl.CONNECTTIMEOUT,15) self._curl.setopt(pycurl.TIMEOUT,15) self._curl.setopt(pycurl.WRITEFUNCTION,self.body.write) self._curl.setopt(pycurl.NOSIGNAL,1) self._curl.debug=0 def perform(self): self._curl.perform() def close(self): try: self.http_code=self._curl.getinfo(pycurl.HTTP_CODE) except pycurl.error: assert c.debug self.http_code=0 self._curl.close()queue=Queue.Queue()for url in urls: url=url.strip() if not url or url[0] == "#": continue queue.put(url) assert queue.queue, "no urls are given"num_urls=len(queue.queue)#num_conn=min(num_conn,num_urls)num_conn=num_urls#assert 1 <= num_conn < = 1000,"invalid number of concurrent connections"class WorkerThread(threading.Thread): def __init__(self,queue): threading.Thread.__init__(self) self.queue=queue def run(self): while 1: try: url=self.queue.get_nowait() except Queue.Empty: raise SystemExit c=Curl(url) c.perform() c.close() print "http_url:" + url + "\t" + "http_code:" + str(c.http_code)#start a bunch of threads threads=[]for dummy in range(num_conn): t=WorkerThread(queue) t.start() threads.append(t)#wait for all threads to finishfor thread in threads: thread.join() |
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real 0m10.500suser 0m0.149ssys 0m0.196s |
可以看到时间明显比以上两种方法所短了很多
所以,对于有大量url需要用pycurl来处理时,应该结合threading模块
参考资料:
http://pycurl.sourceforge.net/
http://pycurl.io/docs/latest/index.html
https://curl.haxx.se/libcurl/c/libcurl-multi.html
标签:inf top html ogr 打开 table 运行 begin completed
原文地址:http://www.cnblogs.com/saryli/p/6722211.html