分类：

2007-07-26 18:56

698人阅读

(1)

 

可以扩充成为简单的抓取工具，定时抓取

 

#

!usr/bin/python

import

 urllib2,time;

class

 ErrorHandler(urllib2.HTTPDefaultErrorHandler):

    

def

 http_error_default(self, req, fp, code, msg, headers):

        result 

=

 urllib2.HTTPError(req.get_full_url(), code, msg, headers, fp)

        result.status 

=

 code

        

return

 result

URL

=

'

http://www.ibm.com/developerworks/js/ajax1.js

'

req

=

urllib2.Request(URL)

mgr

=

urllib2.build_opener(ErrorHandler())

while

 True:

    ns

=

mgr.open(req)

    

if

(ns.headers.has_key(

'

last-modified

'

)):

        modified

=

ns.headers.get(

'

last-modified

'

)

    

if

(ns.code

==

304

):

        

print

 

'''

          ==============================

              NOT MODIFIED

          ==============================

        

'''

    

elif

(ns.code

==

200

):

        

print

 ns.read()

    

else

:

        

print

 

'

there is an error

'

;

        

    

if

(

not

 locals().has_key(

'

modified

'

)):

        modified

=

time.time();

    req.add_header(

'

If-Modified-Since

'

,modified)

    time.sleep(

10

)