Making HTTP POST request

Question

I'm trying to make a POST request to retrieve information about a book. Here is the code that returns HTTP code: 302, Moved

import httplib, urllib
params = urllib.urlencode({
    'isbn' : '9780131185838',
    'catalogId' : '10001',
    'schoolStoreId' : '15828',
    'search' : 'Search'
    })
headers = {"Content-type": "application/x-www-form-urlencoded",
           "Accept": "text/plain"}
conn = httplib.HTTPConnection("bkstr.com:80")
conn.request("POST", "/webapp/wcs/stores/servlet/BuybackSearch",
             params, headers)
response = conn.getresponse()
print response.status, response.reason
data = response.read()
conn.close()

When I try from a browser, from this page: http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackMaterialsView?langId=-1&catalogId=10001&storeId=10051&schoolStoreId=15828 , it works. What am I missing in my code?

EDIT: Here's what I get when I call print response.msg

302 Moved Date: Tue, 07 Sep 2010 16:54:29 GMT
Vary: Host,Accept-Encoding,User-Agent
Location: http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackSearch
X-UA-Compatible: IE=EmulateIE7
Content-Length: 0
Content-Type: text/plain; charset=utf-8

Seems that the location points to the same url I'm trying to access in the first place?

EDIT2:

I've tried using urllib2 as suggested here. Here is the code:

import urllib, urllib2

url = 'http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackSearch'
values = {'isbn' : '9780131185838',
          'catalogId' : '10001',
          'schoolStoreId' : '15828',
          'search' : 'Search' }


data = urllib.urlencode(values)
req = urllib2.Request(url, data)
response = urllib2.urlopen(req)
print response.geturl()
print response.info()
the_page = response.read()
print the_page

And here is the output:

http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackSearch
Date: Tue, 07 Sep 2010 16:58:35 GMT
Pragma: No-cache
Cache-Control: no-cache
Expires: Thu, 01 Jan 1970 00:00:00 GMT
Set-Cookie: JSESSIONID=0001REjqgX2axkzlR6SvIJlgJkt:1311s25dm; Path=/
Vary: Accept-Encoding,User-Agent
X-UA-Compatible: IE=EmulateIE7
Content-Length: 0
Connection: close
Content-Type: text/html; charset=utf-8
Content-Language: en-US
Set-Cookie: TSde3575=225ec58bcb0fdddfad7332c2816f1f152224db2f71e1b0474c866f3b; Path=/

Answer 1

Their server seems to want you to acquire the proper cookie. This works:

import urllib, urllib2, cookielib

cookie_jar = cookielib.CookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cookie_jar))
urllib2.install_opener(opener)

# acquire cookie
url_1 = 'http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackMaterialsView?langId=-1&catalogId=10001&storeId=10051&schoolStoreId=15828'
req = urllib2.Request(url_1)
rsp = urllib2.urlopen(req)

# do POST
url_2 = 'http://www.bkstr.com/webapp/wcs/stores/servlet/BuybackSearch'
values = dict(isbn='9780131185838', schoolStoreId='15828', catalogId='10001')
data = urllib.urlencode(values)
req = urllib2.Request(url_2, data)
rsp = urllib2.urlopen(req)
content = rsp.read()

# print result
import re
pat = re.compile('Title:.*')
print pat.search(content).group()

# OUTPUT: Title:&nbsp;&nbsp;Statics & Strength of Materials for Arch (w/CD)<br />