POST URL Encoded vs Line-based text data via Python Requests

I'm trying to scrape some data from a website and I can't get the POST to work, it acts as though I didn't give it the input data ("appnote").

When I examine the POST data it looks relatively the same except that the actual webform's POST is called "URL Encoded" and lists each form input, whereas mine is labeled "Line-based text data".

Here's my code: (appnote) and Search (Search) are the most relevant pieces I need

import requests
import cookielib


jar = cookielib.CookieJar()
url = 'http://www.vivotek.com/faq/'
headers = {'content-type': 'application/x-www-form-urlencoded'}

post_data = {#'__EVENTTARGET':'',
             #'__EVENTARGUMENT':'',
             '__LASTFOCUS':'',
             '__VIEWSTATE':'',
             '__VIEWSTATEGENERATOR':'',
             '__VIEWSTATEENCRYPTED':'',
             '__PREVIOUSPAGE':'',
             '__EVENTVALIDATION':''
             'ctl00$HeaderUc1$LanguageDDLUc1$ddlLanguage':'en',
             'ctl00$ContentPlaceHolder1$CategoryDDLUc1$DropDownList1':'-1',
             'ctl00$ContentPlaceHolder1$ProductDDLUc1$DropDownList1':'-1',
             'ctl00$ContentPlaceHolder1$Content':'appnote',
             'ctl00$ContentPlaceHolder1$Search':'Search'
            }
response = requests.get(url, cookies=jar)

response = requests.post(url, cookies=jar, data=post_data, headers=headers)

print(response.text)

Links to images of what I'm talking about in Wireshark:

I also tried it using wget with the same results.

Solution

The main problem is that you are not setting the important hidden field values, like __VIEWSTATE.

For this to work using requests, you need to parse the page html and get the appropriate input values.

Here's the solution using BeautifulSoup HTML parser and requests:

from bs4 import BeautifulSoup
import requests

url = 'http://www.vivotek.com/faq/'
query = 'appnote'

headers = {'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.124 Safari/537.36'}

session = requests.Session()
response = session.get(url, headers=headers)

soup = BeautifulSoup(response.content)

post_data = {'__EVENTTARGET':'',
             '__EVENTARGUMENT':'',
             '__LASTFOCUS':'',
             '__VIEWSTATE': soup.find('input', id='__VIEWSTATE')['value'],
             '__VIEWSTATEGENERATOR': soup.find('input', id='__VIEWSTATEGENERATOR')['value'],
             '__VIEWSTATEENCRYPTED': '',
             '__PREVIOUSPAGE': soup.find('input', id='__PREVIOUSPAGE')['value'],
             '__EVENTVALIDATION': soup.find('input', id='__EVENTVALIDATION')['value'],

             'ctl00$HeaderUc1$LanguageDDLUc1$ddlLanguage': 'en',
             'ctl00$ContentPlaceHolder1$CategoryDDLUc1$DropDownList1': '-1',
             'ctl00$ContentPlaceHolder1$ProductDDLUc1$DropDownList1': '-1',
             'ctl00$ContentPlaceHolder1$Content': query,
             'ctl00$ContentPlaceHolder1$Search': 'Search'
            }

response = session.post(url, data=post_data, headers=headers)

soup = BeautifulSoup(response.content)
for item in soup.select('a#ArticleShowLink'):
    print item.text.strip()

Prints the specific results for the appnote query:

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