How to programmatically log into website in Python

问题

I have searched all over the Internet, looking at many examples and have tried every one I've found, yet none of them are working for me, so please don't think this is a duplicate - I need help with my specific case.

I'm trying to log into a website using Python (in this instance I'm trying with v2.7 but am not opposed to using a more recent version, it's just I've been able to find the most info on 2.7).

I need to fill out a short form, consisting simply of a username and password. The form of the webpage I need to fill out and log in to is as follows (it's messy, I know):

<form method="post" action="login.aspx?ReturnUrl=..%2fwebclient%2fstorepages%2fviewshifts.aspx" id="Form1">
<div class="aspNetHidden">
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKMTU4MTgwOTM1NWRkBffWXYjjifsi875vSMg9OVkhxOQYYstGTNcN9/PFb+M=" />
</div>

<div class="aspNetHidden">

    <input type="hidden" name="__EVENTVALIDATION" id="__EVENTVALIDATION" value="/wEdAAVrmuRkG3j6RStt7rezNSLKVK7BrRAtEiqu9nGFEI+jB3Y2+Mc6SrnAqio3oCKbxYY85pbWlDO2hADfoPXD/5td+Ot37oCEEXP3EjBFcbJhKJGott7i4PNQkjYd3HFozLgRvbhbY2j+lPBkCGQJXOEe" />
</div>
            <div><span></span>
                <table style="BORDER-COLLAPSE: collapse" borderColor="#000000" cellSpacing="0" cellPadding="0"
                    width="600" align="center" border="1">
                    <tr>
                        <td>
                            <table cellSpacing="0" cellPadding="0" width="100%" align="center" border="0">
                                <tr>
                                    <td width="76%"><span id="centercontentTitle"></span>
                                        <H1 align="center"><br>
                                            <span>
                                                <IMG height="52" src="../images/logo-GMR.jpg" width="260"></span><span><br>
                                            </span></H1>
                                        <div id="centercontentbody">
                                            <div align="center">
                                                <TABLE width="350">
                                                    <TR>
                                                        <TD class="style7">Username:</TD>
                                                        <TD>
                                                            <div align="right"><input name="txtUsername" type="text" id="txtUsername" style="width:250px;" /></div>
                                                        </TD>
                                                    </TR>
                                                    <TR>
                                                        <TD class="style7">Password:</TD>
                                                        <TD>
                                                            <div align="right"><input name="txtPassword" type="password" id="txtPassword" style="width:250px;" /></div>
                                                        </TD>
                                                    </TR>
                                                    <TR>
                                                        <TD></TD>
                                                        <TD align="right"><input type="submit" name="btnSubmit" value="Submit" id="btnSubmit" /><input type="submit" name="btnCancel" value="Cancel" id="btnCancel" /></TD>
                                                    </TR>
                                                    <TR>
                                                        <TD colspan="2" align="center"></TD>
                                                    </TR>
                                                </TABLE>
                                            </div>
                                        </div>
                                    </td>
                                    <td>
                                        <div align="center" style='height:250px'></div>
                                    </td>
                                </tr>
                            </table>
                        </td>
                    </tr>
                </table>
                <br>
                <br>
                <p>&nbsp;</p>
        </form>

From searching around online, the best Python code I have found to fill out this form and log into the website is as follows:

Note: This is not my code, I got it from this question/example, where many people have said they've found it to work well.

import cookielib
import urllib
import urllib2


# Store the cookies and create an opener that will hold them
cj = cookielib.CookieJar()
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))

# Add our headers
opener.addheaders = [('User-agent', 'LoginTesting')]

# Install our opener (note that this changes the global opener to the one
# we just made, but you can also just call opener.open() if you want)
urllib2.install_opener(opener)

# The action/ target from the form
authentication_url = '<URL I am trying to log into>'

# Input parameters we are going to send
payload = {
  '__EVENTVALIDATION': '/wEdAAVrmuRkG3j6RStt7rezNSLKVK7BrRAtEiqu9nGFEI+jB3Y2+Mc6SrnAqio3oCKbxYY85pbWlDO2hADfoPXD/5td+Ot37oCEEXP3EjBFcbJhKJGott7i4PNQkjYd3HFozLgRvbhbY2j+lPBkCGQJXOEe"',
  'txtUsername': '<USERNAME>',
  'txtPassword': '<PASSWORD>',
  }

# Use urllib to encode the payload
data = urllib.urlencode(payload)

# Build our Request object (supplying 'data' makes it a POST)
req = urllib2.Request(authentication_url, data)

# Make the request and read the response
resp = urllib2.urlopen(req)
contents = resp.read()

Unfortunately, this is not working for me and I'm unable to figure out why. If someone could please please please look over the code and tell me how I could improve it so as it works as it should. It would be so greatly appreciated!

Thanks in advance for all help I receive :)

回答1:

__EVENTVALIDATION is probably not static, you need to load the login page in python, get the __EVENTVALIDATION field and then do the login.

Something like this should work:

import requests
from bs4 import BeautifulSoup

s = requests.session()

def get_eventvalidation():
    r = s.get("http://url.to.login.page")
    bs = BeautifulSoup(r.text)

    return bs.find("input", {"name":"__EVENTVALIDATION"}).attrs['value']

authentication_url = '<URL I am trying to log into>'

payload = {
  '__EVENTVALIDATION': get_eventvalidation(),
  'txtUsername': '<USERNAME>',
  'txtPassword': '<PASSWORD>',
  }

login = s.post(authentication_url, data=payload)

print login.text

You need the requests module and beautifulsoup4. Or you can just rewrite it to not use libraries.

Edit: You probably need __VIEWSTATE as a POST value.

来源：https://stackoverflow.com/questions/23516527/how-to-programmatically-log-into-website-in-python

标签

python

web

urllib