Login on a site using urllib

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I\'m trying to get information from this site http://cheese.formice.com/maps/@5865339 , but when i request using urllib.urlopen, its says that i need to login, i was using t

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南笙

2020-12-10 00:36

It's not using urllib directly, but you may find it easier working with the requests package. requests has a session object see this answer

import requests

url = 'http://cheese.formice.com/forum/login/login'
login_data = dict(login='Cfmaccount', password='tfmdev321')
session = requests.session()

r = session.post(url, data=login_data)

That will log you in to the site. You can verify with:

print r.text #prints the <html> response.

Once logged in, you can call the specific url you want.

r2 = session.get('http://cheese.formice.com/maps/@5865339')
print r2.content #prints the raw html you can now parse and scrape

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爱一瞬间的悲伤

2020-12-10 00:39

It is possible to do this with only the standard library using a custom opener with a cookie processor. An example is provided below.

# Login to website using just Python 3 Standard Library
import urllib.parse
import urllib.request
import http.cookiejar

def scraper_login():
    ####### change variables here, like URL, action URL, user, pass
    # your base URL here, will be used for headers and such, with and without https://
    base_url = 'www.example.com'
    https_base_url = 'https://' + base_url

    # here goes URL that's found inside form action='.....'
    #   adjust as needed, can be all kinds of weird stuff
    authentication_url = https_base_url + '/login'

    # username and password for login
    username = 'yourusername'
    password = 'SoMePassw0rd!'

    # we will use this string to confirm a login at end
    check_string = 'Logout'

    ####### rest of the script is logic
    # but you will need to tweak couple things maybe regarding "token" logic
    #   (can be _token or token or _token_ or secret ... etc)

    # big thing! you need a referer for most pages! and correct headers are the key
    headers={"Content-Type":"application/x-www-form-urlencoded",
    "User-agent":"Mozilla/5.0 Chrome/81.0.4044.92",    # Chrome 80+ as per web search
    "Host":base_url,
    "Origin":https_base_url,
    "Referer":https_base_url}

    # initiate the cookie jar (using : http.cookiejar and urllib.request)
    cookie_jar = http.cookiejar.CookieJar()
    opener = urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cookie_jar))
    urllib.request.install_opener(opener)

    # first a simple request, just to get login page and parse out the token
    #       (using : urllib.request)
    request = urllib.request.Request(https_base_url)
    response = urllib.request.urlopen(request)
    contents = response.read()

    # parse the page, we look for token eg. on my page it was something like this:
    #    <input type="hidden" name="_token" value="random1234567890qwertzstring">
    #       this can probably be done better with regex and similar
    #       but I'm newb, so bear with me
    html = contents.decode("utf-8")
    # text just before start and just after end of your token string
    mark_start = '<input type="hidden" name="_token" value="'
    mark_end = '">'
    # index of those two points
    start_index = html.find(mark_start) + len(mark_start)
    end_index = html.find(mark_end, start_index)
    # and text between them is our token, store it for second step of actual login
    token = html[start_index:end_index]

    # here we craft our payload, it's all the form fields, including HIDDEN fields!
    #   that includes token we scraped earler, as that's usually in hidden fields
    #   make sure left side is from "name" attributes of the form,
    #       and right side is what you want to post as "value"
    #   and for hidden fields make sure you replicate the expected answer,
    #       eg. "token" or "yes I agree" checkboxes and such
    payload = {
        '_token':token,
    #    'name':'value',    # make sure this is the format of all additional fields !
        'login':username,
        'password':password
    }

    # now we prepare all we need for login
    #   data - with our payload (user/pass/token) urlencoded and encoded as bytes
    data = urllib.parse.urlencode(payload)
    binary_data = data.encode('UTF-8')
    # and put the URL + encoded data + correct headers into our POST request
    #   btw, despite what I thought it is automatically treated as POST
    #   I guess because of byte encoded data field you don't need to say it like this:
    #       urllib.request.Request(authentication_url, binary_data, headers, method='POST')
    request = urllib.request.Request(authentication_url, binary_data, headers)
    response = urllib.request.urlopen(request)
    contents = response.read()

    # just for kicks, we confirm some element in the page that's secure behind the login
    #   we use a particular string we know only occurs after login,
    #   like "logout" or "welcome" or "member", etc. I found "Logout" is pretty safe so far
    contents = contents.decode("utf-8")
    index = contents.find(check_string)
    # if we find it
    if index != -1:
        print(f"We found '{check_string}' at index position : {index}")
    else:
        print(f"String '{check_string}' was not found! Maybe we did not login ?!")

scraper_login()

Link to this script on GitHub

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