autologin 0.1.4
A utility for finding login links, forms and autologging into websites with a set of valid credentials.
License: MIT
Keywords: login

Autologin: Automatic login for web spiders
==========================================

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   :alt: Code Coverage


Autologin is a library that makes it easier for web spiders to
**crawl websites that require login**.
Provide it with credentials and a URL or the html source of a page
(normally the homepage), and it will attempt to login for you.
Cookies are returned to be used by your spider.

The goal of Autologin is to make it easier for web spiders to crawl websites
that require authentication
**without having to re-write login code for each website.**

Autologin can be used as a library, on the command line, or as a service.
You can make use of Autologin without generating http requests,
so you can drop it right into your spider without worrying about
impacting rate limits.

If you are using `Scrapy <scrapy.readthedocs.org>`_ for crawling, check out
`autologin-middleware <https://github.com/TeamHG-Memex/autologin-middleware>`_,
which is a scrapy middleware that uses autologin http-api to maintain
a logged-in state for a scrapy spider.

Autologin works on Python 2.7 and 3.3+.

.. note:: The library is in the alpha stage.
   API can still change, especially around the keychain UI.

.. contents::

Features
--------

* Automatically find login forms and fields
* Obtain authenticated cookies
* Obtain form requests to submit from your own spider
* Extract links to login pages
* Use as a library with or without making http requests
* Command line client
* Web service
* UI for managing login credentials
* Captcha support


Quickstart
----------

Don't like reading documentation?

::

    from autologin import AutoLogin

    url = 'https://reddit.com'
    username = 'foo'
    password = 'bar'
    al = AutoLogin()
    cookies = al.auth_cookies_from_url(url, username, password)

You now have a `cookiejar <https://docs.python.org/2/library/cookielib.html>`_
that you can use in your spider.  Don't want a cookiejar?

::

    cookies.__dict__

You now have a dictionary.


Installation
------------

Install the latest release from PyPI::

    $ pip install -U autologin

or the version with the latest changes from Github::

    $ pip install git+https://github.com/TeamHG-Memex/autologin.git

Autologin depends on
`Formasaurus <https://github.com/TeamHG-Memex/Formasaurus>`_
for field and form classification, which has quite a lot of dependencies.
These packages may require extra steps to install, so the command above
may fail.
In this case install dependencies manually, one by one
(follow their install instructions).

A recent ``pip`` is recommended (update it with ``pip install pip -U``).
On Ubuntu, the following packages are required::

    $ apt-get install build-essential libssl-dev libffi-dev \
                      libxml2-dev libxslt1-dev \
                      python-dev  # or python3-dev for python 3


Auth cookies from URL
---------------------

This method makes an http request to the URL,
extracts the login form (if there is one),
fills the fields and submits the form.
It then return any cookies it has picked up::

    cookies = al.auth_cookies_from_url(url, username, password)

Note that it returns all cookies, they may be session cookies rather
than authenticated cookies.

This call is blocking, and uses Crochet to run the Twisted reactor
and a Scrapy spider in a separate thread.
If you have a Scrapy spider (or use Twisted in some other way),
use the HTTP API, or the non-blocking API (it's not documented,
see ``http_api.AutologinAPI._login``).

There are also optional arguments for ``AutoLogin.auth_cookies_from_url``:

- ``settings`` is a dictionary with Scrapy settings to override.
  Useful settings to pass include:

    * ``HTTP_PROXY``, ``HTTPS_PROXY`` set proxies to use for all requests.
    * ``SPLASH_URL`` if set, `Splash <http://splash.readthedocs.org>`_
      will be used to make all requests. Use it if your crawler also uses
      splash and the session is tied to IP and User-Agent, or for Tor sites.
    * ``USER_AGENT`` overrides default User-Agent.

- ``extra_js`` (experimental)
  is a string with an extra JS script that should be executed
  on the login page before making a POST request. For example, it can be used
  to accept cookie use. It is supported only when ``SPLASH_URL`` is also given
  in ``settings``.

An example of using this options::

    cookies = al.auth_cookies_from_url(
        url, username, password,
        extra_js='document.getElementById("accept-cookies").click();',
        settings={
            'SPLASH_URL': 'http://127.0.0.1:8050',
            'USER_AGENT': 'Mozilla/2.02 [fr] (WinNT; I)',
        })


Login request
-------------

This method extracts the login form (if there is one),
fills the fields and returns a dictionary with the form url and args
for your spider to submit. No http requests are made::

    >>> al.login_request(html_source, username, password, base_url=None)
    {'body': 'login=admin&password=secret',
     'headers': {b'Content-Type': b'application/x-www-form-urlencoded'},
     'method': 'POST',
     'url': '/login'}

Relative form action will be resolved against the ``base_url``.


Command Line
------------

::

    $ autologin
    usage: autologin [-h] [--splash-url SPLASH_URL] [--http-proxy HTTP_PROXY]
                     [--https-proxy HTTPS_PROXY] [--extra-js EXTRA_JS]
                     [--show-in-browser]
                     username password url

HTTP API
--------

You can start the autologin HTTP API with::

    $ autologin-http-api

and use ``/login-cookies`` endpoint. Make a POST request with JSON body.
The following arguments are supported:

- ``url`` (required): url of the site where we would like to login
- ``username`` (optional): if not provided, it will be fetched from the
  login keychain
- ``password`` (optional): if not provided, it will be fetched from the
  login keychain
- ``extra_js`` (optional, experimental)
  is a string with an extra JS script that should be executed
  on the login page before making a POST request. For example, it can be used
  to accept cookie use. It is supported only when ``SPLASH_URL`` is also given
  in ``settings``.
- ``settings`` (optional) - a dictionary with Scrapy settings to override,
  useful values are described above.

If ``username`` and ``password`` are not provided, autologin tries to find
them in the login keychain. If no matching credentials are found (they are
matched by domain, not by precise url), then human is expected to eventually
provide them in the keychain UI, or mark domain as "skipped".

Response is JSON with the following fields:

- ``status``, which can take the following values:

    - ``error`` status means an error occurred, ``error`` field has more info
    - ``skipped`` means that domain is marked as "skipped" in keychain UI
    - ``pending`` means there is an item in keychain UI (or it was just created),
      and no credentials have been entered yet
    - ``solved`` means that login was successful and cookies were obtained

- ``error`` - human-readable explanation of the error.
- ``response`` - last response received by autologin (can be None in some cases).
  This is a dict with ``cookies``, ``headers``, and either a
  ``text`` or ``body_b64`` fields (depending on response content type).
- ``cookies`` - a list of dictionaries in ``Cookie.__dict__`` format. Present only
  if status is ``solved``.
- ``start_url`` - a url that was reached after successful login.


Proxy support
-------------

Proxies can be specified via ``HTTP_PROXY`` and ``HTTPS_PROOXY`` keys
in ``settings`` argument. Username and password can be specified
as part of the proxy url (the format is ``protocol://username:password@url``).

If you are using proxy with Splash, it is assumed that
you want to have Splash make requests via given proxy,
and not make a request **to** Splash via proxy.
``HTTP_PROXY`` is always used for Splash.


Captcha support
---------------

There is experimental captcha support: if the login form contains a captcha,
we will try to solve it using an external service (DeathByCaptcha),
and will submit it as part of login request. This does not affect API in any
way, you only have to provide environment variables with your DeathByCaptcha
account details: ``DEATHBYCAPTCHA_USERNAME`` and ``DEATHBYCAPTCHA_PASSWORD``.
This applies to all APIs: ``autologin-http-api``, ``autologin``, and
the Python API.

You also need to install the ``decaptcha`` library::

    pip install git+https://github.com/TeamHG-Memex/decaptcha.git

Support is still experimental, new Google ReCaptcha/NoCaptcha are not supported.
Also, it currently works only with splash (when ``SPLASH_URL`` is passed in
``settings``).


Keychain UI
-----------

Start keychain UI with::

    $ autologin-server

Note that both ``autologin-server`` and ``autologin-http-api``
are not protected by any authentication.

Keychain UI stores credentials in an sqlite database. It is located near
the library itself by default, which is not always good, especially if you want
to persist the data between updates or do not have write permissions
for that folder. You can configure database location and
``secret_key`` used by the flask app by creating an ``/etc/autologin.cfg`` or
``~/.autologin.cfg`` file (should be the same user under which autologin
services are running). Here is an example config that changes default secret_key
and specifies a different database path (both items are optional)::

    [autologin]
    secret_key = 8a0b923820dcc509a6f75849b
    db = /var/autologin/db.sqlite


Contributors
------------

Source code and bug tracker are on github:
https://github.com/TeamHG-Memex/autologin.

Run tests with ``tox``::

    $ tox

Splash support is not tested directly here, but there are indirect tests for it
in the `autologin-middleware <https://github.com/TeamHG-Memex/autologin-middleware>`_
test suite.


License
-------

License is MIT.