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A Scrapy middleware to use with autologin

Project Description

This is a a Scrapy middleware that uses autologin http-api to maintain a logged-in state for a scrapy spider.

Autologin middleware uses autologin to make all requests while being logged in. It uses autologin to get cookies, detects logouts and tries to avoid them in the future. A single authorization domain for the spider is assumed. Autologin middleware also puts autologin_active into request.meta, which is True only if we are logged in (and to False if domain is skipped or login failed). If requests are made via splash (and SPLASH_URL is set), autologin middleware passes it to autologin, and this splash instance is also used to obtain login cookies.

Installation

It works on python 2.7 and python 3, and requires at least scrapy 1.1. Install with pip:

pip install autologin-middleware

Configuration

  1. Include the autologin middleware into the project settings and specify autologin url:

    AUTOLOGIN_URL = 'http://127.0.0.1:8089'
    AUTOLOGIN_ENABLED = True
    DOWNLOADER_MIDDLEWARES['autologin_middleware.AutologinMiddleware'] = 605
    
  2. Cookie support is also required. There are currently several options:

  • scrapy cookie middleware (COOKIES_ENABLED = True), but autologin middleware requires access to cookies, so you need to enable a custom cookie middleware:

    DOWNLOADER_MIDDLEWARES = {
        'autologin_middleware.AutologinMiddleware': 605,
        'scrapy.downloadermiddlewares.cookies.CookiesMiddleware': None,
        'autologin_middleware.ExposeCookiesMiddleware': 700,
    }
    
  • scrapy-splash cookie middleware (scrapy_splash.SplashCookiesMiddleware)

  • any other middleware that gets cookies from request.cookies and sets response.cookiejar like scrapy-splash middleware, or exposes them in response.flags like ExposeCookiesMiddleware.

  1. Optional but highly recommended: avoid logouts - see optional settings and “Avoiding logouts” section below. The reason why it’s important is that logout detection is less robust, on some sites the old cookies might still work so you’ll be using multiple sessions, etc. If you don’t ever logout, you avoid all this problems.

There are some optional settings:

  • AUTOLOGIN_COOKIES: pass auth cookies after manual login (format is name=value; name2=value2).
  • AUTOLOGIN_LOGOUT_URL: pass url substring to avoid.
  • AUTOLOGIN_CHECK_LOGOUT: set to False in order to disable automatic logout detection: it remembers cookies obtained during login and checks them on each response to see if any disappeared. This can be problematic for sites that set a lot of cookies on login, so this is an option to disable it. If you disable it, you must rely on avoiding logout links with link_looks_like_logout (see below), or setting a custom AUTOLOGIN_LOGOUT_URL.
  • AUTOLOGIN_USERNAME, AUTOLOGIN_PASSWORD, AUTOLOGIN_LOGIN_URL, AUTOLOGIN_EXTRA_JS are passed to autologin and override values from stored credentials. AUTOLOGIN_LOGIN_URL is a relative url, and can be omitted if it is the same as the start url. AUTOLOGIN_EXTRA_JS is required only if you want to use the extra_js feature of the autologin.

It is also possible to override some settings per-request via corresponding lower-case keys in request.meta: autologin_username, autologin_password, autologin_extra_js, autologin_login_url and autologin_logout_url.

Autologin middleware passes the following settings to the autologin: SPLASH_URL, USER_AGENT, HTTP_PROXY, HTTPS_PROXY, so they are used for autologin requests.

Avoiding logouts

There is also an utility autologin_middleware.link_looks_like_logout for checking if a links looks like a logout link: you can use it in the spider to avoid logout links. Logouts are handled by the autologin middleware by default (unless AUTOLOGIN_CHECK_LOGOUT is False), but avoiding logout links can be beneficial for two reasons:

  • no time is waster retrying requests that were logged out
  • in some cases, logout urls can be unique, and the spider will be logging out continuously (for example, /logout?sid=UNIQUE_ID).

API

There is no special API: autologin middleware just ensures that all requests are made while being logged in. As mentioned in the “Configuration” section above, you can override some settings on the per-request basis in reqeuest.meta.

Autologin response is available in response.meta['autologin_response'], if we made requests to autologin while processing this request. You might want to use the "status" field of the autologin response to do some bookkeeping.

Middleware also always puts "autologin_active" into response.meta, which is True only if we are logged in (and False if domain is skipped or login failed).

Additionally, you set skip_autologin key in request.meta to True in order to completely disable middleware for this request.

Usage with Splash

Autologin middleware supports splash via scrapy-splash, but correctly settings everything up can be tricky.

First, you need to specify the following settings (check scrapy-splash docs for more details):

SPLASH_URL = 'http://127.0.0.1:8050'
SPIDER_MIDDLEWARES = {
    'scrapy_splash.SplashDeduplicateArgsMiddleware': 100,
}
DUPEFILTER_CLASS = 'scrapy_splash.SplashAwareDupeFilter'
DOWNLOADER_MIDDLEWARES = {
    'autologin_middleware.AutologinMiddleware': 605,
    'scrapy_splash.SplashCookiesMiddleware': 723,
    'scrapy_splash.SplashMiddleware': 725,
    'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware': 810,
}

Second, you need to make requests to splash and pass cookies with splash:init_cookies(splash.args.cookies), and return them in the cookies field using splash:get_cookies(). If you are already using a splash script (execute endpoint), modify your script accordingly. But if you just want to crawl using splash, you can use autologin_middleware.splash.splash_request instead of scrapy.Request. It has a minimal lua script that passes cookies and returns html, so you won’t need to change anything else in you spider.

Development

You need to start autologin-http-api (from autologin), and splash (the easiest option is to run docker run -p 8050:8050 scrapinghub/splash).

Run tests with tox:

tox

When using Docker to run Splash on OS X and Windows, it will start on a non-default address, so you need to specify it when running tests, for example:

SPLASH_URL=http://192.168.99.100:8050 tox

License

License is MIT.

Release History

Release History

This version
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0.1.6

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0.1.5

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0.1.4

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0.1.3

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0.1.2

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0.1.1

History Node

0.1.0

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