passing selenium response url to scrapy

Question

I am learning Python and am trying to scrape this page for a specific value on the dropdown menu. After that I need to click each item on the resulted table to retrieve the

Answer 1

Use Downloader Middleware to catch selenium-required pages before you process them regularly with Scrapy:

The downloader middleware is a framework of hooks into Scrapy’s request/response processing. It’s a light, low-level system for globally altering Scrapy’s requests and responses.

Here's a very basic example using PhantomJS:

from scrapy.http import HtmlResponse
from selenium import webdriver

class JSMiddleware(object):
    def process_request(self, request, spider):
        driver = webdriver.PhantomJS()
        driver.get(request.url)

        body = driver.page_source
        return HtmlResponse(driver.current_url, body=body, encoding='utf-8', request=request)

Once you return that HtmlResponse (or a TextResponse if that's what you really want), Scrapy will cease processing downloaders and drop into the spider's parse method:

If it returns a Response object, Scrapy won’t bother calling any other process_request() or process_exception() methods, or the appropriate download function; it’ll return that response. The process_response() methods of installed middleware is always called on every response.

In this case, you can continue to use your spider's parse method as you normally would with HTML, except that the JS on the page has already been executed.

Tip: Since the Downloader Middleware's process_request method accepts the spider as an argument, you can add a conditional in the spider to check whether you need to process JS at all, and that will let you handle both JS and non-JS pages with the exact same spider class.

Answer 2

Here is a middleware for Scrapy and Selenium

from scrapy.http import HtmlResponse
from scrapy.utils.python import to_bytes
from selenium import webdriver
from scrapy import signals


class SeleniumMiddleware(object):

    @classmethod
    def from_crawler(cls, crawler):
        middleware = cls()
        crawler.signals.connect(middleware.spider_opened, signals.spider_opened)
        crawler.signals.connect(middleware.spider_closed, signals.spider_closed)
        return middleware

    def process_request(self, request, spider):
        request.meta['driver'] = self.driver  # to access driver from response
        self.driver.get(request.url)
        body = to_bytes(self.driver.page_source)  # body must be of type bytes 
        return HtmlResponse(self.driver.current_url, body=body, encoding='utf-8', request=request)

    def spider_opened(self, spider):
        self.driver = webdriver.Firefox()

    def spider_closed(self, spider):
        self.driver.close()

Also need to add in settings.py

DOWNLOADER_MIDDLEWARES = {
    'youproject.middlewares.selenium.SeleniumMiddleware': 200
}

Decide weather its 200 or something else based on docs.

Update firefox headless mode with scrapy and selenium

If you want to run firefox in headless mode then install xvfb

sudo apt-get install -y xvfb

and PyVirtualDisplay

sudo pip install pyvirtualdisplay

and use this middleware

from shutil import which

from pyvirtualdisplay import Display
from scrapy import signals
from scrapy.http import HtmlResponse
from scrapy.utils.project import get_project_settings
from selenium import webdriver
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary

settings = get_project_settings()

HEADLESS = True


class SeleniumMiddleware(object):

    @classmethod
    def from_crawler(cls, crawler):
        middleware = cls()
        crawler.signals.connect(middleware.spider_opened, signals.spider_opened)
        crawler.signals.connect(middleware.spider_closed, signals.spider_closed)
        return middleware

    def process_request(self, request, spider):
        self.driver.get(request.url)
        request.meta['driver'] = self.driver
        body = str.encode(self.driver.page_source)
        return HtmlResponse(self.driver.current_url, body=body, encoding='utf-8', request=request)

    def spider_opened(self, spider):
        if HEADLESS:
            self.display = Display(visible=0, size=(1280, 1024))
            self.display.start()
        binary = FirefoxBinary(settings.get('FIREFOX_EXE') or which('firefox'))
        self.driver = webdriver.Firefox(firefox_binary=binary)

    def spider_closed(self, spider):
        self.driver.close()
        if HEADLESS:
            self.display.stop()

where settings.py contains

FIREFOX_EXE = '/path/to/firefox.exe'

The problem is that some versions of firefox don't work with selenium. To solve this problem you can download firefox version 47.0.1 (this version works flawlessly) from here then extract it and put it inside your selenium project. Afterwards modify firefox path as

FIREFOX_EXE = '/path/to/your/scrapyproject/firefox/firefox.exe'