How can Scrapy deal with Javascript

问题

Spider for reference:

import scrapy
from scrapy.spiders import Spider
from scrapy.selector import Selector
from script.items import ScriptItem



    class RunSpider(scrapy.Spider):
        name = "run"
        allowed_domains = ["stopitrightnow.com"]
        start_urls = (
            'http://www.stopitrightnow.com/',
        )



        def parse(self, response):


            for widget in response.xpath('//div[@class="shopthepost-widget"]'):
                #print widget.extract()
                item = ScriptItem()
                item['url'] = widget.xpath('.//a/@href').extract()
                url = item['url']
                #print url
                yield item

When I run this the output in terminal is as follows:

2015-08-21 14:23:51 [scrapy] DEBUG: Scraped from <200 http://www.stopitrightnow.com/>
{'url': []}
<div class="shopthepost-widget" data-widget-id="708473">
<script type="text/javascript">!function(d,s,id){var e, p = /^http:/.test(d.location) ? 'http' : 'https';if(!d.getElementById(id)) {e = d.createElement(s);e.id = id;e.src = p + '://' + 'widgets.rewardstyle.com' + '/js/shopthepost.js';d.body.appendChild(e);}if(typeof window.__stp === 'object') if(d.readyState === 'complete') {window.__stp.init();}}(document, 'script', 'shopthepost-script');</script><br>

This is the html:

<div class="shopthepost-widget" data-widget-id="708473" data-widget-uid="1"><div id="stp-55d44feabd0eb" class="stp-outer stp-no-controls">
    <a class="stp-control stp-left stp-hidden">&lt;</a>
    <div class="stp-inner" style="width: auto">
        <div class="stp-slide" style="left: -0%">
                        <a href="http://rstyle.me/iA-n/zzhv34c_" target="_blank" rel="nofollow" class="stp-product " data-index="0" style="margin: 0 0px 0 0px">
                <span class="stp-help"></span>
                <img src="//images.rewardstyle.com/img?v=2.13&amp;p=n_24878713">
                            </a>
                        <a href="http://rstyle.me/iA-n/zzhvw4c_" target="_blank" rel="nofollow" class="stp-product " data-index="1" style="margin: 0 0px 0 0px">
                <span class="stp-help"></span>
                <img src="//images.rewardstyle.com/img?v=2.13&amp;p=n_24878708">

To me it seems to hit a block when trying to activate the Javascript. I am aware that javascript can not run in scrapy but there must be a way of getting to those links. I have looked at selenium but can not get a handle on it.

Any and all help welcome.

回答1:

I've solved it with ScrapyJS.

Follow the setup instructions in the official documentation and this answer.

Here is the test spider I've used:

# -*- coding: utf-8 -*-
import scrapy


class TestSpider(scrapy.Spider):
    name = "run"
    allowed_domains = ["stopitrightnow.com"]
    start_urls = (
        'http://www.stopitrightnow.com/',
    )

    def start_requests(self):
        for url in self.start_urls:
            yield scrapy.Request(url, meta={
                'splash': {
                    'endpoint': 'render.html',
                    'args': {'wait': 0.5}
                }
            })

    def parse(self, response):
        for widget in response.xpath('//div[@class="shopthepost-widget"]'):
            print widget.xpath('.//a/@href').extract()

And here is what I've got on the console:

[u'http://rstyle.me/iA-n/7bk8r4c_', u'http://rstyle.me/iA-n/7bk754c_', u'http://rstyle.me/iA-n/6th5d4c_', u'http://rstyle.me/iA-n/7bm3s4c_', u'http://rstyle.me/iA-n/2xeat4c_', u'http://rstyle.me/iA-n/7bi7f4c_', u'http://rstyle.me/iA-n/66abw4c_', u'http://rstyle.me/iA-n/7bm4j4c_']
[u'http://rstyle.me/iA-n/zzhv34c_', u'http://rstyle.me/iA-n/zzhvw4c_', u'http://rstyle.me/iA-n/zwuvk4c_', u'http://rstyle.me/iA-n/zzhvr4c_', u'http://rstyle.me/iA-n/zzh9g4c_', u'http://rstyle.me/iA-n/zzhz54c_', u'http://rstyle.me/iA-n/zwuuy4c_', u'http://rstyle.me/iA-n/zzhx94c_']

回答2:

A non-javascript alternative to Alecxe's is to inspect where the page is loading the content from manually, and adding in that functionally (see this SO question for more details).

In this case, we get the following:

So, for <div class="shopthepost-widget" data-widget-id="708473">, Javascript is executed to embed the url "widgets.rewardstyle.com/stps/708473.html".

You could handle this yourself by manually generating a request for these URLs yourself:

def parse(self, response):
    for widget in response.xpath('//div[@class="shopthepost-widget"]'):
        widget_id = widget.xpath('@data-widget-id').extract()[0]
        widget_url = "http://widgets.rewardstyle.com/stps/{id}.html".format(id=widget_id)
        yield Request(widget_url, callback=self.parse_widget)

def parse_widget(self, response):
    for link in response.xpath('//a[contains(@class, "stp-product")]'):
        item = JavasItem()  # Name provided by author, see comments below
        item['link'] = links.xpath("@href").extract()
        yield item

    # Do whatever else you want with the opened page.

If you need to keep these widgets associated with whatever post/article they are a part of, pass that information into the request via meta.

EDIT: parse_widget() was updated. It uses contains for figuring out the class, as it has a space at the end. You could alternatively use a CSS selector, but it's really your call.

来源：https://stackoverflow.com/questions/32141967/how-can-scrapy-deal-with-javascript