Scrapy-splash

Splash是一个javascript渲染服务。它是一个带有HTTP API的轻量级Web浏览器，使用Twisted和QT5在Python 3中实现。QT反应器用于使服务彻底异步，容许经过QT主循环利用webkit并发。
一些Splash功能：javascript

并行处理多个网页
获取HTML源代码或截取屏幕截图
关闭图像或使用Adblock Plus规则使渲染更快
在页面上下文中执行自定义JavaScript
可经过Lua脚原本控制页面的渲染过程
在Splash-Jupyter 笔记本中开发Splash Lua脚本。
以HAR格式获取详细的渲染信息

1.splash安装

Scrapy-Splash的安装分为两部分，一个是Splash服务的安装，具体经过Docker来安装服务，运行服务会启动一个Splash服务，经过它的接口来实现JavaScript页面的加载；另一个是Scrapy-Splash的Python库的安装，安装后就可在Scrapy中使用Splash服务了，下面咱们分三部份来安装：html

1.安装docker

passjava

2.安装splash服务

docker pull scrapinghub/splash
docker run -d -p 8050:8050 scrapinghub/splash

3.Python包Scrapy-Splash安装

pip3 install scrapy-splash

2.Scrapy-Splash使用

1.setting添加配置

SPIDER_MIDDLEWARES = {
    'scrapy_splash.SplashDeduplicateArgsMiddleware': 100,  # 配置splash服务
}

DOWNLOADER_MIDDLEWARES = {
    'scrapy_splash.SplashCookiesMiddleware': 723,  # 配置splash服务
    'scrapy_splash.SplashMiddleware': 725,  # 配置splash服务
    'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware': 810,  # 配置splash服务
}


# 添加splash服务器地址：
SPLASH_URL = "http://192.168.31.111:8050/"
# 设置去重过滤器：
DUPEFILTER_CLASS = "scrapy_splash.SplashAwareDupeFilter"

# 开启换成
HTTPCACHE_ENABLED = True
# 缓存超时时间
HTTPCACHE_EXPIRATION_SECS = 0
# 缓存保存路径
HTTPCACHE_DIR = 'httpcache'
# 缓存忽略的Http状态码
HTTPCACHE_IGNORE_HTTP_CODES = []
# 最后配置一个Cache存储
HTTPCACHE_STORAGE = 'scrapy_splash.SplashAwareFSCacheStorage'

2.spider.py

import scrapy
from scrapy.http import Request, FormRequest
from scrapy.selector import Selector
from scrapy_splash.request import SplashRequest, SplashFormRequest


class JdSpiderSpider(scrapy.Spider):
    name = 'jd_spider'
    allowed_domains = ['.com']
    start_urls = ['https://www.baidu.com']

    def start_requests(self):
        splash_args = {"lua_source": """
                    --splash.response_body_enabled = true
                    splash.private_mode_enabled = false
                    splash:set_user_agent("Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.186 Safari/537.36")
                    assert(splash:go("https://item.jd.com/5089239.html"))
                    splash:wait(3)
                    return {html = splash:html()}
                    """}
        # yield SplashRequest("https://item.jd.com/5089239.html", endpoint='run', args=splash_args, callback=self.onSave)
        yield SplashRequest("https://item.jd.com/35674728065.html", endpoint='run', args=splash_args,
                            callback=self.onSave)

    def onSave(self, response):
        value = response.xpath('//span[@class="p-price"]//text()').extract()
        print(value)

    def parse(self, response):
        pass


def SplashRequest(url=None, callback=None, method='GET', endpoint='render.html', args=None, splash_url=None, slot_policy=SlotPolicy.PER_DOMAIN, splash_headers=None, dont_process_response=False, dont_send_headers=False, magic_response=True,
             session_id='default', http_status_from_error_code=True, cache_args=None, meta=None, **kwargs):
    url:与scrapy.Request中的url相同,也就是待爬取页面的url
    headers:与scrapy.Request中的headers相同
    cookies:与scrapy.Request中的cookies相同
    args:传递给Splash的参数,如wait(等待时间),timeout(超时时间),images(是否禁止加载图片,0禁止,1不由止), proxy(设置代理)等
    args={'wait': 5,
              'lua_source': source，
              'proxy': 'http://proxy_ip:proxy_port'
              }
    endpoint:Splash服务端点,默认为'render.html',即JS页面渲染服务
    splash_url:Splash服务器地址,默认为None,即便用settings.py配置文件中的SPLASH_URL = 'http://localhost:8050'
    method:请求类型


def SplashFormRequest(url=None, callback=None, method=None, formdata=None,
             body=None, **kwargs):
    body:请求体