day13

day13

1.scrapy对接selenium

selenium可以实现抓取动态数据
scrapy不能抓取动态数据, 如果是ajax请求, 可以请求接口, 如果是js动态加载, 需要结合selenium

import scrapy
from selenium import webdriver
from ..items import WynewsItem
from selenium.webdriver import ChromeOptions


class NewsSpider(scrapy.Spider):
    name = 'news'
    # allowed_domains = ['www.baidu.com']
    start_urls = ['https://news.163.com/domestic/']
    option = ChromeOptions()
    option.add_experimental_option('excludeSwitches', ['enable-automation'])
    bro = webdriver.Chrome(executable_path=r'C:\Users\Administrator\Desktop\news\wynews\wynews\spiders\chromedriver.exe', options=option)
    # bro = webdriver.Chrome(executable_path=r'C:\Users\Administrator\Desktop\news\wynews\wynews\spiders\chromedriver.exe')

    def detail_parse(self, response):
        content_list = response.xpath('//div[@id="endText"]/p//text()').extract()
        content = ''
        title = response.meta['title']
        for s in content_list:
            content += s
        item = WynewsItem()
        item["title"] = title
        item["content"] = content
        yield item

    def parse(self, response):
        div_list = response.xpath('//div[contains(@class, "data_row")]')
        for div in div_list:
            link = div.xpath('./a/@href').extract_first()
            title = div.xpath('./div/div[1]/h3/a/text()').extract_first()
            yield scrapy.Request(url=link, callback=self.detail_parse, meta={"title":title})

# 中间件编码:
from scrapy.http import HtmlResponse
class WynewsDownloaderMiddleware(object):
        def process_response(self, request, response, spider):
        bro = spider.bro
        if request.url in spider.start_urls:
            bro.get(request.url)
            time.sleep(3)
            js = 'window.scrollTo(0, document.body.scrollHeight)'
            bro.execute_script(js)
            time.sleep(3)
            response_selenium = bro.page_source
            return HtmlResponse(url=bro.current_url, body=response_selenium, encoding="utf-8", request=request)

        return response

# Pipeline编码:
import pymongo

class WynewsPipeline(object):
    conn = pymongo.MongoClient('localhost', 27017)
    db = conn.wynews
    table = db.newsinfo
    def process_item(self, item, spider):
        self.table.insert(dict(item))
        return item

---

2.pipeline数据持久化

# 介绍:
	1.pipelines: 用于数据持久化
     2.数据持久化的方式有很多种: MongoDB, MySQL, Redis, CSV
    3.必须实现的方法: process_item

# 核心方法讲解:
open_spider(self, spider): spider开启是被调用
close_spider(self, spider): spider关闭是被调用
from_crawler(cls, crawler): 类方法, 用@classmethod标识, 可以获取配置信息
Process_item(self, item, spider): 与数据库交互存储数据, 该方法必须实现 *****

# MongoDB交互:
import Pymongo
class MongoPipeline(object):
    def __init__(self, mongo_uri, mongo_db):
        self.mongo_uri = mongo_uri
        self.mongo_db = mongo_db
        
    @classmethod
    def from_crawler(cls, crawler):
        return cls(
        	mongo_uri = crawler.settings.get('MONGO_URI'),
            mongo_db = crawler.settings.get('MONGO_DB')
        )
    
    def open_spider(self, spider):
        self.client = pymongo.MongoClient(self.mongo_uri)
        self.db = self.client[self.mongo_db]
        
    def process_item(self, item, spider):
        self.db['news'].insert(dict(item))
        return item
    
    def close_spider(self, spider):
        self.client.close()

# MySQL交互:
import pymysql

def MysqlPipeline(object):
    def __init__(self, host, database, user, password, port):
        self.host = host
        self.database = database
        self.user = user
        self.password = password
        self.port = port
    
    @classmethod  
    def from_crawler(self, crawler):
        return cls(
        	host = crawler.settings.get('MYSQL_HOST')
            database = crawler.settings.get('MYSQL_DATABASE')
            user = crawler.settings.get('MYSQL_USER')
            password= crawler.settings.get('MYSQL_PASSWORD')
            port = crawler.settings.get('MYSQL_PORT')
        )
    
    def open_spider(self, spider):
        self.db = pymysql.connect(self.host, self.user, self.password, self.database, charset='utf-8', port=self.port)
        self.cursor = self.db.cursor()
        
    def process_item(self, item, spider):
        data = dict(item)
        
        keys = ','.join(data.keys())
        values = ','.join(['%s']*len(data))
        sql = 'insert into %s (%s) values (%s)' % (table, keys, value)
        self.cursor.execute(sql, tuple(data.values()))
        self.db.commit()
        return item

# 用于文件下载的管道类

# spider编码:
import scrapy
from ..items import XhxhItem
class XhSpider(scrapy.Spider):
    name = 'xh'
    # allowed_domains = ['www.baidu.com']
    start_urls = ['http://www.521609.com/qingchunmeinv/']
    def parse(self, response):
        li_list = response.xpath('//div[@class="index_img list_center"]/ul/li')
        for li in li_list:
            item = XhxhItem()
            link = li.xpath('./a[1]/img/@src').extract_first()
            item['img_link'] = 'http://www.521609.com' + link
            print(item)
            yield item

# items编码:
import scrapy
class XhxhItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    img_link = scrapy.Field()

# 管道编码:
import scrapy
from scrapy.pipelines.images import ImagesPipeline

class XhxhPipeline(object):
    def process_item(self, item, spider):
        return item


class ImgPipeLine(ImagesPipeline):

    def get_media_requests(self, item, info):
        yield scrapy.Request(url=item['img_link'])

    def file_path(self, request, response=None, info=None):
        url = request.url
        file_name = url.split('/')[-1]
        return file_name

    def item_completed(self, results, item, info):
        return item

# settings编码:
ITEM_PIPELINES = {
   'xhxh.pipelines.XhxhPipeline': 300,
   'xhxh.pipelines.ImgPipeLine': 301,
}
IMAGES_STORE = './mvs'

mpleted(self, results, item, info):
return item

```Python
# settings编码:
ITEM_PIPELINES = {
   'xhxh.pipelines.XhxhPipeline': 300,
   'xhxh.pipelines.ImgPipeLine': 301,
}
IMAGES_STORE = './mvs'