python框架Scrapy中crawlSpider的使用

一、创建Scrapy工程

#scrapy startproject 工程名
scrapy startproject demo3

二、进入工程目录，根据爬虫模板生成爬虫文件

#scrapy genspider -l # 查看可用模板
#scrapy genspider -t 模板名 爬虫文件名 允许的域名
scrapy genspider -t crawl test sohu.com

三、设置IP池或用户代理（middlewares.py文件）

# -*- coding: utf-8 -*-
# 导入随机模块
import random
# 导入有关IP池有关的模块
from scrapy.downloadermiddlewares.httpproxy import HttpProxyMiddleware
# 导入有关用户代理有关的模块
from scrapy.downloadermiddlewares.useragent import UserAgentMiddleware

# IP池
class HTTPPROXY(HttpProxyMiddleware):
    # 初始化 注意一定是 ip=''
    def __init__(self, ip=''):
        self.ip = ip

    def process_request(self, request, spider):
        item = random.choice(IPPOOL)
        try:
            print("当前的IP是："+item["ipaddr"])
            request.meta["proxy"] = "http://"+item["ipaddr"]
        except Exception as e:
            print(e)
            pass


# 设置IP池
IPPOOL = [
    {"ipaddr": "182.117.102.10:8118"},
    {"ipaddr": "121.31.102.215:8123"},
    {"ipaddr": "1222.94.128.49:8118"}
]


# 用户代理
class USERAGENT(UserAgentMiddleware):
    #初始化 注意一定是 user_agent=''
    def __init__(self, user_agent=''):
        self.user_agent = user_agent

    def process_request(self, request, spider):
        item = random.choice(UPPOOL)
        try:
            print("当前的User-Agent是："+item)
            request.headers.setdefault('User-Agent', item)
        except Exception as e:
            print(e)
            pass


# 设置用户代理池
UPPOOL = [
    "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.115 Safari/537.36", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.79 Safari/537.36 Edge/14.14393"
]

四、settngs.py配置

#========================================

# 设置IP池和用户代理

# 禁止本地Cookie
COOKIES_ENABLED = False

# 下载中间件配置指向（注意这里的工程名字是"demo3",指向DOWNLOADER_MIDDLEWARES = {
    # 'scrapy.downloadermiddlewares.httpproxy.HttpProxyMiddleware':123,
    # 'demo3.middlewares.HTTPPROXY' : 125,
    'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': 2,
    'demo3.middlewares.USERAGENT': 1
}

# 管道指向配置（注意这里的工程名字是"demo3",指向ITEM_PIPELINES = {
    'demo3.pipelines.Demo3Pipeline': 300,
}

#============================================

五、定义爬取关注的数据（items.py文件）

# -*- coding: utf-8 -*-
import scrapy
# Define here the models for your scraped items
#
# See documentation in:
# http://doc.scrapy.org/en/latest/topics/items.html
class Demo3Item(scrapy.Item):    
    name = scrapy.Field()
    link = scrapy.Field()

六、爬虫文件编写（test.py）

# -*- coding: utf-8 -*-
import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from demo3.items import Demo3Item

class TestSpider(CrawlSpider):
    name = 'test'
    allowed_domains = ['sohu.com']
    start_urls = ['http://www.sohu.com/']

    rules = (
        Rule(LinkExtractor(allow=('http://news.sohu.com'), allow_domains=('sohu.com')), callback='parse_item', follow=False),
        #Rule(LinkExtractor(allow=('.*?/n.*?shtml'),allow_domains=('sohu.com')), callback='parse_item', follow=False),
    )

    def parse_item(self, response):
        i = Demo3Item()
        i['name'] = response.xpath('//div[@class="news"]/h1/a/text()').extract()
        i['link'] = response.xpath('//div[@class="news"]/h1/a/@href').extract()
        return i

七、管道文件编写（pipelines.py）

# -*- coding: utf-8 -*-
import codecs
import json
# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: http://doc.scrapy.org/en/latest/topics/item-pipeline.html
class Demo3Pipeline(object):
    def __init__(self):
        self.file = codecs.open("E:/workspace/PyCharm/codeSpace/books/python_web_crawler_book/chapter17/demo3/1.json", "wb", encoding='utf-8')

    def process_item(self, item, spider):
        for j in range(0, len(item["name"])):
            name = item["name"][j]
            link = item["link"][j]
            datas = {"name": name, "link": link}
            i = json.dumps(dict(datas), ensure_ascii=False)
            line = i + '
'
            self.file.write(line)
        return item
    def close_spider(self, spider):
        self.file.close()

八、测试（scrapy crawl test ）之后，生成了1.json文件