本篇主要給大家分享一下Scrapy爬蟲框架，以及通過spider獲取更多美麗小知識的文章。

　　上圖你感興趣嗎?如果想獲取更多的文章信息，就從一起寫成爬蟲程序開始吧!

　　首先我們創(chuàng)建一個項目

　　scrapy startproject guoke

　　進入到guoke目錄執(zhí)行下面的命令

　　scrapy genspider beauty www.guokr.com

　　此時使用Pycharm打開我們的新建的guoke項目，通過分析發(fā)現(xiàn)果殼中美麗也是技術活更多的內容加載是通過XHR請求的json數(shù)據(jù)。

　　我們不僅要獲取每條json數(shù)據(jù)，還要獲取每條數(shù)據(jù)的詳情頁。

　　我們不僅要獲取文章的title，id，summary，url，date_created，以及要將每個詳情內容保存到txt文檔中。

　　爬蟲參考代碼：

import scrapy
import json

from guoke.items import GuokeItem, GuokeDetailItem


class BeautySpider(scrapy.Spider):
    name = 'beauty'
    allowed_domains = ['www.guokr.com']
    offset = 0
    start_urls = [
        'https://www.guokr.com/apis/minisite/article.json?retrieve_type=by_wx&channel_key=pac&offset=0&limit=10']

    def parse(self, response):
        rs = json.loads(response.text)
        article_list = rs.get('result')
        for article in article_list:
            item = GuokeItem()
            item['title'] = article.get('title')
            item['id'] = article.get('id')
            url = article.get('url')
            item['url'] = url
            item['summary'] = article.get('summary')
            item['date_created'] = article.get('date_created')
            yield scrapy.Request(url, callback=self.parse_item, headers={'Referer': 'https://www.guokr.com/pretty',
                                                                         'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.1.2 Safari/605.1.15'})
            yield item
        if self.offset <= 71130:
            self.offset += 10
            url = 'https://www.guokr.com/apis/minisite/article.json?retrieve_type=by_wx&channel_key=beauty&offset=' + str(
                self.offset) + '&limit=10'
            yield scrapy.Request(url, callback=self.parse)

    def parse_item(self, response):
        item = GuokeDetailItem()
        item['url'] = response.url
        all_txt = response.xpath('//p[@style="white-space: normal;"]//text()').extract()
        detail_str = ''
        for txt in all_txt:
            detail_str += txt

        item['detail'] = detail_str
        yield item

items.py參考代碼：

import scrapy


class GuokeItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    id = scrapy.Field()
    title = scrapy.Field()
    url = scrapy.Field()
    summary = scrapy.Field()
    date_created = scrapy.Field()


class GuokeDetailItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    url = scrapy.Field()
    detail = scrapy.Field()

　　在爬取過程中可能出現(xiàn)一些常見的錯誤代碼，如下：

　　Frequentresponse with HTTP404,301 or 50x errors

　　(1)301 MovedTemporarily

　　(2)401unauthorized

　　(3)403forbidden (aAatch處理的)

　　(4)404 notfound

　　(5)408 requesttimeout

　　(6)429 too manyrequests

　　(7)503 serviceunavailable

　　解決辦法：

　　在settings中將rebots改為False

　　在settings中將DOWNLOAD_DELAY 適當設置一個時間，默認是0

　　設置中間件middlewares

　　具體步驟如下：

　　在settings中添加USERAGENTSLIST，內容如下

 USER_AGENTS_LIST = [
    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; AcooBrowser; .NET CLR 1.1.4322; .NET CLR 2.0.50727)",
    "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Acoo Browser; SLCC1; .NET CLR 2.0.50727; Media Center PC 5.0; .NET CLR 3.0.04506)",
    "Mozilla/4.0 (compatible; MSIE 7.0; AOL 9.5; AOLBuild 4337.35; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)",
    "Mozilla/5.0 (Windows; U; MSIE 9.0; Windows NT 9.0; en-US)",
    "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 2.0.50727; Media Center PC 6.0)",
    "Mozilla/5.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET CLR 1.0.3705; .NET CLR 1.1.4322)",
    "Mozilla/4.0 (compatible; MSIE 7.0b; Windows NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727; InfoPath.2; .NET CLR 3.0.04506.30)",
    "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN) AppleWebKit/523.15 (KHTML, like Gecko, Safari/419.3) Arora/0.3 (Change: 287 c9dfb30)",
    "Mozilla/5.0 (X11; U; Linux; en-US) AppleWebKit/527+ (KHTML, like Gecko, Safari/419.3) Arora/0.6",
    "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.2pre) Gecko/20070215 K-Ninja/2.1.1",
    "Mozilla/5.0 (Windows; U; Windows NT 5.1; zh-CN; rv:1.9) Gecko/20080705 Firefox/3.0 Kapiko/3.0",
    "Mozilla/5.0 (X11; Linux i686; U;) Gecko/20070322 Kazehakase/0.4.5",
    "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.8) Gecko Fedora/1.9.0.8-1.fc10 Kazehakase/0.5.6",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.56 Safari/535.11",
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3) AppleWebKit/535.20 (KHTML, like Gecko) Chrome/19.0.1036.7 Safari/535.20",
    "Opera/9.80 (Macintosh; Intel Mac OS X 10.6.8; U; fr) Presto/2.9.168 Version/11.52",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/536.11 (KHTML, like Gecko) Chrome/20.0.1132.11 TaoBrowser/2.0 Safari/536.11",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.71 Safari/537.1 LBBROWSER",
    "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; LBBROWSER)",
    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E; LBBROWSER)",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.84 Safari/535.11 LBBROWSER",
    "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)",
    "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E; QQBrowser/7.0.3698.400)",
    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)",
    "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SV1; QQDownload 732; .NET4.0C; .NET4.0E; 360SE)",
    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)",
    "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)",
    "Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1",
    "Mozilla/5.0 (iPad; U; CPU OS 4_2_1 like Mac OS X; zh-cn) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5",
    "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.0b13pre) Gecko/20110307 Firefox/4.0b13pre",
    "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:16.0) Gecko/20100101 Firefox/16.0",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11",
    "Mozilla/5.0 (X11; U; Linux x86_64; zh-CN; rv:1.9.2.10) Gecko/20100922 Ubuntu/10.10 (maverick) Firefox/3.6.10"
]

　　新建一個python文件，名字可以是：useragentmiddlewares.py，在里面添加如下代碼

 import scrapy
from scrapy import signals
from scrapy.downloadermiddlewares.useragent import UserAgentMiddleware
import random


class MyUserAgentMiddleware(UserAgentMiddleware):
    '''
    設置User-Agent
    '''

    def __init__(self, user_agent):
        super(MyUserAgentMiddleware, self).__init__(user_agent)
        self.user_agent = user_agent

    @classmethod
    def from_crawler(cls, crawler):
        return cls(
            user_agent=crawler.settings.get('USER_AGENTS_LIST')
        )

    def process_request(self, request, spider):
        agent = random.choice(self.user_agent)
        request.headers['User-Agent'] = agent

 c. 在settings.py中添加MyUserAgentMiddleware

 DOWNLOADER_MIDDLEWARES = {
   'guoke.randomAgentMiddleware.MyUserAgentMiddleware' :400,
   'guoke.middlewares.GuokeDownloaderMiddleware': 543,
}

　　此時就會發(fā)現(xiàn)一些錯誤就不見了，因為爬取速度過快或者一直是同一個瀏覽器，會被對方識別為爬蟲進行反扒處理。

pipelines.py的代碼如下，主要是存儲數(shù)據(jù)

useful for handling different item types with a single interface
from itemadapter import ItemAdapter
import csv

from guoke.items import GuokeItem, GuokeDetailItem


class GuokePipeline:
    def __init__(self):
        self.article_stream = open('articles.csv', 'w', newline='', encoding='utf-8')
        self.f = csv.writer(self.article_stream)

    def process_item(self, item, spider):
        if isinstance(item, GuokeItem):
            data = [item.get('id'), item.get('title'), item.get('summary'), item.get('url'), item.get('date_created')]
            self.f.writerow(data)

        elif isinstance(item, GuokeDetailItem):
            url = item['url']
            id = url[:-1].rsplit('/')[-1]
            with open(str(id) + '.txt', 'w') as stream:
                stream.write(item['detail'])

　　完畢之后，我們就可以運行爬蟲進行測試了。

scrapy crawl beauty

　　結果展示一下：

　　打開文本看一下

　　當然因為在解析的時候我是把里面的換行給去掉了，所以沒有一些換行的效果，大家可以再次優(yōu)化一下上面的spider.py里面的代碼。

更多關于python培訓的問題，歡迎咨詢千鋒教育在線名師。千鋒教育擁有多年IT培訓服務經(jīng)驗，采用全程面授高品質、高體驗培養(yǎng)模式，擁有國內一體化教學管理及學員服務，助力更多學員實現(xiàn)高薪夢想。