Python Scrapy 爬蟲簡單教程

導覽

1. Scrapy install

2. Scrapy 項目創建

3. Scrapy 自定義爬蟲類

4. Scrapy 處理邏輯

5. Scrapy 擴展

1. Scrapy install

准備知識

• pip 包管理
• Python 安裝
• Xpath
• Css

Windows安裝 Scrapy

$>- pip install scrapy

Linux安裝 Scrapy

$>- apt-get install python-scrapy

2. Scrapy 項目創建

在開始爬取之前，必須創建一個新的Scrapy項目。進入自定義的項目目錄中，運行下列命令：

$>- scrapy startproject mySpider

其中， mySpider 為項目名稱，可以看到將會創建一個 mySpider 文件夾，使用命令查看目錄結構

$>- tree mySpider

3. Scrapy 自定義爬蟲類

通過Scrapy的Spider基礎模版順便建立一個基礎的爬蟲。（也可以不用Scrapy命令建立基礎爬蟲，）

$>- scrapy genspider gzrbSpider dayoo.com

scrapy genspider是一個命令，也是scrapy最常用的幾個命令之一。至此，一個最基本的爬蟲項目已經建立完畢了.

文件描述：

序列	文件名	描述
1	scrapy.cfg	是整個Scrapy項目的配置文件
2	settings.py	是上層目錄中scrapy.cfg定義的設置文件(決定由誰去處理爬取的內容)
3	init.pyc	是__init__.py的字節碼文件
4	init.py	作用就是將它的上級目錄變成了一個模塊 ，否則，文件夾沒有__init__.py不能作為模塊導入
5	items.py	是定義爬蟲最終需要哪些項 (決定爬取哪些項目)
5	pipelines.py	Scrapy爬蟲爬取了網頁中的內容后，這些內容怎么處理就取決於pipelines.py如何設置 (決定爬取后的內容怎樣處理)
6	gzrbSpider.py	自定義爬蟲類（決定怎么爬）

命令描述：

序列	操作	描述
1	模擬爬廣州日報網頁	scrapy shell https://www.dayoo.com
2	模擬查看節點數據	response.xpath('.//div[@class="mt35"]//ul[@class="news-list"]').extract()
3	運行爬蟲	scrapy crawl gzrbSpider

4. Scrapy 處理邏輯

文件 \spiders\gzrbSpider.py

import scrapy
from mySpider.items import MySpiderItem

class gzrbSpider(scrapy.Spider):
    name = "gzrbSpider"
    allowed_domains = ["dayoo.com/"]
    start_urls = (
       'https://www.dayoo.com',
    )

    def parse(self, response):
        subSelector = response.xpath('.//div[@class="mt35"]//ul[@class="news-list"]')
        items = []
        for sub in subSelector:
           item = MySpiderItem()
           item['newName'] = sub.xpath('./li/a/text()').extract()
           items.append(item)
        return items

文件 Item.py

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.html

import scrapy


class MySpiderItem(scrapy.Item):
    # define the fields for your item here like:
    # name = scrapy.Field()
    newName = scrapy.Field()

文件 Setting.py

# Scrapy settings for mySpider project
#
# For simplicity, this file contains only settings considered important or
# commonly used. You can find more settings consulting the documentation:
#
#     https://docs.scrapy.org/en/latest/topics/settings.html
#     https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#     https://docs.scrapy.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'mySpider'

SPIDER_MODULES = ['mySpider.spiders']
NEWSPIDER_MODULE = 'mySpider.spiders'


# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = 'mySpider(+http://www.yourdomain.com)'

# Obey robots.txt rules
ROBOTSTXT_OBEY = True

# Configure maximum concurrent requests performed by Scrapy (default: 16)
#CONCURRENT_REQUESTS = 32

# Configure a delay for requests for the same website (default: 0)
# See https://docs.scrapy.org/en/latest/topics/settings.html#download-delay
# See also autothrottle settings and docs
#DOWNLOAD_DELAY = 3
# The download delay setting will honor only one of:
#CONCURRENT_REQUESTS_PER_DOMAIN = 16
#CONCURRENT_REQUESTS_PER_IP = 16

# Disable cookies (enabled by default)
#COOKIES_ENABLED = False

# Disable Telnet Console (enabled by default)
#TELNETCONSOLE_ENABLED = False

# Override the default request headers:
#DEFAULT_REQUEST_HEADERS = {
#   'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
#   'Accept-Language': 'en',
#}

# Enable or disable spider middlewares
# See https://docs.scrapy.org/en/latest/topics/spider-middleware.html
#SPIDER_MIDDLEWARES = {
#    'mySpider.middlewares.mySpiderSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    'mySpider.middlewares.mySpiderDownloaderMiddleware': 543,
#}

# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    'scrapy.extensions.telnet.TelnetConsole': None,
#}

# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {
   'mySpider.pipelines.mySpiderPipeline': 300,
}

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/autothrottle.html
#AUTOTHROTTLE_ENABLED = True
# The initial download delay
#AUTOTHROTTLE_START_DELAY = 5
# The maximum download delay to be set in case of high latencies
#AUTOTHROTTLE_MAX_DELAY = 60
# The average number of requests Scrapy should be sending in parallel to
# each remote server
#AUTOTHROTTLE_TARGET_CONCURRENCY = 1.0
# Enable showing throttling stats for every response received:
#AUTOTHROTTLE_DEBUG = False

# Enable and configure HTTP caching (disabled by default)
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html#httpcache-middleware-settings
#HTTPCACHE_ENABLED = True
#HTTPCACHE_EXPIRATION_SECS = 0
#HTTPCACHE_DIR = 'httpcache'
#HTTPCACHE_IGNORE_HTTP_CODES = []
#HTTPCACHE_STORAGE = 'scrapy.extensions.httpcache.FilesystemCacheStorage'

文件 pipelines.py

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://docs.scrapy.org/en/latest/topics/item-pipeline.html


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


# class mySpiderPipeline:
#     def process_item(self, item, spider):
#         return item


class MySpiderPipeline(object):
    def process_item(self, item, spider):
        now = time.strftime('%Y-%m-%d', time.localtime())
        fileName = 'gzrb' + now + '.txt'
        for it in item['newName ']:
            with open(fileName,encoding='utf-8',mode = 'a') as fp:
                # fp.write(item['newName '][0].encode('utf8') + '\n\n')
                fp.write(it + '\n\n')
        return item

本文代碼結果展示：

5. Scrapy 擴展

Xpath:

Css: