Python Scrapy爬虫框架学习笔记（一）

最近学完Python之后感觉要学明白一门编程语言就需要不停用，因此就选择了相对难度小的爬虫练习，话不多说，看笔记：

运行环境：

OS：Win10

Python：3.6

Scrapy：1.5.1

IDE：Pycharm

工程代码：

目前主要做了一个爬取豆瓣前250电影的小爬虫，代码也是按照Scrapy的手册上学到的现学现用，还望各位大神赐教。

1，setting.py文件

# -*- coding: utf-8 -*-
import time

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

BOT_NAME = 'scrawlDianpingData'

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


# Crawl responsibly by identifying yourself (and your website) on the user-agent
RANDOM_UA_TYPE = 'random'

DOWNLOADER_MIDDLEWARES = {
    'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware': None,
    'scrapy_fake_useragent.middleware.RandomUserAgentMiddleware': 400,
}

# 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://doc.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://doc.scrapy.org/en/latest/topics/spider-middleware.html
SPIDER_MIDDLEWARES = {
   'scrawlDianpingData.middlewares.ScrawldianpingdataSpiderMiddleware': 543,
}

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

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

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

# Enable and configure the AutoThrottle extension (disabled by default)
# See https://doc.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://doc.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'
HTTPERROR_ALLOWED_CODES = [403]

#Export report
FEED_FORMAT = "csv"
FEED_EXPORT_ENCODING = 'utf-8-sig'
FEED_URI = "file:///C:/Spider_Output/%s.csv" % ("report_"+time.strftime("%Y%m%d%H%M%S", time.localtime()))
           

,2，主程序crawlmovie.py文件

import scrapy
import os


class CrawlMovie(scrapy.Spider):
    name = "movie"

    start_urls = [
        'https://movie.douban.com/top250',
    ]

    def parse(self, response):
           for item in response.css('div.item'):
               yield{
                   '排名': item.css('div.pic em::text').extract_first().strip(),
                   '电影名': item.css('span.title::text').extract_first().strip(),
                   '链接': item.css('div.hd a::attr(href)').extract_first().strip(),
                   '详细': item.css('div.bd p::text').extract_first().strip(),
                   '评分': item.css('span.rating_num::text').extract_first().strip(),
                   '评分人数': item.css('div.star span:nth-child(4)::text').extract_first().strip(),
                   '格言': item.css('span.inq::text').extract_first(),
               }

           next_page = response.css('span.next a::attr(href)').extract_first()
           if next_page is not None:
               yield response.follow(next_page, self.parse)

           #delete empty files
           path = 'C:/Spider_Output/'
           for file in os.listdir(path):
               if os.stat(path+file).st_size == 0:
                   try:
                       os.remove(path+file)
                       self.log('delete %s success!!!' % file)
                   except OSError as oe:
                       print("file is using.")


           

3，程序启动入口，主要用在配置

from scrapy import cmdline


cmdline.execute("scrapy crawl movie".split())
           

练习中遇到的问题：

1，编码问题，如果爬去的内容有中文汉字，在setting.py中加入下边代码

FEED_EXPORT_ENCODING = 'utf-8-sig'
           

其他的解决方案都试过了，但是就这个好用

2，从网页上爬去的时候会出现无值的情况，所以每个爬取之后及得用上extract_first()这个方法，并且后边记得别用strip()

去首位空格

3，如果一些网站禁掉爬虫，记得加上fake-useragent这个package

最后把结果也分享了