Python3 Scrapy框架安装与配置

最新推荐文章于 2024-11-24 20:09:44 发布

M996246017

最新推荐文章于 2024-11-24 20:09:44 发布

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本文链接：https://blog.youkuaiyun.com/M996246017/article/details/81346434

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本文介绍Scrapy框架的基本概念及安装步骤，并提供详细的项目文件说明，包括配置文件、模型文件、管道文件等内容，帮助读者快速上手。

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Scrapy框架简介:

Scrapy是用Python实现的一个为了爬取网站数据、提取结构性数据而编写的应用框可以应用于数据挖掘，用户

只需要定制开发几个模块就可以轻松实现一个爬虫，它能使我们更好的完成爬虫任务。

Scrapy框架安装方法:

如果已经安装过pycharm，在控制台下(Ctrl + r cmd)输入以下命令
```
conda install Scrapy
```
安装好后输入以下命令，如果结果如下图，即代表安装成功,否则，代表安装失败
```
scrapy
```
如果安装失败，需要进入这网站，里面是编译的各种库：http://www.lfd.uci.edu/~gohlke/pythonlibs/#lxml，然后找到下图文件并根据自己的python版本和电脑系统来选择自己需要的文件, .
下载完后，运行如下命令安装wheel文件(这里以3.6版 32位文件为例，其他文件更换文件名即可),安装完成后，再使用第2步命令测试是否安装成功
```
pip install wheel
pip install lxml‑3.7.2‑cp35‑cp35m‑win32.whl
```
安装成功以后，再创建个项目试一下吧！首先创建用来存放项目的文件夹
移动到Scrapy文件夹下输入以下命令创建一个项目
```
scrapy startproject baidu
```
创建项目成功以后可以使用tree查看文件结构

项目中主要包括以下文件

csrapy.fg :项目配置文件

# Automatically created by: scrapy startproject
#
# For more information about the [deploy] section see:
# https://scrapyd.readthedocs.io/en/latest/deploy.html

[settings]
default = baidu.settings

[deploy]
#url = http://localhost:6800/
project = baidu

items.py: 项目items文件

# -*- coding: utf-8 -*-

# model模型
# 在这定义你的爬虫程序的数据模型
# Define here the models for your scraped items
#
# See documentation in:
# https://doc.scrapy.org/en/latest/topics/items.html

import scrapy


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

pipelines.py: 项目管道文件

# -*- coding: utf-8 -*-

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

# 管道文件
class BaiduPipeline(object):
    def process_item(self, item, spider):
        return item

settings.py: 项目配置文件

# -*- coding: utf-8 -*-

# Scrapy settings for baidu 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 = 'baidu'

# 爬虫所在地
SPIDER_MODULES = ['baidu.spiders']
NEWSPIDER_MODULE = 'baidu.spiders'


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

# Obey robots.txt rules
# 遵守爬虫协议
# ROBOTSTXT_OBEY = False

# Configure maximum concurrent requests performed by Scrapy (default: 16)
# 最大请求并发量 默认16
#CONCURRENT_REQUESTS = 32

# Configure 配置 delay延迟  在请求同一个网站的时候的延迟时间
# 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
# cookies_enabled 是否使用cookie
# 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 = {
    #0 1000 值越小优先级越高 优先级越高 越先执行
#    'baidu.middlewares.BaiduSpiderMiddleware': 543,
#}

# Enable or disable downloader middlewares
# See https://doc.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#       0 - 1000 值越小优先级越高 优先级越高 越先执行
#    'baidu.middlewares.BaiduDownloaderMiddleware': 543,
#}

# Enable or disable extensions   是否进行扩展
# 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 = {
#     值越小优先级越高 优先级越高 越先执行
   'baidu.pipelines.BaiduPipeline': 1,
}

# 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'

middleware.py:爬虫中间件

# -*- coding: utf-8 -*-

# Define here the models for your spider middleware
#
# See documentation in:
# https://doc.scrapy.org/en/latest/topics/spider-middleware.html

from scrapy import signals

# 爬虫中间件
class BaiduSpiderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the spider middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_spider_input(self, response, spider):
        # Called for each response that goes through the spider
        # middleware and into the spider.

        # Should return None or raise an exception.
        return None

    def process_spider_output(self, response, result, spider):
        # Called with the results returned from the Spider, after
        # it has processed the response.

        # Must return an iterable of Request, dict or Item objects.
        for i in result:
            yield i

    def process_spider_exception(self, response, exception, spider):
        # Called when a spider or process_spider_input() method
        # (from other spider middleware) raises an exception.

        # Should return either None or an iterable of Response, dict
        # or Item objects.
        pass

    def process_start_requests(self, start_requests, spider):
        # Called with the start requests of the spider, and works
        # similarly to the process_spider_output() method, except
        # that it doesn’t have a response associated.

        # Must return only requests (not items).
        for r in start_requests:
            yield r

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)


class BaiduDownloaderMiddleware(object):
    # Not all methods need to be defined. If a method is not defined,
    # scrapy acts as if the downloader middleware does not modify the
    # passed objects.

    @classmethod
    def from_crawler(cls, crawler):
        # This method is used by Scrapy to create your spiders.
        s = cls()
        crawler.signals.connect(s.spider_opened, signal=signals.spider_opened)
        return s

    def process_request(self, request, spider):
        # Called for each request that goes through the downloader
        # middleware.

        # Must either:
        # - return None: continue processing this request
        # - or return a Response object
        # - or return a Request object
        # - or raise IgnoreRequest: process_exception() methods of
        #   installed downloader middleware will be called
        return None

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest
        return response

    def process_exception(self, request, exception, spider):
        # Called when a download handler or a process_request()
        # (from other downloader middleware) raises an exception.

        # Must either:
        # - return None: continue processing this exception
        # - return a Response object: stops process_exception() chain
        # - return a Request object: stops process_exception() chain
        pass

    def spider_opened(self, spider):
        spider.logger.info('Spider opened: %s' % spider.name)