Python爬虫——scrapy-4-编程知识

免责声明

目标

过程

先修改配置文件

再修改pipelines.py

最后的结果是这样的

read.py

pipelines.py

items.py

settings.py

scrapy日志信息以及日志级别

settings.py文件设置

用百度实验一下

指定日志级别

WARNING

日志文件

注意

scrapy的post请求

简介

爬取百度翻译

总结

免责声明

本文章仅用于学习交流，无任何商业用途

目标

这次我们要学习把爬取到的数据存入数据库之中

过程

先修改配置文件

settings中添加下面的内容

# todo 配置 mysql数据库
# 这里是我的阿里云地址，你填你mysql的地址
DB_HOST = 'xx.xx.xx.xx'
DB_PORT = 3306
DB_USER = 'root'
DB_PASSWORD = '12345678'
DB_NAME = 'spider01'
DB_CHARSET = 'utf-8'

再修改pipelines.py

添加下面的代码


class MysqlPipeline:def process_item(self, item, spider):return item

再添加配置

ITEM_PIPELINES = {"scrapy_readbook_090.pipelines.ScrapyReadbook090Pipeline": 300,# MysqlPipeline"scrapy_readbook_090.pipelines.MysqlPipeline": 301
}

。。。。

最后的结果是这样的

read.py

import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from scrapy_readbook_090.items import ScrapyReadbook090Itemclass ReadSpider(CrawlSpider):name = "read"allowed_domains = ["www.dushu.com"]start_urls = ["https://www.dushu.com/book/1188_1.html"]rules = (Rule(LinkExtractor(allow=r"/book/1188_\d+\.html"),callback="parse_item",# true代表是否跟进# 打开follow为true就会爬取全部网页follow=True),)def parse_item(self, response):img_list = response.xpath('//div[@class="bookslist"]//img')for img in img_list:name = img.xpath('./@alt').extract_first()img_src = img.xpath('./@data-original').extract_first()book = ScrapyReadbook090Item(name=name, src=img_src)yield book

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 ItemAdapterclass ScrapyReadbook090Pipeline:def open_spider(self, spider):self.fp = open('book.json', 'w', encoding='utf-8')def process_item(self, item, spider):self.fp.write(str(item))return itemdef close_spider(self, spider):self.fp.close()# 加载settings文件
from scrapy.utils.project import get_project_settings
import pymysqlclass MysqlPipeline:def open_spider(self, spider):settings = get_project_settings()self.host = settings['DB_HOST']self.port = settings['DB_PORT']self.user = settings['DB_USER']self.password = settings['DB_PASSWORD']self.name = settings['DB_NAME']self.charset = settings['DB_CHARSET']self.connect()def connect(self):self.conn = pymysql.connect(host=self.host,port=self.port,user=self.user,password=self.password,db=self.name,charset=self.charset)# 可执行sql语句self.cursor = self.conn.cursor()def process_item(self, item, spider):sql = 'insert into book2(name,src) values("{}","{}")'.format(item['name'], item['src'])# 执行SQL语句self.cursor.execute(sql)# 提交self.conn.commit()return itemdef close_spider(self, spider):self.cursor.close()self.conn.close()

items.py

# Define here the models for your scraped items
#
# See documentation in:
# https://docs.scrapy.org/en/latest/topics/items.htmlimport scrapyclass ScrapyReadbook090Item(scrapy.Item):# define the fields for your item here like:# name = scrapy.Field()name = scrapy.Field()src = scrapy.Field()

settings.py

# Scrapy settings for scrapy_readbook_090 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.htmlBOT_NAME = "scrapy_readbook_090"SPIDER_MODULES = ["scrapy_readbook_090.spiders"]
NEWSPIDER_MODULE = "scrapy_readbook_090.spiders"# Crawl responsibly by identifying yourself (and your website) on the user-agent
#USER_AGENT = "scrapy_readbook_090 (+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 = {
#    "scrapy_readbook_090.middlewares.ScrapyReadbook090SpiderMiddleware": 543,
#}# Enable or disable downloader middlewares
# See https://docs.scrapy.org/en/latest/topics/downloader-middleware.html
#DOWNLOADER_MIDDLEWARES = {
#    "scrapy_readbook_090.middlewares.ScrapyReadbook090DownloaderMiddleware": 543,
#}# Enable or disable extensions
# See https://docs.scrapy.org/en/latest/topics/extensions.html
#EXTENSIONS = {
#    "scrapy.extensions.telnet.TelnetConsole": None,
#}# todo 配置 mysql数据库
DB_HOST = '8.137.20.36'
# 端口号要是整形
DB_PORT = 3306
DB_USER = 'root'
DB_PASSWORD = '12345678'
DB_NAME = 'spider01'
# utf-8的 -  不要写
DB_CHARSET = 'utf8'# Configure item pipelines
# See https://docs.scrapy.org/en/latest/topics/item-pipeline.html
ITEM_PIPELINES = {"scrapy_readbook_090.pipelines.ScrapyReadbook090Pipeline": 300,# MysqlPipeline"scrapy_readbook_090.pipelines.MysqlPipeline": 301
}# 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"# Set settings whose default value is deprecated to a future-proof value
REQUEST_FINGERPRINTER_IMPLEMENTATION = "2.7"
TWISTED_REACTOR = "twisted.internet.asyncioreactor.AsyncioSelectorReactor"
FEED_EXPORT_ENCODING = "utf-8"

最后是找到了4000条数据

可能是io进服务器的顺序问题，军娃不是最后一个，但是一页40本书，一共100页也是没有一点毛病了。(* ^ ▽ ^ *)

scrapy日志信息以及日志级别

Scrapy是一个基于Python的网络爬虫框架，它提供了强大的日志功能。Scrapy的日志信息以及日志级别如下：

DEBUG：调试级别，用于输出详细的调试信息，一般在开发和测试阶段使用。
INFO：信息级别，用于输出一些重要的信息，如爬虫的启动信息、请求的URL等。
WARNING：警告级别，用于输出一些不太严重的警告信息，如某个网页的解析出错，但不影响整个爬虫的执行。
ERROR：错误级别，用于输出一些错误信息，如爬虫的配置出错、网络连接异常等。
CRITICAL：严重级别，用于输出一些非常严重的错误信息，如爬虫的关键逻辑出错、无法连接到目标网站等。

默认的日志级别是DEBUG

Scrapy的日志信息可以在控制台中直接输出，也可以保存到文件中。可以通过设置Scrapy的配置文件或使用命令行参数来调整日志级别和输出方式。

以下是Scrapy的日志信息的示例：

2021-01-01 12:00:00 [scrapy.core.engine] INFO: Spider opened
2021-01-01 12:00:01 [scrapy.core.engine] DEBUG: Crawled 200 OK
2021-01-01 12:00:01 [scrapy.core.engine] DEBUG: Crawled 404 Not Found
2021-01-01 12:00:02 [scrapy.core.engine] WARNING: Ignoring response <404 Not Found>
2021-01-01 12:00:02 [scrapy.core.engine] DEBUG: Crawled 200 OK
2021-01-01 12:00:02 [scrapy.core.engine] ERROR: Spider error processing <GET http://example.com>: Error parsing HTML
2021-01-01 12:00:03 [scrapy.core.engine] DEBUG: Crawled 200 OK
2021-01-01 12:00:03 [scrapy.core.engine] INFO: Closing spider (finished)
2021-01-01 12:00:03 [scrapy.statscollectors] INFO: Dumping Scrapy stats

settings.py文件设置

默认的级别是DEBUG，会显示上面的所有信息

在配置文件中 settings.py

LOG_FILE : 将屏幕显示的信息全部记录到文件中，屏幕不再显示，注意文件后最有一定是 .log

LOG_LEVEL : 设置日志的等级，就是显示那些，不显示那些

用百度实验一下

先把 “君子协议” 撕碎

# ROBOTSTXT_OBEY = True

指定日志级别

WARNING

在settings.py中添加下述代码

# 指定日志的级别
LOG_LEVEL = 'WARNING'

==========是我在log.py中添加要打印的

就可以发现没有日志了

日志文件

我们先把上面配置的等级删除掉，再加上下述的代码

# 日志文件
LOG_FILE = 'logDemo.log'

运行

世界依然清晰

但是日志已经存储在日志文件中了

注意

其实一般来说不要修改log的等级，如果报错也太难发现是什么问题了，所以一般为了控制台别打印那么多东西

scrapy的post请求

简介

在Scrapy中进行POST请求可以通过scrapy.FormRequest类来实现。下面是一个使用Scrapy进行POST请求的示例：

import scrapyclass MySpider(scrapy.Spider):name = 'example.com'start_urls = ['http://www.example.com/login']def parse(self, response):# 提取登录页的csrf tokencsrf_token = response.css('input[name="csrf_token"]::attr(value)').get()# 构建POST请求的表单数据formdata = {'username': 'myusername','password': 'mypassword','csrf_token': csrf_token}# 发送POST请求yield scrapy.FormRequest(url='http://www.example.com/login', formdata=formdata, callback=self.after_login)def after_login(self, response):# 检查登录是否成功if response.url == 'http://www.example.com/home':self.log('Login successful')# 处理登录成功后的响应数据# ...else:self.log('Login failed')

在上面的示例中，首先在parse方法中抓取登录页，并提取登录页的csrf token。然后构建一个包含用户名、密码和csrf token的字典，作为formdata参数传递给FormRequest对象。最后使用yield关键字发送POST请求，并指定回调函数after_login来处理登录后的响应。

在after_login方法中，可以根据响应的URL来判断登录是否成功。如果URL为登录后的首页URL，则登录成功，否则登录失败。可以在登录成功时做进一步的处理，如抓取用户信息，然后在控制台或日志中输出相应的信息。

需要注意的是，Scrapy的POST请求默认使用application/x-www-form-urlencoded方式来编码数据。如果需要发送JSON或其他类型的请求，可以通过设置headers参数来指定请求头，如：yield scrapy.FormRequest(url='http://www.example.com/login', formdata=formdata, headers={'Content-Type': 'application/json'}, callback=self.after_login)。

另外，如果需要在POST请求中上传文件，可以使用scrapy.FormRequest的files参数，将文件的路径作为值传递给表单字段。更多关于POST请求的用法和参数配置，请查阅Scrapy官方文档。

爬取百度翻译

只需要修改testpost.py这个自己创建的文件就行了

import scrapy
import jsonclass TestpostSpider(scrapy.Spider):name = "testpost"allowed_domains = ["fanyi.baidu.com"]# post请求如果没有参数，那抹这个请求将没有任何的意义# 所以 start_urls 也是没有用# 而且 parse 方法也没有用了# 所以直接注释掉# TODO# start_urls = ["https://fanyi.baidu.com/sug"]## def parse(self, response):#     print("==========================")# post请求就使用这个方法def start_requests(self):url = 'https://fanyi.baidu.com/sug'data = {'kw': 'final'}yield scrapy.FormRequest(url=url, formdata=data, callback=self.parse_second)def parse_second(self, response):content = response.textobj = json.loads(content, encoding='utf-8')print(obj)