Scrapy安装及demo测试笔记

Scrapy安装及demo测试笔记
2016年09月01日 16:34:00 panguoyuan 阅读数：1903
Scrapy安装及demo测试笔记

一、环境搭建

1. 安装scrapy：pip install scrapy

2.安装：PyWin32，可以从网上载已编译好的安装包：http://www.lfd.uci.edu/~gohlke/pythonlibs/#pywin32

安装完之后会报如下错误

解决办法，把以下两个文件拷贝到C:\Windows\System32目录下

二、创建scrapy工程（在此用网上别人提供的例子）

1.cmd的方式进到某个指定目录（d:/tmp/）下执行：scrapy startproject myscrapy，命令执行完之后，生成的目录结构如下

2.设置items

-- coding: utf-8 --

Define here the models for your scraped items

See documentation in:

http://doc.scrapy.org/en/latest/topics/items.html

import scrapy

class MyscrapyItem(scrapy.Item):
news_title = scrapy.Field() #南邮新闻标题
news_date = scrapy.Field() #南邮新闻时间
news_url = scrapy.Field() #南邮新闻的详细链接
3.编写 spider

-- coding: utf-8 --

mport scrapy
from myscrapy.items import MyscrapyItem
import logging
class myscrapySpider(scrapy.Spider):
name = "myscrapy"
allowed_domains = ["njupt.edu.cn"]
start_urls = [
"http://news.njupt.edu.cn/s/222/t/1100/p/1/c/6866/i/1/list.htm",
]

def parse(self, response):
    news_page_num = 14
    page_num = 386
    if response.status == 200:
        for i in range(2,page_num+1):
            for j in range(1,news_page_num+1):
                item = MyscrapyItem() 
                item['news_url'],item['news_title'],item['news_date'] = response.xpath(
                "//div[@id='newslist']/table[1]/tr["+str(j)+"]//a/font/text()"
                "|//div[@id='newslist']/table[1]/tr["+str(j)+"]//td[@class='postTime']/text()"
                "|//div[@id='newslist']/table[1]/tr["+str(j)+"]//a/@href").extract()
              
                yield item
                
            next_page_url = "http://news.njupt.edu.cn/s/222/t/1100/p/1/c/6866/i/"+str(i)+"/list.htm"
            yield scrapy.Request(next_page_url,callback=self.parse_news)
    
def parse_news(self, response):
    news_page_num = 14
    if response.status == 200:
        for j in range(1,news_page_num+1):
            item = MyscrapyItem()
            item['news_url'],item['news_title'],item['news_date'] = response.xpath(
            "//div[@id='newslist']/table[1]/tr["+str(j)+"]//a/font/text()"
            "|//div[@id='newslist']/table[1]/tr["+str(j)+"]//td[@class='postTime']/text()"
            "|//div[@id='newslist']/table[1]/tr["+str(j)+"]//a/@href").extract()
            yield item

4.编写pipelines

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

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

import json

class MyscrapyPipeline(object):
def init(self):
self.file = open('myscrapy.txt',mode='wb')
def process_item(self, item, spider):
self.file.write(item['news_title'].encode("GBK"))
self.file.write("\n")
self.file.write(item['news_date'].encode("GBK"))
self.file.write("\n")
self.file.write(item['news_url'].encode("GBK"))
self.file.write("\n")
return item
5.编写settings.py

-- coding: utf-8 --

Scrapy settings for myscrapy project

For simplicity, this file contains only settings considered important or

commonly used. You can find more settings consulting the documentation:

http://doc.scrapy.org/en/latest/topics/settings.html

http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html

http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html

BOT_NAME = 'myscrapy'

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

Crawl responsibly by identifying yourself (and your website) on the user-agent

USER_AGENT = 'myscrapy (+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 http://scrapy.readthedocs.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 http://scrapy.readthedocs.org/en/latest/topics/spider-middleware.html

SPIDER_MIDDLEWARES = {

'myscrapy.middlewares.MyCustomSpiderMiddleware': 543,

}

Enable or disable downloader middlewares

See http://scrapy.readthedocs.org/en/latest/topics/downloader-middleware.html

DOWNLOADER_MIDDLEWARES = {

'myscrapy.middlewares.MyCustomDownloaderMiddleware': 543,

}

Enable or disable extensions

See http://scrapy.readthedocs.org/en/latest/topics/extensions.html

EXTENSIONS = {

'scrapy.extensions.telnet.TelnetConsole': None,

}

Configure item pipelines

See http://scrapy.readthedocs.org/en/latest/topics/item-pipeline.html

TEM_PIPELINES = {
'myscrapy.pipelines.MyscrapyPipeline': 1,
}

Enable and configure the AutoThrottle extension (disabled by default)

See http://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 http://scrapy.readthedocs.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'

6.进到D:\tmp\myscrapy\myscrapy\spiders启动爬虫并查看结果：scrapy crawl myscrapy