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(11)Scrapy第一个Spider



Spider定义从提取数据的初始 URL,如何遵循分页链接以及如何提取和分析在 items.py 定义字段的类。Scrapy 提供了不同类型的蜘蛛,每个都给出了一个具体的目的。

在 first_scrapy/spiders 目录下创建了一个叫作 “first_spider.py” 文件,在这里可以告诉 scrapy 。要如何查找确切数据,这里必须要定义一些属性:

  • name: 它定义了蜘蛛的唯一名称;

  • allowed_domains: 它包含了蜘蛛抓取的基本URL;

  • start-urls: 蜘蛛开始爬行的URL列表;

  • parse(): 这是提取并解析刮下数据的方法;

下面的代码演示了蜘蛛代码的样子:

# -*- 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 firstSpider(scrapy.Spider):
    name = "first"
    allowed_domains = ["yiibai.com"]
    start_urls = [
        "http://www.yiibai.com/scrapy/scrapy_create_project.html",
        "http://www.yiibai.com/scrapy/scrapy_environment.html"
    ]

    def parse(self, response):
        filename = response.url.split("/")[-1]
        print 'Curent URL => ', filename
        with open(filename, 'wb') as f:
            f.write(response.body)

执行结果如下所示 –

D:first_scrapy>scrapy crawl first
2016-10-03 10:40:10 [scrapy] INFO: Scrapy 1.1.2 started (bot: first_scrapy)
2016-10-03 10:40:10 [scrapy] INFO: Overridden settings: {'NEWSPIDER_MODULE': 'first_scrapy.spiders', 'SPIDER_MODULES': ['first_scrapy.spiders'], 'ROBOTSTXT_OBEY': True, 'BOT_NAME': 'first_scrapy'}
2016-10-03 10:40:10 [scrapy] INFO: Enabled extensions:
['scrapy.extensions.logstats.LogStats',
 'scrapy.extensions.telnet.TelnetConsole',
 'scrapy.extensions.corestats.CoreStats']
2016-10-03 10:40:11 [scrapy] INFO: Enabled downloader middlewares:
['scrapy.downloadermiddlewares.robotstxt.RobotsTxtMiddleware',
 'scrapy.downloadermiddlewares.httpauth.HttpAuthMiddleware',
 'scrapy.downloadermiddlewares.downloadtimeout.DownloadTimeoutMiddleware',
 'scrapy.downloadermiddlewares.useragent.UserAgentMiddleware',
 'scrapy.downloadermiddlewares.retry.RetryMiddleware',
 'scrapy.downloadermiddlewares.defaultheaders.DefaultHeadersMiddleware',
 'scrapy.downloadermiddlewares.redirect.MetaRefreshMiddleware',
 'scrapy.downloadermiddlewares.httpcompression.HttpCompressionMiddleware',
 'scrapy.downloadermiddlewares.redirect.RedirectMiddleware',
 'scrapy.downloadermiddlewares.cookies.CookiesMiddleware',
 'scrapy.downloadermiddlewares.chunked.ChunkedTransferMiddleware',
 'scrapy.downloadermiddlewares.stats.DownloaderStats']
2016-10-03 10:40:11 [scrapy] INFO: Enabled spider middlewares:
['scrapy.spidermiddlewares.httperror.HttpErrorMiddleware',
 'scrapy.spidermiddlewares.offsite.OffsiteMiddleware',
 'scrapy.spidermiddlewares.referer.RefererMiddleware',
 'scrapy.spidermiddlewares.urllength.UrlLengthMiddleware',
 'scrapy.spidermiddlewares.depth.DepthMiddleware']
2016-10-03 10:40:11 [scrapy] INFO: Enabled item pipelines:
[]
2016-10-03 10:40:11 [scrapy] INFO: Spider opened
2016-10-03 10:40:11 [scrapy] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2016-10-03 10:40:11 [scrapy] DEBUG: Telnet console listening on 127.0.0.1:6023
2016-10-03 10:40:11 [scrapy] DEBUG: Crawled (200) <GET http://www.yiibai.com/robots.txt> (referer: None)
2016-10-03 10:40:11 [scrapy] DEBUG: Crawled (200) <GET http://www.yiibai.com/scrapy/scrapy_create_project.html> (referer: None)
2016-10-03 10:40:11 [scrapy] DEBUG: Crawled (200) <GET http://www.yiibai.com/scrapy/scrapy_environment.html> (referer: None)
Curent URL =>  scrapy_create_project.html
Curent URL =>  scrapy_environment.html
2016-10-03 10:40:12 [scrapy] INFO: Closing spider (finished)
2016-10-03 10:40:12 [scrapy] INFO: Dumping Scrapy stats:
{'downloader/request_bytes': 709,
 'downloader/request_count': 3,
 'downloader/request_method_count/GET': 3,
 'downloader/response_bytes': 15401,
 'downloader/response_count': 3,
 'downloader/response_status_count/200': 3,
 'finish_reason': 'finished',
 'finish_time': datetime.datetime(2016, 10, 3, 2, 40, 12, 98000),
 'log_count/DEBUG': 4,
 'log_count/INFO': 7,
 'response_received_count': 3,
 'scheduler/dequeued': 2,
 'scheduler/dequeued/memory': 2,
 'scheduler/enqueued': 2,
 'scheduler/enqueued/memory': 2,
 'start_time': datetime.datetime(2016, 10, 3, 2, 40, 11, 614000)}
2016-10-03 10:40:12 [scrapy] INFO: Spider closed (finished)

D:first_scrapy>

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