服務請求

Python 網頁爬蟲

Thomas Laetsch

Data Scientist, NYU

回顧 Spider

import scrapy
from scrapy.crawler import CrawlerProcess

class SpiderClassName(scrapy.Spider):
    name = "spider_name"
    # the code for your spider
    ...

process = CrawlerProcess()

process.crawl(SpiderClassName)

process.start()

回顧 Spider

class DCspider( scrapy.Spider ):
    name = "dc_spider"

    def start_requests( self ):
        urls = [ 'https://www.datacamp.com/courses/all' ]
        for url in urls:
            yield scrapy.Request( url = url, callback = self.parse )

    def parse( self, response ):
        # simple example: write out the html
        html_file = 'DC_courses.html'
        with open( html_file, 'wb' ) as fout:
            fout.write( response.body )

start_requests 要點

def start_requests( self ):

    urls = ['https://www.datacamp.com/courses/all']

    for url in urls:
        yield scrapy.Request( url = url, callback = self.parse )

def start_requests( self ):
    url = 'https://www.datacamp.com/courses/all'
    yield scrapy.Request( url = url, callback = self.parse )

這裡的 scrapy.Request 會為我們填入 response 變數
url 參數指定要擷取的網站
callback 參數指定將 response 變數送去處理的位置

放大視野

class DCspider( scrapy.Spider ):
    name = "dc_spider"

    def start_requests( self ):
        urls = [ 'https://www.datacamp.com/courses/all' ]
        for url in urls:
            yield scrapy.Request( url = url, callback = self.parse )

    def parse( self, response ):
        # simple example: write out the html
        html_file = 'DC_courses.html'
        with open( html_file, 'wb' ) as fout:
            fout.write( response.body )

結束請求

Python 網頁爬蟲