Link extractor with Scrapy

As their name indicates, link extractors are the objects that are used to extract links from the Scrapy response object. Scrapy has built-in link extractors, such as scrapy.linkextractors.

How to do it...

Let's build a simple link extractor with Scrapy:

1. As we did for the previous recipe, we have to create another spider for getting all the links.

In the new spider file, import the required modules:

import scrapy 
from scrapy.linkextractor import LinkExtractor 
from scrapy.spiders import Rule, CrawlSpider  

2. Create a new spider class and initialize the variables:

class HomeSpider2(CrawlSpider): 
    name = 'home2' 
    allowed_domains = ['books.toscrape.com'] 
    start_urls = ['http://books.toscrape.com/']

3. Now we have to initialize the rule for crawling the URL:

rules = [ 
    Rule( 
        LinkExtractor( 
            canonicalize=True, 
            unique=True 
        ), 
        follow=True, 
        callback="parse_page" 
    ) 
]   

This rule orders the extraction of...