Python Scrapy - 从多个网站 URL 中抓取数据

Question

For one of my web project I need to scrape data from different web sources. To keep it simple i am explaining with an example.

Lets say i want to scrape the data about mobiles listed in their manufacturer site.

http://www.somebrand1.com/mobiles/ . . http://www.somebrand3.com/phones/

I have huge list of URLs. Every brand's page will have their own way of HTML presentation for browser.

How can i write a normalized script to traverse the HTML of those listing web page URLs and scrape the data irrespective of the format they are in?

Or else do i need to write a script to scrape data from every pattern?

Answer 1

This is called a Broad Crawling and, generally speaking, this is not an easy thing to implement because of the different nature, representation, loading mechanisms web-sites use.

The general idea would be to have a generic spider and some sort of a site-specific configuration where you would have a mapping between item fields and xpath expressions or CSS selectors used to retrieve the field values from the page. In a real life, things are not that simple as it seems, some fields would require post-processing, other fields would need to be extracted after sending a separate request etc. In other words, it would be very difficult to keep generic and reliable at the same time .

The generic spider should receive a target site as a parameter , read the site-specific configuration and crawl the site according to it.

Also see:

• Broad Crawls