Data Extraction, Screen Scraping, Web Scraping
January 9th, 2013
Google Crawler . Google Scraping . Learn Screen Scraping . Learn Web Scraping . PHP Simple HTML DOM . Simple HTML DOM
The title tells it a lot, but let us give you a view of this post. We have been planning for many months now that we would share our scraping knowledge to people interested in this field. This is because we feel that this field has a lot of opportunities than the number of real experts available. We already created quite a few scraping professionals in our region but the manual teaching could create only this few; we wanted to help a lot more others. Our today’s topic is on one of the most asked/requested crawling tasks e.g. Scraping Google Search. This post is intended for people already have some knowledge on PHP.
To learn the intention of this post, please be sure you already have the PHP Simple HTML DOM library and took a look at the first page. Read the “Quick Start” block which has stated how to grab image links from a given page.
In our example, we have searched Google by a keyword “Beautiful Bangladesh” and parsed the names & associated links from the results. Here is link we used to search the keyword in Google:
Then, we located the first result using Firebug inspector. It gives us the path to the DOM element for the result.
You can see the result item is accommodated by an “h3″ element of class “r” under which the link is found. This can be easily captured by the HTML DOM Library as below:
Here, we traversed through all links and extracted titles & links. We found direct link in “href”. But not always the links are straight, Google sometimes keep in a different structure, with their own reference and in a parameter. So we used a regular expression to match and extract the URL in that case. Please learn basics of Perl Compatible Regular Expressions (PCRE) if you’re new to PHP.
Finally, my result looked like this (as of Jan 08, 2013):
If you want the script as a file, please click follow this link:
For developers – please feel free to ask questions, we are eager to help you learn technologies related to web scraping.
For webmasters – please contact us to develop your complex web scraping solution.
Thanks for reading.