What is a web crawler?
A web crawler is a program which is used for extracting HTML pages or documents from various websites. A web crawler is used for creating an index such as a search engine index. The crawling software is known as web spider which is built for visiting each webpage at a predefined time gap.
How does it work?
This is a search engine program known as crawler or robot which helps in finding useful data in the internet. This program lands at a website and start following each and every link in belonging to the whole website. With this specific capacity, this web crawler tool finds information sought by the user. The crawler starts crawling from one site to another in search of information and loads content into a database to index the content of the website.
What is its architecture?
The architecture of the crawler is very crucial. A standard web crawler would have the following architecture:
HTTP fetcher – Http fetcher helps in retrieving web pages from the server.
Extractor – Extractor indented to provide adequate assistance to extract URL from pages like anchor links.
Duplicate eliminator – This is an important architectural element of any web crawler as it ensure that there is no duplicity happened due to double data extraction unintentionally.
URL frontier – It is another vital component of web crawler architecture as it helps in prioritizing URLs that have to be fetched and parsed. It would allow them suitable crawl queue prioritization and categorization.
Database: Database is the major component which helps to store the collected data and other metadata.
Text extractor – good data extraction software should have excellent text extractor features. It should be able to download text in HTML, PDF, Office format, etc.
Full-text search – Your crawler should have the ability to search and extract full text data which is an unavoidable feature of a standard web capture software.
Database integration – A web crawler should be smart enough to get data from various websites across internet and store them in the integrated database.
Dynamic clustering – A web crawler software has always been designed with an intention to have dynamic clustering with apt mining algorithm which would help in classification and clustering of the data dynamically.
Custom Web Crawler
Although the standard features are desirable, sometimes we may want a customized web crawler which is often required in an enterprise set up. When web crawler tools are built with custom features, they work pretty decently for the desired tasks other than mere web page scraping.
A web crawler tool can be a real blessing if it is created with necessary features. Creating it with its core architecture as well as customized feature requires technical expertise. The entire process warrants dedication and focus. Data solution providers with long-standing experience can offer an absolute data extraction software solution because they know the intricacies of data mining and its associated complexities. WebDataGuru develops software like data extraction software, web page scraping tools, custom web crawler, etc for a number of enterprises from different industry verticals.