Web crawling and web scraping are often used interchangeably, but is that really the case? Maybe not.
There’s a fine line of distinction between the two concepts. To put things simply, a typical crawling function includes docking onto a webpage and tracking the relevant links while scanning through the actual text and subsequently proceeds to the next webpage and so on.
On the flipside, web scraping refers to parsing through content on a webpage and collecting particular data points like title tags, header tags, meta keywords and descriptions. Along with this, a web scraping process can also entail scanning through the webpage for a specific data set such as stock availability, prices and similar more.
Web scrapers, quite often than not, behave in a personified manner. You can think of it as a pseudo-human interacting with the webpage and executing activities such as filling in required input fields and using a browser in order to camouflage its identity.
Crawlers specifically designed for search engines like google and bing usually function in a manner similar to that of web scraping bots since the role is pretty similar in terms of collecting data and processing it for specific programs. However, unlike generic web scraping bots, these crawlers would not try to fetch any particular data point, but would parse the entire content on the web page and would even go as beyond as tracking the loading time for the web page. One good thing about search engine crawling bots in specific is that they don’t try to camouflage as a user, instead it reveals its identity as a web crawler which helps the webpage administrator to filter out bot activities from the real human user activity and hence making tracking much more efficient.
Web crawling services and bots have a rather interesting history. The evolution of web crawlers is quite fascinating considering the fact that it spent its early days of inception as a simple tool to collect various statistical information about different webpages. However, times have changed a lot and the role of web crawlers is much beyond fetching and building a statistical repository of certain webpages. The modern web crawler is extremely powerful and intelligent to execute various level checks – right from accessibility to vulnerability of web based applications as well as pages.
The rapid extension of the internet and the world wide web has brought along various complex online applications and programs which makes web crawling quite a challenging task. Though the challenges and limitations faced by web crawlers has been discussed at length at various forums across the world and there have been equivalent number of proposed solutions, but the concern continues to lie at the heart of the very concept – can web crawlers be super-charged to keep pace with increasing dynamics and be made more effective as well as efficient?
While there’s no clear answer to this, the community is definitely working on making web crawlers more robust, one string of code at a time. The consensus says that the evolution of web crawlers is well on track, in fact ahead of what was expected a few years back.