To sum it up web scraping is the process of extracting data from a website, web source, or third party application or API through automation. So rather than a human going and manually recording data by looking it up and writing it down, we write a script using a regex pattern or through algorithms to have the computer itself retrieve the data. In short, rather than having humans retrieve data we write a program or script to do it in a much faster time. There really are not many limitations to what data can be retrieved or stored. But a few examples could be text-based information, images, videos, blobs, etc. One of the best aspects of web scraping is that you are able to program scripts and programs in nearly any available programming language.
There are definitely several challenges when it comes to web scraping but knowing how to work with the limitations and find mitigations is what makes a good programmer. After all, a programmer is an engineer of a software/script. A good engineer can build a house from anything he is given, which is applicable for software engineers as well. A few of the challenges you may run into are before, during, and after the development. To explain, before you need to make sure you are able to retrieve information properly. To do this you need to analyze existing code and try to identify a repetitive pattern in which you can automate (one of the hardest things to do).
During the process of retrieval, you have to make sure there are no timeouts. What this means is you need to look at how fast requests are created and retrieved, this is important because if it is created and retrieved too fast the host server can easily blacklist your IP address which will limit you from getting the data needed. The reason this occurs is because of the security measures that are in place. To explain, the multiple connections at a fast rate triggers a red flag which the server is interpreted as a possible attack which is called a Denial of Service (DoS) attack. To prevent this attack the server takes drastic security measures which temporarily disables your IP address from accessing their website. Which leads us into after the software and script are completed.
Just because a web scraping project or script is completed doesn’t mean you are done with the actual project. To explain, if the developer of the web application, website, application, or even API changes how the structure was initially the script that was written needs to be altered. In some cases, it could be a simple fix, but in other cases, it could mean redoing the entire script it all depends on how major or minor the change is. Sometimes it may not even affect your web scraping script or program.
This really depends on what the project is sometimes it would be definitely worth it and other times it could be more costly to maintain it rather than do the task manually. For example, if you have a script that was created to retrieve data from a website and it is able to pull data in a microsecond versus going in manually and pulling the same data in hours or days it could be worth it however the other aspect that needs to be considered and looked at to determine if it is worth doing is how often the architecture of the source changes. If the source changes often then you would run into the issue of constantly updating the software which could get quite costly. However, if the software is able to work efficiently and productively to a point where the company is making money rather than losing it could definitely be a benefit. But as you can tell there are several factors influencing if creating a Web Scraping project is worth it or not.