Semalt Explains How To Extract Data From HTML Pages Into A PDF File
In this article, we are going to take you through the process of extracting data from your HTML pages and teach how to use the information to build a PDF file. The first step is to determine the programming tools and language that you are going to use for the task. In this case, you'd better use the Mojolicious framework of Perl.
This framework resembles Ruby on Rails even though it has additional features that could exceed your expectations. We will not be using this framework to create a new website but extract information from an already existing page. Mojolicious has excellent features to fetch and process HTML pages. It'll take you nearly 30 seconds to install this application on your machine.
Methodology
Stage One: It's important to understand the methodology you need to use when writing applications. In the first stage, you are expected to write a small ad-hoc script after getting a general idea of what you want to do and have a clear understanding of your final goal. Note that this linear code has to be straightforward without any procedures or subroutines.
Second Stage: Now you have a clear understanding of the direction you need to take and the libraries to use. It is the time to "divide and rule"! If you have accumulated codes that logically do the same things, subdivide them into subroutines. The advantage of subroutine coding is that you can make several changes without impacting other codes. It'll also provide better readability.
Stage Three: This stage allows you to componentize your codes. You can manipulate code pieces with ease after gaining the relevant experience. Now, you can cross from procedural coding to object-oriented especially if you are using an object-oriented language. Any person who uses a functional type of language can separate applications to packages or/and 'interfaces.' Why do you have to use this approach when programming? This is because you need some "breathing space" especially if you are writing a sophisticated application.
The Algorithm
After the theory, it's time to move to the current program. Here are the steps you need to undertake while implementing the web scrubber:
- Create an URL list of the articles you would like to collect;
- Loop over your list and fetch these URLs one after the other;
- Extract your content of the HTML element;
- Save your results in the HTML file;
- Compile a pdf file out of your files once you have all of them ready;
Everything is as easy as ABC! Just download the web scrubber program, and you will be ready for the task.
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