Custom Parser

There are three main steps to building your own parser: 

1. Create multiple functions and ensure they are concise. Each function should have a single purpose and excel at it. 
2. Avoid utilizing regular expressions for parsing tasks, as they tend to be ineffective. Refrain from making assumptions. 
3. If uncertain about how to parse something, raise an error and include the error location (line/column) in the error message.

Oxylabs’ Custom Parser is a tool that transforms data from raw to structured. According to the pre-written code and rules, the parser will select the necessary information and convert it into a readable JSON format.

Check parsing instruction examples in our documentation.

Building custom parsers is considered a moderately-difficult task, depending on the volume of the data you want to extract. A general rule of thumb is building your own custom parser if you have a small-scale web scraping task and vice versa – if you’re scraping large volumes of data, you may consider buying a third-party tool instead.

We’ve discussed the topic of building a custom parser vs. buying one in our blog post: What Is Parsing of Data?

Parser is the tool of transforming raw data into a readable format, while parsing is the process of it.

Custom Parser is a free additional feature to our Scraper APIs. Hence, you should be an active customer of either of them to use the custom parsing functionality. 

Dedicated parsers are parsing tools built and managed by Oxylabs’ Scraper API specialists. They’re specifically designed for extracting data from certain targets and organizing data according to our set instructions. 

According to their needs, our Scraper API customers are welcome to choose between the Custom and dedicated parsers. However, they cannot use both of them at the same time, because their parsing instructions will override ours.

XPath and CSS selectors are two different methods for selecting specific elements within HTML or XML documents.. CSS selectors are generally easier to use, while XPath expressions are more powerful but rather difficult to use. 

Learn more:

XPath vs CSS Selectors