Request Interception

In general, request interception refers to capturing and manipulating requests made by a software application or a network communication. This interception can occur at various system levels, such as at the application layer, network layer, or even within a web browser. This enables to modify requests before they reach the destination or receiver side.

In web scraping, request interception is crucial in extracting data from websites. Web scraping involves the automated extraction of information from web pages, and intercepting requests is used to understand, control, and enhance this data extraction process. Here are some ways request interception is used in web scraping:

• Modifying headers and parameters

• Rate limiting and throttling

• Handling authentication

• Blocking unwanted requests

In this lesson, we will first see how to enable request interception in Puppeteer and then a few detailed use cases where we can benefit from it, with code examples to understand how to implement them.

Enabling request interception

First, we need to enable request interception. We can configure Puppeteer to use request interception like the one below.

Once request interception is enabled, every request will stall unless it’s continued, responded or aborted.

Therefore, we must define how to handle intercepted requests after enabling request interception. This can be done using an event called request emitted by the page. We can listen to this event and provide a callback function to handle each intercepted request. The callback receives the intercepted request object as a parameter.

Use cases of request interception

Below are some scenarios in which we must use Puppeteer’s request interception feature. These are not the only scenarios in which we can use request ...