> For the complete documentation index, see [llms.txt](https://coldbox.ortusbooks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://coldbox.ortusbooks.com/v4.x-1/digging-deeper/interceptors/how-do-they-work.md).

# How do they work?

Interceptors are CFCs that extend the ColdBox Interceptor class (`coldbox.system.Interceptor`), implement a configuration method called `configure()`, and then contain methods for the events it will listen for. All interceptors are treated as **singletons** in your application, so make sure they are thread safe and var scoped.

![](https://github.com/ortus/coldbox-platform-documentation/tree/24d3f3d16693b36ca41bf5ce0329c6ff33316ef0/images/ColdBoxMajorClasses.jpg)

```
/**
* My Interceptor
*/
component extends="coldbox.system.Interceptor"{

    function configure(){}

    function preProcess( event, interceptData, buffer, rc, prc ){}
}
```

> **Info** You can also remove the inheritance from the CFC (preferred method) and WireBox will extend the `coldbox.system.Interceptor` for you using [Virtual Inheritance](https://wirebox.ortusbooks.com/content/virtual_inheritance/).

You can use CommandBox to create interceptors as well:

```bash
coldbox create interceptor help
```

## Registration

Interceptors can be registered in your `Coldbox.cfc` configuration file using the `interceptors` struct, or they can be registered manually via the system's interceptor service.

In `ColdBox.cfc`:

```
// Interceptors registration
interceptors = [
    {
        class   = "cfc.path",
        name    = "unique name/wirebox ID",
        properties = {
            // configuration
        }
    }
];
```

Registered manually:

```
controller.getInterceptorService().registerInterceptor( interceptorClass="cfc.path" );
```

## The `configure()` Method

The interceptor has one important method that you can use for configuration called `configure()`. This method will be called right after the interceptor gets created and injected with your interceptor properties.

> **Info** These properties are local to the interceptor only!

As you can see on the diagram, the interceptor class is part of the ColdBox framework super type family, and thus inheriting the functionality of the framework.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://coldbox.ortusbooks.com/v4.x-1/digging-deeper/interceptors/how-do-they-work.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.