But it's possible to customize it, you can set a specific CDN, or serve the files yourself.

## Custom CDN for JavaScript and CSS

Let's say that you want to use a different <abbr title="Content Delivery Network">CDN</abbr>, for example you want to use `https://unpkg.com/`.

     */
    int getValidationLevel();

    /**
     * Sets the level of validation to perform on processed models. For building of projects,
     * {@link #VALIDATION_LEVEL_STRICT} should be used to ensure proper building. For the mere retrieval of dependencies
     * during artifact resolution, {@link #VALIDATION_LEVEL_MINIMAL} should be used to account for models of poor

In some cases, you may want to override the logic used by the `Request` and `APIRoute` classes.

In particular, this may be a good alternative to logic in a middleware.

For example, if you want to read or manipulate the request body before it is processed by your application.

/// danger

This is an "advanced" feature.

If you are just starting with **FastAPI** you might want to skip this section.

///

## Use cases

`secrets.compare_digest()` needs to take `bytes` or a `str` that only contains ASCII characters (the ones in English), this means it wouldn't work with characters like `á`, as in `Sebastián`.

To handle that, we first convert the `username` and `password` to `bytes` encoding them with UTF-8.

Up to here, everything would work as normally.

    }

    /**
     * Get the absolute path to the private key file.
     *
     * @return absolute path to private key
     */
    public String getPrivateKey() {
        return privateKey;
    }

    /**
     * Set the absolute path to private key file.
     *
     * @param privateKey path to private key in local file system
     */

    }

    /**
     * Attaches a produced artifact to the project at the specified path. This is the base method
     * that the other attachArtifact methods delegate to.
     *
     * @param project the project to attach the artifact to
     * @param artifact the produced artifact to attach
     * @param path the path to the artifact file

But there could be cases where you want to be able to set parameters on the dependency, without having to declare many different functions or classes.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

But we want to be able to parameterize that fixed content.

## A "callable" instance

In Python there's a way to make an instance of a class a "callable".

// caller should not use buf after this call. NewBuffer is intended to
// prepare a [Buffer] to read existing data. It can also be used to set
// the initial size of the internal buffer for writing. To do that,
// buf should have the desired capacity but a length of zero.
//
// In most cases, new([Buffer]) (or just declaring a [Buffer] variable) is
// sufficient to initialize a [Buffer].

# OpenAPI Webhooks

There are cases where you want to tell your API **users** that your app could call *their* app (sending a request) with some data, normally to **notify** of some type of **event**.

This means that instead of the normal process of your users sending requests to your API, it's **your API** (or your app) that could **send requests to their system** (to their API, their app).

This is normally called a **webhook**.

## Webhooks steps