$font-family-base;\n  // We deliberately do NOT reset font-size or word-wrap.\n  font-style: normal;\n  font-weight: $font-weight-normal;\n  line-height: $line-height-base;\n  text-align: left; // Fallback for where `start` is not supported\n  text-align: start;\n  text-decoration: none;\n  text-shadow: none;\n  text-transform: none;\n  letter-spacing: normal;\n  word-break: normal;\n  white-space: normal;\n  word-spacing: normal;\n  line-break: auto;\n}\n",".popover {\n  position: absolute;\n  top: 0;\n  left:...

# Extending OpenAPI

There are some cases where you might need to modify the generated OpenAPI schema.

In this section you will see how.

## The normal process

The normal (default) process, is as follows.

A `FastAPI` application (instance) has an `.openapi()` method that is expected to return the OpenAPI schema.

# Extendendo o OpenAPI

Existem alguns casos em que pode ser necessário modificar o esquema OpenAPI gerado.

Nesta seção, você verá como fazer isso.

## O processo normal

O processo normal (padrão) é o seguinte:

Uma aplicação (instância) do `FastAPI` possui um método `.openapi()` que deve retornar o esquema OpenAPI.

## O aplicativo **FastAPI** normal

Vamos primeiro ver como o aplicativo da API normal se pareceria antes de adicionar o callback.

Ele terá uma *operação de rota* que receberá um corpo `Invoice`, e um parâmetro de consulta `callback_url` que conterá a URL para o callback.

Essa parte é bastante normal, a maior parte do código provavelmente já é familiar para você:

/**
 * Maven encrypt CLI "new-gen".
 */
public class MavenEncCling extends ClingSupport<EncryptOptions, EncryptInvokerRequest> {
    /**
     * "Normal" Java entry point. Note: Maven uses ClassWorld Launcher and this entry point is NOT used under normal
     * circumstances.
     */
    public static void main(String[] args) throws IOException {
        int exitCode = new MavenEncCling().run(args);

# 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

/**
 * Maven CLI "new-gen".
 */
public class MavenCling extends ClingSupport<MavenOptions, MavenInvokerRequest<MavenOptions>> {
    /**
     * "Normal" Java entry point. Note: Maven uses ClassWorld Launcher and this entry point is NOT used under normal
     * circumstances.
     */
    public static void main(String[] args) throws IOException {
        int exitCode = new MavenCling().run(args);

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <executions>
          <execution>
            <id>normal</id>

            <goals>
              <goal>compile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>

## HTTPX

Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath.

    protected final ClassWorld classWorld;
    protected final boolean classWorldManaged;

    /**
     * Ctor that creates "managed" ClassWorld. This constructor is not used in "normal" circumstances.
     */
    public ClingSupport() {
        this(new ClassWorld(CORE_CLASS_REALM_ID, Thread.currentThread().getContextClassLoader()), true);
    }

    /**