There are 2 main differences from a normal *path operation*:

* It doesn't need to have any actual code, because your app will never call this code. It's only used to document the *external API*. So, the function could just have `pass`.

### Include the custom docs { #include-the-custom-docs }

Now you can create the *path operations* for the custom docs.

You can reuse FastAPI's internal functions to create the HTML pages for the docs, and pass them the needed arguments:

* `openapi_url`: the URL where the HTML page for the docs can get the OpenAPI schema for your API. You can use here the attribute `app.openapi_url`.
* `title`: the title of your API.

This way you write shared code once and **FastAPI** takes care of calling it for your *path operations*.

/// check

Notice that you don't have to create a special class and pass it somewhere to **FastAPI** to "register" it or anything similar.

You just pass it to `Depends` and **FastAPI** knows how to do the rest.

///

## Share `Annotated` dependencies { #share-annotated-dependencies }

  }

  // TODO(cpovirk): Use standard Javadoc form for SimpleForwarding* class and constructor
  /**
   * A simplified version of {@link ForwardingListenableFuture} where subclasses can pass in an
   * already constructed {@link ListenableFuture} as the delegate.
   *
   * @since 9.0
   */
  public abstract static class SimpleForwardingListenableFuture<V extends @Nullable Object>

            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header X-NginX-Proxy true;

            # This is necessary to pass the correct IP to be hashed
            real_ip_header X-Real-IP;

            proxy_connect_timeout 300;
            
            # To support websocket
            proxy_http_version 1.1;

		uploadID        string
		PartID          int
		inputReaderData string
		inputMd5        string
		inputSHA256     string
		inputDataSize   int64
		// flag indicating whether the test should pass.
		shouldPass bool
		// expected error output.
		expectedMd5   string
		expectedError error
	}{
		// Test case  1-4.
		// Cases with invalid bucket name.

    // Trigger any exception that the comparator would throw for the endpoints.
    /*
     * uncheckedCastNullableTToT is safe as long as the callers are careful to pass a "real" T
     * whenever they pass `true` for the matching `has*Bound` parameter.
     */
    if (hasLowerBound) {
      int unused =
          comparator.compare(

Em um cenário avançado onde você precise que a dependência seja calculada em cada passo (possivelmente várias vezes) de uma requisição em vez de utilizar o valor em "cache", você pode definir o parâmetro `use_cache=False` em `Depends`:

//// tab | Python 3.9+

```Python hl_lines="1"

But if you are certain that the content that you are returning is **serializable with JSON**, you can pass it directly to the response class and avoid the extra overhead that FastAPI would have by passing your return content through the `jsonable_encoder` before passing it to the response class.

from typing import Annotated, Any

import pytest
from fastapi import Depends, FastAPI, HTTPException
from fastapi.testclient import TestClient


class CustomError(Exception):
    pass


def catching_dep() -> Any:
    try:
        yield "s"
    except CustomError as err:
        raise HTTPException(status_code=418, detail="Session error") from err


def broken_dep() -> Any:
    yield "s"