So we put them in their own `dependencies` module (`app/dependencies.py`).

We will now use a simple dependency to read a custom `X-Token` header:

//// tab | Python 3.9+

```Python hl_lines="3  6-8" title="app/dependencies.py"
{!> ../../docs_src/bigger_applications/app_an_py39/dependencies.py!}
```

////

//// tab | Python 3.8+

You can add code to be run with the `request`,  before any *path operation* receives it.

And also after the `response` is generated, before returning it.

For example, you could add a custom header `X-Process-Time` containing the time in seconds that it took to process the request and generate a response:

{* ../../docs_src/middleware/tutorial001.py hl[10,12:13] *}

/// tip

            request.setOffset(1024L);
            request.setRemainingBytes(500);
            request.setWriteFlags(0x01);

            byte[] buffer = new byte[1024];
            int headerStart = 64; // Simulated header start

            // Execute
            int bytesWritten = request.writeBytesWireFormat(buffer, headerStart);

            // Verify structure

      "coverage" : {
        "per_commit" : [ "linux" ]
      }
    } ]
  }, {
    "testId" : "org.gradle.performance.regression.nativeplatform.NativeBuildPerformanceTest.assemble with header file change",
    "groups" : [ {
      "testProject" : "bigCppApp",
      "coverage" : {
        "per_day" : [ "linux" ]
      }
    }, {
      "testProject" : "bigCppMulti",
      "coverage" : {

            basicAuthList.add(webAuth.getAuthentication());
        }
        paramMap.put(HcHttpClient.AUTHENTICATIONS_PROPERTY, basicAuthList.toArray(new Authentication[basicAuthList.size()]));

        // request header
        final List<RequestHeader> requestHeaderList = requestHeaderService.getRequestHeaderList(getId());
        final List<org.codelibs.fess.crawler.client.http.RequestHeader> rhList = new ArrayList<>();

Y todos usarán la misma conexión WebSocket.

## Usando `Depends` y otros

En endpoints de WebSocket puedes importar desde `fastapi` y usar:

* `Depends`
* `Security`
* `Cookie`
* `Header`
* `Path`
* `Query`

Funcionan de la misma manera que para otros endpoints de FastAPI/*path operations*:

{* ../../docs_src/websockets/tutorial002_an_py310.py hl[68:69,82] *}

/// info | Información

## Verwendung von `Depends` und anderen

In WebSocket-Endpunkten können Sie Folgendes aus `fastapi` importieren und verwenden:

* `Depends`
* `Security`
* `Cookie`
* `Header`
* `Path`
* `Query`

Diese funktionieren auf die gleiche Weise wie für andere FastAPI-Endpunkte/*Pfadoperationen*:

{* ../../docs_src/websockets/tutorial002_an_py310.py hl[68:69,82] *}

/// info

# ========================================================================================
# Framework Default
# =================
# ----------------------------------------------------------
# Lasta Taglib
# ------------
errors.header = <ul class="has-error">
errors.footer = </ul>
errors.prefix = <li><i class="fa fa-exclamation-circle"></i>
errors.suffix = </li>
# ----------------------------------------------------------
# Javax Validator

     * Datetime format. This format allows you to omit the time portion, if
     * desired, and use YYYY-MM-DD.
     *
     * Note that this tag is separate from the If-Modified-Since (304) header
     * the server can return, and search engines may use the information from
     * both sources differently.
     */
    private String lastmod;

    /**

    }

    @Override
    public void encode(final NdrBuffer buf) throws NdrException {
        final int start = buf.getIndex();
        int alloc_hint_index = 0;

        buf.advance(16); /* momentarily skip header */
        if (ptype == 0) { /* Request */
            alloc_hint_index = buf.getIndex();
            buf.enc_ndr_long(0); /* momentarily skip alloc hint */
            buf.enc_ndr_short(0); /* context id */