It is just a standard function that can receive parameters.

It can be an `async def` or normal `def` function, **FastAPI** will know how to handle it correctly.

In this case, the task function will write to a file (simulating sending an email).

And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Add the background task

 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.maven;

import org.apache.maven.plugin.MojoFailureException;

/**
 * Exception which occurs when a normal (i.e. non-aggregator) mojo fails to
 * execute. In this case, the mojo failed while executing against a particular
 * project instance, so we can wrap the {@link MojoFailureException} with context

```Python hl_lines="2  12  15-18"
{!../../docs_src/app_testing/tutorial001.py!}
```

/// tip

Notice that the testing functions are normal `def`, not `async def`.

And the calls to the client are also normal calls, not using `await`.

This allows you to use `pytest` directly without complications.

///

/// note | "Technical Details"

class MessageDeflater(
  private val noContextTakeover: Boolean,
) : Closeable {
  private val deflatedBytes = Buffer()

  private val deflater =
    Deflater(
      Deflater.DEFAULT_COMPRESSION,
      // nowrap (omits zlib header):
      true,
    )

  private val deflaterSink = DeflaterSink(deflatedBytes, deflater)

  /** Deflates [buffer] in place as described in RFC 7692 section 7.2.1. */
  @Throws(IOException::class)

\":\"linear\"},\"labels\":{\"show\":true,\"truncate\":100},\"title\":{}}],\"valueAxes\":[{\"id\":\"ValueAxis-1\",\"name\":\"LeftAxis-1\",\"type\":\"value\",\"position\":\"left\",\"show\":true,\"style\":{},\"scale\":{\"type\":\"linear\",\"mode\":\"normal\"},\"labels\":{\"show\":true,\"rotate\":0,\"filter\":false,\"truncate\":100},\"title\":{\"text\":\"Query Count\"}}],\"seriesParams\":[{\"show\":\"true\",\"type\":\"histogram\",\"mode\":\"stacked\",\"data\":{\"label\":\"Query Count\",\"id\":\"1\"}...

value="<font face="Roboto" data-font-src="https://fonts.googleapis.com/css?family=Roboto" style="font-size: 24px ; font-weight: normal">Another app</font><font face="Roboto" data-font-src="https://fonts.googleapis.com/css?family=Roboto" style="font-size: 24px ; font-weight: normal">: another.example.com</font>" style="rounded=0;whiteSpace=wrap;html=1;fontStyle=1;strokeWidth=4;fillColor=#dae8fc;strokeColor=#6c8ebf;" parent="1"...

class MessageInflater(
  private val noContextTakeover: Boolean,
) : Closeable {
  private val deflatedBytes = Buffer()

  private val inflater =
    Inflater(
      // nowrap (omits zlib header):
      true,
    )

  private val inflaterSource = InflaterSource(deflatedBytes, inflater)

  /** Inflates [buffer] in place as described in RFC 7692 section 7.2.2. */
  @Throws(IOException::class)

Si tienes bastante conocimiento técnico (coroutines, threads, bloqueos, etc.) y tienes curiosidad acerca de cómo FastAPI gestiona `async def` vs `def` normal, continúa.

///

### Path operation functions

}

.daterangepicker .calendar-table th, .daterangepicker .calendar-table td {
  white-space: nowrap;
  text-align: center;
  vertical-align: middle;
  min-width: 32px;
  width: 32px;
  height: 24px;
  line-height: 24px;
  font-size: 12px;
  border-radius: 4px;
  border: 1px solid transparent;
  white-space: nowrap;
  cursor: pointer;
}

.daterangepicker .calendar-table {
  border: 1px solid #fff;

# GraphQL

As **FastAPI** is based on the **ASGI** standard, it's very easy to integrate any **GraphQL** library also compatible with ASGI.

You can combine normal FastAPI *path operations* with GraphQL on the same application.

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.