KEEP_OPEN,
  DISCONNECT_AT_END,
  UPGRADE_TO_SSL_AT_END,
  DISCONNECT_AT_START,
  DISCONNECT_AFTER_REQUEST,
  DISCONNECT_DURING_REQUEST_BODY,
  DISCONNECT_DURING_RESPONSE_BODY,
  DO_NOT_READ_REQUEST_BODY,
  FAIL_HANDSHAKE,
  SHUTDOWN_INPUT_AT_END,
  SHUTDOWN_OUTPUT_AT_END,
  STALL_SOCKET_AT_START,
  NO_RESPONSE,
  RESET_STREAM_AT_START,
  EXPECT_CONTINUE,
  CONTINUE_ALWAYS,

* Create a file `main.py` with:

```Python
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>Or use <code>async def</code>...</summary>

Takes some data and returns an `application/json` encoded response.

This is the default response used in **FastAPI**, as you read above.

### `ORJSONResponse`

A fast alternative JSON response using <a href="https://github.com/ijl/orjson" class="external-link" target="_blank">`orjson`</a>, as you read above.

### `UJSONResponse`

  companion object {
    fun load(): List<WebPlatformToAsciiData> {
      val path = okHttpRoot / "okhttp/src/test/resources/web-platform-test-toascii.json"
      return SYSTEM_FILE_SYSTEM.read(path) {
        Json.decodeFromString<List<WebPlatformToAsciiData>>(readUtf8())
      }
    }
  }

```mermaid
graph TB

query_extractor(["query_extractor"])
query_or_cookie_extractor(["query_or_cookie_extractor"])

read_query["/items/"]

query_extractor --> query_or_cookie_extractor --> read_query
```

## ⚙️ 🎏 🔗 💗 🕰

🚥 1️⃣ 👆 🔗 📣 💗 🕰 🎏 *➡ 🛠️*, 🖼, 💗 🔗 ✔️ ⚠ 🎧-🔗, **FastAPI** 🔜 💭 🤙 👈 🎧-🔗 🕴 🕐 📍 📨.

#### Shared reader thread

   * a default value.
   *
   * If this does read a value, it starts with the tag and length, and reads an entire value,
   * including any potential composed values.
   *
   * If there's nothing to read and no default value, this will throw an exception.
   */
  fun fromDer(reader: DerReader): T

  fun fromDer(byteString: ByteString): T {

  private val countingSource: CountingSource = CountingSource(source)
  private val source: BufferedSource = countingSource.buffer()

  /** Total bytes read thus far. */
  private val byteCount: Long
    get() = countingSource.bytesRead - source.buffer.size

  /** How many bytes to read before [peekHeader] should return false, or -1L for no limit. */
  private var limit = -1L

- Liveness probe available at `/minio/health/live`
- Cluster probe available at `/minio/health/cluster`

Read more on how to use these endpoints in [MinIO healthcheck guide](https://github.com/minio/minio/blob/master/docs/metrics/healthcheck/README.md).

## Prometheus Probe

**FastAPI** will make sure to read that data from the right place instead of JSON.

!!! note "Technical Details"
    Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

    But when the form includes files, it is encoded as `multipart/form-data`. You'll read about handling files in the next chapter.