If it doesn't, it generates them using the utility function at `fastapi.openapi.utils.get_openapi`.

And that function `get_openapi()` receives as parameters:

* `title`: The OpenAPI title, shown in the docs.
* `version`: The version of your API, e.g. `2.5.0`.
* `openapi_version`: The version of the OpenAPI specification used. By default, the latest: `3.1.0`.
* `summary`: A short summary of the API.

Calling this program outputs:

```
John Doe
```

The function does the following:

* Takes a `first_name` and `last_name`.
* Converts the first letter of each one to upper case with `title()`.
* <abbr title="Puts them together, as one. With the contents of one after the other.">Concatenates</abbr> them with a space in the middle.

{* ../../docs_src/python_types/tutorial001_py39.py hl[2] *}

### Edit it { #edit-it }

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: str | None = Query(
        default=None,
        title="Query string",
        description="Query string for the items to search in the database that have a good match",
        min_length=3,
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {},

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/users/me": {
                "get": {
                    "responses": {
                        "200": {

Vous pouvez aussi rajouter un second paramètre `min_length` :

{* ../../docs_src/query_params_str_validations/tutorial003.py hl[9] *}

## Ajouter des validations par expressions régulières

On peut définir une <abbr title="Une expression régulière, regex ou regexp est une suite de caractères qui définit un pattern de correspondance pour les chaînes de caractères.">expression régulière</abbr> à laquelle le paramètre doit correspondre :

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(
    q: Union[str, None] = Query(
        default=None,
        title="Query string",
        description="Query string for the items to search in the database that have a good match",
        min_length=3,
    ),
):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {
            "title": "FastAPI",
            "version": "0.1.0",
        },
        "paths": {},

def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/users/me": {
                "get": {
                    "responses": {
                        "200": {

        Please open Gradle Native-related issues on [the Gradle Native repository](https://github.com/gradle/gradle-native/issues)

        Provide a brief summary of the issue in the title above
  - type: textarea
    id: expected-behavior
    attributes:
      label: Expected Behavior
      description: Tell us how it should work
    validations:
      required: true
  - type: textarea