///

## Declare model attributes { #declare-model-attributes }

You can then use `Field` with model attributes:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[11:14] *}

`Field` works the same way as `Query`, `Path` and `Body`, it has all the same parameters, etc.

/// note | Technical Details

func (k *KeycloakProvider) LookupUser(userid string) (User, error) {
	req, err := http.NewRequest(http.MethodGet, k.adminURL, nil)
	if err != nil {
		return User{}, err
	}
	req.URL.Path = path.Join(req.URL.Path, "realms", k.realm, "users", userid)

	k.Lock()
	accessToken := k.accessToken
	k.Unlock()
	if accessToken.AccessToken == "" {
		return User{}, ErrAccessTokenExpired
	}

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[1,23] *}

### Create the callback *path operation* { #create-the-callback-path-operation }

To create the callback *path operation* use the same `APIRouter` you created above.

It should look just like a normal FastAPI *path operation*:

* It should probably have a declaration of the body it should receive, e.g. `body: InvoiceEvent`.

    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": {
                            "description": "Successful Response",

    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": {
                            "description": "Successful Response",

    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": {
                            "description": "Successful Response",

"Mounting" means adding a completely "independent" application in a specific path, that then takes care of handling everything under that path, with the _path operations_ declared in that sub-application.

### Top-level application { #top-level-application }

First, create the main, top-level, **FastAPI** application, and its *path operations*:

{* ../../docs_src/sub_applications/tutorial001_py39.py hl[3, 6:8] *}

object, for example placed at `ALIAS/bucket/path/to/file.txt` append `/xl.meta`, for instance `mc support inspect ALIAS/bucket/path/to/file.txt/xl.meta`. All files can be collected, so this can also be used to retrieve `part.*` files, etc.

Wildcards can be used, for example `mc support inspect ALIAS/bucket/path/**/xl.meta` will collect all `xl.meta` recursively. `mc support inspect ALIAS/bucket/path/to/file.txt/*/part.*` will collect parts for all versions for the object located at `buc...

    assert response.status_code == 200, response.text
    assert response.json() == {
        "openapi": "3.1.0",
        "info": {
            "title": "FastAPI",
            "version": "0.1.0",
        },
        "paths": {
            "/items/": {
                "get": {
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "responses": {

path-key@^3.1.0:
  version "3.1.1"
  resolved "https://registry.yarnpkg.com/path-key/-/path-key-3.1.1.tgz#581f6ade658cbba65a0d3380de7753295054f375"
  integrity sha512-ojmeN0qd+y0jszEtoY48r0Peq5dwMEkIlCOu6Q5f41lfkswXuKtYrhgoTpLnyIcHm24Uhqx+5Tqm2InSwLhE6Q==

path-parse@^1.0.7:
  version "1.0.7"