app = FastAPI()


@app.get(
    "/items/{item_id}",
    response_model=Item,
    responses={
        200: {
            "content": {"image/png": {}},
            "description": "Return the JSON item or an image.",
        }
    },
)
async def read_item(item_id: str, img: Union[bool, None] = None):
    if img:
        return FileResponse("image.png", media_type="image/png")
    else:

```txt
Hello, World from Flask!
```

And if you go to <a href="http://localhost:8000/v2" class="external-link" target="_blank">http://localhost:8000/v2</a> you will see the response from FastAPI:

```JSON
{
    "message": "Hello World"
}

        ("inf", 422),
        ("-inf", 422),
        ("nan", 422),
        ("0", 200),
        ("342", 200),
    ],
)
def test_allow_inf_nan_body(value: str, code: int):
    response = client.post("/", json=value)

        return "https://golang.org/change/" + match[1];
    }

    if (pkgRE.test(t)) {
        // TODO: make this smarter, using a list of packages + substring matches.
        // Get the list from godoc itself in JSON format?
        return "https://golang.org/pkg/" + t;
    }

    return null;

Als Teil der Erstellung des Anwendungsobjekts wird eine *Pfadoperation* für `/openapi.json` (oder welcher Wert für den Parameter `openapi_url` gesetzt wurde) registriert.

Diese gibt lediglich eine JSON-Response zurück, mit dem Ergebnis der Methode `.openapi()` der Anwendung.

注意，模型属性的类型、默认值及 `Field` 的代码结构与*路径操作函数*的参数相同，只不过是用 `Field` 替换了`Path`、`Query`、`Body`。

///

## 添加更多信息

`Field`、`Query`、`Body` 等对象里可以声明更多信息，并且 JSON Schema 中也会集成这些信息。

*声明示例*一章中将详细介绍添加更多信息的知识。

## 小结

Pydantic 的 `Field` 可以为模型属性声明更多校验和元数据。

Il ne peut pas très bien gérer les modèles imbriqués. Ainsi, si le corps JSON de la requête est un objet JSON comportant des champs internes qui sont à leur tour des objets JSON imbriqués, il ne peut pas être correctement documenté et validé.

/// check | "A inspiré **FastAPI** à"

// See the License for the specific language governing permissions and
// limitations under the License.

package nodeagent

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net"
	"net/http"
	"net/netip"
	"time"

	corev1 "k8s.io/api/core/v1"

	pconstants "istio.io/istio/cni/pkg/constants"
	"istio.io/istio/cni/pkg/pluginlistener"

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package configdump

import (
	"encoding/json"
	"fmt"
	"sort"
	"strconv"
	"strings"
	"text/tabwriter"

	core "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
	route "github.com/envoyproxy/go-control-plane/envoy/config/route/v3"

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package logger

import (
	"encoding/json"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"time"

	"github.com/klauspost/compress/gzip"
	xioutil "github.com/minio/minio/internal/ioutil"
	"github.com/minio/pkg/v3/logger/message/log"
)