}
```

しかし、クライアントが`http://example.com/items/bar`（存在しない`item_id` `"bar"`）をリクエストした場合、HTTPステータスコード404（"not found"エラー）と以下のJSONレスポンスが返されます:

```JSON
{
  "detail": "Item not found"
}
```

/// tip | "豆知識"

`HTTPException`を発生させる際には、`str`だけでなく、JSONに変換できる任意の値を`detail`パラメータとして渡すことができます。

`dist`や`list`などを渡すことができます。

これらは **FastAPI** によって自動的に処理され、JSONに変換されます。

///

## カスタムヘッダーの追加

m
n
s
t
y
été
étée
étées
étés
étant
suis
es
est
sommes
êtes
sont
serai
seras
sera
serons
serez
seront
serais
serait
serions
seriez
seraient
étais
était
étions
étiez
étaient
fus
fut
fûmes
fûtes
furent
sois
soit
soyons
soyez
soient
fusse
fusses
fût
fussions
fussiez
fussent
ayant
eu
eue

* `username`: `Rick`
* `password`: `Portal Gun`
* `extra`: `Mr. Poopybutthole`

Ele receberá um retorno de erro informando-o que o campo `extra` não é permitido:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["body", "extra"],
            "msg": "Extra inputs are not permitted",
            "input": "Mr. Poopybutthole"
        }
    ]
}

        // TODO better way than static? this might hide messages in a reactor
        if (!ignoredArtifacts.contains(artifact)) {
            logger.warn("\n\tArtifact " + artifact + " retains local artifactScope '" + artifact.getScope()
                    + "' overriding broader artifactScope '" + ignoredScope + "'\n"

        Element section = document.createElement("section");
        parent.appendChild(section);
        section.setAttribute("id", methodDoc.getId());
        section.setAttribute("role", "detail");

        Element title = document.createElement("title");
        section.appendChild(title);
        title.appendChild(linkRenderer.link(methodDoc.getMetaData().getReturnType(), listener));

            },
            "HTTPValidationError": {
                "title": "HTTPValidationError",
                "type": "object",
                "properties": {
                    "detail": {
                        "title": "Detail",
                        "type": "array",
                        "items": {
                            "$ref": "#/components/schemas/ValidationError"
                        }

            },
            "HTTPValidationError": {
                "title": "HTTPValidationError",
                "type": "object",
                "properties": {
                    "detail": {
                        "title": "Detail",
                        "type": "array",
                        "items": {
                            "$ref": "#/components/schemas/ValidationError"
                        }

For example, if the client tries to send a `tool` header with a value of `plumbus`, they will receive an **error** response telling them that the header parameter `tool` is not allowed:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["header", "tool"],
            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```

                "HTTPValidationError": {
                    "title": "HTTPValidationError",
                    "type": "object",
                    "properties": {
                        "detail": {
                            "title": "Detail",
                            "type": "array",
                            "items": {"$ref": "#/components/schemas/ValidationError"},
                        }
                    },

Por exemplo, se o cliente tentar enviar um cabeçalho `tool` com o valor `plumbus`, ele irá receber uma resposta de **erro** informando que o parâmetro do cabeçalho `tool` não é permitido:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",
            "loc": ["header", "tool"],
            "msg": "Extra inputs are not permitted",
            "input": "plumbus",
        }
    ]
}
```