///

## 编写模板 { #writing-templates }

编写模板 `templates/item.html`，代码如下：

```jinja hl_lines="7"
{!../../docs_src/templates/templates/item.html!}
```

### 模板上下文值 { #template-context-values }

在包含如下语句的html中:

{% raw %}

```jinja
Item ID: {{ id }}
```

{% endraw %}

...这将显示你从 "context" 字典传递的 `id`:

```Python
{"id": id}
```

        });
        return asJson(new ApiBulkResponse().items(Arrays.stream(response.getItems()).map(item -> {
            final Map<String, Object> itemMap = new HashMap<>();
            itemMap.put("result", item.status().name());
            if (item.isFailed()) {
                itemMap.put("message", item.getFailureMessage());
            } else {
                itemMap.put("id", item.getId());
            }
            return itemMap;

    System.out.println(response.getContentAsString());
}
```

### Asynchronous request

```java
import org.codelibs.curl.Curl;

Curl.post("https://api.example.com/items")
    .body("{\"name\":\"item1\"}")
    .header("Content-Type", "application/json")
    .execute(
        response -> System.out.println("Async status: " + response.getHttpStatusCode()),
        error -> error.printStackTrace());
```

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: int = Path(title="The ID of the item to get", ge=0, le=1000),
    q: str,
    size: float = Query(gt=0, lt=10.5),
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if size:
        results.update({"size": size})

## Alias para parámetros { #alias-parameters }

Imagina que quieres que el parámetro sea `item-query`.

Como en:

```
http://127.0.0.1:8000/items/?item-query=foobaritems
```

Pero `item-query` no es un nombre de variable válido en Python.

Lo más cercano sería `item_query`.

Pero aún necesitas que sea exactamente `item-query`...

sequenceDiagram
    participant App
    participant Client

    App->>App: Produce Item 1
    App->>Client: Send Item 1
    App->>App: Produce Item 2
    Client->>Client: Process Item 1
    App->>Client: Send Item 2
    App->>App: Produce Item 3
    Client->>Client: Process Item 2
    App->>Client: Send Item 3
    Client->>Client: Process Item 3
    Note over App: Keeps producing...
    Note over Client: Keeps consuming...
```

        raise


@app.get("/items/{item_id}")
def get_item(item_id: str, username: str = Depends(get_username)):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(
            status_code=404, detail="Item not found, there's only a plumbus here"
        )

from typing import Annotated

from fastapi import FastAPI, Path, Query

app = FastAPI()


@app.get("/items/{item_id}")
async def read_items(
    *,
    item_id: Annotated[int, Path(title="The ID of the item to get", ge=0, le=1000)],
    q: str,
    size: Annotated[float, Query(gt=0, lt=10.5)],
):
    results = {"item_id": item_id}
    if q:
        results.update({"q": q})
    if size:
        results.update({"size": size})

```JSON
{
  "item": "The Foo Wrestlers"
}
```

But if the client requests `http://example.com/items/bar` (a non-existent `item_id` `"bar"`), that client will receive an HTTP status code of 404 (the "not found" error), and a JSON response of:

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

/// tip

When raising an `HTTPException`, you can pass any value that can be converted to JSON as the parameter `detail`, not only `str`.

        raise


@app.get("/items/{item_id}")
def get_item(item_id: str, username: Annotated[str, Depends(get_username)]):
    if item_id == "portal-gun":
        raise InternalError(
            f"The portal gun is too dangerous to be owned by {username}"
        )
    if item_id != "plumbus":
        raise HTTPException(
            status_code=404, detail="Item not found, there's only a plumbus here"
        )