For example, to declare a header of `X-Token` that can appear more than once, you can write:

{* ../../docs_src/header_params/tutorial003_an_py310.py hl[9] *}

If you communicate with that *path operation* sending two HTTP headers like:

```
X-Token: foo
X-Token: bar
```

The response would be like:

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

	// This is traditionally the client identifier issued to the application that
	// requested the client grants.
	Audience string `xml:",omitempty"`

	// The temporary security credentials, which include an access key ID, a secret
	// access key, and a security (or session) token.
	//
	// Note: The size of the security token that STS APIs return is not fixed. We

///

## Return the token { #return-the-token }

The response of the `token` endpoint must be a JSON object.

It should have a `token_type`. In our case, as we are using "Bearer" tokens, the token type should be "`bearer`".

And it should have an `access_token`, with a string containing our access token.

        @Override
        public byte[] initSecContext(byte[] token, int off, int len) throws CIFSException {
            if (token == null) {
                if (len == 0) {
                    return new byte[0];
                }
                throw new CIFSException("token is null but len > 0");
            }
            if (off < 0 || len < 0 || off > token.length || off + len > token.length) {

    private static SpnegoToken getToken(final byte[] token, final int off, final int len) throws SpnegoException {
        byte[] b = new byte[len];
        if (off == 0 && token.length == len) {
            b = token;
        } else {
            System.arraycopy(token, off, b, 0, len);
        }
        return getToken(b);
    }

    private static SpnegoToken getToken(final byte[] token) throws SpnegoException {

<img src="/img/tutorial/security/image11.png">

## 內含 scopes 的 JWT token { #jwt-token-with-scopes }

現在，修改 token 的路徑操作以回傳所請求的 scopes。

我們仍然使用相同的 `OAuth2PasswordRequestForm`。它包含屬性 `scopes`，其為 `list` 的 `str`，列出請求中收到的每個 scope。

並且我們將這些 scopes 作為 JWT token 的一部分回傳。

/// danger

為了簡化，這裡我們只是直接把接收到的 scopes 加進 token。

但在你的應用中，為了安全性，你應確保只加入該使用者實際可擁有或你預先定義的 scopes。

///

from fastapi import FastAPI, File, Form, UploadFile

app = FastAPI()


@app.post("/files/")
async def create_file(
    file: bytes = File(), fileb: UploadFile = File(), token: str = Form()
):
    return {
        "file_size": len(file),
        "token": token,
        "fileb_content_type": fileb.content_type,

from fastapi import Depends, FastAPI, Header, HTTPException


async def verify_token(x_token: str = Header()):
    if x_token != "fake-super-secret-token":
        raise HTTPException(status_code=400, detail="X-Token header invalid")


async def verify_key(x_key: str = Header()):
    if x_key != "fake-super-secret-key":
        raise HTTPException(status_code=400, detail="X-Key header invalid")
    return x_key

## API Request Parameters

### Token

The OAuth 2.0 access token that is provided by the identity provider. Application must get this token by authenticating the application using client credential grants before the application makes an AssumeRoleWithClientGrants call.

        SpnegoContext ctx = newContext();

        // The initial token path should ask the mechanism for a zero-length optimistic token
        when(this.mechContext.getFlags()).thenReturn(0x1234);
        when(this.mechContext.initSecContext(any(byte[].class), eq(0), eq(0))).thenReturn(new byte[] { 0x01, 0x02 });

        // Act: len==0 triggers initial token construction
        byte[] out = ctx.initSecContext(null, 0, 0);