tokens = need + hdr

		} else { // part of header can be accommodated
			r.opts.HeaderSize -= b - 1
			need = 1 // to ensure we read at least one byte for every Read
			tokens = b
		}
	} else { // all tokens go towards payload
		need = int(math.Min(float64(b), float64(need)))
		tokens = need
	}
	// reduce tokens requested according to availability

```

////

## Die Abhängigkeiten aktualisieren

Aktualisieren Sie `get_current_user`, um den gleichen Token wie zuvor zu erhalten, dieses Mal jedoch unter Verwendung von JWT-Tokens.

Dekodieren Sie den empfangenen Token, validieren Sie ihn und geben Sie den aktuellen Benutzer zurück.

Wenn der Token ungültig ist, geben Sie sofort einen HTTP-Fehler zurück.

//// tab | Python 3.10+

```Python hl_lines="89-106"

		return nil, &ErrInvalidARN{s}
	}

	tokens := strings.Split(s, ":")
	if len(tokens) != 6 {
		return nil, &ErrInvalidARN{s}
	}

	if tokens[4] == "" || tokens[5] == "" {
		return nil, &ErrInvalidARN{s}
	}

	return &ARN{
		region: tokens[3],
		TargetID: TargetID{
			ID:   tokens[4],
			Name: tokens[5],
		},
	}, nil

func Tokenize(str string) []Token {
	t := NewTokenizer("command line", strings.NewReader(str), nil)
	var tokens []Token
	for {
		tok := t.Next()
		if tok == scanner.EOF {
			break
		}
		tokens = append(tokens, Make(tok, t.Text()))
	}
	return tokens

        List<String> tokens = new ArrayList<String>();
        for (int i = 0; i < NUM; i++) {
            tokens.add(accessTokenHelper.generateAccessToken());
        }
        for (int i = 0; i < NUM; i++) {
            assertFalse(tokens.get(i).isEmpty());
            for (int j = i + 1; j < NUM; j++) {
                assertFalse(tokens.get(i).equals(tokens.get(j)));
            }
        }
    }

	return nil
}

// parseTargetID - parses string to TargetID.
func parseTargetID(s string) (*TargetID, error) {
	tokens := strings.Split(s, ":")
	if len(tokens) != 2 {
		return nil, fmt.Errorf("invalid TargetID format '%v'", s)
	}

	return &TargetID{
		ID:   tokens[0],
		Name: tokens[1],
	}, nil

{!> ../../docs_src/security/tutorial004.py!}
```

////

## Update the dependencies

Update `get_current_user` to receive the same token as before, but this time, using JWT tokens.

Decode the received token, verify it, and return the current user.

If the token is invalid, return an HTTP error right away.

//// tab | Python 3.10+

```Python hl_lines="90-107"

	var tokens []Token
	for _, tok := range macro.tokens {
		if tok.ScanToken != scanner.Ident {
			tokens = append(tokens, tok)
			continue
		}
		substitution := actuals[tok.text]
		if substitution == nil {
			tokens = append(tokens, tok)
			continue
		}
		tokens = append(tokens, substitution...)
	}
	in.Push(NewSlice(in.Base(), in.Line(), tokens))
}

		tlsPublicCert string
	)

	var err error
	for _, arg := range args {
		tokens := strings.SplitN(arg, "=", 2)
		if len(tokens) != 2 {
			logger.Fatal(fmt.Errorf("invalid arguments passed to --ftp=%s", arg), "unable to start FTP server")
		}
		switch tokens[0] {
		case "address":
			host, portStr, err := net.SplitHostPort(tokens[1])
			if err != nil {

///

## 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.