# Query Parameters and String Validations

**FastAPI** allows you to declare additional information and validation for your parameters.

Let's take this application as example:

=== "Python 3.10+"

    ```Python hl_lines="7"
    {!> ../../../docs_src/query_params_str_validations/tutorial001_py310.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="9"
    {!> ../../../docs_src/query_params_str_validations/tutorial001.py!}
    ```

	Seal(dst, nonce, plaintext, additionalData []byte) []byte

	// Open decrypts and authenticates ciphertext, authenticates the
	// additional data and, if successful, appends the resulting plaintext
	// to dst, returning the updated slice. The nonce must be NonceSize()
	// bytes long and both it and the additional data must match the
	// value passed to Seal.
	//
	// To reuse ciphertext's storage for the decrypted output, use ciphertext[:0]

Note that a daemon is compatible if it has additional JVM arguments beyond those requested (except for those treated especially, such as heap settings, assertions, debug, etc.).

system properties::
A daemon is considered compatible if it has set all the system properties requested with the same values. +
Note that a daemon is compatible if it has additional system properties beyond those requested.

environment variables::

	n := len(p)
	if n < 1 {
		return RuneError, 0
	}
	p0 := p[0]
	x := first[p0]
	if x >= as {
		// The following code simulates an additional check for x == xx and
		// handling the ASCII and invalid cases accordingly. This mask-and-or
		// approach prevents an additional branch.
		mask := rune(x) << 31 >> 31 // Create 0x0000 or 0xFFFF.
		return rune(p[0])&^mask | RuneError&mask, 1
	}
	sz := int(x & 7)

 * definition of reduced distributions (e.g. a Core distribution without Native plugins)
 * to be used for testing.
 *
 * Other projects may depend on distributions using on their test runtime classpath
 * or as additional test data (see DistributionTest).
 */
plugins {
    id("gradlebuild.module-identity")
    id("gradlebuild.instrumentation-metadata")
}

    @Override
    public ClassPath transform(ClassPath classPath, ClassTransform additional) {
        if (classPath.isEmpty()) {
            return classPath;
        }
        return transformFiles(
            classPath,
            instrumentingClasspathFileTransformerFor(
                classpathElementTransformFactoryForLegacy,
                additional
            )
        );
    }

    @Override

        then:
        nonJarLibEntries.isEmpty()
    }

    def "no additional jars are added to the distribution"() {
        when:
        def jarLibEntries = libZipEntries.findAll { it.name.endsWith(".jar") }

        then:
        //ME: This is not a foolproof way of checking that additional jars have not been accidentally added to the distribution

	type tct struct {
		name    string
		schema  Structural
		options ValidationOptions
		error   string
	}

	testCases := []tct{
		{
			name: "allowed properties valuevalidation, additional properties structure",
			schema: Structural{
				AdditionalProperties: &StructuralOrBool{
					Structural: &Structural{
						Generic: Generic{
							Type: "object",
						},

        pingRequestCount == 3 || pingRequestCount == 4
        timer.elapsedMillis > 3000 // See: DefaultFileLockContentionHandler.PING_DELAY
    }

    def "the lock holder starts the release request only once and discards additional requests in the meantime"() {
        given:
        def requestReceived = false
        def terminate = false
        setupLockOwner {
            requestReceived = true

	checkHeader       = "x-ext-authz"
	allowedValue      = "allow"
	resultHeader      = "x-ext-authz-check-result"
	receivedHeader    = "x-ext-authz-check-received"
	overrideHeader    = "x-ext-authz-additional-header-override"
	overrideGRPCValue = "grpc-additional-header-override-value"
	resultAllowed     = "allowed"
	resultDenied      = "denied"
)

var (
	serviceAccount = flag.String("allow_service_account", "a",