{* ../../docs_src/query_params_str_validations/tutorial014_an_py310.py hl[10] *}

## Custom Validation { #custom-validation }

There could be cases where you need to do some **custom validation** that can't be done with the parameters shown above.

In those cases, you can use a **custom validator function** that is applied after the normal validation (e.g. after validating that the value is a `str`).

		}
		if creds.AzSP.ClientSecret != "" {
			cfg.Azure.SPAuth.ClientSecret = creds.AzSP.ClientSecret
		}
	case madmin.GCS:
		if creds.CredsJSON == nil {
			return errTierMissingCredentials
		}
		cfg.GCS.Creds = base64.URLEncoding.EncodeToString(creds.CredsJSON)
	case madmin.MinIO:
		if creds.AccessKey == "" || creds.SecretKey == "" {
			return errTierMissingCredentials
		}
		cfg.MinIO.AccessKey = creds.AccessKey

     * Covers all defined error classes and codes, including default cases.
     */
    private static Stream<Arguments> provideErrorClassAndCodeForGetErrorString() {
        return Stream.of(
                // SUCCESS
                Arguments.of(NbtException.SUCCESS, 0, "SUCCESS"),

                // ERR_NAM_SRVC
                // Note: FMT_ERR case has a bug in NbtException.getErrorString() - missing break statement causes fallthrough

	case errUploadIDNotFound.Error():
		return errUploadIDNotFound
	case errFaultyDisk.Error():
		return errFaultyDisk
	case errFaultyRemoteDisk.Error():
		return errFaultyRemoteDisk
	case errFileCorrupt.Error():
		return errFileCorrupt
	case errUnexpected.Error():
		return errUnexpected
	case errDiskFull.Error():
		return errDiskFull
	case errVolumeNotFound.Error():
		return errVolumeNotFound

# Advanced Dependencies { #advanced-dependencies }

## Parameterized dependencies { #parameterized-dependencies }

All the dependencies we have seen are a fixed function or class.

But there could be cases where you want to be able to set parameters on the dependency, without having to declare many different functions or classes.

Let's imagine that we want to have a dependency that checks if the query parameter `q` contains some fixed content.

 * This class currently pins a certificate's Subject Public Key Info as described on
 * [Adam Langley's Weblog][langley]. Pins are either base64 SHA-256 hashes as in
 * [HTTP Public Key Pinning (HPKP)][rfc_7469] or SHA-1 base64 hashes as in Chromium's
 * [static certificates][static_certificates].
 *
 * ## Setting up Certificate Pinning
 *

import okio.Buffer

/**
 * Tests Hpack implementation using https://github.com/http2jp/hpack-test-case/
 */
open class HpackDecodeTestBase {
  private val bytesIn = Buffer()
  private val hpackReader = Hpack.Reader(bytesIn, 4096)

  protected fun testDecoder(story: Story) {
    for (testCase in story.cases) {
      val encoded = testCase.wire ?: continue
      bytesIn.write(encoded)
      hpackReader.readHeaders()

   * will return {@code Double.MAX_VALUE}, not {@code Double.POSITIVE_INFINITY}.
   *
   * <p>For the case of {@link RoundingMode#HALF_EVEN}, this implementation uses the IEEE 754
   * default rounding mode: if the two nearest representable values are equally near, the one with
   * the least significant bit zero is chosen. (In such cases, both of the nearest representable

- `X-Amz-Server-Side-Encryption-Customer-Key`: Base64 encoded new key.
- `X-Amz-Copy-Source-Server-Side-Encryption-Customer-Key`: Base64 encoded current key.

Such a special COPY request is also known as S3 SSE-C key rotation.

### Server-Side Encryption with a KMS

				// In this case we will just collapse this into "eq" for all use cases.
				parsedPolicy.Conditions.Policies = append(parsedPolicy.Conditions.Policies, struct {
					Operator string
					Key      string
					Value    string
				}{
					policyCondEqual, "$" + strings.ToLower(k), toString(v),
				})
			}
		case []any: // Handle array types.