# Query Parameters and String Validations

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

Let's take this application as example:

//// tab | Python 3.10+

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

////

//// tab | Python 3.8+

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

      }
      b.append(',').append(' ');
    }
  }

  /**
   * Saves the state to a stream (that is, serializes it).
   *
   * @serialData The length of the array is emitted (int), followed by all of its elements (each a
   *     {@code double}) in the proper order.
   */
  private void writeObject(ObjectOutputStream s) throws IOException {
    s.defaultWriteObject();

    // Write out array length

        int bufferNdx = (int)(count % BLOCK_LENGTH);
        int padLen = (bufferNdx < 56) ? (56 - bufferNdx) : (120 - bufferNdx);

        // padding is alwas binary 1 followed by binary 0s
        byte[] tail = new byte[padLen + 8];
        tail[0] = (byte)0x80;

        // append length before final transform:
        // save number of bits, casting the long to an array of 8 bytes

			return '0'
		case r == '_', r == '$':
			return r
		default:
			valid = false
			return -1
		}
	}, name)

	if valid {
		// check for simple name or quoted name
		// - letter/underscore followed by one or more letter/digit/underscore
		// - any text between quotes (text cannot contain a quote itself)
		if match, err := regexp.MatchString("^[a_][a0_$]*$", cleaned); err != nil {
			return err
		} else if match {

    protected Map<String, String> propertyMap = new HashMap<>();

    protected Map<String, String> childUrlRuleMap = new LinkedHashMap<>();

    protected String defaultEncoding;

    // If you want to follow a html spec, use 512.
    protected int preloadSizeForCharset = 2048;

    protected Pattern invalidUrlPattern = Pattern.compile("^\\s*javascript:|" //
            + "^\\s*mailto:|" //
            + "^\\s*irc:|" //

You might remember that request bodies are also declared with Pydantic models.

Here **FastAPI** won't get confused because you are using `Depends`.

///

/// check

The way this dependency system is designed allows us to have different dependencies (different "dependables") that all return a `User` model.

We are not restricted to having only one dependency that can return that type of data.

///

## Other models

    steps:
    - name: Checkout code
      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
    - name: Update the RBE Configs
      run: |
        function map() {
          # The "digest" that allows us to pull an image is not the digest as
          # returned by the API, but a sha256sum of the entire chunk of image
          # metadata. gcr.io helpfully includes it in the header of the response

documentation. ## Install from Source Use the following commands to compile and run a standalone MinIO server from source. Source installation is only intended for developers and advanced users. If you do not have a working Golang environment, please follow [How to install Golang](https://golang.org/doc/install). Minimum version required is [go1.21](https://golang.org/dl/#stable) ```sh go install github.com/minio/minio@latest ``` The MinIO deployment starts using default root credentials `minioadmin:minioadmin`....

    body: Union[str, None] = None,
) -> Dict[str, Any]:
    headers = {"Authorization": f"token {settings.input_token.get_secret_value()}"}
    # some fields are only used by one query, but GraphQL allows unused variables, so
    # keep them here for simplicity
    variables = {
        "after": after,
        "category_id": category_id,
        "discussion_number": discussion_number,

option go_package = "k8s.io/api/admission/v1";

// AdmissionRequest describes the admission.Attributes for the admission request.
message AdmissionRequest {
  // UID is an identifier for the individual request/response. It allows us to distinguish instances of requests which are
  // otherwise identical (parallel requests, requests when earlier requests did not modify etc)