"content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

        if (isValid) {
            log.debug("Preauth integrity validation passed for session {}", sessionId);
        } else {
            log.error("Preauth integrity validation FAILED for session {}", sessionId);
            context.invalidate();
            if (enforceIntegrity) {
                throw new CIFSException("Preauth integrity validation failed - possible downgrade attack detected");
            }
        }

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

But by default, it all **"just works"**.

### Validation { #validation }

* Validation for most (or all?) Python **data types**, including:
    * JSON objects (`dict`).
    * JSON array (`list`) defining item types.
    * String (`str`) fields, defining min and max lengths.
    * Numbers (`int`, `float`) with min and max values, etc.

* Validation for more exotic types, like:
    * URL.
    * Email.

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {

@Named
public interface ModelTransformer extends SpiService {

    /**
     * Apply a transformation on the file model.
     *
     * This method will be called on each file model being loaded,
     * just before validation.
     *
     * @param model the input model
     * @return the transformed model, or the input model if no transformation is needed
     * @throws ModelTransformerException
     */
    @Nonnull

-type")||"image";if(!f)throw new Error("Google reCaptcha site key is required.");var j=grecaptcha.render(e,{sitekey:f,theme:g,size:h,type:i,callback:function(a){b.find('[data-validation~="recaptcha"]').trigger("validation",a&&""!==a)},"expired-callback":function(){b.find('[data-validation~="recaptcha"]').trigger("validation",!1)}});d.valAttr("recaptcha-widget-id",j).hide().on("beforeValidation",function(a){a.stopImmediatePropagation()}).parent().append(e)})})},a(b).on("validatorsLoaded formValid...

So, with that type declaration, **FastAPI** gives you automatic request <dfn title="converting the string that comes from an HTTP request into Python data">"parsing"</dfn>.

///

## Data validation { #data-validation }

But if you go to the browser at [http://127.0.0.1:8000/items/foo](http://127.0.0.1:8000/items/foo), you will see a nice HTTP error of:

```JSON
{
  "detail": [
    {
      "type": "int_parsing",

import org.slf4j.LoggerFactory;

import jcifs.smb.SmbException;

/**
 * Path validation utility to prevent directory traversal and other path-based attacks.
 *
 * Features:
 * - Directory traversal prevention
 * - Path normalization
 * - Blacklist/whitelist support
 * - UNC path validation
 * - Special character filtering
 * - Length validation
 */
public class PathValidator {

                                "content": {"application/json": {"schema": {}}},
                            },
                            "422": {
                                "description": "Validation Error",
                                "content": {
                                    "application/json": {
                                        "schema": {