## 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`).

         */
        BASE,

        /**
         * Validation for Maven 2.0 POM format.
         */
        V20,

        /**
         * Validation for Maven 3.0 POM format.
         */
        V30,

        /**
         * Validation for Maven 3.1 POM format.
         */
        V31,

        /**
         * Validation for Maven 4.0 POM format.
         */
        V40,

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import org.codelibs.fess.validation.UriTypeValidator.ProtocolType;

import jakarta.validation.Constraint;
import jakarta.validation.Payload;

/**
 * Validation annotation for URI type constraints.
 * This annotation validates URI strings based on specified protocol types.
 */

@app.get("/model-optional-validation-alias")
def read_model_optional_validation_alias(
    p: Annotated[CookieModelOptionalValidationAlias, Cookie()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-validation-alias", "/model-optional-validation-alias"],
)
def test_optional_validation_alias_schema(path: str):

@app.get("/model-optional-list-validation-alias")
def read_model_optional_list_validation_alias(
    p: Annotated[HeaderModelOptionalListValidationAlias, Header()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-list-validation-alias", "/model-optional-list-validation-alias"],
)
def test_optional_list_validation_alias_schema(path: str):

@app.get("/model-required-list-validation-alias")
async def read_model_required_list_validation_alias(
    p: Annotated[QueryModelRequiredListValidationAlias, Query()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/required-list-validation-alias", "/model-required-list-validation-alias"],
)
def test_required_list_validation_alias_schema(path: str):

import java.lang.annotation.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import jakarta.validation.Constraint;
import jakarta.validation.Payload;

/**
 * Validation constraint to ensure that a string is a valid cron expression.
 */
@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
@Retention(RUNTIME)
@Documented

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

    assert response.json() == {"file_size": 5}


# =====================================================================================
# Validation alias


@app.post(
    "/optional-bytes-validation-alias", operation_id="optional_bytes_validation_alias"
)
def read_optional_bytes_validation_alias(
    p: Annotated[Optional[bytes], File(validation_alias="p_val_alias")] = None,
):

@app.post(
    "/model-optional-validation-alias", operation_id="model_optional_validation_alias"
)
def read_model_optional_validation_alias(
    p: Annotated[FormModelOptionalValidationAlias, Form()],
):
    return {"p": p.p}


@pytest.mark.parametrize(
    "path",
    ["/optional-validation-alias", "/model-optional-validation-alias"],
)
def test_optional_validation_alias_schema(path: str):