update to 0.5.0

src/extra.rs

@@ -0,0 +1,71 @@
+//! # Implementation of the `HasValidate` trait for the extractor in `axum-extra`.
+//!
+
+#[cfg(feature = "extra_form")]
+pub mod form;
+#[cfg(feature = "extra_protobuf")]
+pub mod protobuf;
+#[cfg(feature = "extra_query")]
+pub mod query;
+
+use crate::HasValidate;
+use axum_extra::extract::{Cached, WithRejection};
+use validator::Validate;
+
+impl<T: Validate> HasValidate for Cached<T> {
+    type Validate = T;
+
+    fn get_validate(&self) -> &Self::Validate {
+        &self.0
+    }
+}
+
+impl<T: Validate, R> HasValidate for WithRejection<T, R> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{Rejection, ValidTest};
+    use axum::http::StatusCode;
+    use axum_extra::extract::{Cached, WithRejection};
+    use reqwest::RequestBuilder;
+
+    impl<T: ValidTest> ValidTest for Cached<T> {
+        const ERROR_STATUS_CODE: StatusCode = T::ERROR_STATUS_CODE;
+
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder {
+            T::set_valid_request(builder)
+        }
+
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder {
+            // cached never fails
+            T::set_error_request(builder)
+        }
+
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder {
+            T::set_invalid_request(builder)
+        }
+    }
+
+    impl<T: ValidTest, R: Rejection> ValidTest for WithRejection<T, R> {
+        // just use conflict to test
+        const ERROR_STATUS_CODE: StatusCode = R::STATUS_CODE;
+
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder {
+            T::set_valid_request(builder)
+        }
+
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder {
+            // cached never fails
+            T::set_error_request(builder)
+        }
+
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder {
+            T::set_invalid_request(builder)
+        }
+    }
+}

src/extra/form.rs

@@ -0,0 +1,13 @@
+//! # Implementation of the `HasValidate` trait for the `Form` extractor in `axum-extra`.
+//!
+
+use crate::HasValidate;
+use axum_extra::extract::Form;
+use validator::Validate;
+
+impl<T: Validate> HasValidate for Form<T> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}

src/extra/protobuf.rs

@@ -0,0 +1,13 @@
+//! # Implementation of the `HasValidate` trait for the `Form` extractor.
+//!
+
+use crate::HasValidate;
+use axum_extra::protobuf::Protobuf;
+use validator::Validate;
+
+impl<T: Validate> HasValidate for Protobuf<T> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}

src/extra/query.rs

@@ -0,0 +1,13 @@
+//! # Implementation of the `HasValidate` trait for the `Query` extractor in `axum-extra`.
+//!
+
+use crate::HasValidate;
+use axum_extra::extract::Query;
+use validator::Validate;
+
+impl<T: Validate> HasValidate for Query<T> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}

src/form.rs

@@ -1,21 +1,37 @@
 //! # Implementation of the `HasValidate` trait for the `Form` extractor.
 //!
 
-use crate::{HasValidate, ValidRejection};
-use axum::extract::rejection::FormRejection;
+use crate::HasValidate;
 use axum::Form;
 use validator::Validate;
 
 impl<T: Validate> HasValidate for Form<T> {
     type Validate = T;
-    type Rejection = FormRejection;
     fn get_validate(&self) -> &T {
         &self.0
     }
 }
 
-impl From<FormRejection> for ValidRejection<FormRejection> {
-    fn from(value: FormRejection) -> Self {
-        Self::Inner(value)
+#[cfg(test)]
+mod tests {
+    use crate::tests::{ValidTest, ValidTestParameter};
+    use axum::http::StatusCode;
+    use axum::Form;
+    use reqwest::RequestBuilder;
+
+    impl<T: ValidTestParameter> ValidTest for Form<T> {
+        const ERROR_STATUS_CODE: StatusCode = StatusCode::UNPROCESSABLE_ENTITY;
+
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.form(T::valid())
+        }
+
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.form(T::error())
+        }
+
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.form(T::invalid())
+        }
     }
 }

src/json.rs

@@ -1,21 +1,37 @@
 //! # Implementation of the `HasValidate` trait for the `Json` extractor.
 //!
 
-use crate::{HasValidate, ValidRejection};
-use axum::extract::rejection::JsonRejection;
+use crate::HasValidate;
 use axum::Json;
 use validator::Validate;
 
 impl<T: Validate> HasValidate for Json<T> {
     type Validate = T;
-    type Rejection = JsonRejection;
     fn get_validate(&self) -> &T {
         &self.0
     }
 }
 
-impl From<JsonRejection> for ValidRejection<JsonRejection> {
-    fn from(value: JsonRejection) -> Self {
-        Self::Inner(value)
+#[cfg(test)]
+mod tests {
+    use crate::tests::{ValidTest, ValidTestParameter};
+    use axum::http::StatusCode;
+    use axum::Json;
+    use reqwest::RequestBuilder;
+
+    impl<T: ValidTestParameter> ValidTest for Json<T> {
+        const ERROR_STATUS_CODE: StatusCode = StatusCode::UNPROCESSABLE_ENTITY;
+
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.json(T::valid())
+        }
+
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.json(T::error())
+        }
+
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.json(T::invalid())
+        }
     }
 }

src/lib.rs

@@ -1,19 +1,30 @@
 #![doc = include_str!("../README.md")]
 #![deny(unsafe_code, missing_docs, clippy::unwrap_used)]
 
+#[cfg(feature = "extra")]
+pub mod extra;
 #[cfg(feature = "form")]
 pub mod form;
 #[cfg(feature = "json")]
 pub mod json;
+#[cfg(feature = "msgpack")]
+pub mod msgpack;
 pub mod path;
 #[cfg(feature = "query")]
 pub mod query;
+#[cfg(test)]
+pub mod test;
+#[cfg(feature = "typed_header")]
+pub mod typed_header;
+#[cfg(feature = "yaml")]
+pub mod yaml;
 
 use axum::async_trait;
 use axum::extract::{FromRequest, FromRequestParts};
 use axum::http::request::Parts;
 use axum::http::{Request, StatusCode};
 use axum::response::{IntoResponse, Response};
+use std::ops::{Deref, DerefMut};
 use validator::{Validate, ValidationErrors};
 
 /// Http status code returned when there are validation errors.
@@ -25,7 +36,21 @@ pub const VALIDATION_ERROR_STATUS: StatusCode = StatusCode::BAD_REQUEST;
 
 /// Valid entity extractor
 #[derive(Debug, Clone, Copy, Default)]
-pub struct Valid<T>(pub T);
+pub struct Valid<E>(pub E);
+
+impl<E> Deref for Valid<E> {
+    type Target = E;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl<E> DerefMut for Valid<E> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
 
 /// If the valid extractor fails it'll use this "rejection" type.
 /// This rejection type can be converted into a response.
@@ -64,44 +89,84 @@ impl<E: IntoResponse> IntoResponse for ValidRejection<E> {
 pub trait HasValidate {
     /// Inner type that can be validated for correctness
     type Validate: Validate;
-    /// If the inner extractor fails it'll use this "rejection" type.
-    /// A rejection is a kind of error that can be converted into a response.
-    type Rejection: IntoResponse;
-    /// get the inner type
+    /// Get the inner value
     fn get_validate(&self) -> &Self::Validate;
 }
 
 #[async_trait]
-impl<S, B, T> FromRequest<S, B> for Valid<T>
+impl<S, B, E> FromRequest<S, B> for Valid<E>
 where
     S: Send + Sync + 'static,
     B: Send + Sync + 'static,
-    T: HasValidate + FromRequest<S, B>,
-    T::Validate: Validate,
-    ValidRejection<<T as HasValidate>::Rejection>: From<<T as FromRequest<S, B>>::Rejection>,
+    E: HasValidate + FromRequest<S, B>,
+    E::Validate: Validate,
 {
-    type Rejection = ValidRejection<<T as HasValidate>::Rejection>;
+    type Rejection = ValidRejection<<E as FromRequest<S, B>>::Rejection>;
 
     async fn from_request(req: Request<B>, state: &S) -> Result<Self, Self::Rejection> {
-        let inner = T::from_request(req, state).await?;
+        let inner = E::from_request(req, state)
+            .await
+            .map_err(ValidRejection::Inner)?;
         inner.get_validate().validate()?;
         Ok(Valid(inner))
     }
 }
 
 #[async_trait]
-impl<S, T> FromRequestParts<S> for Valid<T>
+impl<S, E> FromRequestParts<S> for Valid<E>
 where
     S: Send + Sync + 'static,
-    T: HasValidate + FromRequestParts<S>,
-    T::Validate: Validate,
-    ValidRejection<<T as HasValidate>::Rejection>: From<<T as FromRequestParts<S>>::Rejection>,
+    E: HasValidate + FromRequestParts<S>,
+    E::Validate: Validate,
 {
-    type Rejection = ValidRejection<<T as HasValidate>::Rejection>;
+    type Rejection = ValidRejection<<E as FromRequestParts<S>>::Rejection>;
 
     async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
-        let inner = T::from_request_parts(parts, state).await?;
+        let inner = E::from_request_parts(parts, state)
+            .await
+            .map_err(ValidRejection::Inner)?;
         inner.get_validate().validate()?;
         Ok(Valid(inner))
     }
 }
+
+#[cfg(test)]
+pub mod tests {
+    use reqwest::{RequestBuilder, StatusCode};
+    use serde::Serialize;
+
+    /// # Valid test parameter
+    pub trait ValidTestParameter: Serialize + 'static {
+        /// Create a valid parameter
+        fn valid() -> &'static Self;
+        /// Create an error serializable array
+        fn error() -> &'static [(&'static str, &'static str)];
+        /// Create a invalid parameter
+        fn invalid() -> &'static Self;
+    }
+
+    /// # Valid Tests
+    ///
+    /// This trait defines three test cases to check
+    /// if an extractor combined with the Valid type works properly.
+    ///
+    /// 1. For a valid request, the server should return `200 OK`.
+    /// 2. For an invalid request according to the extractor, the server should return the error HTTP status code defined by the extractor itself.
+    /// 3. For an invalid request according to Valid, the server should return VALIDATION_ERROR_STATUS as the error code.
+    ///
+    pub trait ValidTest {
+        /// Http status code when inner extractor failed
+        const ERROR_STATUS_CODE: StatusCode;
+        /// Build a valid request, the server should return `200 OK`.
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder;
+        /// Build an invalid request according to the extractor, the server should return `Self::ERROR_STATUS_CODE`
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder;
+        /// Build an invalid request according to Valid, the server should return VALIDATION_ERROR_STATUS
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder;
+    }
+
+    #[cfg(feature = "extra")]
+    pub trait Rejection {
+        const STATUS_CODE: StatusCode;
+    }
+}

src/msgpack.rs

@@ -0,0 +1,20 @@
+//! # Implementation of the `HasValidate` trait for the `MsgPack` extractor.
+//!
+
+use crate::HasValidate;
+use axum_msgpack::{MsgPack, MsgPackRaw};
+use validator::Validate;
+
+impl<T: Validate> HasValidate for MsgPack<T> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}
+
+impl<T: Validate> HasValidate for MsgPackRaw<T> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}

src/path.rs

@@ -1,21 +1,13 @@
 //! # Implementation of the `HasValidate` trait for the `Path` extractor.
 //!
 
-use crate::{HasValidate, ValidRejection};
-use axum::extract::rejection::PathRejection;
+use crate::HasValidate;
 use axum::extract::Path;
 use validator::Validate;
 
 impl<T: Validate> HasValidate for Path<T> {
     type Validate = T;
-    type Rejection = PathRejection;
     fn get_validate(&self) -> &T {
         &self.0
     }
 }
-
-impl From<PathRejection> for ValidRejection<PathRejection> {
-    fn from(value: PathRejection) -> Self {
-        Self::Inner(value)
-    }
-}

src/query.rs

@@ -1,21 +1,37 @@
 //! # Implementation of the `HasValidate` trait for the `Query` extractor.
 //!
 
-use crate::{HasValidate, ValidRejection};
-use axum::extract::rejection::QueryRejection;
+use crate::HasValidate;
 use axum::extract::Query;
 use validator::Validate;
 
 impl<T: Validate> HasValidate for Query<T> {
     type Validate = T;
-    type Rejection = QueryRejection;
     fn get_validate(&self) -> &T {
         &self.0
     }
 }
 
-impl From<QueryRejection> for ValidRejection<QueryRejection> {
-    fn from(value: QueryRejection) -> Self {
-        Self::Inner(value)
+#[cfg(test)]
+mod tests {
+    use crate::tests::{ValidTest, ValidTestParameter};
+    use axum::extract::Query;
+    use axum::http::StatusCode;
+    use reqwest::RequestBuilder;
+
+    impl<T: ValidTestParameter> ValidTest for Query<T> {
+        const ERROR_STATUS_CODE: StatusCode = StatusCode::BAD_REQUEST;
+
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.query(&T::valid())
+        }
+
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.query(T::error())
+        }
+
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.query(&T::invalid())
+        }
     }
 }

src/test.rs

@@ -0,0 +1,430 @@
+use crate::tests::{ValidTest, ValidTestParameter};
+use crate::{Valid, VALIDATION_ERROR_STATUS};
+use axum::extract::{Path, Query};
+use axum::routing::{get, post};
+use axum::{Form, Json, Router};
+use hyper::Method;
+use reqwest::{StatusCode, Url};
+use serde::{Deserialize, Serialize};
+use std::any::type_name;
+use std::borrow::Cow;
+use std::net::SocketAddr;
+use validator::Validate;
+
+#[derive(Debug, Clone, Deserialize, Serialize, Validate, Eq, PartialEq)]
+pub struct Parameters {
+    #[validate(range(min = 5, max = 10))]
+    v0: i32,
+    #[validate(length(min = 1, max = 10))]
+    v1: Cow<'static, str>,
+}
+
+static VALID_PARAMETERS: Parameters = Parameters {
+    v0: 5,
+    v1: Cow::Borrowed("0123456789"),
+};
+
+static INVALID_PARAMETERS: Parameters = Parameters {
+    v0: 6,
+    v1: Cow::Borrowed("01234567890"),
+};
+
+impl ValidTestParameter for Parameters {
+    fn valid() -> &'static Self {
+        &VALID_PARAMETERS
+    }
+
+    fn error() -> &'static [(&'static str, &'static str)] {
+        &[("not_v0_or_v1", "value")]
+    }
+
+    fn invalid() -> &'static Self {
+        &INVALID_PARAMETERS
+    }
+}
+
+#[tokio::test]
+async fn test_main() -> anyhow::Result<()> {
+    let router = Router::new()
+        .route(route::PATH, get(extract_path))
+        .route(route::QUERY, get(extract_query))
+        .route(route::FORM, post(extract_form))
+        .route(route::JSON, post(extract_json));
+
+    #[cfg(feature = "typed_header")]
+    let router = router.route(
+        typed_header::route::TYPED_HEADER,
+        post(typed_header::extract_typed_header),
+    );
+
+    #[cfg(feature = "extra")]
+    let router = router
+        .route(route::extra::CACHED, post(extra::extract_cached))
+        .route(
+            route::extra::WITH_REJECTION,
+            post(extra::extract_with_rejection),
+        );
+
+    let server = axum::Server::bind(&SocketAddr::from(([0u8, 0, 0, 0], 0u16)))
+        .serve(router.into_make_service());
+    let server_addr = server.local_addr();
+    println!("Axum server address: {}.", server_addr);
+
+    let (server_guard, close) = tokio::sync::oneshot::channel::<()>();
+    let server_handle = tokio::spawn(server.with_graceful_shutdown(async move {
+        let _ = close.await;
+    }));
+
+    let server_url = format!("http://{}", server_addr);
+    let test_executor = TestExecutor::from(Url::parse(&format!("http://{}", server_addr))?);
+
+    // Valid<Path<...>>
+    let valid_path_response = test_executor
+        .client()
+        .get(format!(
+            "{}/path/{}/{}",
+            server_url, VALID_PARAMETERS.v0, VALID_PARAMETERS.v1
+        ))
+        .send()
+        .await?;
+    assert_eq!(valid_path_response.status(), StatusCode::OK);
+
+    let invalid_path_response = test_executor
+        .client()
+        .get(format!("{}/path/not_i32/path", server_url))
+        .send()
+        .await?;
+    assert_eq!(invalid_path_response.status(), StatusCode::BAD_REQUEST);
+
+    let invalid_path_response = test_executor
+        .client()
+        .get(format!(
+            "{}/path/{}/{}",
+            server_url, INVALID_PARAMETERS.v0, INVALID_PARAMETERS.v1
+        ))
+        .send()
+        .await?;
+    assert_eq!(invalid_path_response.status(), VALIDATION_ERROR_STATUS);
+    #[cfg(feature = "into_json")]
+    check_json(invalid_path_response).await;
+    println!("Valid<Path<...>> works.");
+
+    test_executor
+        .execute::<Query<Parameters>>(Method::GET, route::QUERY)
+        .await?;
+
+    test_executor
+        .execute::<Form<Parameters>>(Method::POST, route::FORM)
+        .await?;
+
+    test_executor
+        .execute::<Json<Parameters>>(Method::POST, route::JSON)
+        .await?;
+
+    #[cfg(feature = "typed_header")]
+    {
+        use axum::TypedHeader;
+        test_executor
+            .execute::<TypedHeader<Parameters>>(Method::POST, typed_header::route::TYPED_HEADER)
+            .await?;
+    }
+
+    #[cfg(feature = "extra")]
+    {
+        use axum_extra::extract::{Cached, WithRejection};
+        use extra::TestRejection;
+        test_executor
+            .execute::<Cached<Parameters>>(Method::POST, route::extra::CACHED)
+            .await?;
+        test_executor
+            .execute::<WithRejection<Parameters, TestRejection>>(
+                Method::POST,
+                route::extra::WITH_REJECTION,
+            )
+            .await?;
+    }
+
+    drop(server_guard);
+    server_handle.await??;
+    Ok(())
+}
+
+#[derive(Debug, Clone)]
+pub struct TestExecutor {
+    client: reqwest::Client,
+    server_url: Url,
+}
+
+impl From<Url> for TestExecutor {
+    fn from(server_url: Url) -> Self {
+        Self {
+            client: Default::default(),
+            server_url,
+        }
+    }
+}
+
+impl TestExecutor {
+    /// Execute all tests
+    pub async fn execute<T: ValidTest>(&self, method: Method, route: &str) -> anyhow::Result<()> {
+        let url = {
+            let mut url_builder = self.server_url.clone();
+            url_builder.set_path(route);
+            url_builder
+        };
+
+        let valid_builder = self.client.request(method.clone(), url.clone());
+        let valid_response = T::set_valid_request(valid_builder).send().await?;
+        assert_eq!(valid_response.status(), StatusCode::OK);
+
+        let error_builder = self.client.request(method.clone(), url.clone());
+        let error_response = T::set_error_request(error_builder).send().await?;
+        assert_eq!(error_response.status(), T::ERROR_STATUS_CODE);
+
+        let invalid_builder = self.client.request(method, url);
+        let invalid_response = T::set_invalid_request(invalid_builder).send().await?;
+        assert_eq!(invalid_response.status(), VALIDATION_ERROR_STATUS);
+        #[cfg(feature = "into_json")]
+        check_json(invalid_response).await;
+        println!("{} works.", type_name::<T>());
+
+        Ok(())
+    }
+
+    pub fn client(&self) -> &reqwest::Client {
+        &self.client
+    }
+}
+
+/// Check if the response is a json response
+#[cfg(feature = "into_json")]
+pub async fn check_json(response: reqwest::Response) {
+    assert_eq!(
+        response.headers()[axum::http::header::CONTENT_TYPE],
+        axum::http::HeaderValue::from_static(mime::APPLICATION_JSON.as_ref())
+    );
+    assert!(response.json::<serde_json::Value>().await.is_ok());
+}
+
+mod route {
+    pub const PATH: &str = "/path/:v0/:v1";
+    pub const QUERY: &str = "/query";
+    pub const FORM: &str = "/form";
+    pub const JSON: &str = "/json";
+
+    #[cfg(feature = "extra")]
+    pub mod extra {
+        pub const CACHED: &str = "/cached";
+        pub const WITH_REJECTION: &str = "/with_rejection";
+    }
+}
+
+async fn extract_path(Valid(Path(parameters)): Valid<Path<Parameters>>) -> StatusCode {
+    validate_again(parameters)
+}
+
+async fn extract_query(Valid(Query(parameters)): Valid<Query<Parameters>>) -> StatusCode {
+    validate_again(parameters)
+}
+
+async fn extract_form(Valid(Form(parameters)): Valid<Form<Parameters>>) -> StatusCode {
+    validate_again(parameters)
+}
+
+async fn extract_json(Valid(Json(parameters)): Valid<Json<Parameters>>) -> StatusCode {
+    validate_again(parameters)
+}
+
+fn validate_again(parameters: Parameters) -> StatusCode {
+    // The `Valid` extractor has validated the `parameters` once,
+    // it should have returned `400 BAD REQUEST` if the `parameters` were invalid,
+    // Let's validate them again to check if the `Valid` extractor works well.
+    // If it works properly, this function will never return `500 INTERNAL SERVER ERROR`
+    match parameters.validate() {
+        Ok(_) => StatusCode::OK,
+        Err(_) => StatusCode::INTERNAL_SERVER_ERROR,
+    }
+}
+
+#[cfg(feature = "typed_header")]
+mod typed_header {
+
+    pub(crate) mod route {
+        pub const TYPED_HEADER: &str = "/typedHeader";
+    }
+
+    use super::{validate_again, Parameters};
+    use crate::Valid;
+    use axum::headers::{Error, Header, HeaderName, HeaderValue};
+    use axum::http::StatusCode;
+    use axum::TypedHeader;
+    use std::borrow::Cow;
+
+    pub static AXUM_VALID_PARAMETERS: HeaderName = HeaderName::from_static("axum-valid-parameters");
+
+    pub(super) async fn extract_typed_header(
+        Valid(TypedHeader(parameters)): Valid<TypedHeader<Parameters>>,
+    ) -> StatusCode {
+        validate_again(parameters)
+    }
+
+    impl Header for Parameters {
+        fn name() -> &'static HeaderName {
+            &AXUM_VALID_PARAMETERS
+        }
+
+        fn decode<'i, I>(values: &mut I) -> Result<Self, Error>
+        where
+            Self: Sized,
+            I: Iterator<Item = &'i HeaderValue>,
+        {
+            let value = values.next().ok_or_else(Error::invalid)?;
+            let src = std::str::from_utf8(value.as_bytes()).map_err(|_| Error::invalid())?;
+            let split = src.split(',').collect::<Vec<_>>();
+            match split.as_slice() {
+                [v0, v1] => Ok(Parameters {
+                    v0: v0.parse().map_err(|_| Error::invalid())?,
+                    v1: Cow::Owned(v1.to_string()),
+                }),
+                _ => Err(Error::invalid()),
+            }
+        }
+
+        fn encode<E: Extend<HeaderValue>>(&self, values: &mut E) {
+            let v0 = self.v0.to_string();
+            let mut vec = Vec::with_capacity(v0.len() + 1 + self.v1.len());
+            vec.extend_from_slice(v0.as_bytes());
+            vec.push(b',');
+            vec.extend_from_slice(self.v1.as_bytes());
+            let value = HeaderValue::from_bytes(&vec).expect("Failed to build header");
+            values.extend(::std::iter::once(value));
+        }
+    }
+
+    #[test]
+    fn parameter_is_header() -> anyhow::Result<()> {
+        let parameter = Parameters {
+            v0: 123456,
+            v1: Cow::Owned("111111".to_string()),
+        };
+        let mut vec = Vec::new();
+        parameter.encode(&mut vec);
+        let mut iter = vec.iter();
+        assert_eq!(parameter, Parameters::decode(&mut iter)?);
+        Ok(())
+    }
+}
+
+#[cfg(feature = "extra")]
+mod extra {
+    use crate::test::{validate_again, Parameters};
+    use crate::tests::{Rejection, ValidTest, ValidTestParameter};
+    use crate::Valid;
+    use axum::extract::FromRequestParts;
+    use axum::http::request::Parts;
+    use axum::http::StatusCode;
+    use axum::response::{IntoResponse, Response};
+    use axum_extra::extract::{Cached, WithRejection};
+    use reqwest::RequestBuilder;
+
+    pub const PARAMETERS_HEADER: &str = "parameters-header";
+    pub const CACHED_REJECTION_STATUS: StatusCode = StatusCode::FORBIDDEN;
+
+    //  1.2. Define you own `Rejection` type and implement `IntoResponse` for it.
+    pub enum ParametersRejection {
+        Null,
+        InvalidJson(serde_json::error::Error),
+    }
+
+    impl IntoResponse for ParametersRejection {
+        fn into_response(self) -> Response {
+            match self {
+                ParametersRejection::Null => {
+                    (CACHED_REJECTION_STATUS, "My-Data header is missing").into_response()
+                }
+                ParametersRejection::InvalidJson(e) => (
+                    CACHED_REJECTION_STATUS,
+                    format!("My-Data is not valid json string: {e}"),
+                )
+                    .into_response(),
+            }
+        }
+    }
+
+    //  1.3. Implement your extractor (`FromRequestParts` or `FromRequest`)
+    #[axum::async_trait]
+    impl<S> FromRequestParts<S> for Parameters
+    where
+        S: Send + Sync,
+    {
+        type Rejection = ParametersRejection;
+
+        async fn from_request_parts(parts: &mut Parts, _: &S) -> Result<Self, Self::Rejection> {
+            let Some(value) = parts.headers.get(PARAMETERS_HEADER) else {
+                return Err(ParametersRejection::Null);
+            };
+
+            serde_json::from_slice(value.as_bytes()).map_err(ParametersRejection::InvalidJson)
+        }
+    }
+
+    impl ValidTest for Parameters {
+        const ERROR_STATUS_CODE: StatusCode = CACHED_REJECTION_STATUS;
+
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.header(
+                PARAMETERS_HEADER,
+                serde_json::to_string(Parameters::valid()).expect("Failed to serialize parameters"),
+            )
+        }
+
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.header(
+                PARAMETERS_HEADER,
+                serde_json::to_string(Parameters::error()).expect("Failed to serialize parameters"),
+            )
+        }
+
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder {
+            builder.header(
+                PARAMETERS_HEADER,
+                serde_json::to_string(Parameters::invalid())
+                    .expect("Failed to serialize parameters"),
+            )
+        }
+    }
+
+    pub struct TestRejection {
+        _inner: ParametersRejection,
+    }
+
+    impl Rejection for TestRejection {
+        const STATUS_CODE: StatusCode = StatusCode::CONFLICT;
+    }
+
+    impl IntoResponse for TestRejection {
+        fn into_response(self) -> Response {
+            Self::STATUS_CODE.into_response()
+        }
+    }
+
+    // satisfy the `WithRejection`'s extractor trait bound
+    // R: From<E::Rejection> + IntoResponse
+    impl From<ParametersRejection> for TestRejection {
+        fn from(_inner: ParametersRejection) -> Self {
+            Self { _inner }
+        }
+    }
+
+    pub async fn extract_cached(
+        Valid(Cached(parameters)): Valid<Cached<Parameters>>,
+    ) -> StatusCode {
+        validate_again(parameters)
+    }
+
+    pub async fn extract_with_rejection(
+        Valid(WithRejection(parameters, _)): Valid<WithRejection<Parameters, TestRejection>>,
+    ) -> StatusCode {
+        validate_again(parameters)
+    }
+}

src/typed_header.rs

@@ -0,0 +1,43 @@
+//! # Implementation of the `HasValidate` trait for the `TypedHeader` extractor.
+//!
+
+use crate::HasValidate;
+use axum::TypedHeader;
+use validator::Validate;
+
+impl<T: Validate> HasValidate for TypedHeader<T> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{ValidTest, ValidTestParameter};
+    use axum::headers::{Header, HeaderMapExt};
+    use axum::http::StatusCode;
+    use axum::TypedHeader;
+    use reqwest::header::HeaderMap;
+    use reqwest::RequestBuilder;
+
+    impl<T: ValidTestParameter + Header + Clone> ValidTest for TypedHeader<T> {
+        const ERROR_STATUS_CODE: StatusCode = StatusCode::BAD_REQUEST;
+
+        fn set_valid_request(builder: RequestBuilder) -> RequestBuilder {
+            let mut headers = HeaderMap::default();
+            headers.typed_insert(T::valid().clone());
+            builder.headers(headers)
+        }
+
+        fn set_error_request(builder: RequestBuilder) -> RequestBuilder {
+            builder
+        }
+
+        fn set_invalid_request(builder: RequestBuilder) -> RequestBuilder {
+            let mut headers = HeaderMap::default();
+            headers.typed_insert(T::invalid().clone());
+            builder.headers(headers)
+        }
+    }
+}

src/yaml.rs

@@ -0,0 +1,13 @@
+//! # Implementation of the `HasValidate` trait for the `Yaml` extractor.
+//!
+
+use crate::HasValidate;
+use axum_yaml::Yaml;
+use validator::Validate;
+
+impl<T: Validate> HasValidate for Yaml<T> {
+    type Validate = T;
+    fn get_validate(&self) -> &T {
+        &self.0
+    }
+}