first implementation

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "axum-oidc"
-description = "A OpenID Connect Client and Bearer Token Libary for axum"
+description = "A OpenID Connect Client Libary for axum"
 version = "0.0.0"
 edition = "2021"
 authors = [ "Paul Z <info@pfz4.de>" ]
@@ -12,3 +12,15 @@ keywords = [ "axum", "oidc", "openidconnect", "authentication" ]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+thiserror = "1.0.50"
+axum-core = "0.3"
+axum = { version = "0.6", default-features = false, features = [ "query" ] }
+tower-service = "0.3.2"
+tower-layer = "0.3.2"
+tower-sessions = { version = "0.4", default-features = false, features = [ "axum-core" ] }
+http = "0.2"
+async-trait = "0.1"
+openidconnect = "3.4"
+serde = "1.0"
+futures-util = "0.3"
+reqwest = { version = "0.11", default-features = false }

README.md

@@ -1,13 +1,72 @@
-**This crate is still under construction**
+This Library allows using [OpenID Connect](https://openid.net/developers/how-connect-works/) with [axum](https://github.com/tokio-rs/axum). 
+It authenticates the user with the OpenID Conenct Issuer and provides Extractors.
 
-This Library allows using [OpenID Connect](https://openid.net/developers/how-connect-works/) with [axum](https://github.com/tokio-rs/axum). It provides two modes, described below.
+# Usage
+The `OidcAuthLayer` must be loaded on any handler that might use the extractors.
+The user won't be automatically logged in using this layer.
+If a valid session is found, the extractors will return the correct value and fail otherwise.
 
-# Operating Modes
+The `OidcLoginLayer` should be loaded on any handler on which the user is supposed to be authenticated.
-## Client Mode
+The User will be redirected to the OpenId Conect Issuer to authenticate.
-In Client mode, the user visits the axum server with a web browser. The user gets redirected to and authenticated with the Issuer.
+The extractors will always return a value.
 
-## Token Mode
+The `OidcClaims`-extractor can be used to get the OpenId Conenct Claims.
-In Token mode, the another system is using the access token of the user to authenticate against the axum server.
+The `OidcAccessToken`-extractor can be used to get the OpenId Connect Access Token.
+
+Your OIDC-Client must be allowed to redirect to **every** subpath of your application base url.
+
+```rust
+#[tokio::main]
+async fn main() {
+
+    let session_store = MemoryStore::default();
+    let session_service = ServiceBuilder::new()
+        .layer(HandleErrorLayer::new(|_: BoxError| async {
+            StatusCode::BAD_REQUEST
+        }))
+        .layer(SessionManagerLayer::new(session_store).with_same_site(SameSite::Lax));
+
+    let oidc_login_service = ServiceBuilder::new()
+        .layer(HandleErrorLayer::new(|e: MiddlewareError| async {
+            e.into_response()
+        }))
+        .layer(OidcLoginLayer::<EmptyAdditionalClaims>::new());
+
+    let oidc_auth_service = ServiceBuilder::new()
+        .layer(HandleErrorLayer::new(|e: MiddlewareError| async {
+            e.into_response()
+        }))
+        .layer(
+            OidcAuthLayer::<EmptyAdditionalClaims>::discover_client(
+                Uri::from_static("https://example.com"),
+                "<issuer>".to_string(),
+                "<client_id>".to_string(),
+                "<client_secret>".to_owned(),
+                vec![],
+            ).await.unwrap(),
+        );
+
+    let app = Router::new()
+        .route("/", get(|| async { "Hello, authenticated World!" }))
+        .layer(oidc_login_service)
+        .layer(oidc_auth_service)
+        .layer(session_service);
+
+    axum::Server::bind(&"[::]:8080".parse().unwrap())
+        .serve(app.into_make_service())
+        .await
+        .unwrap();
+}
+```
+
+# Example Projects
+Here is a place for projects that are using this library.
+- [zettoIT ARS - AudienceResponseSystem](https://git2.zettoit.eu/zettoit/ars) (by me)
+
+# Contributing
+I'm happy about any contribution in any form.
+Feel free to submit feature requests and bug reports using a GitHub Issue.
+PR's are also appreciated.
 
 # License
 This Library is licensed under [LGPLv3](https://www.gnu.org/licenses/lgpl-3.0.en.html).

src/error.rs

@@ -0,0 +1,100 @@
+use axum_core::{response::IntoResponse, BoxError};
+use http::{
+    uri::{InvalidUri, InvalidUriParts},
+    StatusCode,
+};
+use openidconnect::{core::CoreErrorResponseType, StandardErrorResponse};
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum ExtractorError {
+    #[error("unauthorized")]
+    Unauthorized,
+}
+
+#[derive(Debug, Error)]
+pub enum MiddlewareError {
+    #[error("access token hash invalid")]
+    AccessTokenHashInvalid,
+
+    #[error("csrf token invalid")]
+    CsrfTokenInvalid,
+
+    #[error("id token missing")]
+    IdTokenMissing,
+
+    #[error("signing: {0:?}")]
+    Signing(#[from] openidconnect::SigningError),
+
+    #[error("claims verification: {0:?}")]
+    ClaimsVerification(#[from] openidconnect::ClaimsVerificationError),
+
+    #[error("url parsing: {0:?}")]
+    UrlParsing(#[from] openidconnect::url::ParseError),
+
+    #[error("uri parsing: {0:?}")]
+    UriParsing(#[from] InvalidUri),
+
+    #[error("uri parts parsing: {0:?}")]
+    UriPartsParsing(#[from] InvalidUriParts),
+
+    #[error("request token: {0:?}")]
+    RequestToken(
+        #[from]
+        openidconnect::RequestTokenError<
+            openidconnect::reqwest::Error<reqwest::Error>,
+            StandardErrorResponse<CoreErrorResponseType>,
+        >,
+    ),
+
+    #[error("session error: {0:?}")]
+    Session(#[from] tower_sessions::session::Error),
+
+    #[error("session not found")]
+    SessionNotFound,
+
+    #[error("next middleware")]
+    NextMiddleware(#[from] BoxError),
+
+    #[error("auth middleware not found")]
+    AuthMiddlewareNotFound,
+}
+
+#[derive(Debug, Error)]
+pub enum Error {
+    #[error("url parsing: {0:?}")]
+    UrlParsing(#[from] openidconnect::url::ParseError),
+
+    #[error("discovery: {0:?}")]
+    Discovery(#[from] openidconnect::DiscoveryError<openidconnect::reqwest::Error<reqwest::Error>>),
+
+    #[error("extractor: {0:?}")]
+    Extractor(#[from] ExtractorError),
+
+    #[error("extractor: {0:?}")]
+    Middleware(#[from] MiddlewareError),
+}
+
+impl IntoResponse for ExtractorError {
+    fn into_response(self) -> axum_core::response::Response {
+        (StatusCode::UNAUTHORIZED, "unauthorized").into_response()
+    }
+}
+
+impl IntoResponse for Error {
+    fn into_response(self) -> axum_core::response::Response {
+        dbg!(&self);
+        match self {
+            _ => (StatusCode::INTERNAL_SERVER_ERROR, "internal server error").into_response(),
+        }
+    }
+}
+
+impl IntoResponse for MiddlewareError {
+    fn into_response(self) -> axum_core::response::Response {
+        dbg!(&self);
+        match self {
+            _ => (StatusCode::INTERNAL_SERVER_ERROR, "internal server error").into_response(),
+        }
+    }
+}

src/extractor.rs

@@ -0,0 +1,50 @@
+use crate::{error::ExtractorError, AdditionalClaims};
+use async_trait::async_trait;
+use axum_core::extract::FromRequestParts;
+use http::request::Parts;
+use openidconnect::{core::CoreGenderClaim, IdTokenClaims};
+
+/// Extractor for the OpenID Connect Claims.
+///
+/// This Extractor will only return the Claims when the cached session is valid and [crate::middleware::OidcAuthMiddleware] is loaded.
+#[derive(Clone)]
+pub struct OidcClaims<AC: AdditionalClaims>(pub IdTokenClaims<AC, CoreGenderClaim>);
+
+#[async_trait]
+impl<S, AC> FromRequestParts<S> for OidcClaims<AC>
+where
+    S: Send + Sync,
+    AC: AdditionalClaims,
+{
+    type Rejection = ExtractorError;
+
+    async fn from_request_parts(parts: &mut Parts, _: &S) -> Result<Self, Self::Rejection> {
+        parts
+            .extensions
+            .get::<Self>()
+            .cloned()
+            .ok_or(ExtractorError::Unauthorized)
+    }
+}
+
+/// Extractor for the OpenID Connect Access Token.
+///
+/// This Extractor will only return the Access Token when the cached session is valid and [crate::middleware::OidcAuthMiddleware] is loaded.
+#[derive(Clone)]
+pub struct OidcAccessToken(pub String);
+
+#[async_trait]
+impl<S> FromRequestParts<S> for OidcAccessToken
+where
+    S: Send + Sync,
+{
+    type Rejection = ExtractorError;
+
+    async fn from_request_parts(parts: &mut Parts, _: &S) -> Result<Self, Self::Rejection> {
+        parts
+            .extensions
+            .get::<Self>()
+            .cloned()
+            .ok_or(ExtractorError::Unauthorized)
+    }
+}

src/lib.rs

@@ -0,0 +1,125 @@
+#![doc = include_str!("../README.md")]
+
+use crate::error::Error;
+use http::Uri;
+use openidconnect::{
+    core::{
+        CoreAuthDisplay, CoreAuthPrompt, CoreErrorResponseType, CoreGenderClaim, CoreJsonWebKey,
+        CoreJsonWebKeyType, CoreJsonWebKeyUse, CoreJweContentEncryptionAlgorithm,
+        CoreJwsSigningAlgorithm, CoreProviderMetadata, CoreRevocableToken,
+        CoreRevocationErrorResponse, CoreTokenIntrospectionResponse, CoreTokenType,
+    },
+    reqwest::async_http_client,
+    ClientId, ClientSecret, CsrfToken, EmptyExtraTokenFields, IdTokenFields, IssuerUrl, Nonce,
+    PkceCodeVerifier, StandardErrorResponse, StandardTokenResponse,
+};
+use serde::{Deserialize, Serialize};
+
+pub mod error;
+mod extractor;
+mod middleware;
+mod util;
+
+pub use extractor::{OidcAccessToken, OidcClaims};
+pub use middleware::{OidcAuthLayer, OidcAuthMiddleware, OidcLoginLayer, OidcLoginMiddleware};
+
+const SESSION_KEY: &str = "axum-oidc";
+
+pub trait AdditionalClaims: openidconnect::AdditionalClaims + Clone + Sync + Send {}
+
+type OidcTokenResponse<AC> = StandardTokenResponse<
+    IdTokenFields<
+        AC,
+        EmptyExtraTokenFields,
+        CoreGenderClaim,
+        CoreJweContentEncryptionAlgorithm,
+        CoreJwsSigningAlgorithm,
+        CoreJsonWebKeyType,
+    >,
+    CoreTokenType,
+>;
+
+pub type IdToken<AZ> = openidconnect::IdToken<
+    AZ,
+    CoreGenderClaim,
+    CoreJweContentEncryptionAlgorithm,
+    CoreJwsSigningAlgorithm,
+    CoreJsonWebKeyType,
+>;
+
+type Client<AC> = openidconnect::Client<
+    AC,
+    CoreAuthDisplay,
+    CoreGenderClaim,
+    CoreJweContentEncryptionAlgorithm,
+    CoreJwsSigningAlgorithm,
+    CoreJsonWebKeyType,
+    CoreJsonWebKeyUse,
+    CoreJsonWebKey,
+    CoreAuthPrompt,
+    StandardErrorResponse<CoreErrorResponseType>,
+    OidcTokenResponse<AC>,
+    CoreTokenType,
+    CoreTokenIntrospectionResponse,
+    CoreRevocableToken,
+    CoreRevocationErrorResponse,
+>;
+
+pub type BoxError = Box<dyn std::error::Error + Send + Sync>;
+
+/// OpenID Connect Client
+#[derive(Clone)]
+pub struct OidcClient<AC: AdditionalClaims> {
+    scopes: Vec<String>,
+    client: Client<AC>,
+    application_base_url: Uri,
+}
+
+impl<AC: AdditionalClaims> OidcClient<AC> {
+    pub async fn discover_new(
+        application_base_url: Uri,
+        issuer: String,
+        client_id: String,
+        client_secret: Option<String>,
+        scopes: Vec<String>,
+    ) -> Result<Self, Error> {
+        let provider_metadata =
+            CoreProviderMetadata::discover_async(IssuerUrl::new(issuer)?, async_http_client)
+                .await?;
+        let client = Client::from_provider_metadata(
+            provider_metadata,
+            ClientId::new(client_id),
+            client_secret.map(|x| ClientSecret::new(x)),
+        );
+        Ok(Self {
+            scopes,
+            client,
+            application_base_url,
+        })
+    }
+}
+
+/// an empty struct to be used as the default type for the additional claims generic
+#[derive(Deserialize, Serialize, Debug, Clone, Copy, Default)]
+pub struct EmptyAdditionalClaims {}
+impl AdditionalClaims for EmptyAdditionalClaims {}
+impl openidconnect::AdditionalClaims for EmptyAdditionalClaims {}
+
+/// response data of the openid issuer after login
+#[derive(Debug, Deserialize)]
+struct OidcQuery {
+    code: String,
+    state: String,
+    #[allow(dead_code)]
+    session_state: String,
+}
+
+/// oidc session
+#[derive(Serialize, Deserialize, Debug)]
+struct OidcSession {
+    nonce: Nonce,
+    csrf_token: CsrfToken,
+    pkce_verifier: PkceCodeVerifier,
+    id_token: Option<String>,
+    access_token: Option<String>,
+}

src/middleware.rs

@@ -0,0 +1,334 @@
+use std::{
+    marker::PhantomData,
+    str::FromStr,
+    task::{Context, Poll},
+};
+
+use axum::{
+    extract::Query,
+    response::{IntoResponse, Redirect},
+};
+use axum_core::{extract::FromRequestParts, response::Response};
+use futures_util::future::BoxFuture;
+use http::{Request, Uri};
+use tower_layer::Layer;
+use tower_service::Service;
+use tower_sessions::Session;
+
+use openidconnect::{
+    core::CoreAuthenticationFlow, reqwest::async_http_client, AccessTokenHash, AuthorizationCode,
+    CsrfToken, Nonce, OAuth2TokenResponse, PkceCodeChallenge, PkceCodeVerifier, RedirectUrl, Scope,
+    TokenResponse,
+};
+
+use crate::{
+    error::{Error, MiddlewareError},
+    extractor::{OidcAccessToken, OidcClaims},
+    util::strip_oidc_from_path,
+    AdditionalClaims, BoxError, IdToken, OidcClient, OidcQuery, OidcSession, SESSION_KEY,
+};
+
+/// Layer for the [OidcLoginMiddleware].
+#[derive(Clone, Default)]
+pub struct OidcLoginLayer<AC>
+where
+    AC: AdditionalClaims,
+{
+    additional: PhantomData<AC>,
+}
+
+impl<AC: AdditionalClaims> OidcLoginLayer<AC> {
+    pub fn new() -> Self {
+        Self {
+            additional: PhantomData,
+        }
+    }
+}
+
+impl<I, AC> Layer<I> for OidcLoginLayer<AC>
+where
+    AC: AdditionalClaims,
+{
+    type Service = OidcLoginMiddleware<I, AC>;
+
+    fn layer(&self, inner: I) -> Self::Service {
+        OidcLoginMiddleware {
+            inner,
+            additional: PhantomData,
+        }
+    }
+}
+
+/// This middleware forces the user to be authenticated and redirects the user to the OpenID Connect
+/// Issuer to authenticate. This Middleware needs to be loaded afer [OidcAuthMiddleware].
+#[derive(Clone)]
+pub struct OidcLoginMiddleware<I, AC>
+where
+    AC: AdditionalClaims,
+{
+    inner: I,
+    additional: PhantomData<AC>,
+}
+
+impl<I, AC, B> Service<Request<B>> for OidcLoginMiddleware<I, AC>
+where
+    I: Service<Request<B>, Response = Response> + Send + 'static + Clone,
+    I::Error: Send + Into<BoxError>,
+    I::Future: Send + 'static,
+    AC: AdditionalClaims,
+    B: Send + 'static,
+{
+    type Response = I::Response;
+    type Error = MiddlewareError;
+    type Future = BoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner
+            .poll_ready(cx)
+            .map_err(|e| MiddlewareError::NextMiddleware(e.into()))
+    }
+
+    fn call(&mut self, request: Request<B>) -> Self::Future {
+        let inner = self.inner.clone();
+        let mut inner = std::mem::replace(&mut self.inner, inner);
+
+        if request.extensions().get::<OidcAccessToken>().is_some() {
+            Box::pin(async move {
+                let response: Response = inner
+                    .call(request)
+                    .await
+                    .map_err(|e| MiddlewareError::NextMiddleware(e.into()))?;
+                return Ok(response);
+            })
+        } else {
+            Box::pin(async move {
+                let (mut parts, _) = request.into_parts();
+
+                let mut oidcclient: OidcClient<AC> = parts
+                    .extensions
+                    .get()
+                    .cloned()
+                    .ok_or(MiddlewareError::AuthMiddlewareNotFound)?;
+
+                let query = Query::<OidcQuery>::from_request_parts(&mut parts, &())
+                    .await
+                    .ok();
+
+                let session = parts
+                    .extensions
+                    .get::<Session>()
+                    .ok_or(MiddlewareError::SessionNotFound)?;
+                let login_session: Option<OidcSession> =
+                    session.get(SESSION_KEY).map_err(MiddlewareError::from)?;
+
+                let handler_uri =
+                    strip_oidc_from_path(oidcclient.application_base_url.clone(), &parts.uri)?;
+
+                oidcclient.client = oidcclient
+                    .client
+                    .set_redirect_uri(RedirectUrl::new(handler_uri.to_string())?);
+
+                if let (Some(mut login_session), Some(query)) = (login_session, query) {
+                    if login_session.csrf_token.secret() != &query.state {
+                        return Err(MiddlewareError::CsrfTokenInvalid);
+                    }
+
+                    let token_response = oidcclient
+                        .client
+                        .exchange_code(AuthorizationCode::new(query.code.to_string()))
+                        // Set the PKCE code verifier.
+                        .set_pkce_verifier(PkceCodeVerifier::new(
+                            login_session.pkce_verifier.secret().to_string(),
+                        ))
+                        .request_async(async_http_client)
+                        .await?;
+
+                    // Extract the ID token claims after verifying its authenticity and nonce.
+                    let id_token = token_response
+                        .id_token()
+                        .ok_or(MiddlewareError::IdTokenMissing)?;
+                    let claims = id_token
+                        .claims(&oidcclient.client.id_token_verifier(), &login_session.nonce)?;
+
+                    // Verify the access token hash to ensure that the access token hasn't been substituted for
+                    // another user's.
+                    if let Some(expected_access_token_hash) = claims.access_token_hash() {
+                        let actual_access_token_hash = AccessTokenHash::from_token(
+                            token_response.access_token(),
+                            &id_token.signing_alg()?,
+                        )?;
+                        if actual_access_token_hash != *expected_access_token_hash {
+                            return Err(MiddlewareError::AccessTokenHashInvalid);
+                        }
+                    }
+
+                    login_session.id_token = Some(id_token.to_string());
+                    login_session.access_token =
+                        Some(token_response.access_token().secret().to_string());
+
+                    session.insert(SESSION_KEY, login_session).unwrap();
+
+                    Ok(Redirect::temporary(&handler_uri.to_string()).into_response())
+                } else {
+                    let (pkce_challenge, pkce_verifier) = PkceCodeChallenge::new_random_sha256();
+                    let (auth_url, csrf_token, nonce) = {
+                        let mut auth = oidcclient.client.authorize_url(
+                            CoreAuthenticationFlow::AuthorizationCode,
+                            CsrfToken::new_random,
+                            Nonce::new_random,
+                        );
+
+                        for scope in oidcclient.scopes.iter() {
+                            auth = auth.add_scope(Scope::new(scope.to_string()));
+                        }
+
+                        auth.set_pkce_challenge(pkce_challenge).url()
+                    };
+
+                    let oidc_session = OidcSession {
+                        nonce,
+                        csrf_token,
+                        pkce_verifier,
+                        id_token: None,
+                        access_token: None,
+                    };
+
+                    session.insert(SESSION_KEY, oidc_session).unwrap();
+
+                    Ok(Redirect::temporary(auth_url.as_str()).into_response())
+                }
+            })
+        }
+    }
+}
+
+/// Layer for the [OidcAuthMiddleware].
+#[derive(Clone)]
+pub struct OidcAuthLayer<AC>
+where
+    AC: AdditionalClaims,
+{
+    client: OidcClient<AC>,
+}
+
+impl<AC: AdditionalClaims> OidcAuthLayer<AC> {
+    pub fn new(client: OidcClient<AC>) -> Self {
+        Self { client }
+    }
+
+    pub async fn discover_client(
+        application_base_url: Uri,
+        issuer: String,
+        client_id: String,
+        client_secret: Option<String>,
+        scopes: Vec<String>,
+    ) -> Result<Self, Error> {
+        Ok(Self {
+            client: OidcClient::<AC>::discover_new(
+                application_base_url,
+                issuer,
+                client_id,
+                client_secret,
+                scopes,
+            )
+            .await?,
+        })
+    }
+}
+
+impl<I, AC> Layer<I> for OidcAuthLayer<AC>
+where
+    AC: AdditionalClaims,
+{
+    type Service = OidcAuthMiddleware<I, AC>;
+
+    fn layer(&self, inner: I) -> Self::Service {
+        OidcAuthMiddleware {
+            inner,
+            client: self.client.clone(),
+        }
+    }
+}
+
+/// This middleware checks if the cached session is valid and injects the Claims, the AccessToken
+/// and the OidcClient in the request. This middleware needs to be loaded for every handler that is
+/// using on of the Extractors. This middleware **doesn't force a user to be
+/// authenticated**.
+#[derive(Clone)]
+pub struct OidcAuthMiddleware<I, AC>
+where
+    AC: AdditionalClaims,
+{
+    inner: I,
+    client: OidcClient<AC>,
+}
+
+impl<I, AC, B> Service<Request<B>> for OidcAuthMiddleware<I, AC>
+where
+    I: Service<Request<B>> + Send + 'static + Clone,
+    I::Response: IntoResponse + Send,
+    I::Error: Send + Into<BoxError>,
+    I::Future: Send + 'static,
+    AC: AdditionalClaims,
+    B: Send + 'static,
+{
+    type Response = Response;
+    type Error = MiddlewareError;
+    type Future = BoxFuture<'static, Result<Self::Response, Self::Error>>;
+
+    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.inner
+            .poll_ready(cx)
+            .map_err(|e| MiddlewareError::NextMiddleware(e.into()))
+    }
+
+    fn call(&mut self, request: Request<B>) -> Self::Future {
+        let inner = self.inner.clone();
+        let mut inner = std::mem::replace(&mut self.inner, inner);
+        let mut oidcclient = self.client.clone();
+        Box::pin(async move {
+            let (mut parts, body) = request.into_parts();
+
+            let session = parts
+                .extensions
+                .get::<Session>()
+                .ok_or(MiddlewareError::SessionNotFound)?;
+            let login_session: Option<OidcSession> =
+                session.get(SESSION_KEY).map_err(MiddlewareError::from)?;
+
+            let handler_uri =
+                strip_oidc_from_path(oidcclient.application_base_url.clone(), &parts.uri)?;
+
+            oidcclient.client = oidcclient
+                .client
+                .set_redirect_uri(RedirectUrl::new(handler_uri.to_string())?);
+
+            if let Some(OidcSession {
+                nonce,
+                csrf_token: _,
+                pkce_verifier: _,
+                id_token: Some(id_token),
+                access_token,
+            }) = &login_session
+            {
+                let id_token = IdToken::<AC>::from_str(&id_token).unwrap();
+                if let Ok(claims) = id_token.claims(&oidcclient.client.id_token_verifier(), nonce) {
+                    parts.extensions.insert(OidcClaims(claims.clone()));
+                    parts
+                        .extensions
+                        .insert(OidcAccessToken(access_token.clone().unwrap_or_default()));
+                }
+            }
+
+            parts.extensions.insert(oidcclient);
+
+            let request = Request::from_parts(parts, body);
+            let response: Response = inner
+                .call(request)
+                .await
+                .map_err(|e| MiddlewareError::NextMiddleware(e.into()))?
+                .into_response();
+            return Ok(response);
+        })
+    }
+}

src/util.rs

@@ -0,0 +1,32 @@
+use http::{uri::PathAndQuery, Uri};
+
+use crate::error::MiddlewareError;
+
+/// Helper function to remove the OpenID Connect authentication response query attributes from a
+/// [`Uri`].
+pub fn strip_oidc_from_path(base_url: Uri, uri: &Uri) -> Result<Uri, MiddlewareError> {
+    let mut base_url = base_url.into_parts();
+
+    base_url.path_and_query = uri
+        .path_and_query()
+        .map(|path_and_query| {
+            let query = path_and_query
+                .query()
+                .and_then(|uri| {
+                    uri.split('&')
+                        .filter(|x| {
+                            !x.starts_with("code")
+                                && !x.starts_with("state")
+                                && !x.starts_with("session_state")
+                        })
+                        .map(|x| x.to_string())
+                        .reduce(|acc, x| acc + "&" + &x)
+                })
+                .unwrap_or_default();
+
+            PathAndQuery::from_maybe_shared(format!("{}?{}", path_and_query.path(), query))
+        })
+        .transpose()?;
+
+    Ok(Uri::from_parts(base_url)?)
+}