Added first implementation of RP Initiated Logout

Created a new extractor for RP-Initiated-Logout and modified example to
use it.

src/error.rs

@@ -10,6 +10,9 @@ use thiserror::Error;
 pub enum ExtractorError {
     #[error("unauthorized")]
     Unauthorized,
+
+    #[error("rp initiated logout information not found")]
+    RpInitiatedLogoutInformationNotFound,
 }
 
 #[derive(Debug, Error)]
@@ -65,6 +68,9 @@ pub enum Error {
     #[error("url parsing: {0:?}")]
     UrlParsing(#[from] openidconnect::url::ParseError),
 
+    #[error("invalid end_session_endpoint uri: {0:?}")]
+    InvalidEndSessionEndpoint(http::uri::InvalidUri),
+
     #[error("discovery: {0:?}")]
     Discovery(#[from] openidconnect::DiscoveryError<openidconnect::reqwest::Error<reqwest::Error>>),
 
@@ -77,7 +83,12 @@ pub enum Error {
 
 impl IntoResponse for ExtractorError {
     fn into_response(self) -> axum_core::response::Response {
-        (StatusCode::UNAUTHORIZED, "unauthorized").into_response()
+        match self {
+            Self::Unauthorized => (StatusCode::UNAUTHORIZED, "unauthorized").into_response(),
+            Self::RpInitiatedLogoutInformationNotFound => {
+                (StatusCode::INTERNAL_SERVER_ERROR, "intenal server error").into_response()
+            }
+        }
     }
 }
 

src/extractor.rs

@@ -1,9 +1,13 @@
-use std::ops::Deref;
+use std::{borrow::Cow, ops::Deref};
 
 use crate::{error::ExtractorError, AdditionalClaims};
 use async_trait::async_trait;
-use axum_core::extract::FromRequestParts;
-use http::request::Parts;
+use axum::response::Redirect;
+use axum_core::{
+    extract::FromRequestParts,
+    response::{IntoResponse, Response},
+};
+use http::{request::Parts, uri::PathAndQuery, Uri};
 use openidconnect::{core::CoreGenderClaim, IdTokenClaims};
 
 /// Extractor for the OpenID Connect Claims.
@@ -81,3 +85,80 @@ impl AsRef<str> for OidcAccessToken {
         self.0.as_str()
     }
 }
+
+#[derive(Clone)]
+pub struct OidcRpInitiatedLogout {
+    pub(crate) end_session_endpoint: Uri,
+    pub(crate) id_token_hint: String,
+    pub(crate) client_id: String,
+    pub(crate) post_logout_redirect_uri: Option<Uri>,
+    pub(crate) state: Option<String>,
+}
+
+impl OidcRpInitiatedLogout {
+    pub fn with_post_logout_redirect(mut self, uri: Uri) -> Self {
+        self.post_logout_redirect_uri = Some(uri);
+        self
+    }
+    pub fn with_state(mut self, state: String) -> Self {
+        self.state = Some(state);
+        self
+    }
+    pub fn uri(self) -> Uri {
+        let mut parts = self.end_session_endpoint.into_parts();
+
+        let query = {
+            let mut query = Vec::with_capacity(4);
+            query.push(("id_token_hint", Cow::Borrowed(&self.id_token_hint)));
+            query.push(("client_id", Cow::Borrowed(&self.client_id)));
+
+            if let Some(post_logout_redirect_uri) = &self.post_logout_redirect_uri {
+                query.push((
+                    "post_logout_redirect_uri",
+                    Cow::Owned(post_logout_redirect_uri.to_string()),
+                ));
+            }
+            if let Some(state) = &self.state {
+                query.push(("state", Cow::Borrowed(state)));
+            }
+
+            query
+                .into_iter()
+                .map(|(k, v)| format!("{}={}", k, urlencoding::encode(v.as_str())))
+                .collect::<Vec<_>>()
+                .join("&")
+        };
+
+        let path_and_query = match parts.path_and_query {
+            Some(path_and_query) => {
+                PathAndQuery::from_maybe_shared(format!("{}?{}", path_and_query.path(), query))
+            }
+            None => PathAndQuery::from_maybe_shared(format!("?{}", query)),
+        };
+        parts.path_and_query = Some(path_and_query.unwrap());
+
+        Uri::from_parts(parts).unwrap()
+    }
+}
+#[async_trait]
+impl<S> FromRequestParts<S> for OidcRpInitiatedLogout
+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)
+    }
+}
+
+#[async_trait]
+impl IntoResponse for OidcRpInitiatedLogout {
+    fn into_response(self) -> Response {
+        Redirect::temporary(&self.uri().to_string()).into_response()
+    }
+}

src/lib.rs

@@ -6,10 +6,12 @@ use crate::error::Error;
 use http::Uri;
 use openidconnect::{
     core::{
-        CoreAuthDisplay, CoreAuthPrompt, CoreErrorResponseType, CoreGenderClaim, CoreJsonWebKey,
-        CoreJsonWebKeyType, CoreJsonWebKeyUse, CoreJweContentEncryptionAlgorithm,
-        CoreJwsSigningAlgorithm, CoreProviderMetadata, CoreRevocableToken,
-        CoreRevocationErrorResponse, CoreTokenIntrospectionResponse, CoreTokenType,
+        CoreAuthDisplay, CoreAuthPrompt, CoreClaimName, CoreClaimType, CoreClientAuthMethod,
+        CoreErrorResponseType, CoreGenderClaim, CoreGrantType, CoreJsonWebKey, CoreJsonWebKeyType,
+        CoreJsonWebKeyUse, CoreJweContentEncryptionAlgorithm, CoreJweKeyManagementAlgorithm,
+        CoreJwsSigningAlgorithm, CoreProviderMetadata, CoreResponseMode, CoreResponseType,
+        CoreRevocableToken, CoreRevocationErrorResponse, CoreSubjectIdentifierType,
+        CoreTokenIntrospectionResponse, CoreTokenType,
     },
     reqwest::async_http_client,
     ClientId, ClientSecret, CsrfToken, EmptyExtraTokenFields, IdTokenFields, IssuerUrl, Nonce,
@@ -21,7 +23,7 @@ pub mod error;
 mod extractor;
 mod middleware;
 
-pub use extractor::{OidcAccessToken, OidcClaims};
+pub use extractor::{OidcAccessToken, OidcClaims, OidcRpInitiatedLogout};
 pub use middleware::{OidcAuthLayer, OidcAuthMiddleware, OidcLoginLayer, OidcLoginMiddleware};
 
 const SESSION_KEY: &str = "axum-oidc";
@@ -66,14 +68,34 @@ type Client<AC> = openidconnect::Client<
     CoreRevocationErrorResponse,
 >;
 
+type ProviderMetadata = openidconnect::ProviderMetadata<
+    AdditionalProviderMetadata,
+    CoreAuthDisplay,
+    CoreClientAuthMethod,
+    CoreClaimName,
+    CoreClaimType,
+    CoreGrantType,
+    CoreJweContentEncryptionAlgorithm,
+    CoreJweKeyManagementAlgorithm,
+    CoreJwsSigningAlgorithm,
+    CoreJsonWebKeyType,
+    CoreJsonWebKeyUse,
+    CoreJsonWebKey,
+    CoreResponseMode,
+    CoreResponseType,
+    CoreSubjectIdentifierType,
+>;
+
 pub type BoxError = Box<dyn std::error::Error + Send + Sync>;
 
 /// OpenID Connect Client
 #[derive(Clone)]
 pub struct OidcClient<AC: AdditionalClaims> {
     scopes: Vec<String>,
+    client_id: String,
     client: Client<AC>,
     application_base_url: Uri,
+    end_session_endpoint: Option<Uri>,
 }
 
 impl<AC: AdditionalClaims> OidcClient<AC> {
@@ -85,17 +107,25 @@ impl<AC: AdditionalClaims> OidcClient<AC> {
         scopes: Vec<String>,
     ) -> Result<Self, Error> {
         let provider_metadata =
-            CoreProviderMetadata::discover_async(IssuerUrl::new(issuer)?, async_http_client)
-                .await?;
+            ProviderMetadata::discover_async(IssuerUrl::new(issuer)?, async_http_client).await?;
+        let end_session_endpoint = provider_metadata
+            .additional_metadata()
+            .end_session_endpoint
+            .clone()
+            .map(Uri::from_maybe_shared)
+            .transpose()
+            .map_err(Error::InvalidEndSessionEndpoint)?;
         let client = Client::from_provider_metadata(
             provider_metadata,
-            ClientId::new(client_id),
+            ClientId::new(client_id.clone()),
             client_secret.map(ClientSecret::new),
         );
         Ok(Self {
             scopes,
             client,
+            client_id,
             application_base_url,
+            end_session_endpoint,
         })
     }
 }
@@ -138,3 +168,9 @@ impl OidcSession {
             .map(|x| RefreshToken::new(x.to_string()))
     }
 }
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+struct AdditionalProviderMetadata {
+    end_session_endpoint: Option<String>,
+}
+impl openidconnect::AdditionalProviderMetadata for AdditionalProviderMetadata {}

src/middleware.rs

@@ -25,7 +25,7 @@ use openidconnect::{
 
 use crate::{
     error::{Error, MiddlewareError},
-    extractor::{OidcAccessToken, OidcClaims},
+    extractor::{OidcAccessToken, OidcClaims, OidcRpInitiatedLogout},
     AdditionalClaims, BoxError, OidcClient, OidcQuery, OidcSession, SESSION_KEY,
 };
 
@@ -334,6 +334,16 @@ where
                         parts.extensions.insert(OidcAccessToken(
                             login_session.access_token.clone().unwrap_or_default(),
                         ));
+                        if let Some(end_session_endpoint) = oidcclient.end_session_endpoint.clone()
+                        {
+                            parts.extensions.insert(OidcRpInitiatedLogout {
+                                end_session_endpoint,
+                                id_token_hint: login_session.id_token.clone().unwrap(),
+                                client_id: oidcclient.client_id.clone(),
+                                post_logout_redirect_uri: None,
+                                state: None,
+                            });
+                        }
                     }
                     // stored id token is invalid and can't be uses, but we have a refresh token
                     // and can use it and try to get another id token.