OAuth 2.0 logout handler resolves uri placeholders

- OidcClientInitiatedLogoutSuccessHandler can automatically resolve placeholders like baseUrl and registrationId inside the postLogoutRedirectUri

Issue gh-7900

Author: Enkosz

oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,7 +18,8 @@
 
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
-import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
@@ -67,7 +68,7 @@ protected String determineTargetUrl(HttpServletRequest request, HttpServletRespo
 			URI endSessionEndpoint = this.endSessionEndpoint(clientRegistration);
 			if (endSessionEndpoint != null) {
 				String idToken = idToken(authentication);
-				String postLogoutRedirectUri = postLogoutRedirectUri(request);
+				String postLogoutRedirectUri = postLogoutRedirectUri(request, clientRegistration);
 				targetUrl = endpointUri(endSessionEndpoint, idToken, postLogoutRedirectUri);
 			}
 		}
@@ -89,7 +90,7 @@ private String idToken(Authentication authentication) {
 		return ((OidcUser) authentication.getPrincipal()).getIdToken().getTokenValue();
 	}
 
-	private String postLogoutRedirectUri(HttpServletRequest request) {
+	private String postLogoutRedirectUri(HttpServletRequest request, ClientRegistration clientRegistration) {
 		if (this.postLogoutRedirectUri == null) {
 			return null;
 		}
@@ -100,8 +101,13 @@ private String postLogoutRedirectUri(HttpServletRequest request) {
 				.replaceQuery(null)
 				.fragment(null)
 				.build();
+
+		Map<String, String> uriVariables = new HashMap<>();
+		uriVariables.put("baseUrl", uriComponents.toUriString());
+		uriVariables.put("registrationId", clientRegistration.getRegistrationId());
+
 		return UriComponentsBuilder.fromUriString(this.postLogoutRedirectUri)
-				.buildAndExpand(Collections.singletonMap("baseUrl", uriComponents.toUriString()))
+				.buildAndExpand(uriVariables)
 				.toUriString();
 		// @formatter:on
 	}

oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -138,6 +138,22 @@ public void logoutWhenUsingPostLogoutRedirectUriTemplateThenBuildsItForRedirect(
 				"https://endpoint?" + "id_token_hint=id-token&" + "post_logout_redirect_uri=https://rp.example.org");
 	}
 
+	@Test
+	public void logoutWhenUsingPostLogoutRedirectUriTemplateThenBuildsItForRedirectExpanded()
+			throws IOException, ServletException {
+		OAuth2AuthenticationToken token = new OAuth2AuthenticationToken(TestOidcUsers.create(),
+				AuthorityUtils.NO_AUTHORITIES, this.registration.getRegistrationId());
+		this.handler.setPostLogoutRedirectUri("{baseUrl}/{registrationId}");
+		this.request.setScheme("https");
+		this.request.setServerPort(443);
+		this.request.setServerName("rp.example.org");
+		this.request.setUserPrincipal(token);
+		this.handler.onLogoutSuccess(this.request, this.response, token);
+		assertThat(this.response.getRedirectedUrl()).isEqualTo(String.format(
+				"https://endpoint?" + "id_token_hint=id-token&" + "post_logout_redirect_uri=https://rp.example.org/%s",
+				this.registration.getRegistrationId()));
+	}
+
 	// gh-9511
 	@Test
 	public void logoutWhenUsingPostLogoutRedirectUriWithQueryParametersThenBuildsItForRedirect()