Support OAuth2 token introspection

fixes #157

Signed-off-by: Nageswara Rao Maridu <maridu.nageswararao@gmail.com>

Author: nrmaridu

mock/src/main/java/com/tngtech/keycloakmock/impl/UrlConfiguration.java

@@ -16,6 +16,9 @@ public class UrlConfiguration {
   private static final String OPEN_ID_JWKS_PATH = "certs";
   private static final String OPEN_ID_AUTHORIZATION_PATH = "auth";
   private static final String OPEN_ID_END_SESSION_PATH = "logout";
+
+  private static final String TOKEN_INTROSPECTION_PATH = "/introspect";
+
   @Nonnull private final Protocol protocol;
   private final int port;
   @Nonnull private final String hostname;
@@ -132,4 +135,9 @@ public String getHostname() {
   public String getRealm() {
     return realm;
   }
+
+  @Nonnull
+  public URI getTokenIntrospectionEndPoint() {
+    return getOpenIdPath(OPEN_ID_TOKEN_PATH + TOKEN_INTROSPECTION_PATH);
+  }
 }

mock/src/main/java/com/tngtech/keycloakmock/impl/dagger/ServerModule.java

@@ -14,6 +14,7 @@
 import com.tngtech.keycloakmock.impl.handler.OutOfBandLoginRoute;
 import com.tngtech.keycloakmock.impl.handler.RequestUrlConfigurationHandler;
 import com.tngtech.keycloakmock.impl.handler.ResourceFileHandler;
+import com.tngtech.keycloakmock.impl.handler.TokenIntrospectionRoute;
 import com.tngtech.keycloakmock.impl.handler.TokenRoute;
 import com.tngtech.keycloakmock.impl.handler.WellKnownRoute;
 import dagger.Lazy;
@@ -148,7 +149,8 @@ Router provideRouter(
       @Nonnull LogoutRoute logoutRoute,
       @Nonnull DelegationRoute delegationRoute,
       @Nonnull OutOfBandLoginRoute outOfBandLoginRoute,
-      @Nonnull @Named("keycloakJs") ResourceFileHandler keycloakJsRoute) {
+      @Nonnull @Named("keycloakJs") ResourceFileHandler keycloakJsRoute,
+      @Nonnull TokenIntrospectionRoute tokenIntrospectionRoute) {
     UrlConfiguration routing = defaultConfiguration.forRequestContext(null, ":realm");
     Router router = Router.router(vertx);
     router
@@ -180,6 +182,10 @@ Router provideRouter(
     router.get(routing.getOpenIdPath("delegated").getPath()).handler(delegationRoute);
     router.get(routing.getOutOfBandLoginLoginEndpoint().getPath()).handler(outOfBandLoginRoute);
     router.route("/auth/js/keycloak.js").handler(keycloakJsRoute);
+    router
+        .post(routing.getTokenIntrospectionEndPoint().getPath())
+        .handler(BodyHandler.create())
+        .handler(tokenIntrospectionRoute);
     return router;
   }
 

mock/src/main/java/com/tngtech/keycloakmock/impl/handler/TokenIntrospectionRoute.java

@@ -0,0 +1,83 @@
+package com.tngtech.keycloakmock.impl.handler;
+
+import com.tngtech.keycloakmock.impl.helper.TokenHelper;
+import io.jsonwebtoken.Claims;
+import io.netty.handler.codec.http.HttpResponseStatus;
+import io.vertx.core.Handler;
+import io.vertx.core.json.Json;
+import io.vertx.ext.web.RoutingContext;
+import java.time.Instant;
+import java.util.HashMap;
+import java.util.Map;
+import javax.annotation.Nonnull;
+import javax.inject.Inject;
+import javax.inject.Singleton;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Singleton
+public class TokenIntrospectionRoute implements Handler<RoutingContext> {
+
+  private static final Logger LOG = LoggerFactory.getLogger(TokenIntrospectionRoute.class);
+
+  private static final String TOKEN_PREFIX = "token=";
+  private static final String ACTIVE_CLAIM = "active";
+
+  @Nonnull private final TokenHelper tokenHelper;
+
+  @Inject
+  public TokenIntrospectionRoute(@Nonnull TokenHelper tokenHelper) {
+    this.tokenHelper = tokenHelper;
+  }
+
+  @Override
+  public void handle(RoutingContext routingContext) {
+    LOG.info(
+        "Inside TokenIntrospectionRoute. Request body is : {}", routingContext.body().asString());
+
+    String body = routingContext.body().asString();
+
+    if (!body.startsWith(TOKEN_PREFIX)) {
+      routingContext
+          .response()
+          .putHeader("content-type", "application/json")
+          .setStatusCode(HttpResponseStatus.BAD_REQUEST.code())
+          .end("Invalid request body");
+    }
+
+    String token = body.replaceFirst("^" + TOKEN_PREFIX, "");
+
+    LOG.debug("Received a request to introspect token : {}", token);
+
+    Map<String, Object> claims;
+    try {
+      claims = tokenHelper.parseToken(token);
+    } catch (Exception e) {
+      // If the token is invalid, initialize an empty claims map
+      claims = new HashMap<>();
+    }
+
+    // To support various use cases, we are returning the same claims as the input token
+    Map<String, Object> responseClaims = new HashMap<>(claims);
+
+    if (responseClaims.get(Claims.EXPIRATION) != null
+        && isExpiryTimeInFuture(responseClaims.get(Claims.EXPIRATION).toString())) {
+      LOG.debug("Introspected token is valid");
+      responseClaims.put(ACTIVE_CLAIM, true);
+    } else {
+      LOG.debug("Introspected token is invalid");
+      responseClaims.put(ACTIVE_CLAIM, false);
+    }
+
+    routingContext
+        .response()
+        .putHeader("content-type", "application/json")
+        .end(Json.encode(responseClaims));
+  }
+
+  private boolean isExpiryTimeInFuture(String expiryTime) {
+    long currentTimeInSec = Instant.now().getEpochSecond();
+    long expiryTimeInSec = Long.parseLong(expiryTime);
+    return currentTimeInSec < expiryTimeInSec;
+  }
+}

mock/src/main/java/com/tngtech/keycloakmock/impl/handler/WellKnownRoute.java

@@ -44,7 +44,8 @@ private JsonObject getConfiguration(@Nonnull UrlConfiguration requestConfigurati
         .put("subject_types_supported", new JsonArray(Collections.singletonList("public")))
         .put(
             "id_token_signing_alg_values_supported",
-            new JsonArray(Collections.singletonList("RS256")));
+            new JsonArray(Collections.singletonList("RS256")))
+        .put("introspection_endpoint", requestConfiguration.getTokenIntrospectionEndPoint());
     return result;
   }
 }

mock/src/test/java/com/tngtech/keycloakmock/impl/UrlConfigurationTest.java

@@ -156,6 +156,9 @@ void urls_are_correct() {
         .hasToString("http://localhost:8000/auth/realms/master/protocol/openid-connect/certs");
     assertThat(urlConfiguration.getTokenEndpoint())
         .hasToString("http://localhost:8000/auth/realms/master/protocol/openid-connect/token");
+    assertThat(urlConfiguration.getTokenIntrospectionEndPoint())
+        .hasToString(
+            "http://localhost:8000/auth/realms/master/protocol/openid-connect/token/introspect");
   }
 
   @Test
@@ -174,6 +177,9 @@ void urls_are_correct_with_no_context_path() {
         .hasToString("http://localhost:8000/realms/master/protocol/openid-connect/certs");
     assertThat(urlConfiguration.getTokenEndpoint())
         .hasToString("http://localhost:8000/realms/master/protocol/openid-connect/token");
+    assertThat(urlConfiguration.getTokenIntrospectionEndPoint())
+        .hasToString(
+            "http://localhost:8000/realms/master/protocol/openid-connect/token/introspect");
   }
 
   @Test
@@ -198,6 +204,10 @@ void urls_are_correct_with_custom_context_path() {
     assertThat(urlConfiguration.getTokenEndpoint())
         .hasToString(
             "http://localhost:8000/custom/context/path/realms/master/protocol/openid-connect/token");
+
+    assertThat(urlConfiguration.getTokenIntrospectionEndPoint())
+        .hasToString(
+            "http://localhost:8000/custom/context/path/realms/master/protocol/openid-connect/token/introspect");
   }
 
   @Test

mock/src/test/java/com/tngtech/keycloakmock/impl/handler/WellKnownRouteTest.java

@@ -24,6 +24,7 @@ class WellKnownRouteTest extends HandlerTestBase {
   private static final String END_SESSION_ENDPOINT = "endSessionEndpoint";
   private static final String JWKS_URI = "jwksUri";
   private static final String TOKEN_ENDPOINT = "tokenEndpoint";
+  private static final String TOKEN_INTROSPECTION_ENDPOINT = "tokenIntrospectionEndpoint";
 
   @Mock private UrlConfiguration urlConfiguration;
 
@@ -37,6 +38,9 @@ void well_known_configuration_is_complete() throws URISyntaxException {
     doReturn(new URI(END_SESSION_ENDPOINT)).when(urlConfiguration).getEndSessionEndpoint();
     doReturn(new URI(JWKS_URI)).when(urlConfiguration).getJwksUri();
     doReturn(new URI(TOKEN_ENDPOINT)).when(urlConfiguration).getTokenEndpoint();
+    doReturn(new URI(TOKEN_INTROSPECTION_ENDPOINT))
+        .when(urlConfiguration)
+        .getTokenIntrospectionEndPoint();
 
     wellKnownRoute.handle(routingContext);
 
@@ -57,6 +61,7 @@ private ConfigurationResponse getExpectedResponse() {
         Arrays.asList("code", "code id_token", "id_token", "token id_token");
     response.subject_types_supported = Collections.singletonList("public");
     response.id_token_signing_alg_values_supported = Collections.singletonList("RS256");
+    response.introspection_endpoint = TOKEN_INTROSPECTION_ENDPOINT;
     return response;
   }
 }

mock/src/test/java/com/tngtech/keycloakmock/test/ConfigurationResponse.java

@@ -11,4 +11,6 @@ public class ConfigurationResponse {
   public List<String> subject_types_supported;
   public List<String> id_token_signing_alg_values_supported;
   public String end_session_endpoint;
+
+  public String introspection_endpoint;
 }