Add JwkSet endpoint as filter

Fixes gh-2

build.gradle

@@ -16,6 +16,8 @@ group = 'org.springframework.security.experimental'
 description = 'Spring Authorization Server'
 version = '0.0.1-SNAPSHOT'
 
+ext['junit-jupiter.version'] = '5.4.0'
+
 repositories {
 	mavenCentral()
 }

samples/boot/minimal/README.md

@@ -0,0 +1,12 @@
+## Minimal Authorization Server Sample
+
+#### How to run
+
+```
+./gradlew spring-authorization-server-samples-boot-minimal:bootRun
+```
+
+```
+curl http://localhost:8080/.well-known/jwk_uris
+```
+

samples/boot/minimal/spring-authorization-server-samples-boot-minimal.gradle

@@ -1,10 +1,19 @@
 apply plugin: 'io.spring.convention.spring-sample-boot'
 
 dependencies {
-	implementation 'org.springframework.boot:spring-boot-starter'
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	implementation 'org.springframework.boot:spring-boot-starter-security'
+
+	implementation 'com.nimbusds:oauth2-oidc-sdk'
+
 	testImplementation('org.springframework.boot:spring-boot-starter-test') {
 		exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
 	}
+
+    testImplementation 'org.springframework.security:spring-security-test'
+
+    testRuntime("org.junit.platform:junit-platform-runner")
+    testRuntime("org.junit.jupiter:junit-jupiter-engine")
 }
 
 test {

samples/boot/minimal/src/main/java/sample/JwkSetEndpointFilter.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample;
+
+import static org.springframework.http.HttpMethod.GET;
+import static org.springframework.http.MediaType.APPLICATION_JSON_VALUE;
+
+import java.io.IOException;
+import java.io.Writer;
+
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.security.web.util.matcher.AntPathRequestMatcher;
+import org.springframework.security.web.util.matcher.RequestMatcher;
+import org.springframework.util.Assert;
+import org.springframework.web.filter.OncePerRequestFilter;
+import org.springframework.web.util.UrlPathHelper;
+
+import com.nimbusds.jose.jwk.JWKSet;
+
+public class JwkSetEndpointFilter extends OncePerRequestFilter {
+
+	static final String WELL_KNOWN_JWK_URIS = "/.well-known/jwk_uris";
+
+	private final RequestMatcher requestMatcher = new AntPathRequestMatcher(WELL_KNOWN_JWK_URIS, GET.name(), true,
+			new UrlPathHelper());
+
+	private final JWKSet jwkSet;
+
+	public JwkSetEndpointFilter(JWKSet jwkSet) {
+		Assert.notNull(jwkSet, "jwkSet cannot be null");
+		this.jwkSet = jwkSet;
+	}
+
+	@Override
+	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
+			throws ServletException, IOException {
+
+		if (ifRequestMatches(request)) {
+			respond(response);
+		} else {
+			filterChain.doFilter(request, response);
+		}
+	}
+
+	private void respond(HttpServletResponse response) throws IOException {
+		response.setContentType(APPLICATION_JSON_VALUE);
+		try (Writer writer = response.getWriter()) {
+			writer.write(jwkSet.toPublicJWKSet().toJSONObject().toJSONString());
+		}
+	}
+
+	private boolean ifRequestMatches(HttpServletRequest request) {
+		return this.requestMatcher.matches(request);
+	}
+
+}

samples/boot/minimal/src/main/java/sample/SecurityConfig.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample;
+
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+import org.springframework.security.web.access.channel.ChannelProcessingFilter;
+
+import com.nimbusds.jose.JOSEException;
+import com.nimbusds.jose.jwk.JWK;
+import com.nimbusds.jose.jwk.JWKSet;
+import com.nimbusds.jose.jwk.KeyUse;
+import com.nimbusds.jose.jwk.gen.RSAKeyGenerator;
+
+@EnableWebSecurity
+public class SecurityConfig extends WebSecurityConfigurerAdapter {
+
+	@Override
+	protected void configure(HttpSecurity http) throws Exception {
+		http.addFilterBefore(new JwkSetEndpointFilter(generateJwkSet()), ChannelProcessingFilter.class);
+	}
+
+	protected JWKSet generateJwkSet() throws JOSEException {
+		JWK jwk = new RSAKeyGenerator(2048).keyID("minimal-ASA").keyUse(KeyUse.SIGNATURE).generate();
+		return new JWKSet(jwk);
+	}
+
+}

samples/boot/minimal/src/test/java/sample/JwkSetEndpointFilterTest.java

@@ -0,0 +1,127 @@
+/*
+ * Copyright 2020 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package sample;
+
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.hamcrest.Matchers.is;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.only;
+import static org.mockito.Mockito.verify;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+import static sample.JwkSetEndpointFilter.WELL_KNOWN_JWK_URIS;
+
+import javax.servlet.FilterChain;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.TestInstance.Lifecycle;
+import org.mockito.Mockito;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.setup.MockMvcBuilders;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.nimbusds.jose.JOSEException;
+import com.nimbusds.jose.jwk.JWK;
+import com.nimbusds.jose.jwk.JWKSet;
+import com.nimbusds.jose.jwk.KeyUse;
+import com.nimbusds.jose.jwk.gen.RSAKeyGenerator;
+
+@TestInstance(Lifecycle.PER_CLASS)
+public class JwkSetEndpointFilterTest {
+
+	private MockMvc mvc;
+	private JWKSet jwkSet;
+	private JWK jwk;
+	private JwkSetEndpointFilter filter;
+
+	@BeforeAll
+	void setup() throws JOSEException {
+		this.jwk = new RSAKeyGenerator(2048).keyID("endpoint-test").keyUse(KeyUse.SIGNATURE).generate();
+		this.jwkSet = new JWKSet(jwk);
+		this.filter = new JwkSetEndpointFilter(jwkSet);
+		this.mvc = MockMvcBuilders.standaloneSetup(new FakeController()).addFilters(filter).alwaysDo(print()).build();
+	}
+
+	@Test
+	void constructorWhenJsonWebKeySetIsNullThrowIllegalArgumentException() {
+		assertThatThrownBy(() -> new JwkSetEndpointFilter(null)).isInstanceOf(IllegalArgumentException.class);
+	}
+
+	@Test
+	void doFilterWhenPathMatches() throws Exception {
+		String requestUri = WELL_KNOWN_JWK_URIS;
+		MockHttpServletRequest request = new MockHttpServletRequest("GET", requestUri);
+		request.setServletPath(requestUri);
+
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		FilterChain filterChain = mock(FilterChain.class);
+
+		this.filter.doFilter(request, response, filterChain);
+
+		verify(filterChain, never()).doFilter(Mockito.any(HttpServletRequest.class),
+				Mockito.any(HttpServletResponse.class));
+	}
+
+	@Test
+	void doFilterWhenPathDoesNotMatch() throws Exception {
+		String requestUri = "/stuff/" + WELL_KNOWN_JWK_URIS;
+		MockHttpServletRequest request = new MockHttpServletRequest("GET", requestUri);
+		request.setServletPath(requestUri);
+
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		FilterChain filterChain = mock(FilterChain.class);
+
+		this.filter.doFilter(request, response, filterChain);
+
+		verify(filterChain, only()).doFilter(Mockito.any(HttpServletRequest.class),
+				Mockito.any(HttpServletResponse.class));
+	}
+
+	@Test
+	void testResponseIfRequestMatches() throws Exception {
+		mvc.perform(get(WELL_KNOWN_JWK_URIS)).andDo(print()).andExpect(status().isOk())
+				.andExpect(jsonPath("$.keys").isArray()).andExpect(jsonPath("$.keys").isNotEmpty())
+				.andExpect(jsonPath("$.keys[0].kid").value(jwk.getKeyID()))
+				.andExpect(jsonPath("$.keys[0].kty").value(jwk.getKeyType().toString()));
+	}
+
+	@Test
+	void testResponseIfNotRequestMatches() throws Exception {
+		mvc.perform(get("/fake")).andDo(print()).andExpect(status().isOk())
+				.andExpect(content().string(is("fake")));
+	}
+
+	@RestController
+	class FakeController {
+
+		@RequestMapping("/fake")
+		public String hello() {
+			return "fake";
+		}
+	}
+}

samples/boot/minimal/src/test/java/sample/MinimalAuthorizationServerApplicationTests.java

@@ -15,18 +15,29 @@
  */
 package sample;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.http.HttpStatus.OK;
+
 import org.junit.jupiter.api.Test;
 import org.springframework.boot.test.context.SpringBootTest;
-import org.springframework.context.ApplicationContext;
-
-import static org.assertj.core.api.Assertions.assertThat;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.web.server.LocalServerPort;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.client.RestTemplate;
 
-@SpringBootTest
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
 public class MinimalAuthorizationServerApplicationTests {
 
+	private RestTemplate rest = new RestTemplate();
+
+	@LocalServerPort
+	private int serverPort;
+
 	@Test
-	public void loadContext(ApplicationContext context) {
-		assertThat(context).isNotNull();
+	void verifyJwkSetEndpointFilterAccessibleWithoutAuthentication() {
+		ResponseEntity<String> responseEntity = rest.getForEntity(
+				"http://localhost:" + serverPort + JwkSetEndpointFilter.WELL_KNOWN_JWK_URIS, String.class);
+		assertThat(responseEntity.getStatusCode()).isEqualTo(OK);
 	}
 
 }