ADDED: Swagger UI for API documentation

pom.xml

@@ -4,6 +4,9 @@
 	<groupId>org.qora</groupId>
 	<artifactId>qora-core</artifactId>
 	<version>2.0.0-SNAPSHOT</version>
+	<properties>
+		<swagger-ui.version>3.19.0</swagger-ui.version>
+	</properties>
 	<build>
 		<sourceDirectory>src</sourceDirectory>
 		<plugins>
@@ -15,6 +18,74 @@
 					<target>1.8</target>
 				</configuration>
 			</plugin>
+			<!-- unpack swagger-ui to target folder -->
+			<plugin>
+				<artifactId>maven-dependency-plugin</artifactId>
+				<executions>
+					<execution>
+						<id>swagger ui</id>
+						<phase>generate-resources</phase>
+						<goals>
+							<goal>unpack</goal>
+						</goals>
+						<configuration>
+							<artifactItems>
+								<artifactItem>
+									<groupId>org.webjars</groupId>
+									<artifactId>swagger-ui</artifactId>
+									<version>${swagger-ui.version}</version>
+								</artifactItem>
+							</artifactItems>
+							<outputDirectory>${project.build.directory}/swagger-ui.unpacked</outputDirectory>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+			<!-- inject correct url to swagger json file into swwagger-ui -->
+			<plugin>
+				<groupId>com.google.code.maven-replacer-plugin</groupId>
+				<artifactId>replacer</artifactId>
+				<version>1.5.3</version>
+				<executions>
+					<execution>
+						<phase>generate-resources</phase>
+						<goals>
+							  <goal>replace</goal>
+						</goals>
+					</execution>
+				</executions>
+				<configuration>
+					<file>${project.build.directory}/swagger-ui.unpacked/META-INF/resources/webjars/swagger-ui/${swagger-ui.version}/index.html</file>
+					<replacements>
+						<replacement>
+							<token>https://petstore.swagger.io/v2/swagger.json</token>
+							<value>/openapi.json</value>
+						</replacement>
+					</replacements>
+				</configuration>
+			</plugin>
+			<!-- add swagger-ui as resource to output package -->
+			<plugin>
+				<artifactId>maven-resources-plugin</artifactId>
+				<version>3.1.0</version>
+				<executions>
+					<execution>
+						<id>copy-resources</id>
+						<phase>generate-resources</phase>
+						<goals>
+							<goal>copy-resources</goal>
+						</goals>
+						<configuration>
+							<outputDirectory>${project.build.directory}/classes/resources/swagger-ui</outputDirectory>
+							<resources>
+								<resource>
+									<directory>${project.build.directory}/swagger-ui.unpacked/META-INF/resources/webjars/swagger-ui/${swagger-ui.version}</directory>
+								</resource>
+							</resources>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 	<repositories>
@@ -128,15 +199,25 @@
 			<artifactId>hamcrest-library</artifactId>
 			<version>1.3</version>
 		</dependency>
-	 <dependency>
+		<dependency>
-	  <groupId>org.glassfish.jersey.media</groupId>
+			<groupId>org.glassfish.jersey.media</groupId>
-	  <artifactId>jersey-media-multipart</artifactId>
+			<artifactId>jersey-media-multipart</artifactId>
-	  <version>2.27</version>
+			<version>2.27</version>
-	 </dependency>
+		</dependency>
-	 <dependency>
+		<dependency>
-	  <groupId>javax.mail</groupId>
+			<groupId>javax.mail</groupId>
-	  <artifactId>mail</artifactId>
+			<artifactId>mail</artifactId>
-	  <version>1.5.0-b01</version>
+			<version>1.5.0-b01</version>
-	 </dependency>
+		</dependency>
+		<dependency>
+			<groupId>org.webjars</groupId>
+			<artifactId>swagger-ui</artifactId>
+			<version>${swagger-ui.version}</version>
+		</dependency>
+		<dependency>
+			<groupId>org.eclipse.jetty</groupId>
+			<artifactId>jetty-rewrite</artifactId>
+			<version>9.4.11.v20180605</version>
+		</dependency>
 	</dependencies>
 </project>

src/api/ApiService.java

@@ -1,11 +1,15 @@
 package api;
 
 import io.swagger.v3.jaxrs2.integration.resources.OpenApiResource;
+import java.io.File;
 import java.util.HashSet;
 import java.util.Set;
+import org.eclipse.jetty.rewrite.handler.RedirectPatternRule;
+import org.eclipse.jetty.rewrite.handler.RewriteHandler;
 
 import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.handler.InetAccessHandler;
+import org.eclipse.jetty.servlet.DefaultServlet;
 import org.eclipse.jetty.servlet.ServletContextHandler;
 import org.eclipse.jetty.servlet.ServletHolder;
 import org.glassfish.jersey.server.ResourceConfig;
@@ -36,16 +40,30 @@ public class ApiService {
 		}
 		this.server.setHandler(accessHandler);
 
+		// url rewriting
+		RewriteHandler rewriteHandler = new RewriteHandler();
+		accessHandler.setHandler(rewriteHandler);
+
 		// context
 		ServletContextHandler context = new ServletContextHandler(ServletContextHandler.NO_SESSIONS);
 		context.setContextPath("/");
-		accessHandler.setHandler(context);
+		rewriteHandler.setHandler(context);
-
+				
 		// API servlet
 		ServletContainer container = new ServletContainer(config);
 		ServletHolder apiServlet = new ServletHolder(container);
 		apiServlet.setInitOrder(1);
 		context.addServlet(apiServlet, "/*");
+		
+		// Swagger-UI static content
+		ClassLoader loader = this.getClass().getClassLoader();
+		File swaggerUIResourceLocation = new File(loader.getResource("resources/swagger-ui/").getFile());
+        ServletHolder swaggerUIServlet = new ServletHolder("static-swagger-ui", DefaultServlet.class);
+        swaggerUIServlet.setInitParameter("resourceBase", swaggerUIResourceLocation.getAbsolutePath());
+        swaggerUIServlet.setInitParameter("dirAllowed","true");
+        swaggerUIServlet.setInitParameter("pathInfoOnly","true");
+        context.addServlet(swaggerUIServlet,"/api-documentation/*");
+		rewriteHandler.addRule(new RedirectPatternRule("/api-documentation", "/api-documentation/index.html")); // redirect to swagger ui start page
 	}
 
 	//XXX: replace singleton pattern by dependency injection?