Make dimension limits Option<Integer> instead of using the magic value of 0 for "no limit", and add more tests for the ServerConfig.

pom.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
     <parent>
@@ -57,7 +58,7 @@
     <properties>
         <maze-generator.version>0.2.1</maze-generator.version>
         <maven-site-plugin.version>4.0.0-M8</maven-site-plugin.version>
-        <undertow.version>2.3.13.Final</undertow.version>
+        <undertow.version>2.3.18.Final</undertow.version>
     </properties>
 
     <dependencies>
@@ -95,6 +96,11 @@
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>
@@ -104,7 +110,8 @@
                 <artifactId>maven-shade-plugin</artifactId>
                 <configuration>
                     <transformers>
-                        <transformer implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
+                        <transformer
+                                implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                             <mainClass>ch.fritteli.maze.server.Main</mainClass>
                         </transformer>
                     </transformers>

src/main/java/ch/fritteli/maze/server/MazeServer.java

@@ -18,11 +18,11 @@ public class MazeServer {
     private final Undertow undertow;
 
     private MazeServer(@NotNull final ServerConfig config) {
-        final String hostAddress = config.getAddress().getHostAddress();
-        final int port = config.getPort();
+        final String hostAddress = config.address().getHostAddress();
+        final int port = config.port();
         log.info("Starting Server at http://{}:{}/", hostAddress, port);
         final RoutingHandler routingHandler = new RoutingHandler()
-                .get(CreateHandler.PATH_TEMPLATE, new CreateHandler())
+                .get(CreateHandler.PATH_TEMPLATE, new CreateHandler(config.maxMazeHeight(), config.maxMazeWidth()))
                 .post(RenderV1Handler.PATH_TEMPLATE, new RenderV1Handler())
                 .post(RenderV2Handler.PATH_TEMPLATE, new RenderV2Handler());
 
@@ -47,7 +47,7 @@ public class MazeServer {
     private void start() {
         Runtime.getRuntime().addShutdownHook(new Thread(this::stop, "listener-stopper"));
         this.undertow.start();
-        final InetSocketAddress address = (InetSocketAddress) this.undertow.getListenerInfo().get(0).getAddress();
+        final InetSocketAddress address = (InetSocketAddress) this.undertow.getListenerInfo().getFirst().getAddress();
         final String hostAddress = address.getAddress().getHostAddress();
         final int port = address.getPort();
 

src/main/java/ch/fritteli/maze/server/ServerConfig.java

@@ -1,42 +1,56 @@
 package ch.fritteli.maze.server;
 
+import io.vavr.control.Option;
 import io.vavr.control.Try;
-import lombok.AccessLevel;
-import lombok.AllArgsConstructor;
-import lombok.Value;
 import lombok.extern.slf4j.Slf4j;
+import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
-import org.wildfly.common.annotation.NotNull;
 
 import java.net.InetAddress;
 
-@AllArgsConstructor(access = AccessLevel.PRIVATE)
 @Slf4j
-@Value
-public class ServerConfig {
+public record ServerConfig(@NotNull InetAddress address,
+                           int port,
+                           @NotNull Option<Integer> maxMazeHeight,
+                           @NotNull Option<Integer> maxMazeWidth) {
     public static final String SYSPROP_HOST = "fritteli.maze.server.host";
     public static final String SYSPROP_PORT = "fritteli.maze.server.port";
+    public static final String SYSPROP_MAX_MAZE_HEIGHT = "fritteli.maze.maxheight";
+    public static final String SYSPROP_MAX_MAZE_WIDTH = "fritteli.maze.maxwidth";
 
-    @NotNull
-    InetAddress address;
-    int port;
-
-    public ServerConfig(@Nullable final String address, final int port) throws ConfigurationException {
-        this.address = validateAddress(address);
+    public ServerConfig(@NotNull final InetAddress address,
+                        final int port,
+                        @NotNull final Option<Integer> maxMazeHeight,
+                        @NotNull final Option<Integer> maxMazeWidth) {
+        this.address = address;
         this.port = validatePort(port);
-        log.debug("host={}, port={}", this.address, this.port);
+        this.maxMazeHeight = validateDimension(maxMazeHeight, "height");
+        this.maxMazeWidth = validateDimension(maxMazeWidth, "width");
+        log.debug("host={}, port={}, maxHeight={}, maxWidth={}", this.address, this.port, this.maxMazeHeight, this.maxMazeWidth);
+    }
+
+    public ServerConfig(@Nullable final String address,
+                        final int port,
+                        @NotNull final Option<Integer> maxMazeHeight,
+                        @NotNull final Option<Integer> maxMazeWidth)
+            throws ConfigurationException {
+        this(validateAddress(address), port, maxMazeHeight, maxMazeWidth);
     }
 
     @NotNull
     public static ServerConfig init() throws ConfigurationException {
         final String host = System.getProperty(SYSPROP_HOST);
         final String portString = System.getProperty(SYSPROP_PORT);
+        final String maxMazeHeightString = System.getProperty(SYSPROP_MAX_MAZE_HEIGHT);
+        final String maxMazeWidthString = System.getProperty(SYSPROP_MAX_MAZE_WIDTH);
         final int port = validatePort(portString);
-        return new ServerConfig(host, port);
+        final Option<Integer> maxMazeHeight = validateDimension(maxMazeHeightString, "height", SYSPROP_MAX_MAZE_HEIGHT);
+        final Option<Integer> maxMazeWidth = validateDimension(maxMazeWidthString, "width", SYSPROP_MAX_MAZE_WIDTH);
+        return new ServerConfig(host, port, maxMazeHeight, maxMazeWidth);
     }
 
     @NotNull
-    private static InetAddress validateAddress(@Nullable final String address) {
+    private static InetAddress validateAddress(@Nullable final String address) throws ConfigurationException {
         return Try.of(() -> InetAddress.getByName(address))
                 .getOrElseThrow(cause -> new ConfigurationException(
                         "Invalid hostname/address: %s".formatted(address),
@@ -44,22 +58,48 @@ public class ServerConfig {
                 ));
     }
 
-    private static int validatePort(final int port) {
+    private static int validatePort(final int port) throws ConfigurationException {
         if (port < 0 || port > 0xFFFF) {
             throw new ConfigurationException("Port out of range (0..65535): %s".formatted(port));
         }
         return port;
     }
 
-    private static int validatePort(@Nullable final String portString) {
+    private static int validatePort(@Nullable final String portString) throws ConfigurationException {
         if (portString == null) {
             log.info("No port configured; using default.");
             return 0;
         }
-        return Try.of(() -> Integer.valueOf(portString))
+        return Try.of(() -> Integer.parseInt(portString))
                 .getOrElseThrow(cause -> new ConfigurationException(
                         "Failed to parse port specified in system property '%s': %s".formatted(SYSPROP_PORT, portString),
                         cause
                 ));
     }
+
+    @NotNull
+    private static Option<Integer> validateDimension(@NotNull final Option<Integer> dimension,
+                                                     @NotNull final String identifier) {
+        if (dimension.exists(d -> d <= 1)) {
+            throw new ConfigurationException("Maximum %s must be greater than 1: %s"
+                    .formatted(identifier, dimension.get()));
+        }
+        return dimension;
+    }
+
+    private static Option<Integer> validateDimension(@Nullable final String dimensionString,
+                                                     @NotNull final String identifier,
+                                                     @NotNull final String syspropName) {
+        if (dimensionString == null) {
+            log.info("No maximum {} configured; using default (unlimited).", identifier);
+            return Option.none();
+        }
+        final int desiredDimension = Try.of(() -> Integer.parseInt(dimensionString))
+                .getOrElseThrow(cause -> new ConfigurationException(
+                        "Failed to parse maximum %s specified in system property '%s': %s"
+                                .formatted(identifier, syspropName, dimensionString),
+                        cause
+                ));
+        return Option.some(desiredDimension);
+    }
 }

src/main/java/ch/fritteli/maze/server/handler/CreateHandler.java

@@ -7,6 +7,7 @@ import io.undertow.server.HttpServerExchange;
 import io.undertow.util.Headers;
 import io.undertow.util.HttpString;
 import io.undertow.util.StatusCodes;
+import io.vavr.control.Option;
 import io.vavr.control.Try;
 import lombok.extern.slf4j.Slf4j;
 import org.jetbrains.annotations.NotNull;
@@ -22,6 +23,15 @@ import java.util.Map;
 public class CreateHandler extends AbstractHttpHandler {
 
     public static final String PATH_TEMPLATE = "/create/{output}";
+    @NotNull
+    private final Option<Integer> maxHeight;
+    @NotNull
+    private final Option<Integer> maxWidth;
+
+    public CreateHandler(@NotNull final Option<Integer> maxHeight, @NotNull final Option<Integer> maxWidth) {
+        this.maxHeight = maxHeight;
+        this.maxWidth = maxWidth;
+    }
 
     @Override
     protected void handle(@NotNull final HttpServerExchange exchange) {
@@ -29,10 +39,11 @@ public class CreateHandler extends AbstractHttpHandler {
         log.debug("Handling create request");
         this.createMazeFromRequestParameters(exchange.getQueryParameters())
                 .onFailure(e -> {
-                    log.error("Error creating maze from request", e);
                     if (e instanceof InvalidRequestParameterException) {
+                        log.debug("Error creating maze from request", e);
                         exchange.setStatusCode(StatusCodes.BAD_REQUEST);
                     } else {
+                        log.error("Error creating maze from request", e);
                         exchange.setStatusCode(StatusCodes.INTERNAL_SERVER_ERROR);
                     }
                     exchange.getResponseSender()
@@ -75,6 +86,6 @@ public class CreateHandler extends AbstractHttpHandler {
 
     @NotNull
     private Try<ParametersToMazeExtractor.GeneratedMaze> createMazeFromRequestParameters(final Map<String, Deque<String>> queryParameters) {
-        return new ParametersToMazeExtractor(queryParameters).createMaze();
+        return new ParametersToMazeExtractor(queryParameters, this.maxHeight, this.maxWidth).createMaze();
     }
 }

src/main/java/ch/fritteli/maze/server/handler/ParametersToMazeExtractor.java

@@ -20,6 +20,10 @@ class ParametersToMazeExtractor {
 
     @NotNull
     private final Map<String, Deque<String>> queryParameters;
+    @NotNull
+    private final Option<Integer> maxHeight;
+    @NotNull
+    private final Option<Integer> maxWidth;
 
     @NotNull
     Try<GeneratedMaze> createMaze() {
@@ -49,12 +53,29 @@ class ParametersToMazeExtractor {
             )));
         }
 
+        final int desiredHeight = height.get();
+        final int desiredWidth = width.get();
+
+        if (desiredHeight <= 1) {
+            return Try.failure(new InvalidRequestParameterException("Specified height (%s) must be > 1".formatted(desiredHeight)));
+        }
+        if (desiredWidth <= 1) {
+            return Try.failure(new InvalidRequestParameterException("Specified width (%s) must be > 1".formatted(desiredHeight)));
+        }
+        if (this.maxHeight.exists(max -> desiredHeight > max)) {
+            return Try.failure(new InvalidRequestParameterException("Specified height (%s) is greater than allowed maximum of %s".formatted(desiredHeight, this.maxHeight.get())));
+        }
+
+        if (this.maxWidth.exists(max -> desiredWidth > max)) {
+            return Try.failure(new InvalidRequestParameterException("Specified width (%s) is greater than allowed maximum of %s".formatted(desiredWidth, this.maxWidth.get())));
+        }
+
         return Try.of(() -> {
             final Maze maze;
             if (start.isDefined() && end.isDefined()) {
-                maze = new Maze(width.get(), height.get(), id.getOrElse(() -> new Random().nextLong()), start.get(), end.get());
+                maze = new Maze(desiredWidth, desiredHeight, id.getOrElse(() -> new Random().nextLong()), start.get(), end.get());
             } else {
-                maze = new Maze(width.get(), height.get(), id.getOrElse(() -> new Random().nextLong()));
+                maze = new Maze(desiredWidth, desiredHeight, id.getOrElse(() -> new Random().nextLong()));
             }
             new RandomDepthFirst(maze).run();
             return new GeneratedMaze(maze, output.get(), RandomDepthFirst.class.getSimpleName());

src/test/java/ch/fritteli/maze/server/ServerConfigTest.java

@@ -3,16 +3,16 @@ package ch.fritteli.maze.server;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import java.net.UnknownHostException;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
 
 class ServerConfigTest {
     @BeforeEach
     void clearSysProperties() {
         System.clearProperty(ServerConfig.SYSPROP_HOST);
         System.clearProperty(ServerConfig.SYSPROP_PORT);
+        System.clearProperty(ServerConfig.SYSPROP_MAX_MAZE_HEIGHT);
+        System.clearProperty(ServerConfig.SYSPROP_MAX_MAZE_WIDTH);
     }
 
     @Test
@@ -22,9 +22,27 @@ class ServerConfigTest {
         final ServerConfig sut = ServerConfig.init();
 
         // assert
-        assertEquals("127.0.0.1", sut.getAddress().getHostAddress());
-        assertEquals("localhost", sut.getAddress().getHostName());
-        assertEquals(0, sut.getPort());
+        assertThat(sut.address())
+                .satisfies(
+                        address -> assertThat(address.getHostAddress()).isEqualTo("127.0.0.1"),
+                        address -> assertThat(address.getHostName()).isEqualTo("localhost")
+                );
+        assertThat(sut.port()).isZero();
+        assertThat(sut.maxMazeHeight()).isEmpty();
+        assertThat(sut.maxMazeWidth()).isEmpty();
+    }
+
+
+    @Test
+    void testInit_invalidAddress() {
+        // arrange
+        System.setProperty(ServerConfig.SYSPROP_HOST, "256.2515.19.0");
+
+        // act / assert
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Invalid hostname/address")
+                .withMessageContaining("256.2515.19.0");
     }
 
     @Test
@@ -33,29 +51,101 @@ class ServerConfigTest {
         System.setProperty(ServerConfig.SYSPROP_PORT, "Hello World!");
 
         // act / assert
-        assertThrows(ConfigurationException.class, ServerConfig::init);
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Failed to parse port")
+                .withMessageContaining("Hello World!");
     }
 
     @Test
-    void testInit_invalidPort() {
+    void testInit_invalidPortTooSmall() {
+        // arrange
+        System.setProperty(ServerConfig.SYSPROP_PORT, "-5");
+
+        // act / assert
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Port out of range")
+                .withMessageContaining("-5");
+    }
+
+    @Test
+    void testInit_invalidPortTooLarge() {
         // arrange
         System.setProperty(ServerConfig.SYSPROP_PORT, "99999");
 
         // act / assert
-        assertThrows(ConfigurationException.class, ServerConfig::init);
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Port out of range")
+                .withMessageContaining("99999");
     }
 
     @Test
-    void testInit() throws ConfigurationException, UnknownHostException {
+    void testInit_unparseableMaxMazeHeight() {
         // arrange
-        System.setProperty(ServerConfig.SYSPROP_HOST, "127.0.0.1");
+        System.setProperty(ServerConfig.SYSPROP_MAX_MAZE_HEIGHT, "Hello World!");
+
+        // act / assert
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Failed to parse maximum height")
+                .withMessageContaining("Hello World!");
+
+    }
+
+    @Test
+    void testInit_invalidMaxMazeHeight() {
+        // arrange
+        System.setProperty(ServerConfig.SYSPROP_MAX_MAZE_HEIGHT, "1");
+
+        // act / assert
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Maximum height must be greater than 1:")
+                .withMessageEndingWith("1");
+    }
+
+    @Test
+    void testInit_unparseableMaxMazeWidth() {
+        // arrange
+        System.setProperty(ServerConfig.SYSPROP_MAX_MAZE_WIDTH, "Hello World!");
+
+        // act / assert
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Failed to parse maximum width")
+                .withMessageContaining("Hello World!");
+
+    }
+
+    @Test
+    void testInit_invalidMaxMazeWidth() {
+        // arrange
+        System.setProperty(ServerConfig.SYSPROP_MAX_MAZE_WIDTH, "-24");
+
+        // act / assert
+        assertThatExceptionOfType(ConfigurationException.class)
+                .isThrownBy(ServerConfig::init)
+                .withMessageContaining("Maximum width must be greater than 1:")
+                .withMessageContaining("-24");
+    }
+
+    @Test
+    void testInit() throws ConfigurationException {
+        // arrange
+        System.setProperty(ServerConfig.SYSPROP_HOST, "10.0.9.12");
         System.setProperty(ServerConfig.SYSPROP_PORT, "12345");
+        System.setProperty(ServerConfig.SYSPROP_MAX_MAZE_HEIGHT, "100");
+        System.setProperty(ServerConfig.SYSPROP_MAX_MAZE_WIDTH, "42");
 
         // act
         final ServerConfig sut = ServerConfig.init();
 
         // assert
-        assertEquals("127.0.0.1", sut.getAddress().getHostAddress());
-        assertEquals(12345, sut.getPort());
+        assertThat(sut.address().getHostAddress()).isEqualTo("10.0.9.12");
+        assertThat(sut.port()).isEqualTo(12345);
+        assertThat(sut.maxMazeHeight()).singleElement().isEqualTo(100);
+        assertThat(sut.maxMazeWidth()).singleElement().isEqualTo(42);
     }
 }