Feature/routing separate from plugin (#68)

* Refactor plugin handling by introducing `Router` abstraction; added `SimpleRouter` implementation. Updated pipeline and tests to support new routing system.

* Refactor plugin handling by introducing `Router` abstraction; added `SimpleRouter` implementation. Updated pipeline and tests to support new routing system.

* Improve wildcard routing in `SimpleRouter` with longest-prefix match logic; add test coverage for specific and wildcard match scenarios.

Author: bamsemats

pom.xml

@@ -122,7 +122,7 @@
             <plugin>
                 <groupId>com.diffplug.spotless</groupId>
                 <artifactId>spotless-maven-plugin</artifactId>
-                <version>2.43.0</version>
+                <version>3.2.1</version>
                 <configuration>
                     <java>
                         <includes>

src/main/java/org/juv25d/App.java

@@ -4,7 +4,9 @@
 import org.juv25d.filter.LoggingFilter;
 import org.juv25d.logging.ServerLogging;
 import org.juv25d.http.HttpParser;
+import org.juv25d.plugin.NotFoundPlugin; // New import
 import org.juv25d.plugin.StaticFilesPlugin;
+import org.juv25d.router.SimpleRouter; // New import
 import org.juv25d.util.ConfigLoader;
 
 import java.util.Set;
@@ -25,7 +27,14 @@ public static void main(String[] args) {
             Set.of()
         ), 0);
         pipeline.addGlobalFilter(new LoggingFilter(), 0);
-        pipeline.setPlugin(new StaticFilesPlugin());
+
+        // Initialize and configure SimpleRouter
+        SimpleRouter router = new SimpleRouter();
+        router.registerPlugin("/", new StaticFilesPlugin()); // Register StaticFilesPlugin for the root path
+        router.registerPlugin("/*", new StaticFilesPlugin()); // Register StaticFilesPlugin for all paths
+        router.registerPlugin("/notfound", new NotFoundPlugin()); // Example: Register NotFoundPlugin for a specific path
+
+        pipeline.setRouter(router); // Set the router in the pipeline
 
         DefaultConnectionHandlerFactory handlerFactory =
             new DefaultConnectionHandlerFactory(httpParser, logger, pipeline);

src/main/java/org/juv25d/Pipeline.java

@@ -3,7 +3,7 @@
 import org.juv25d.filter.Filter;
 import org.juv25d.filter.FilterChainImpl;
 import org.juv25d.http.HttpRequest;
-import org.juv25d.plugin.Plugin;
+import org.juv25d.router.Router; // New import
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -18,7 +18,7 @@ public class Pipeline {
     private final List<FilterRegistration> globalFilters = new CopyOnWriteArrayList<>();
     private final Map<String, List<FilterRegistration>> routeFilters = new ConcurrentHashMap<>();
     private volatile List<Filter> sortedGlobalFilters = List.of();
-    private Plugin plugin;
+    private volatile Router router; // Changed from Plugin plugin;
 
     public void addGlobalFilter(Filter filter, int order) {
         globalFilters.add(new FilterRegistration(filter, order, null));
@@ -33,11 +33,11 @@ public void addRouteFilter(Filter filter, int order, String pattern) {
             .add(new FilterRegistration(filter, order, pattern));
     }
 
-    public void setPlugin(Plugin plugin) {
-        if (plugin == null) {
-            throw new IllegalArgumentException("Plugin cannot be null");
+    public void setRouter(Router router) {
+        if (router == null) {
+            throw new IllegalArgumentException("Router cannot be null");
         }
-        this.plugin = plugin;
+        this.router = router;
     }
 
     public FilterChainImpl createChain(HttpRequest request) {
@@ -61,14 +61,14 @@ public FilterChainImpl createChain(HttpRequest request) {
                     .forEach(filters::add);
             }
         }
-        return new FilterChainImpl(filters, plugin);
+        return new FilterChainImpl(filters, router); // Pass router instead of plugin
     }
 
     public List<Filter> getFilters() {
         return Collections.unmodifiableList(sortedGlobalFilters);
     }
 
-    public Plugin getPlugin() {
-        return plugin;
+    public Router getRouter() { // Renamed from getPlugin
+        return router;
     }
 }

src/main/java/org/juv25d/filter/FilterChainImpl.java

@@ -2,20 +2,20 @@
 
 import org.juv25d.http.HttpRequest;
 import org.juv25d.http.HttpResponse;
-import org.juv25d.plugin.Plugin;
+import org.juv25d.router.Router; // New import
 
 import java.io.IOException;
 import java.util.List;
 
 public class FilterChainImpl implements FilterChain {
 
     private final List<Filter> filters;
-    private final Plugin plugin;
+    private final Router router; // Changed from Plugin plugin;
     private int index = 0;
 
-    public FilterChainImpl(List<Filter> filters, Plugin plugin) {
+    public FilterChainImpl(List<Filter> filters, Router router) { // Changed constructor parameter
         this.filters = filters;
-        this.plugin = plugin;
+        this.router = router; // Changed assignment
     }
 
     @Override
@@ -24,9 +24,7 @@ public void doFilter(HttpRequest req, HttpResponse res) throws IOException {
             Filter next = filters.get(index++);
             next.doFilter(req, res, this);
         } else {
-            if (plugin != null) {
-                plugin.handle(req, res);
-            }
+            router.resolve(req).handle(req, res); // Use router to resolve and handle
         }
     }
 }

src/main/java/org/juv25d/router/Router.java

@@ -0,0 +1,19 @@
+package org.juv25d.router;
+
+import org.juv25d.http.HttpRequest;
+import org.juv25d.plugin.Plugin;
+
+/**
+ * The Router interface defines a contract for components that resolve an incoming HTTP request
+ * to a specific Plugin instance responsible for handling that request.
+ */
+public interface Router {
+
+    /**
+     * Resolves the given HttpRequest to a Plugin that can handle it.
+     *
+     * @param request The incoming HttpRequest.
+     * @return The Plugin instance responsible for handling the request. Must not be null.
+     */
+    Plugin resolve(HttpRequest request);
+}

src/main/java/org/juv25d/router/SimpleRouter.java

@@ -0,0 +1,69 @@
+package org.juv25d.router;
+
+import org.juv25d.http.HttpRequest;
+import org.juv25d.plugin.NotFoundPlugin;
+import org.juv25d.plugin.Plugin;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Comparator;
+
+/**
+ * A simple router implementation that maps request paths to specific Plugin instances.
+ * If no specific plugin is registered for a path, it defaults to a NotFoundPlugin.
+ */
+public class SimpleRouter implements Router {
+
+    private final Map<String, Plugin> routes;
+    private final Plugin notFoundPlugin;
+
+    public SimpleRouter() {
+        this.routes = new HashMap<>();
+        this.notFoundPlugin = new NotFoundPlugin();
+    }
+
+    /**
+     * Registers a plugin for a specific path.
+     *
+     * @param path   The path for which the plugin should handle requests.
+     * @param plugin The plugin to handle requests for the given path.
+     */
+    public void registerPlugin(String path, Plugin plugin) {
+        routes.put(path, plugin);
+    }
+
+    /**
+     * Resolves the given HttpRequest to a Plugin that can handle it.
+     * Resolution order:
+     * 1. Exact path match
+     * 2. Wildcard match (longest prefix wins)
+     * 3. NotFoundPlugin
+     *
+     * @param request The incoming HttpRequest.
+     * @return The Plugin instance responsible for handling the request.
+     */
+    @Override
+    public Plugin resolve(HttpRequest request) {
+        String path = request.path();
+
+        // 1. Exact match
+        Plugin exactMatch = routes.get(path);
+        if (exactMatch != null) {
+            return exactMatch;
+        }
+
+        // 2. Wildcard match (deterministic: longest prefix first)
+        return routes.entrySet().stream()
+            .filter(entry -> entry.getKey().endsWith("/*"))
+            .sorted(Comparator.comparingInt(
+                entry -> -entry.getKey().length()
+            )) // longest (most specific) first
+            .filter(entry -> {
+                String prefix = entry.getKey().substring(0, entry.getKey().length() - 1);
+                return path.startsWith(prefix);
+            })
+            .map(Map.Entry::getValue)
+            .findFirst()
+            .orElse(notFoundPlugin);
+    }
+}

src/test/java/org/juv25d/PipelineTest.java

@@ -2,24 +2,27 @@
 
 import org.junit.jupiter.api.Test;
 import org.juv25d.plugin.HelloPlugin;
+import org.juv25d.router.SimpleRouter; // New import
 
 import static org.junit.jupiter.api.Assertions.*;
 
 class PipelineTest {
 
     @Test
-    void throwsExceptionWhenSettingNullPlugin() {
+    void throwsExceptionWhenSettingNullRouter() { // Renamed test method
         Pipeline pipeline = new Pipeline();
-        assertThrows(IllegalArgumentException.class, () -> pipeline.setPlugin(null));
+        assertThrows(IllegalArgumentException.class, () -> pipeline.setRouter(null)); // Changed to setRouter
     }
 
     @Test
-    void customPluginIsUsed() {
+    void customRouterIsUsed() { // Renamed test method
         Pipeline pipeline = new Pipeline();
+        SimpleRouter router = new SimpleRouter(); // Use SimpleRouter
         HelloPlugin hello = new HelloPlugin();
+        router.registerPlugin("/hello", hello); // Register a plugin
 
-        pipeline.setPlugin(hello);
+        pipeline.setRouter(router); // Changed to setRouter
 
-        assertEquals(hello, pipeline.getPlugin());
+        assertEquals(router, pipeline.getRouter()); // Changed to getRouter
     }
 }

src/test/java/org/juv25d/filter/FilterChainImplTest.java

@@ -3,6 +3,7 @@
 import org.juv25d.http.HttpRequest;
 import org.juv25d.http.HttpResponse;
 import org.juv25d.plugin.Plugin;
+import org.juv25d.router.SimpleRouter; // New import
 import org.junit.jupiter.api.Test;
 
 import java.io.IOException;
@@ -33,20 +34,22 @@ void filters_areCalledInOrderAndPluginLast() throws IOException {
         };
 
         Plugin plugin = (req, res) -> calls.add("plugin");
+        SimpleRouter router = new SimpleRouter();
+        router.registerPlugin("/", plugin); // Register the plugin with a path
 
         FilterChainImpl chain = new FilterChainImpl(
             List.of(f1, f2),
-            plugin
+            router // Pass the router
         );
 
         HttpRequest req = new HttpRequest(
             "GET",
             "/",
-            null,
+            null, // queryString
             "HTTP/1.1",
             Map.of(),
             new byte[0],
-            "UNKNOWN"
+            "UNKNOWN" // remoteIp
         );
 
         chain.doFilter(req, new HttpResponse(200, "OK", new HashMap<>(), new byte[0]));
@@ -73,14 +76,22 @@ void filter_canStopChainExecution() throws IOException {
         };
 
         Plugin plugin = (req, res) -> calls.add("plugin");
+        SimpleRouter router = new SimpleRouter();
+        router.registerPlugin("/", plugin); // Register the plugin with a path
 
         FilterChainImpl chain = new FilterChainImpl(
             List.of(blockingFilter),
-            plugin
+            router // Pass the router
         );
 
         HttpRequest req = new HttpRequest(
-            "GET", "/", null, "HTTP/1.1", Map.of(), new byte[0], "UNKNOWN"
+            "GET",
+            "/",
+            null, // queryString
+            "HTTP/1.1",
+            Map.of(),
+            new byte[0],
+            "UNKNOWN" // remoteIp
         );
 
         chain.doFilter(req, new HttpResponse(200, "OK", new HashMap<>(), new byte[0]));
@@ -94,14 +105,22 @@ void plugin_isCalledWhenNoFiltersExist() throws IOException {
         List<String> calls = new ArrayList<>();
 
         Plugin plugin = (req, res) -> calls.add("plugin");
+        SimpleRouter router = new SimpleRouter();
+        router.registerPlugin("/", plugin); // Register the plugin with a path
 
         FilterChainImpl chain = new FilterChainImpl(
             List.of(),
-            plugin
+            router // Pass the router
         );
 
         HttpRequest req = new HttpRequest(
-            "GET", "/", null, "HTTP/1.1", Map.of(), new byte[0], "UNKNOWN"
+            "GET",
+            "/",
+            null, // queryString
+            "HTTP/1.1",
+            Map.of(),
+            new byte[0],
+            "UNKNOWN" // remoteIp
         );
 
         chain.doFilter(req, new HttpResponse(200, "OK", new HashMap<>(), new byte[0]));

src/test/java/org/juv25d/filter/GlobalFilterTests.java

@@ -5,6 +5,7 @@
 import org.juv25d.http.HttpResponse;
 import org.juv25d.plugin.Plugin;
 import org.juv25d.Pipeline;
+import org.juv25d.router.SimpleRouter; // New import
 
 import java.io.IOException;
 
@@ -19,7 +20,11 @@ void globalFilter_shouldExecute_forAnyRoute() throws Exception {
 
         RecordingFilter global = new RecordingFilter("global");
         pipeline.addGlobalFilter(global, 1);
-        pipeline.setPlugin(new NoOpPlugin());
+
+        // Configure SimpleRouter and set it in the pipeline
+        SimpleRouter router = new SimpleRouter();
+        router.registerPlugin("/", new NoOpPlugin()); // Register NoOpPlugin for the root path
+        pipeline.setRouter(router); // Set the router in the pipeline
 
         execute(pipeline, "/anything");
 

src/test/java/org/juv25d/filter/RouteFilterTests.java

@@ -5,6 +5,7 @@
 import org.juv25d.http.HttpRequest;
 import org.juv25d.http.HttpResponse;
 import org.juv25d.plugin.Plugin;
+import org.juv25d.router.SimpleRouter; // New import
 
 import java.io.IOException;
 
@@ -19,7 +20,12 @@ void routeFilter_shouldOnlyRun_whenRouteMatches() throws Exception {
 
         RecordingFilter route = new RecordingFilter("route");
         pipeline.addRouteFilter(route, 1, "/api/*");
-        pipeline.setPlugin(new NoOpPlugin());
+
+        // Configure SimpleRouter and set it in the pipeline
+        SimpleRouter router = new SimpleRouter();
+        router.registerPlugin("/", new NoOpPlugin()); // Register NoOpPlugin for the root path
+        pipeline.setRouter(router); // Set the router in the pipeline
+
         execute(pipeline, "/api/test");
         assertTrue(route.wasExecuted());
         route.reset();
@@ -30,7 +36,12 @@ void routeFilter_shouldOnlyRun_whenRouteMatches() throws Exception {
     @Test
     void routeFilter_shouldMatchExactPath() throws Exception {
         Pipeline pipeline = new Pipeline();
-        pipeline.setPlugin(new NoOpPlugin());
+
+        // Configure SimpleRouter and set it in the pipeline
+        SimpleRouter router = new SimpleRouter();
+        router.registerPlugin("/", new NoOpPlugin()); // Register NoOpPlugin for the root path
+        pipeline.setRouter(router); // Set the router in the pipeline
+
         RecordingFilter exact = new RecordingFilter("exact");
         pipeline.addRouteFilter(exact, 1, "/admin");
         execute(pipeline, "/admin");