Merge remote-tracking branch 'origin/main'

Author: eafalkens

.gitignore

@@ -1,3 +1,5 @@
 target/
 /.idea/
 /META-INF
+
+.DS_Store

README.md

@@ -47,6 +47,8 @@ Pipeline
   ↓
 FilterChain
   ↓
+Router
+  ↓
 Plugin
   ↓
 HttpResponseWriter

docs/adr/ADR-002-ip-based-request-filtering.md

@@ -0,0 +1,65 @@
+# ADR-002: IP-based Request Filtering
+
+**Date:** 2026-02-25
+**Status:** Accepted
+**Deciders:** Team juv25d
+**Technical:** - PR #59 - Add IP filter to request pipeline
+
+---
+
+## Context
+
+We want to restrict access to the HTTP server based on the client IP address.
+This should happen early in the request, before any route/handler/static file logic.
+
+The initial implementation should be simple, easy to configure and safe to use during group development.
+
+---
+
+## Decision
+
+We implement an IP filter as a global filter in the server pipeline.
+
+The filter supports three modes:
+
+- **Whitelist mode:** only IPs explicitly listed are allowed.
+- **Blacklist mode:** all IPs are allowed except those explicitly listed.
+- **Open mode:** if both whitelist and blacklist are empty, all requests are allowed (useful during development)
+
+The initial implementation uses **exact IP address matching**.
+
+---
+
+## Rationale
+
+The design prioritizes:
+- clear and predictable behavior
+- simple configuration
+- low friction for development environments
+
+Whitelist and blacklist are intentionally treated as separate configuration approaches.
+Using both simultaneously can be ambiguous, so the project can either document precedence rules or enforce a single-mode configuration in future iterations.
+
+---
+
+## Consequences
+
+### Positive
+- Centralized access control early in the pipeline
+- Easy to enable/disable restrictions via configuration
+- Works well for group development (open mode)
+
+### Trade-offs
+- Exact IP matching only.
+- Potential ambiguity if both lists are configured
+
+---
+
+## Alternatives Considered
+
+### Enforce single mode (whitelist or blacklist)
+**Pros:** clear API contract
+**Cons:** less flexible during experimentation
+**Status:** considered for future refinement if the team wants stricter validation
+
+---

docs/adr/README.md

@@ -47,6 +47,7 @@ An ADR can have one of the following statuses:
 | ADR | Title | Status | Date |
 |-----|-------|--------|------|
 | [001](ADR-001-static-file-serving-architecture.md) | Static File Serving Architecture | Accepted | 2026-02-11 |
+| [002](ADR-002-ip-based-request-filtering.md) | IP-based Request Filtering | Accepted | 2026-02-25 |
 
 ---
 

pom.xml

@@ -21,6 +21,8 @@
         <junit.jupiter.version>6.0.2</junit.jupiter.version>
         <assertj.core.version>3.27.7</assertj.core.version>
         <mockito.version>5.21.0</mockito.version>
+        <errorprone.version>2.45.0</errorprone.version>
+        <nullaway.version>0.13.1</nullaway.version>
         <build.time>${maven.build.timestamp}</build.time>
         <argLine/>
     </properties>
@@ -43,6 +45,12 @@
             <version>${mockito.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.tngtech.archunit</groupId>
+            <artifactId>archunit</artifactId>
+            <version>1.4.1</version>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.yaml</groupId>
             <artifactId>snakeyaml</artifactId>
@@ -66,6 +74,11 @@
             <version>1.21.4</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.jspecify</groupId>
+            <artifactId>jspecify</artifactId>
+            <version>1.0.0</version>
+        </dependency>
     </dependencies>
     <build>
         <plugins>
@@ -78,6 +91,36 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>3.15.0</version>
+                <configuration>
+                    <fork>true</fork>
+                    <compilerArgs>
+                        <arg>-XDcompilePolicy=simple</arg>
+                        <arg>--should-stop=ifError=FLOW</arg>
+                        <arg>-Xplugin:ErrorProne -Xep:NullAway:ERROR -XepOpt:NullAway:AnnotatedPackages=org.juv25d</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED</arg>
+                        <arg>-J--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED</arg>
+                        <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED</arg>
+                        <arg>-J--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED</arg>
+                    </compilerArgs>
+                    <annotationProcessorPaths>
+                        <path>
+                            <groupId>com.google.errorprone</groupId>
+                            <artifactId>error_prone_core</artifactId>
+                            <version>${errorprone.version}</version>
+                        </path>
+                        <path>
+                            <groupId>com.uber.nullaway</groupId>
+                            <artifactId>nullaway</artifactId>
+                            <version>${nullaway.version}</version>
+                        </path>
+                    </annotationProcessorPaths>
+                </configuration>
             </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>

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

@@ -7,6 +7,7 @@
 import org.juv25d.router.SimpleRouter;
 import org.juv25d.util.ConfigLoader;
 
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 public class App {
@@ -28,12 +29,19 @@ public static void main(String[] args) {
         Server server = new Server(
             config.getPort(),
             logger,
-            handlerFactory,
-            pipeline
+            handlerFactory
         );
 
         Runtime.getRuntime().addShutdownHook(new Thread(() -> {
-            logger.info("Server shutting down...");
+            logger.info("Shutting down...");
+            try {
+                pipeline.stop();
+                logger.info("Shutdown successful");
+            }catch (Exception ex){
+                logger.log(Level.SEVERE, "Error stopping server", ex);
+            }finally {
+                logger.info("Shutdown hook finished");
+            }
         }));
 
         server.start();

src/main/java/org/juv25d/ConnectionHandler.java

@@ -32,7 +32,8 @@ public void run() {
             var out = socket.getOutputStream();
 
             HttpRequest parsed = httpParser.parse(in);
-            String remoteIp = socket.getInetAddress().getHostAddress();
+            java.net.InetAddress inetAddress = socket.getInetAddress();
+            String remoteIp = (inetAddress != null) ? inetAddress.getHostAddress() : "UNKNOWN";
 
             HttpRequest request = new HttpRequest(
                 parsed.method(),

src/main/java/org/juv25d/ConnectionHandlerFactory.java

@@ -3,5 +3,5 @@
 import java.net.Socket;
 
 public interface ConnectionHandlerFactory {
-    Runnable create(Socket socket, Pipeline pipeline);
+    Runnable create(Socket socket);
 }

src/main/java/org/juv25d/DefaultConnectionHandlerFactory.java

@@ -17,7 +17,7 @@ public DefaultConnectionHandlerFactory(HttpParser httpParser, Logger logger, Pip
     }
 
     @Override
-    public Runnable create(Socket socket, Pipeline pipeline) {
-        return new ConnectionHandler(socket, httpParser, logger, pipeline);
+    public Runnable create(Socket socket) {
+        return new ConnectionHandler(socket, httpParser, logger, this.pipeline);
     }
 }

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

@@ -22,4 +22,8 @@ public FilterChainImpl createChain(HttpRequest request) {
         List<Filter> filters = matcher.match(request);
         return new FilterChainImpl(filters, router);
     }
+
+    public void stop() {
+        matcher.destroy();
+    }
 }