feat: improve redirect rule parsing and validation

feat: add regex support and enforce 301/302 redirects

Author: Ericthilen

src/main/java/org/example/server/RedirectRule.java

@@ -1,5 +1,6 @@
 package org.example.server;
 
+import java.util.Objects;
 import java.util.regex.Pattern;
 
 public final class RedirectRule {
@@ -8,8 +9,11 @@ public final class RedirectRule {
     private final int statusCode;
 
     public RedirectRule(Pattern sourcePattern, String targetUrl, int statusCode) {
-        this.sourcePattern = sourcePattern;
-        this.targetUrl = targetUrl;
+        this.sourcePattern = Objects.requireNonNull(sourcePattern, "sourcePattern");
+        this.targetUrl = Objects.requireNonNull(targetUrl, "targetUrl");
+        if (statusCode != 301 && statusCode != 302) {
+            throw new IllegalArgumentException("statusCode must be 301 or 302");
+        }
         this.statusCode = statusCode;
     }
 
@@ -30,3 +34,4 @@ public String toString() {
                 '}';
     }
 }
+

src/main/java/org/example/server/RedirectRulesLoader.java

@@ -3,18 +3,30 @@
 import java.util.regex.Pattern;
 
 public final class RedirectRulesLoader {
+    private static final String REGEX_PREFIX = "regex:";
+
     private RedirectRulesLoader() {}
 
     public static Pattern compileSourcePattern(String sourcePath) {
         if (sourcePath == null || sourcePath.isBlank()) {
             throw new IllegalArgumentException("sourcePath must not be blank");
         }
 
+        String trimmed = sourcePath.trim();
+
+        if (trimmed.startsWith(REGEX_PREFIX)) {
+            String rawRegex = trimmed.substring(REGEX_PREFIX.length());
+            if (rawRegex.isBlank()) {
+                throw new IllegalArgumentException("regex sourcePath must not be blank");
+            }
+            return Pattern.compile(rawRegex);
+        }
+
         String regex;
-        if (sourcePath.contains("*")) {
-            regex = wildcardToRegex(sourcePath);
+        if (trimmed.contains("*")) {
+            regex = wildcardToRegex(trimmed);
         } else {
-            regex = Pattern.quote(sourcePath);
+            regex = Pattern.quote(trimmed);
         }
         return Pattern.compile("^" + regex + "$");
     }
@@ -32,3 +44,4 @@ private static String wildcardToRegex(String wildcard) {
         return sb.toString();
     }
 }
+