Serve .jar files with the correct MIME type

Signed-off-by: Graham <gpe@openrs2.org>

game/src/main/kotlin/org/openrs2/game/net/http/Http.kt

@@ -18,7 +18,10 @@ import org.openrs2.buffer.use
 
 public object Http {
     public const val MAX_CONTENT_LENGTH: Int = 65536
+
+    public const val APPLICATION_JAVA_ARCHIVE: String = "application/java-archive"
     public const val TEXT_X_CROSS_DOMAIN_POLICY: String = "text/x-cross-domain-policy"
+
     private const val BANNER = "OpenRS2"
 
     private fun isKeepAlive(request: HttpRequest, version: HttpVersion): Boolean {

game/src/main/kotlin/org/openrs2/game/net/http/HttpChannelHandler.kt

@@ -34,7 +34,21 @@ public class HttpChannelHandler @Inject constructor(
                 return
             }
 
-            Http.writeResponse(ctx, msg, file, HttpHeaderValues.APPLICATION_OCTET_STREAM)
+            Http.writeResponse(ctx, msg, file, getContentType(uri))
+        }
+    }
+
+    private fun getContentType(uri: String): CharSequence {
+        /*
+         * It doesn't make sense to return a MIME type for some of the files:
+         *
+         * - The .pack200 files are missing two bytes in the header.
+         * - The .lib and .pack files are probably compressed with DEFLATE in
+         *   nowrap mode.
+         */
+        return when {
+            uri.endsWith(".jar") -> Http.APPLICATION_JAVA_ARCHIVE
+            else -> HttpHeaderValues.APPLICATION_OCTET_STREAM
         }
     }