[FIX] Fix resolution of files with special characters for embedded file server (#705)

LaunchServer/src/main/java/pro/gravit/launchserver/socket/handlers/fileserver/FileServerHandler.java

@@ -7,13 +7,13 @@ import io.netty.handler.codec.http.*;
 import io.netty.handler.stream.ChunkedFile;
 import io.netty.util.CharsetUtil;
 import pro.gravit.launchserver.socket.handlers.ContentType;
+import pro.gravit.utils.helper.IOHelper;
 import pro.gravit.utils.helper.VerifyHelper;
 
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.RandomAccessFile;
-import java.net.URI;
-import java.net.URISyntaxException;
+import java.nio.file.InvalidPathException;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.time.Clock;
@@ -182,12 +182,18 @@ public class FileServerHandler extends SimpleChannelInboundHandler<FullHttpReque
             return;
         }
 
-        final String uri = request.uri();
+        // URLDecoder tries to decode string as application/x-www-form-urlencoded which allows + character to be used as space escape therefore breaking file names with +
+        final String uri = IOHelper.urlDecodeStrict(request.uri());
         final String path;
 
+        if (uri == null) {
+            sendError(ctx, NOT_FOUND);
+            return;
+        }
+
         try {
-            path = Paths.get(new URI(uri).getPath()).normalize().toString().substring(1);
-        } catch (URISyntaxException e) {
+            path = Paths.get(IOHelper.getPathFromUrlFragment(uri)).normalize().toString().substring(1);
+        } catch (InvalidPathException e) {
             sendError(ctx, BAD_REQUEST);
             return;
         }

LauncherCore/src/main/java/pro/gravit/utils/helper/IOHelper.java

@@ -5,12 +5,15 @@ import javax.imageio.ImageReader;
 import java.awt.image.BufferedImage;
 import java.io.*;
 import java.net.*;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.FileSystem;
 import java.nio.file.*;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.Collections;
+import java.util.HexFormat;
 import java.util.Set;
 import java.util.jar.JarFile;
 import java.util.jar.Manifest;
@@ -559,6 +562,34 @@ public final class IOHelper {
         return URLEncoder.encode(s, UNICODE_CHARSET);
     }
 
+    public static String urlDecodeStrict(String s) {
+        var builder = new StringBuilder();
+        char[] charArray = s.toCharArray();
+        for (int i = 0; i < charArray.length; i++) {
+            char c = charArray[i];
+            if (c != '%') {
+                builder.append(c);
+                continue;
+            }
+
+            if (i + 2 >= charArray.length) {
+                return null;
+            }
+
+            var buffer = UNICODE_CHARSET.decode(ByteBuffer.wrap(HexFormat.of().parseHex(CharBuffer.wrap(charArray, i + 1, 2))));
+
+            builder.append(buffer);
+
+            i += 2;
+        }
+
+        return builder.toString();
+    }
+
+    public static String getPathFromUrlFragment(String urlFragment) {
+        return urlFragment.indexOf('?') < 0 ? urlFragment : urlFragment.substring(0, urlFragment.indexOf('?'));
+    }
+
     public static String verifyFileName(String fileName) {
         return VerifyHelper.verify(fileName, IOHelper::isValidFileName, String.format("Invalid file name: '%s'", fileName));
     }