Setup the remote client

The remote client exist to help users without a FullClient on their computer to play by downloading resources from an external server. Because pushing directly the fullclient on a server/ftp can provoke some errors, this tool allow to :

• Get the files from a client used in another domain (Cross-origin resource sharing).
• Extracting files directly from GRF archive (versions 0x200 and 0x300 supported).
• Converting BMP files to PNG to speed up the transfer.
• Optimized to don't call any script if files are already extracted/converted (resource friendly).
• File Index for O(1) lookups: Files are indexed at startup for instant lookups instead of sequential search through GRFs.
• Gzip/Deflate Compression: Automatically compresses text-based responses (XML, TXT, LUA, etc.) to reduce bandwidth.
• HTTP Cache Headers (ETag, Cache-Control, 304 Not Modified) for browser caching.
• LRU Cache for fast repeated file access (in-memory caching).
• Missing Files Log for tracking and debugging missing game assets.
• Health Check API (/api/health) for monitoring and diagnostics.
• Korean Path Mapping for CP949/EUC-KR filename encoding support.
• Warm Cache for pre-loading frequently accessed files at startup.

###Add your fullclient###

Just put your GRFs files and DATA.INI file in the resources/ directory. Overwrite the BGM/, data/ and System/ directories with your own folders.

Note: to be sure to use a compatible version of your GRFs, download GRF Builder and repack them manually (Option > Repack type > Repack), it will ensure the GRFs files are converted in the proper version

Performance Features

HTTP Cache Headers

The server implements proper HTTP cache headers for browser caching:

• ETag: Content-based validation for conditional requests
• 304 Not Modified: Reduces bandwidth by validating client cache
• Cache-Control: Optimized per file type
  • Game assets (sprites, maps, etc.): 1 year with immutable
  • Other files: 30 days
• Expires: HTTP/1.0 compatibility

This significantly reduces bandwidth and speeds up repeated requests, as unchanged files are served from browser cache.

LRU File Cache

The server implements an in-memory LRU (Least Recently Used) cache for file content:

• Default: 100 files, 256MB max memory
• O(1) get/set operations
• Automatic eviction of least recently used files
• Configurable via environment variables

CACHE_ENABLED=true
CACHE_MAX_FILES=100
CACHE_MAX_MEMORY_MB=256

Setting	Description	Default
CACHE_ENABLED	Enable/disable cache	true
CACHE_MAX_FILES	Max files in cache	100
CACHE_MAX_MEMORY_MB	Max memory usage	256 MB

Korean Path Mapping

Many Ragnarok GRF files contain Korean filenames encoded in CP949/EUC-KR. When these are read on non-Korean systems, they appear as mojibake (garbled characters).

The Problem:

Client requests: /data/texture/유저인터페이스/t_배경3-3.tga
GRF contains:    /data/texture/À¯ÀúÀÎÅÍÆäÀ̽º/t_¹è°æ3-3.tga

The Solution:

The server uses a path-mapping.json file to map Korean UTF-8 paths to their GRF equivalents:

PATH_MAPPING_ENABLED=true
PATH_MAPPING_FILE=path-mapping.json

Setting	Description	Default
PATH_MAPPING_ENABLED	Enable/disable path mapping	true
PATH_MAPPING_FILE	Path to mapping file	path-mapping.json

Creating a path-mapping.json file:

{
    "generatedAt": "2026-01-18T12:00:00Z",
    "paths": {
        "data/texture/유저인터페이스/file.tga": "data/texture/À¯ÀúÀÎÅÍÆäÀ̽º/file.tga"
    }
}

Warm Cache

The server can pre-load frequently accessed files into the LRU cache at startup or on-demand:

• Essential files pre-loaded for faster initial requests
• Pattern matching with wildcards for file groups
• Memory limit aware - stops warming when limits reached
• Statistics tracking for monitoring
• API endpoint for on-demand warming
• Configurable via environment variables

WARM_CACHE_ENABLED=true
WARM_CACHE_MAX_FILES=50
WARM_CACHE_MAX_MEMORY_MB=50

Setting	Description	Default
WARM_CACHE_ENABLED	Enable/disable warm cache	true
WARM_CACHE_MAX_FILES	Max files to warm	50
WARM_CACHE_MAX_MEMORY_MB	Max memory for warming	50 MB

Essential files warmed by default:

• data\clientinfo.xml - Client configuration
• data\lua files\*.lub - Lua scripts
• data\sprite\*.spr - Character sprites (basic)
• data\texture\*.bmp - UI textures

API Endpoints:

Endpoint	Method	Description
/api/warm-cache	GET	Get warm cache status and stats
/api/warm-cache/run	POST	Trigger cache warming manually

GRF Version Support

Version	Status	Notes
0x200	✅ Supported	32-bit file offsets, no DES encryption
0x300	✅ Supported	64-bit file offsets (files > 4GB), no DES encryption
DES Encrypted	✅ Supported

API Endpoints

The remote client provides several API endpoints for monitoring and diagnostics:

Health Check

Endpoint	Method	Description
GET /api/health	GET	Complete system health status
GET /api/health/simple	GET	Simple status check (fast)
GET /api/cache-stats	GET	Cache and index statistics
GET /api/missing-files	GET	Missing files log summary
POST /api/missing-files/clear	POST	Clear missing files log
GET /api/warm-cache	GET	Warm cache status and stats
POST /api/warm-cache/run	POST	Trigger cache warming
GET /api/path-mapping	Path mapping statistics

Example response for /api/health:

{
    "status": "ok",
    "timestamp": "2026-01-18T12:00:00+00:00",
    "grfs": {
        "total": 2,
        "valid": 2
    },
    "cache": {
        "enabled": true,
        "items": 45,
        "hitRate": "96.5%"
    },
    "index": {
        "totalFiles": 450000
    },
    "hasWarnings": false
}

Running the Remote Client

Using Docker container

You can use this setup with the container to run the remote client API. Using docker container does not handle/copy the game files. You need to set up them first on the directory.

Copy the file .env.example to the same directory as .env

After copying the game files and modifiying your .env file, you can start the container services.

I want to use NGINX server

You can start using the remote client with NGINX using the following command:

docker compose --profile nginx up --build

The webserver will be answering requests on the 80 port.

I want to use Apache server

docker compose --profile apache up --build

FAQ

How I can change NGINX/Apache virtual host configuration?

The vhosts configuration for both Apache and NGINX are baked into the container recipe. If you need to change this, you have to modify the respective Apache Dockerfile or NGINX dockerfile and re-run the docker compose command.

You can also override vhost configuration on /etc/apache2/sites-available/000-default.conf for Apache or /etc/nginx/conf.d/default.conf for NGINX using docker compose specification adding a bind mount, example:

volumes:
  - ./:/var/www/html:ro
  - ./my-own-nginx.conf:/etc/nginx/conf.d/default.conf

How can I make sure that my remote client works as expected?

If you set up all the required files correctly, you can run the python script tester.py. This script reads a file list in the same directory (list.txt) that contains multiple filenames that should be in a GRF. The script will request each file to the target webserver defined in TARGET_SERVER_ADDRESS variable, checking if the server answers with an HTTP code 200, if not, a new log file is created with the HTTP code and the file url requested, so you can debug it afterward.

Example, running the list against a working server (localhost, apache and nginx):

Apache

=== Final result ===
Total: 2784 | OK: 2784 | FAIL: 0
Elapsed time: 110.10 seconds

NGINX

=== Final result ===
Total: 2784 | OK: 2784 | FAIL: 0
Elapsed time: 1.86 seconds

How this remote client works?