Webbol

A minimal static web server written in COBOL using GnuCOBOL.

Features

Serves static files from the current directory
Automatic MIME type detection for common file types
HTTP status codes: 200 (OK), 403 (Forbidden), 404 (Not Found), 413 (Payload Too Large)
Path traversal attack prevention
Clean request logging with full HTTP headers
Defaults to index.html for root path requests

Requirements

GnuCOBOL (cobc) compiler
POSIX-compatible operating system (Linux, macOS, BSD)
make

Installing GnuCOBOL

macOS:

brew install gnucobol

Ubuntu/Debian:

sudo apt-get install gnucobol

Fedora/RHEL:

sudo dnf install gnucobol

Building

Clone or download the repository, then compile:

make

This will compile all modules and create the webserver executable.

To clean build artifacts:

make clean

Usage

Start the server from the directory you want to serve:

./webserver

The server will start on port 8080 and serve files from the current directory.

Example

# Create a test HTML file
echo "<html><body><h1>Hello from COBOL!</h1></body></html>" > index.html

# Start the server
./webserver

# In another terminal, test it
curl http://localhost:8080/

Accessing the Server

Once running, you can access files via:

http://localhost:8080/ - serves index.html from the current directory
http://localhost:8080/filename.html - serves the specified file
http://localhost:8080/path/to/file.txt - serves files from subdirectories

Press Ctrl+C to stop the server.

Configuration

To change the server port, edit config.cpy and modify the SERVER-PORT value:

01 SERVER-PORT          PIC 9(5) VALUE 8080.

Then recompile with make.

Project Structure

webbol/
├── Makefile              # Build configuration
├── README.md            # This file
├── config.cpy           # Server configuration
├── socket-defs.cpy      # Socket structure definitions
├── http-structs.cpy     # HTTP data structures
├── file-structs.cpy     # File handling structures
├── path-utils.cbl       # Path validation and sanitization
├── mime-types.cbl       # MIME type detection
├── file-ops.cbl         # File reading operations
├── http-handler.cbl     # HTTP request/response handling
└── webserver.cbl        # Main server program

Supported MIME Types

HTML: text/html
CSS: text/css
JavaScript: application/javascript
JSON: application/json
XML: application/xml
Plain text: text/plain
PNG: image/png
JPEG: image/jpeg
GIF: image/gif
SVG: image/svg+xml
ICO: image/x-icon
PDF: application/pdf

Additional MIME types can be added by editing mime-types.cbl.

Security Features

Path traversal prevention: Blocks requests containing .. sequences
Directory access restriction: Only serves files from the current directory and subdirectories
Safe file handling: Validates all paths before file system access

Limitations

Single-threaded: Handles one request at a time
No SSL/TLS support
Maximum file size: 64KB
Line sequential file organization only (text files)
No caching or compression
No range requests or partial content support

Troubleshooting

Port already in use:

Bind failed - check if port is in use

Another process is using port 8080. Either stop that process or change the port in config.cpy.

Permission denied: Ensure the files you're trying to serve have read permissions and the current user can access them.

File not found (404): Verify the file exists in the current directory where the server is running. File paths are case-sensitive.

License

This project is released into the public domain. Use it however you'd like.

Acknowledgments

Built with GnuCOBOL, demonstrating that COBOL can still be used for modern systems programming tasks.

Webbol

Install / Use

README

Webbol

Features

Requirements

Installing GnuCOBOL

Building

Usage

Example

Accessing the Server

Configuration

Project Structure

Supported MIME Types

Security Features

Limitations

Troubleshooting

License

Acknowledgments

Related Skills