FTP Library for Go

A production-ready FTP library for Go providing both client and server implementations with extensive RFC compliance, TLS support, and modern extensions.

📦 Quick Links

• FTP Client → - Full client documentation, API reference, examples
• FTP Server → - Server documentation, custom drivers, deployment
• Examples → - Working code examples for common use cases
• Contributing → - How to contribute to this project

Installation

# Client library
go get github.com/gonzalop/ftp

# Server library
go get github.com/gonzalop/ftp/server

Quick Start

Client Example

package main

import (
    "log"
    "github.com/gonzalop/ftp"
)

func main() {
    // Connect to server (handles ftp, ftps, ftp+explicit)
    // and automatically logs in (default: anonymous)
    client, _ := ftp.Connect("ftp://ftp.example.com")
    defer client.Quit()

    // Upload file
    client.UploadFile("local.txt", "remote.txt")

    // Download file
    client.DownloadFile("remote.txt", "download.txt")
}

→ See full client documentation

Server Example

package main

import (
    "log"
    "github.com/gonzalop/ftp/server"
)

func main() {
    // Start a standard server on port 21 serving files from /var/ftp
    log.Println("FTP server listening on :21")
    log.Fatal(server.ListenAndServe(":21", "/var/ftp"))
}

→ See full server documentation

Features

Client Features

• TLS/FTPS - Both explicit (AUTH TLS) and implicit modes
• Bandwidth Limiting - Control upload/download speeds with configurable rate limits
• Automatic Keep-Alive - Prevents timeouts during idle periods or long transfers
• Debug Logging - Structured logging with log/slog for easier debugging
• Progress Tracking - Built-in callbacks for upload/download progress
• File Operations - Upload, download, append, store unique (STOU), delete, rename
• Directory Operations - Create, delete, recursive remove, walk directory trees
• Resume Transfers - Resume interrupted downloads/uploads (REST)
• Modern Extensions - MLST/MLSD, SIZE, MDTM, HASH support
• IPv6 Support - Full IPv6 via EPSV/EPRT (RFC 2428)
• Rich Errors - Detailed protocol error context
• Transport-Agnostic - Pluggable dialer interface for alternative transports (QUIC, Unix sockets, etc.). See examples/quic for a working implementation.

→ Full feature list and API reference

Server Features

• Pluggable Backends - Filesystem, S3, memory, or custom storage
• Bandwidth Limiting - Global and per-user rate limits for transfer control
• Audit Logging - Comprehensive logging for security-relevant operations
• Graceful Shutdown - Stop accepting connections and wait for active transfers
• TLS/FTPS - Explicit and implicit FTPS support
• Virtual Hosting - HOST command for multi-tenant setups (RFC 7151)
• File Hashing - HASH command with SHA-256, SHA-512, MD5, CRC32
• IP-Based Access Control - Authenticate with client IP for security policies
• Secure by Default - Built-in path validation and chroot support
• Extensible - Custom authentication and driver interfaces
• Transport-Agnostic - Pluggable listener factory for alternative transports (QUIC, Unix sockets, etc.). See examples/quic for a working implementation.
• Command Control - Disable specific commands (i.e.,for security or transport compatibility)

→ Full server documentation

RFC Compliance

Both client and server implement modern FTP standards:

• RFC 959 - File Transfer Protocol (base)
• RFC 2389 - Feature Negotiation (FEAT)
• RFC 2428 - IPv6 and NAT Extensions (EPSV/EPRT)
• RFC 3659 - Extensions (MLST/MLSD, SIZE, MDTM, REST)
• RFC 4217 - Securing FTP with TLS
• RFC 5797 - FTP Command Registry
• RFC 7151 - File Transfer Protocol HOST Command

Detailed compliance matrices:

• Client Compliance →
• Server Compliance →

Documentation

• Client Documentation - Complete API reference, examples, TLS setup
• Server Documentation - Server setup, custom drivers, authentication
• Security Best Practices - TLS configuration, authentication, access control
• Performance Guide - Tuning, optimization, benchmarking
• Alternative Transports Guide - QUIC, Unix sockets, custom transports
• Examples Directory - Working code examples
• Client API (GoDoc) - Client API documentation
• Server API (GoDoc) - Server API documentation

License

This software is available under 2 licenses -- choose whichever you prefer:

1. MIT License
2. Public Domain (Unlicense)

See LICENSE for details.

Contributing

Contributions welcome! See CONTRIBUTING.md for guidelines.