opendht

OpenDHT

A lightweight C++17 Distributed Hash Table implementation.

OpenDHT provides an easy to use distributed in-memory data store. Every node in the network can read and write values to the store. Values are distributed over the network, with redundancy.

• Lightweight and scalable, designed for large networks and small devices
• High resilience to network disruption
• Public key cryptography layer providing optional data signature and encryption (using GnuTLS)
• IPv4 and IPv6 support
• Clean and powerful C++17 map API
• Bindings for C, Rust & Python 3
• REST API with optional HTTP client+server with push notification support

Documentation

See the wiki:

How to run a node

You can help contribute to the public network by running a stable node with a public IP address. https://github.com/savoirfairelinux/opendht/wiki/Running-a-node-with-dhtnode

How-to build and install

Build instructions: see BUILD.md

Examples

C++ example

The tools directory includes simple example programs :

• dhtnode, a command line tool, allowing to run a DHT node and perform operations supported by the library (get, put etc.) with text values.
• dhtchat, a very simple IM client working over the dht.

Example program launching a DHT node, connecting to the network and performing some basic operations:

…

Python 3 example

Install on Linux, macOS and Windows with:

pip install opendht

Using the simple, blocking API:

import opendht as dht

node = dht.DhtRunner()
node.run()

# Join the DHT network through any running node,
# here using a known bootstrap node.
node.bootstrap("bootstrap.jami.net", "4222")

# blocking call (provide callback arguments to make the call non-blocking)
node.put(dht.InfoHash.get("unique_key"), dht.Value(b'some binary data'))

results = node.get(dht.InfoHash.get("unique_key"))
for value in results:
    print(value)

Or using asyncio:

…

Dependencies

Core dependencies:

• msgpack-c 1.2+, used for data serialization.
• GnuTLS 3.3+, used for cryptographic operations.
• Nettle 2.4+, a GnuTLS dependency for crypto.
• {fmt} 9.0+, for log formatting.

Optional dependencies for the REST API (DHT proxy client/server):

• (optional) restinio
• (optional) llhttp
• (optional) jsoncpp 1.7.4-3+
• (optional) simdutf

Build environment:

• Build tested with GCC 9+ (GNU/Linux, Windows with MinGW), Clang/LLVM (GNU/Linux, Android, macOS, iOS).
• Build tested with Microsoft Visual Studio 2019, 2022

License

Copyright (c) 2014-2026 Savoir-faire Linux Inc.

OpenDHT is released under the MIT License. See LICENSE for details.

Acknowledgements

This project was originally based on https://github.com/jech/dht by Juliusz Chroboczek.