Extensible implementation of the Kademlia distributed hash table for Node.js and the browser.

Quick Start

For complete documentation on using and extending Kad, read the documentation.

npm install kad

Create your node, plug in your storage adapter, join the network, and party!

var kad = require('kad');

var seed = {
  address: '127.0.0.1',
  port: 1338
};

var dht = new kad.Node({
  transport: kad.transports.UDP(kad.contacts.AddressPortContact({
    address: '127.0.0.1',
    port: 1337
  })),
  storage: kad.storage.FS('path/to/datadir')
});

dht.connect(seed, function(err) {
  // dht.get(key, callback);
  // dht.put(key, value, callback);
});

You can build Kad for the browser by running:

npm run build

This will output to dist/kad.browser.js and will bind to window when loaded in your web application.

You can run a network simulation locally using the included simulator. This will create n nodes (as you define) and connect them to each other, sending STORE messages on an interval and printing information to the console.

# use the default of 6 nodes
npm run simulation
# specify as many nodes as you like
npm run simulation 128

Transports

Kad ships with support for UDP, TCP, and HTTP transports. To explicitly define the transport to use, set the transport option to the appropriate value. See the documentation on {@link RPC} and {@link Contact} for more information.

var dht = new kademlia.Node({
  // ...
  transport: kademlia.transports.TCP(contact, options)
});

If you would like to author your own transport adapter, see kad-transport-boilerplate.

Community Transport Adapters

• WebRTC

Persistence

Kad does not make assumptions about how your nodes will store their data, instead relying on you to implement a storage adapter of your choice. This is as simple as providing get(key, callback), put(key, value, callback), del(key, callback), and createReadStream() methods.

This works well with levelup, but you could conceivably implement any storage layer you like provided you expose the interface described above. Some adapters have already been contributed by the community, listed below.

Community Storage Adapters

• Local Storage
• MongoDB
• File System

Extensions

Sybil/Spartacus Mitigation

You can use kad-spartacus to mitigate 2 types of attacks to which a Kademlia DHT may be vulnerable: the Sybil attack and it's variant, Spartacus.

Read More →

NAT Traversal

You can use kad-traverse to ensure your nodes are able to communicate when behind a NAT or firewall. The extension will use different strategies based on the network configuration.

Read More →

Performance Monitoring

You can use kad-telemetry to track the performance of your peers and extend the default routing algorithm to prioritize the selection of nodes with a higher score.

Read More →

Publish & Subscribe

You can use kad-quasar to extend kad with support for probabilistic, topic-based publish/subscribe capabilities.

Read More →

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.