Clap Peer — TCP-based P2P data transmission

ClapPeer - is a library for creating a distributed network of nodes that supports message exchange between them. Nodes can exchange both plain and encrypted messages.

Contents

• Features
• Example
• Connecting to a Node
• Sending Messages
• Receiving Messages
• Error Handling

Features:

• Message transmission using intermediate nodes.
• TTL mechanism to prevent message loops.
• Encrypted message exchange (RSA + AES).

Example

const {
  ClapPeer,
  DM,
  CRYPTO_DM,
  ERROR,
  INVALID_CRYPTO_DM,
} = require('clap-peer');

//Node - 1
const node_1 = new ClapPeer(1001, 'A');
node_1.on(DM, msg => console.log(msg));
node_1.on(CRYPTO_DM, msg => console.log(msg));

//Node - 2
const node_2 = new ClapPeer(1002, 'B');
node_2.connect({ host: '127.0.0.1', port: 1001 });
node_2
  .send(node_1.nodeId, { hello: 'hello crypto' })
  .catch(error => console.log(error));
node_2.publish(node_1.nodeId, { hello: 'just hello' });

Connecting to a Node

You can use either of two methods to connect to a node: via the .connect method or by passing a configuration object when creating the node. Choose the method based on how you want to structure your code. Here are the two approaches:

1. Connecting using the .connect() method:

const node = new ClapPeer(1001, 'A');
node.connect({ host: '127.0.0.1', port: 1002 });

Here, we create a node and then call the .connect() method, passing the host and port parameters. This allows you to separate the node creation and connection logic.

2. Connecting using a configuration object during node creation:

const node = new ClapPeer(1002, 'A', { host: '127.0.0.1', port: 1002 });

In this case, we pass the connection parameters directly when creating the ClapPeer object. This method is convenient if you need to connect to the node immediately upon creation.

Sending Messages

1. send — Sending an Encrypted Message

The send method is used to send encrypted messages. Before sending, it checks if the target node's public key is available:

• If the key is available, the message is encrypted and sent immediately.
• If the key is not available, the node requests the public key from the target node, then encrypts and sends the message.

Example:

node.send(node_2.nodeId, { text: 'Hello, secure world!' }).catch(error => {
  console.log(error);
});

2. publish — Sending a Plain Message

The publish method sends messages without encryption. It simply forwards the data to the specified node.

Example:

node.publish(node_2.nodeId, {
  text: 'Hello, open world!',
});

Differences Between send and publish:

| Method | Encryption | Public Key Check | Request Public Key if Needed | Routing Through Intermediate Nodes | | --------- | ---------- | ---------------- | ---------------------------- | ---------------------------------- | | send | ✅ | ✅ | ✅ | ✅ | | publish | ❌ | ❌ | ❌ | ✅ |

Receiving Messages

A node can subscribe to events to handle both plain and encrypted messages.

1. Handling Messages from publish (DM)

DM type messages are generated when another node calls the publish method. These messages are transmitted unencrypted.

node.on(DM, msg => console.log(msg));

2. Handling Messages from send (CRYPTO_DM)

Messages of type CRYPTO_DM are generated when the send method is called by another node. These messages are received in encrypted form.

node.on(CRYPTO_DM, msg => console.log(msg));

Differences Between DM and CRYPTO_DM:

| Event | Method That Generates the Message | Message Type | Description | | ----------- | --------------------------------- | ------------------ | ------------------------------------------ | | DM | publish | Plain text message | Handled as a regular, unencrypted message. | | CRYPTO_DM | send | Encrypted message | Sent and received in an encrypted form. |

Error Handling

You can subscribe to the ERROR event to handle all errors.

node.on(ERROR, (messageError, originalError) => {
  console.log(messageError);
  console.error(originalError);
});

The messageError.message parameter may contain one of the following messages:

• TIMEOUT_ERROR_MESSAGE:
  Neighbor check timed out after ${TIMEOUT_DURATION / 1000} seconds

• TIMEOUT_ERROR_REQUEST:
  RSA key retrieval timed out.

• DECRYPT_ERROR:
  Unable to decrypt the message.

• SEND_ERROR:
  Failed to send the data.

• PUBLISH_ERROR:
  Failed to publish the data.