@endo/ocapn

A tentative implementation of the OCapN (Object Capability Network) protocol for Hardened JavaScript. The OCapN specification remains a moving target and this package provides few guarantees of future compatibility. This is a testbed for building specification consensus and early discovery of specification questions.

Overview

OCapN is a protocol for secure distributed object programming. It enables networked programming with the convenience of calling methods on remote objects, much like local asynchronous programming.

This package provides:

• CapTP: The Capability Transport Protocol, the core message-passing layer of OCapN. See also the related @endo/captp package for a minimal CapTP implementation.
• Syrup codec: Encode and decode Syrup, the canonical binary serialization format tentatively used by OCapN.
• Netlayer interface: An abstraction for transport layers, allowing CapTP to operate over various network protocols.
• Third-party handoffs: Cryptographic mechanisms for securely transferring object references between peers.

For more information about the protocol, see ocapn.org.

Status

This package is a work in progress and is not yet published to npm. The API is subject to change.

Syrup Encoding

Syrup is a binary serialization format tentatively used by OCapN for encoding messages. This package includes a partial implementation that is strictly canonical and limited to forms needed to express the passable value model.

Supported types:

| Syrup Type | JavaScript Type | Encoding | |------------|-----------------|----------| | Boolean | true, false | t, f | | Integer | bigint | 0+, 1-, etc. | | Double | number | D + 8 bytes IEEE 754 | | Bytestring | Uint8Array | 3:cat | | String | string | 3"cat | | List | Array (frozen) | [ ... ] | | Dictionary | Object (frozen) | { ... } |

Look to the Syrup codec README for implementation details and limitations.

Architecture

The package is organized in layers, from high to low:

1. Client (src/client/): Session management, handoffs, sturdy references
2. CapTP (src/captp/): Message dispatch and slot management
3. Codecs (src/codecs/): Syrup encoding, descriptors, and operations
4. Netlayer (src/netlayers/): Network and transport abstraction

Related Packages

• @endo/captp: A minimal CapTP implementation using JSON encoding, suitable for simpler use cases.
• @endo/marshal: Serialization of passable objects.
• @endo/eventual-send: The E() proxy for asynchronous message passing.
• @endo/ocapn-noise: Cryptographic utilities for an OCapN network based on Noise Protocol.

License

Apache-2.0