Holochain Client - JavaScript

A JavaScript client for the Holochain Conductor API (works with browsers as well as Nodejs).

API Reference

Complete API reference

Installation

To install from NPM, run

npm install --save-exact @holochain/client

This code is under beta development and you may wish to lock to an exact version of the library for that reason, as shown in the above command.

Sample usage

Use AppAgentWebsocket with implicit zome call signing

  const signalCb = (signal: AppSignal) => {
    // implementation of signal handler
    resolve()
  }

  const TIMEOUT = 12000
  // default timeout is set to 12000
  const appWs = await AppWebsocket.connect(`ws://127.0.0.1:${appPort}`, 12000)

  const client = new AppAgentWebsocket(appWs, 'installed_app_id');
  client.on("signal", signalCb);

  // default timeout set here (30000) will overwrite the defaultTimeout(12000) set above
  await client.callZome({
   role_name: 'dnas_role_name', // role_name is unique per app, so you can unambiguously identify your dna with role_name in this client
   zome_name: "test_zome",
   fn_name: 'test_emitter_fn',
   payload: null,
  }, 30000)

Use AppWebsocket with implicit zome call signing

  const signalCb = (signal: AppSignal) => {
    // impl...
    resolve()
  }

  const TIMEOUT = 12000
  // default timeout is set to 12000
  const client = await AppWebsocket.connect(`ws://127.0.0.1:${appPort}`, TIMEOUT, signalCb)

  // default timeout set here (30000) will overwrite the defaultTimeout(12000) set above
  await client.callZome({
   cell_id,
   zome_name: "test_zome",
   fn_name: 'test_emitter_fn',
   provenance: agentPubKey,
   payload: null,
  }, 30000)

Managing zome call signing credentials in a pure JavaScript browser application

Here is a pattern to manage signing keys for signing zome calls when running pure JavaScript web hApps in a web browser:

const cellIdB64 =
    encodeHashToBase64(cell_id[0]) + encodeHashToBase64(cell_id[1]);
// in case the zome call signing credentials are stored locally in the browser
const signingCredentialsJson = localStorage.getItem(cellIdB64);
let signingCredentials: SigningCredentials | null =
  signingCredentialsJson && JSON.parse(signingCredentialsJson);

if (!signingCredentials) {
  const [keyPair, signingKey] = generateSigningKeyPair();
  const capSecret = await admin.grantSigningKey(
    cell_id,
    { [GrantedFunctionsType.All]: null },
    signingKey
  );
  signingCredentials = {
    capSecret,
    keyPair,
    signingKey,
  };
}
setSigningCredentials(cell_id, signingCredentials);
// possibly store the zome call signing credentials locally in the browser
localStorage.setItem(cellIdB64, JSON.stringify(signingCredentials));

Holochain Compatibility

See default.nix for the Holochain version this package is compatible with.

If updating the Holochain version included in holonix, please use niv update as explained in the Holochain Installation Guide.

Running tests

You need a version (stable toolchain) of Rust available.

You need holochain and hc on your path, best to get them from nix with nix-shell.

To perform the pre-requisite DNA compilation steps, and run the Nodejs test, run:

nix-shell
./run-test.sh

Contribute

Holochain is an open source project. We welcome all sorts of participation and are actively working on increasing surface area to accept it. Please see our contribution guidelines for our general practices and protocols on participating in the community, as well as specific expectations around things like code formatting, testing practices, continuous integration, etc.

• Connect with us on our forum

License

Copyright (C) 2020-2023, Holochain Foundation

This program is free software: you can redistribute it and/or modify it under the terms of the license provided in the LICENSE file (CAL-1.0). 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.