Matrix Redux Wrap :taco:

A library that exposes matrix-js-sdk state via Redux

Contents

• Introduction
• Usage
• Docs

Introduction

Matrix Redux Wrap was motivated by the need to expose the Matrix protocol via a Redux store. The matrix-js-sdk API does not expose a Redux-like pattern through which data flows but rather a number of asyncronous HTTP-request wrappers and a number of models that encapsulate the objects within the Matrix protocol. These models are updated by a mixture of server responses and API calls and do not necessarily lend themselves to simple mental models or the ability to be incorporated into frameworks such as Flux and Redux.

Could we do better?

Wrapping matrix-js-sdk is not the ideal solution. Ideally, the logic contained within it (for handling the Matrix-specific long-polling etc.) could be split out into a special Asynchronous Action Creator. A reducer could be written to handle the dispatched actions and update the store accordingly. However, the complexity of this task iss greater than creating Matrix Redux Wrap, which harnesses the existing logic of the js-sdk whilst paying the price of duplicating js-sdk model state.

Usage

For examples, see the examples directory.

Simple usage:

const { wrapSyncingClient, matrixReduce } = require('matrix-redux-wrap');
const Matrix = require('matrix-js-sdk');

let state = {};
const dispatch = (action) => {
    state = matrixReduce(action, state);

    const roomCount = Object.keys(state.mrw.wrapped_state.rooms).length;
    console.info('You are in ' + roomCount + ' rooms');
}

// initialise store
dispatch(undefined);

const syncClient = Matrix.createClient({
    baseUrl: "https://my.home.server",
    userId: "@myusername:my.home.server",
    accessToken: "myaccesstoken12345",
});
wrapSyncingClient(syncClient, dispatch);
syncClient.startClient();

Output:

...
You are in 1234 rooms
You are in 1234 rooms
You are in 1234 rooms
...

Documentation

Below is a quick explanation of the provided API for using matrix-redux-wrap. For full examples of how these functions can be used, see the examples directory.

asyncAction(stateKey, promise) => (dispatch) => {...}

Returns a function that calls the dispatch argument asyncronously as such:

• Once immediately, dispatching a "pending" action;
• then, depending on whether the promise resolves or is rejected, either:
  • it dispatches a "success" action or
  • it dispatches an "failure" action.

These actions will have namespaced type fields of:

• mrw.wrapped_api.pending
• mrw.wrapped_api.success
• mrw.wrapped_api.failure

Each of these have different fields present and all can be passed to matrixRedux to update the mrw.wrapped_api state.

mrw.wrapped_api.pending

{
  type: "mrw.wrapped_api.pending", 
  method: stateKey, 
  pendingState: ..., 
  id: "bfadef89"
}

• method: the stateKey given to asyncAction
• id: an random opaque identifier for this call to asyncAction

mrw.wrapped_api.success

{
  type: "mrw.wrapped_api.success", 
  method: stateKey, 
  result: ..., 
  id: "bfadef89"
}

• method: see above
• id: an random opaque identifier that refers to the previously dispatched "pending" action
• result: the value that promise resolved to

mrw.wrapped_api.failure

{ 
  type: "mrw.wrapped_api.failure", 
  method: stateKey, 
  error: ..., 
  id: "bfadef89"
}

• method, id: see above
• error: the value that the promise was rejected with

wrapSyncingClient(matrixClient) => void

When given a matrix-js-sdk MatrixClient instance, it will dispatch an action for each event emitted by the instance, taking certain keys from the event, assigning them to fields on the action. Once a client instance is passed to the function, the caller calls startClient to start the long-polling process that will cause the instance to emit events.

This creates actions of the following shape:

{
  type: 'mrw.wrapped_event',
  emittedType: 'Room.timeline',
  emittedArgs: wrappedArgs,
}

matrixReduce can be used to reduce these actions to the current state of the matrix client as exposed in the state under the mrw key.

matrixReduce(action, state) => newState

Reduces state according to the mrw.* action passed, returning the new state. The state has the following structure:

{
  mrw: {
    wrapped_api: {
      login: {
        loading: false,
        status: 'success',
        pendingState: ['username', 'password'],
        lastResult: {
          access_token: '12345',
        },
      },
    },
    wrapped_state: {
      sync: {
        state: 'SYNCING',
      },
      rooms: {
        '!myroomid': {
          members: {
            '@userid:domain': {
              membership: 'join',
              name: 'Morpheus',
            },
          },
          name: "some room name",
          state: {
            'm.room.member': {
              '@userid:domain': {
                id: '$some_awesome_event_id',
                content: {
                  membership: 'join',
                  name: 'Morpheus',
                  avatarUrl: 'mxc://domain/flibblejibble',
                },
                ts: 1234,
              },
            },
            'm.room.avatar': {
              '': {
                content: {
                  url: 'mxc://domain/flibblejibble',
                },
              },
            },
          },
          timeline: [{
            id: '$some_event_id',
            type: 'm.room.message',
            content: { body: 'hello, world!' },
            sender: '@userid:domain',
            ts: 12345,
          }, {
            id: '$some_other_event_id',
            type: 'm.room.message',
            content: { body: 'hello (again), world!' },
            sender: '@userid:domain',
            ts: 123456,
          }, {
            id: '$some_other_event_id2',
            type: 'x.weird.event',
            content: {},
            sender: '@userid:domain',
            ts: 1234567,
            redactedBecause: {
              sender: '@userid:domain',
              ts: 12345678,
            },
          }],
          receipts: {
            '$some_event_id': {
              'm.receipt': {
                '@userid:domain': {
                  ts: 12345,
                },
              },
            },
          },
        },
      },
    },
  },
}