Hydrogen View SDK

This SDK allows developers to integrate parts of the Hydrogen application into the UI of their own application. Hydrogen is written with the MVVM pattern, so to construct a view, you'd first construct a view model, which you then pass into the view. For most view models, you will first need a running client.

Changelog

See CHANGELOG.md

Tutorial

The Hydrogen SDK requires some assets to be shipped along with your app for things like downloading attachments, and end-to-end encryption. A convenient way to make this happen is provided by the SDK (importing hydrogen-view-sdk/paths/vite) but depends on your build system. Currently, only vite is supported, so that's what we'll be using in the example below.

You can create a vite project using the following commands:

# you can pick "vanilla-ts" here for project type if you're not using react or vue
yarn create vite
cd <your-project-name>
yarn
yarn add hydrogen-view-sdk
yarn add https://gitlab.matrix.org/api/v4/projects/27/packages/npm/@matrix-org/olm/-/@matrix-org/olm-3.2.14.tgz

Including the service worker

In addition to the assets mentioned above, you will also need to supply a serviceworker. This is needed for supporting authenticated media (MSC3916, blog post).
This is how you can do that:

1. create a public directory in your project root.
2. In your vite.config.js file, configure publicDir option to point to the directory you just created.
3. Symlink node_modules/hydrogen-view-sdk/lib-build/sw.js to public/sw.js:

   cd public
   ln -s ../node_modules/hydrogen-view-sdk/lib-build/sw.js sw.js

Now sw.js will be in the root of your dev server/ build root.

Rendering the app

You should see a index.html in the project root directory, containing an element with id="app". Add the attribute class="hydrogen" to this element, as the CSS we'll include from the SDK assumes for now that the app is rendered in an element with this classname.

If you go into the src directory, you should see a main.ts file. If you put this code in there, you should see a basic timeline after login and initial sync have finished (might take a while before you see anything on the screen actually).

You'll need to provide the username and password of a user that is already in the #element-dev:matrix.org room (or change the room id).

import {
    Platform,
    Client,
    LoadStatus,
    createNavigation,
    createRouter,
    RoomViewModel,
    TimelineView,
    viewClassForTile,
    FeatureSet
} from "hydrogen-view-sdk";
import downloadSandboxPath from 'hydrogen-view-sdk/download-sandbox.html?url';
import workerPath from 'hydrogen-view-sdk/main.js?url';
import olmWasmPath from '@matrix-org/olm/olm.wasm?url';
import olmJsPath from '@matrix-org/olm/olm.js?url';
import olmLegacyJsPath from '@matrix-org/olm/olm_legacy.js?url';
const assetPaths = {
    downloadSandbox: downloadSandboxPath,
    worker: workerPath,
    olm: {
        wasm: olmWasmPath,
        legacyBundle: olmLegacyJsPath,
        wasmBundle: olmJsPath
    },
    serviceWorker: "sw.js",
};
import "hydrogen-view-sdk/assets/theme-element-light.css";
// OR import "hydrogen-view-sdk/assets/theme-element-dark.css";

async function main() {
    const app = document.querySelector<HTMLDivElement>('#app')!
    const config = {};
    const platform = new Platform({container: app, assetPaths, config, options: { development: import.meta.env.DEV }});
    const navigation = createNavigation();
    platform.setNavigation(navigation);
    await platform.init();
    const urlRouter = createRouter({
        navigation: navigation,
        history: platform.history
    });
    urlRouter.attach();
    const client = new Client(platform);

    const loginOptions = await client.queryLogin("matrix.org").result;
    client.startWithLogin(loginOptions.password("username", "password"));

    await client.loadStatus.waitFor((status: string) => {
        return status === LoadStatus.Ready ||
            status === LoadStatus.Error ||
            status === LoadStatus.LoginFailed;
    }).promise;

    if (client.loginFailure) {
        alert("login failed: " + client.loginFailure);
    } else if (client.loadError) {
        alert("load failed: " + client.loadError.message);
    } else {
        const {session} = client;
        // looks for room corresponding to #element-dev:matrix.org, assuming it is already joined
        const room = session.rooms.get("!bEWtlqtDwCLFIAKAcv:matrix.org");
        const features = await FeatureSet.load(platform.settingsStorage);
        const vm = new RoomViewModel({
            room,
            ownUserId: session.userId,
            platform,
            urlRouter: urlRouter,
            navigation,
            features,
        });
        await vm.load();
        const view = new TimelineView(vm.timelineViewModel, viewClassForTile);
        app.appendChild(view.mount());
    }
}

main();

Typescript support

Typescript support is not yet available while we're converting the Hydrogen codebase to Typescript. In your src directory, you'll need to add a .d.ts (can be called anything, e.g. deps.d.ts) containing this snippet to make Typescript not complain that hydrogen-view-sdk doesn't have types:

declare module "hydrogen-view-sdk";

API Stability

This library follows semantic versioning; there is no API stability promised as long as the major version is still 0. Once 1.0.0 is released, breaking changes will be released with a change in major versioning.

Third-party licenses

This package bundles the bs58 package (license), and the Inter font (license).