0.0.2-5 • Public • Published

    Aries JS Worker

    Aries Framework Go via Javascript.

    Build it

    To build you will need:

    • Go 1.16.x
    • npm 6.13.x
    • Node.JS 12.14.x
    • bash

    Run npm install in this directory. The output bundles will be placed in dist/.


    Note: the API is in the very early stages of development and is still subject to a few changes.


    aries-js-worker has several entrypoints tailored to the environment and needs:

    • dist/node/aries.js: for use in node.js
    • dist/web/aries.js: for use in the browser
    • dist/rest/aries.js: for use in any environment but relying on an external REST controller API server instead of the bundled webassembly module.


    Example: accept a did-exchange invitation:

    // in the browser
    const aries = await new Aries.Framework({
        assetsPath: "/public/dist/assets",
        "agent-default-label": "dem-js-agent",
        "http-resolver-url": [],
        "auto-accept": true,
        "outbound-transport": ["ws", "http"],
        "transport-return-route": "all",
        "log-level": "debug"
    // sample invitation
    const invitation = {
    // listen for connection 'received' notification
    aries.startNotifier(notice => {
        const event = notice.payload
        if (event.Type === "post_state") {
            // accept invitation
    }, ["didexchange_states"])
    // receive invitation
    // listen for connection 'completed' notification
    aries.startNotifier(notice => {
        const event = notice.payload
        if (event.StateID === "completed" && event.Type === "post_state") {
            console.log("connection completed!")
    }, ["didexchange_states"])
    // release resources


    Note: make sure the assets are served correctly.

    Source aries.js in your <script> tag:

    <script src="dist/web/aries.js"></script>

    Then initialize your aries instance:

    const aries = await new Aries.Framework({
        assetsPath: "/path/serving/the/assets",
        "agent-default-label": "dem-js-agent",
        "http-resolver-url": [],
        "auto-accept": true,
        "outbound-transport": ["ws", "http"],
        "transport-return-route": "all",
        "log-level": "debug"


    Note: make sure the assets are served correctly if you're running aries in the browser.

    Assuming you're in the browser, source aries.js in your <script> tag:

    <script src="dist/rest/aries.js"></script>

    Then initialize your aries instance:

    const aries = await new Aries.Framework({
        assetsPath: "/path/serving/the/assets", // still required for assets other than the wasm
        "agent-rest-url": "http://controller.api.example.com", // REST controller URL of the agent
        "agent-rest-wshook": "ws://controller.api.example.com", // Optional REST controller websocket URL from which you can listen to notifications
        "agent-rest-token": "sample_auth_token" // Optional authorization header to be based to rest endpoint for each request


    See vue-framework-go for a sample agent built with Vue.js.

    Note: is the webpack devserver (npm run serve) not working for you? Note the points about serving the assets below. See how vue-aries-framework-go fixes this.


    Note: currently broken, see #1237

    const { Framework } = require('./node_modules/@hyperledger/aries-framework-go/dist/node/aries.js');
    const aries = await new Framework({
        assetsPath: process.cwd() + "/node_modules/@hyperledger/aries-framework-go/dist/assets",
        "agent-default-label": "dem-js-agent",
        "http-resolver-url": [],
        "auto-accept": true,
        "outbound-transport": ["ws", "http"],
        "transport-return-route": "all",
        "log-level": "debug",

    Important - Serving the Assets

    Note: this applies if you are running in the browser.

    aries-js-worker loads some assets at runtime: the web assembly binary and a couple of JS scripts. These assets are located in the dist/assets directory (if you npm install it, you'll find them in ./node_modules/@hyperledger/aries-framework-go/dist/assets).

    Things that need to work if you are to use aries-js-worker on the client side:


    Make sure the content server adds the appropriate headers when serving the compressed aries-js-worker.wasm file. aries-js-worker uses the Fetch API to fetch the wasm.


    Serving gzipped wasm:


    • Content-Type: application/wasm
    • Content-Encoding: gzip

    Serving wasm compressed with brotli:

    If your browser supports it, then the headers are:

    • Content-Type: application/wasm
    • Content-Encoding: br

    Note, however, that your browser may not support this compression mode.

    Not all browsers include br in Accept-Encoding when using fetch() (Firefox doesn't) and it is impossible to override because Accept-Encoding is a forbidden header name.

    Serving uncompressed wasm (not recommended):


    • Content-Type: application/wasm


    The URL used to fetch the WASM file is always <assetsPath>/aries-js-worker.wasm. This path needs to exist even if your content server is serving a compressed version.

    Configuring your content server

    Here are some examples:


    Sending compressed files: enabling gzip_static on a location will automatically serve requests to http://example.com/assets/aries-js-worker.wasm with aries-js-worker.wasm.gz if it exists.

    Example: Nginx serving your assets under /public/assets with gzipped wasm:

    location ~ aries-js-worker\.wasm$ {
        gzip_static on;
        types {
            application/wasm  wasm;

    Files in /public/assets:

    ├── aries-js-worker.wasm.gz
    ├── wasm_exec.js
    ├── worker-impl-node.js
    └── worker-impl-web.js

    Requests for http://example.com/public/assets/aries-js-worker.wasm will be served with the .gz file.


    Here is a hacky one-liner when using goexec (for development purposes):

    goexec -quiet 'http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {dir := http.Dir("."); if strings.HasSuffix(r.RequestURI, ".wasm") && !strings.Contains(r.RequestURI, "wasm=") {w.Header().Add("Content-Encoding", "gzip"); w.Header().Add("Content-Type", "application/wasm"); fmt.Sprintf(r.URL.Path); file, err := dir.Open(r.URL.Path + ".gz"); if err != nil {w.Header().Add("x-error", err.Error()); w.WriteHeader(http.StatusInternalServerError); return; }; buf := make([]byte, 2048); for err == nil { n := 0; n, err = file.Read(buf);if n > 0 {n, err = w.Write(buf[:n]);}}; if !errors.Is(err, io.EOF) {w.WriteHeader(http.StatusInternalServerError); return;}; }; http.FileServer(http.Dir(".")).ServeHTTP(w, r) }); http.ListenAndServe(":8080", nil)'


    npm i @scaffoldly/aries-framework-go-for-slygo

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