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/.

Usage

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

Entrypoints

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.

Snippet

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 = {
    "@id":"4d26ad47-c71b-4e2e-9358-0a76f7fa77e4",
    "@type":"https://didcomm.org/didexchange/1.0/invitation",
    "label":"demo-js-agent",
    "recipientKeys":["7rADm5sA9FHB4enuYXj6PJZDAm1JcesKmbtx7Qh8YZrg"],
    "serviceEndpoint":"routing:endpoint"
};

// listen for connection 'received' notification
aries.startNotifier(notice => {
    const event = notice.payload
    if (event.Type === "post_state") {
        // accept invitation
        aries.didexchange.acceptInvitation(event.Properties.connectionID)
    }
}, ["didexchange_states"])
// receive invitation
aries.didexchange.receiveInvitation(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
aries.destroy()

Browser

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"
})

REST

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
})

Vue.js

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.

Node.js

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",
    "db-namespace":"demoagent"
})

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:

Headers

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.

Examples:

Serving gzipped wasm:

Headers:

• 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):

Headers:

• Content-Type: application/wasm

Path

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:

Nginx

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:

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.

goexec

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)'