storj/satellite/console/wasm

Using WebAssembly in Storj

In order to use the uplink library from the browser, we can compile the uplink library to WebAssembly (wasm).

Setup

To generate wasm code that can create access grants in the web browser, run the following from the storj/wasm directory:

$ GOOS=js GOARCH=wasm go build -o access.wasm access.go

The access.wasm code can then be loaded into the browser in a script tag in an html page. Also needed is a JavaScript support file which ships with golang.

To copy the JavaScript support file, run:

$ cp "$(go env GOROOT)/misc/wasm/wasm_exec.js" .

Ref: Golang WebAssembly docs

The HTML file should include the following:

<script type="text/javascript" src="/path/to/wasm_exec.js"></script>
<script>
    const go = new Go();
    WebAssembly.instantiateStreaming(
        fetch("/path/to/access.wasm"), go.importObject).then(
        (result) => {
            go.run(result.instance);
    });
</script>

Additionally, the HTTP Content-Security-Policy (CSP) script-src directive will need to be modified to allow wasm code to be executed.

See: WebAssembly Content Security Policy docs