initial webassembly demo

lucasmenendez · Apr 4, 2024 · 7cd17a8 · 7cd17a8
1 parent c0e333b
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diff --git a/cmd/webassembly/main.go b/cmd/webassembly/main.go
@@ -0,0 +1,72 @@
+//go:build js && wasm
+// +build js,wasm
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"syscall/js"
+
+	"github.com/lucasmenendez/gosss"
+)
+
+const (
+	// js names
+	jsClassName     = "GoSSS"
+	jsHideMethod    = "hide"
+	jsRecoverMethod = "recover"
+	// required number of arguments for each method
+	hidedNArgs    = 3 // msg, nshares, minshares
+	recoverdNArgs = 1 // shares
+)
+
+func wasmError(err error) js.Value {
+	return js.Global().Call("throwError", js.ValueOf(err.Error()))
+}
+
+func main() {
+	gosssClass := js.ValueOf(map[string]interface{}{})
+	gosssClass.Set(jsHideMethod, js.FuncOf(func(this js.Value, p []js.Value) interface{} {
+		if len(p) != hidedNArgs {
+			return wasmError(fmt.Errorf("invalid number of arguments"))
+		}
+		msg := p[0].String()
+		nshares := p[1].Int()
+		minshares := p[2].Int()
+		// hide the message
+		shares, err := gosss.HideMessage([]byte(msg), &gosss.Config{
+			Shares: nshares,
+			Min:    minshares,
+		})
+		if err != nil {
+			return wasmError(err)
+		}
+		jsonShares, err := json.Marshal(shares)
+		if err != nil {
+			return wasmError(err)
+		}
+		return string(jsonShares)
+	}))
+
+	gosssClass.Set(jsRecoverMethod, js.FuncOf(func(this js.Value, p []js.Value) interface{} {
+		if len(p) != recoverdNArgs {
+			return wasmError(fmt.Errorf("invalid number of arguments"))
+		}
+		// recover the shares from the json string
+		var shares []string
+		if err := json.Unmarshal([]byte(p[0].String()), &shares); err != nil {
+			return wasmError(err)
+		}
+		// recover the message
+		msg, err := gosss.RecoverMessage(shares, nil)
+		if err != nil {
+			return wasmError(err)
+		}
+		return string(msg)
+	}))
+
+	js.Global().Set(jsClassName, gosssClass)
+	// keep the program running forever
+	select {}
+}
diff --git a/web/index.html b/web/index.html
@@ -0,0 +1,30 @@
+<html>
+    <head>
+        <title>Go Shamir Secret Sharing demo</title>
+    </head>
+    <body>
+        <script src="wasm_exec.js"></script>
+        <script>
+            function throwError(e) {
+                console.error(e);
+            }
+
+            function hide(message, sharesCount, threshold) {
+                let rawshares = GoSSS.hide(message, sharesCount, threshold);
+                return JSON.parse(rawshares);
+            }
+
+            function recover(shares) {
+                let message = GoSSS.recover(JSON.stringify(shares));
+                return message;
+            }
+
+            (async function() {
+                const go = new Go();
+                const result = await WebAssembly.instantiateStreaming(fetch("gosss.wasm"), go.importObject);
+                go.run(result.instance);
+            })()
+        </script>
+    </body>
+</html>
+