elastic · jsoriano · Feb 27, 2022 · Feb 28, 2022 · Mar 14, 2022 · Mar 14, 2022
diff --git a/.ci/Jenkinsfile b/.ci/Jenkinsfile
@@ -52,6 +52,7 @@ pipeline {
     stage('Test') {
       steps {
         cleanup()
+        installTools([ [tool: 'nodejs', version: '10.0' ] ])
         withMageEnv(){
           dir("${BASE_DIR}"){
             sh(label: 'Test', script: 'make test')

@@ -0,0 +1 @@
+*.wasm
@@ -0,0 +1,7 @@
+include ../go/common.mk
+
+build:
+	GOOS=js GOARCH=wasm go build -o validator.wasm .
+
+test:
+	GOOS=js GOARCH=wasm go test -v -exec="`go env GOROOT`/misc/wasm/go_js_wasm_exec" . ../go/...
@@ -0,0 +1,12 @@
+## CLI
+
+* Build wasm with `make build`.
+* Run `./validate.js /path/to/package.zip` (or `node validate.js /path/to/package.zip`).
+
+Node.js and Go are required.
+
+## Web server with client validation
+
+* Build wasm with `make build`.
+* Run the server with `go run server.go`.
+* Access http://localhost:8080 and select a file.
@@ -0,0 +1,26 @@
+<!doctype html>
+<html>
+<body>
+  <label for="package">Select a package</label><br />
+  <input name="package" type="file" id="package" />
+  <div id="result">
+  </div>
+
+  <script src="wasm_exec.js"></script>
+  <script src="validate.lib.js"></script>
+  <script>
+    const input = document.getElementById("package");
+    const result = document.getElementById("result");
+    input.addEventListener("change", function() {
+      const reader = new FileReader();
+      reader.onload = function(event) {
+        var buffer = new Uint8Array(reader.result);
+        validateZipBuffer(input.files[0], buffer,
+	  () => { result.innerHTML = "Package is valid" },
+	  (errors) => { result.innerHTML = errors.replaceAll("\n", "<br />") })
+      };
+      reader.readAsArrayBuffer(input.files[0]);
+    })
+  </script>
+</body>
+</html>
@@ -0,0 +1,93 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+//go:build wasm
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"syscall/js"
+
+	"github.com/elastic/package-spec/code/go/pkg/validator"
+)
+
+const moduleName = "elasticPackageSpec"
+
+// asyncFunc helps creating functions that return a promise.
+//
+// Calling async JavaScript APIs causes deadlocks in the JS event loop. Not sure
+// how to find if a Go code does it, but for example ValidateFromZip does, so
+// we need to run this code in a goroutine and return the result as a promise.
+// Related: https://github.com/golang/go/issues/41310
+func asyncFunc(fn func(this js.Value, args []js.Value) interface{}) js.Func {
+	return js.FuncOf(func(this js.Value, args []js.Value) interface{} {
+		handler := js.FuncOf(func(_ js.Value, handlerArgs []js.Value) interface{} {
+			resolve := handlerArgs[0]
+			reject := handlerArgs[1]
+
+			go func() {
+				result := fn(this, args)
+				if err, ok := result.(error); ok {
+					reject.Invoke(err.Error())
+					return
+				}
+				resolve.Invoke(result)
+			}()
+
+			return nil
+		})
+
+		return js.Global().Get("Promise").New(handler)
+	})
+}
+
+func main() {
+	// It doesn't seem to be possible yet to export values as part of the compiled instance.
+	// So we have to expose it by setting a global value. It may worth to explore tinygo for this.
+	// Related: https://github.com/golang/go/issues/42372
+	js.Global().Set(moduleName, make(map[string]interface{}))
+	module := js.Global().Get(moduleName)
+	module.Set("validateFromZip", asyncFunc(
+		func(this js.Value, args []js.Value) interface{} {
+			if len(args) == 0 || args[0].IsNull() || args[0].IsUndefined() {
+				return fmt.Errorf("package path expected")
+			}
+
+			pkgPath := args[0].String()
+			return validator.ValidateFromZip(pkgPath)
+		},
+	))
+
+	module.Set("validateFromZipReader", asyncFunc(
+		func(this js.Value, args []js.Value) interface{} {
+			if len(args) < 1 || args[0].IsNull() || args[0].IsUndefined() {
+				return fmt.Errorf("file object expected")
+			}
+			if len(args) < 2 || args[1].IsNull() || args[1].IsUndefined() {
+				return fmt.Errorf("array buffer with content of package expected")
+			}
+
+			file := args[0]
+			name := file.Get("name").String()
+			size := int64(file.Get("size").Int())
+
+			buf := make([]byte, size)
+			js.CopyBytesToGo(buf, args[1])
+
+			reader := bytes.NewReader(buf)
+			return validator.ValidateFromZipReader(name, reader, size)
+		},
+	))
+
+	// Go runtime must be always available at any moment where exported functionality
+	// can be executed, so keep it running till done.
+	done := make(chan struct{})
+	module.Set("stop", js.FuncOf(func(_ js.Value, _ []js.Value) interface{} {
+		close(done)
+		return nil
+	}))
+	<-done
+}
@@ -0,0 +1,18 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+//go:build !wasm
+
+package main
+
+import (
+	"log"
+	"net/http"
+)
+
+func main() {
+	staticHandler := http.FileServer(http.Dir("."))
+	http.Handle("/", staticHandler)
+	log.Fatal(http.ListenAndServe("localhost:8080", nil))
+}
@@ -0,0 +1,27 @@
+#!/usr/bin/env node
+
+if (process.argv.length < 3) {
+	console.error("usage: " + process.argv[1] + " [package path]");
+	process.exit(1);
+}
+
+const path = require('path')
+const fs = require('fs');
+
+require(path.join(process.env.GOROOT, "misc/wasm/wasm_exec.js"));
+const go = new Go();
+
+const wasmBuffer = fs.readFileSync('validator.wasm');
+WebAssembly.instantiate(wasmBuffer, go.importObject).then((validator) => {
+	go.run(validator.instance);
+
+	elasticPackageSpec.validateFromZip(process.argv[2]).then(() =>
+		console.log("OK")
+	).catch((err) =>
+		console.error(err)
+	).finally(() =>
+		elasticPackageSpec.stop()
+	)
+}).catch((err) => {
+	console.error(err);
+});
@@ -0,0 +1,23 @@
+var wasmBuffer;
+fetch('validator.wasm').then((response) => {
+  return response.arrayBuffer();
+}).then((buffer) => {
+  wasmBuffer = buffer;
+})
+const go = new Go();
+
+function validateZipBuffer(file, buffer, success, error) {
+	WebAssembly.instantiate(wasmBuffer, go.importObject).then((validator) => {
+		go.run(validator.instance);
+
+		elasticPackageSpec.validateFromZipReader(file, buffer).then(() => 
+			success()
+		).catch((err) => 
+			error(err)
+		).finally(() =>
+			elasticPackageSpec.stop()
+		)
+	}).catch((err) => {
+		console.error(err);
+	});
+}