Function call improvements (only cocoa so far)

1. when calling a Python function multiple times from Javascript, Promises will still get settled r0x0r#390
2. Add a per-browser ID so that return values are routed back to the correct client when you have multiple windows
3. allow calling python functions with multiple arguments

Author: rotu

webview/js/api.py

@@ -1,26 +1,34 @@
 src = """
 window.pywebview = {
     token: '%s',
+    _rpc_id_prefix: Math.random().toString(36).substring(2,6)+'.',
+    _rpc_id_sequence: 0,
     _createApi: function(funcList) {
         for (var i = 0; i < funcList.length; i++) {
             window.pywebview.api[funcList[i]] = (function (funcName) {
-                return function(params) {
-                    var promise = new Promise(function(resolve, reject) {
-                        window.pywebview._checkValue(funcName, resolve);
+                return function() {
+                    var rpc_id = window.pywebview._rpc_id_prefix+(
+                        ++window.pywebview._rpc_id_sequence);
+                    var rpc_request = {name:funcName, rpc_id:rpc_id, args:Array.from(arguments)}
+                    window.pywebview._bridge.call(rpc_request);
+                    return new Promise(function(resolve, reject) {
+                        function on_rpc_settle(ev){
+                            if (ev.detail.rpc_id == rpc_request.rpc_id){
+                                window.removeEventListener('rpc_settle', on_rpc_settle);
+                                if (ev.detail.success)
+                                    resolve(ev.detail.value);
+                                else
+                                    reject(ev.detail.value);
+                            }
+                        }
+                        window.addEventListener('rpc_settle', on_rpc_settle); 
                     });
-                    window.pywebview._bridge.call(funcName, JSON.stringify(params));
-                    return promise;
                 }
             })(funcList[i])
-
-            window.pywebview._returnValues[funcList[i]] = {
-                isSet: false,
-                value: undefined,
-            }
         }
     },
     _bridge: {
-        call: function (funcName, params) {
+        call: function (rpc_request) {
             switch(window.pywebview.platform) {
                 case 'mshtml':
                 case 'cef':
@@ -29,7 +37,8 @@
                 case 'edgehtml':
                     return window.external.notify(JSON.stringify([funcName, params]));
                 case 'cocoa':
-                    return window.webkit.messageHandlers.jsBridge.postMessage(JSON.stringify([funcName, params]));
+                    return window.webkit.messageHandlers.jsBridge.postMessage(
+                        JSON.stringify(rpc_request));
                 case 'qtwebengine':
                     new QWebChannel(qt.webChannelTransport, function(channel) {
                         channel.objects.external.call(funcName, params);
@@ -38,25 +47,13 @@
             }
         }
     },
-
-    _checkValue: function(funcName, resolve) {
-         var check = setInterval(function () {
-            var returnObj = window.pywebview._returnValues[funcName];
-            if (returnObj.isSet) {
-                returnObj.isSet = false;
-                try {
-                    resolve(JSON.parse(returnObj.value));
-                } catch(e) {
-                    resolve(returnObj.value);
-                }
-
-                clearInterval(check);
-            }
-         }, 100)
+    _rpcSettle: function(rpc_id, success, value){
+        window.dispatchEvent(
+            new CustomEvent('rpc_settle', {detail:{rpc_id:rpc_id, success:success, value:value}} )
+        );
     },
     platform: '%s',
     api: {},
-    _returnValues: {}
 }
 
 window.pywebview._createApi(%s);

webview/platforms/cocoa.py

@@ -89,10 +89,11 @@ def initWithObject_(self, window):
             return self
 
         def userContentController_didReceiveScriptMessage_(self, controller, message):
-            func_name, param = json.loads(message.body())
-            if param is WebKit.WebUndefined.undefined():
-                param = None
-            js_bridge_call(self.window, func_name, param)
+            rpc_request = json.loads(message.body())
+            name = rpc_request['name']
+            rpc_id = rpc_request['rpc_id']
+            args = rpc_request['args']
+            js_bridge_call(self.window, name, args, rpc_id)
 
     class BrowserDelegate(AppKit.NSObject):
         # Display a JavaScript alert panel containing the specified message

webview/util.py

@@ -83,23 +83,28 @@ def generate_func():
     return js_code
 
 
-def js_bridge_call(window, func_name, param):
+def js_bridge_call(window, func_name, args, rpc_id):
     def _call():
-        result = json.dumps(func(func_params)).replace('\\', '\\\\').replace('\'', '\\\'')
-        code = 'window.pywebview._returnValues["{0}"] = {{ isSet: true, value: \'{1}\'}}'.format(func_name, result)
-        window.evaluate_js(code)
+        try:
+            result = json.dumps(func(*args))
+            code = 'window.pywebview._rpcSettle({0},true,{1})'.format(json.dumps(rpc_id), result)
+            window.evaluate_js(code)
+        except Exception as e:
+            logger.exception('Error occurred while evaluating function {0}'.format(func_name))
+            code = 'window.pywebview._rpcSettle({0},false,{1})'.format(json.dumps(rpc_id), str(e))
+            window.evaluate_js(code)
 
     func = getattr(window.js_api, func_name, None)
 
     if func is not None:
-        try:
-            func_params = param if not param else json.loads(param)
-            t = Thread(target=_call)
-            t.start()
-        except Exception:
-            logger.exception('Error occurred while evaluating function {0}'.format(func_name))
+        t = Thread(target=_call)
+        t.start()
     else:
-        logger.error('Function {}() does not exist'.format(func_name))
+        msg = 'Function {}() does not exist'.format(func_name)
+        logger.error(msg)
+        code = 'window.pywebview._rpcSettle({0},false,{1})'.format(
+            json.dumps(rpc_id), json.dumps(msg))
+        window.evaluate_js(code)
 
 
 def escape_string(string):