JavascriptPostMessageHandler.h

// Copyright © 2019 The CefSharp Authors. All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.

#pragma once

#include "include/cef_v8.h"
#include "..\CefSharp.Core.Runtime\Internals\Messaging\Messages.h"
#include "..\CefSharp.Core.Runtime\Internals\Serialization\Primitives.h"
#include "Serialization\V8Serialization.h"

using namespace System;
using namespace CefSharp::Internals::Messaging;
using namespace CefSharp::BrowserSubprocess::Serialization;

namespace CefSharp
{
    namespace BrowserSubprocess
    {
        const CefString kPostMessage = CefString("PostMessage");
        const CefString kPostMessageCamelCase = CefString("postMessage");

        private class JavascriptPostMessageHandler : public CefV8Handler
        {
        private:
            gcroot<JavascriptCallbackRegistry^> _javascriptCallbackRegistry;

        public:
            JavascriptPostMessageHandler(JavascriptCallbackRegistry^ javascriptCallbackRegistry)
            {
                _javascriptCallbackRegistry = javascriptCallbackRegistry;
            }

            bool Execute(const CefString& name, CefRefPtr<CefV8Value> object, const CefV8ValueList& arguments, CefRefPtr<CefV8Value>& retval, CefString& exception) override
            {
                if (arguments.size() == 0 || arguments.size() > 1)
                {
                    //TODO: Improve error message
                    exception = "Only a single param is accepted";

                    return true;
                }

                auto context = CefV8Context::GetCurrentContext();
                if (context.get())
                {
                    auto frame = context->GetFrame();

                    if (frame.get() && frame->IsValid() && context->Enter())
                    {
                        try
                        {
                            auto global = context->GetGlobal();

                            auto request = CefProcessMessage::Create(kJavascriptMessageReceived);
                            auto argList = request->GetArgumentList();

                            auto params = CefListValue::Create();
                            SerializeV8Object(arguments[0], params, 0, _javascriptCallbackRegistry);

                            //We're only interested in the first param
                            if (params->GetSize() > 0)
                            {
                                argList->SetValue(0, params->GetValue(0));
                            }

                            frame->SendProcessMessage(CefProcessId::PID_BROWSER, request);

                            retval = CefV8Value::CreateNull();
                        }
                        finally
                        {
                            context->Exit();
                        }
                    }
                    else
                    {
                        exception = "Unable to Enter Context";
                    }
                }
                else
                {
                    exception = "Unable to get current context";
                }

                return true;
            }

            IMPLEMENT_REFCOUNTINGM(JavascriptPostMessageHandler);
        };
    }
}