本文相关代码来源于 网易开源duilib https://github.com/netease-im/NIM_Duilib_Framework前端
0. 继承CefAPP CefRenderProcessHandlernode
class ClientApp : public CefApp,
public CefRenderProcessHandler
{
public:
ClientApp();
private:
// CefApp methods.
virtual void OnBeforeCommandLineProcessing(const CefString& process_type, CefRefPtr<CefCommandLine> command_line) OVERRIDE;
virtual void OnRegisterCustomSchemes( CefRefPtr<CefSchemeRegistrar> registrar) OVERRIDE;
// CefApp methods.
void ClientApp::OnBeforeCommandLineProcessing(const CefString& process_type, CefRefPtr<CefCommandLine> command_line)
{
}
//////////////////////////////////////////////////////////////////////////////////////////
void ClientApp::OnRegisterCustomSchemes(CefRefPtr<CefSchemeRegistrar> registrar)
{
// Default schemes that support cookies.
cookieable_schemes_.push_back("http");
cookieable_schemes_.push_back("https");
}
1 处理渲染处理器中的接口git
// CefRenderProcessHandler methods.
virtual CefRefPtr<CefRenderProcessHandler> GetRenderProcessHandler() OVERRIDE{ return this; }
virtual void OnRenderThreadCreated(CefRefPtr<CefListValue> extra_info) OVERRIDE;
virtual void OnWebKitInitialized() OVERRIDE;
virtual void OnBrowserCreated(CefRefPtr<CefBrowser> browser) OVERRIDE;
virtual void OnBrowserDestroyed(CefRefPtr<CefBrowser> browser) OVERRIDE;
virtual CefRefPtr<CefLoadHandler> GetLoadHandler() OVERRIDE;
virtual bool OnBeforeNavigation(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
NavigationType navigation_type,
bool is_redirect) OVERRIDE;
virtual void OnContextCreated(CefRefPtr<CefBrowser> browser, CefRefPtr<CefFrame> frame, CefRefPtr<CefV8Context> context) OVERRIDE;
virtual void OnContextReleased(CefRefPtr<CefBrowser> browser, CefRefPtr<CefFrame> frame, CefRefPtr<CefV8Context> context) OVERRIDE;
virtual void OnUncaughtException(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefV8Context> context,
CefRefPtr<CefV8Exception> exception,
CefRefPtr<CefV8StackTrace> stackTrace) OVERRIDE;
virtual void OnFocusedNodeChanged(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefDOMNode> node) OVERRIDE;
virtual bool OnProcessMessageReceived(
CefRefPtr<CefBrowser> browser,
CefProcessId source_process,
CefRefPtr<CefProcessMessage> message) OVERRIDE;
// CefRenderProcessHandler methods.
void ClientApp::OnRenderThreadCreated(CefRefPtr<CefListValue> extra_info)
{
}
void ClientApp::OnWebKitInitialized()
{
/**
* JavaScript 扩展代码，这里定义一个 NimCefWebFunction 对象提供 call 方法来让 Web 端触发 native 的 CefV8Handler 处理代码
* param[in] functionName 要调用的 C++ 方法名称
* param[in] params 调用该方法传递的参数，在前端指定的是一个 Object，但转到 Native 的时候转为了字符串
* param[in] callback 执行该方法后的回调函数
* 前端调用示例
* NimCefWebHelper.call('showMessage', { message: 'Hello C++' }, (arguments) => {
* console.log(arguments)
* })
*/
std::string extensionCode = R"(
var NimCefWebInstance = {};
(() => {
NimCefWebInstance.call = (functionName, arg1, arg2) => {
if (typeof arg1 === 'function') {
native function call(functionName, arg1);
return call(functionName, arg1);
} else {
const jsonString = JSON.stringify(arg1);
native function call(functionName, jsonString, arg2);
return call(functionName, jsonString, arg2);
}
};
NimCefWebInstance.register = (functionName, callback) => {
native function register(functionName, callback);
return register(functionName, callback);
};
})();
)";
CefRefPtr<CefJSHandler> handler = new CefJSHandler();
if (!render_js_bridge_.get())
render_js_bridge_.reset(new CefJSBridge);
handler->AttachJSBridge(render_js_bridge_);
CefRegisterExtension("v8/extern", extensionCode, handler);
}
void ClientApp::OnBrowserCreated(CefRefPtr<CefBrowser> browser)
{
if (!render_js_bridge_.get())
render_js_bridge_.reset(new CefJSBridge);
}
void ClientApp::OnBrowserDestroyed(CefRefPtr<CefBrowser> browser)
{
}
CefRefPtr<CefLoadHandler> ClientApp::GetLoadHandler()
{
return NULL;
}
bool ClientApp::OnBeforeNavigation(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
NavigationType navigation_type,
bool is_redirect)
{
return false;
}
void ClientApp::OnContextCreated(CefRefPtr<CefBrowser> browser, CefRefPtr<CefFrame> frame, CefRefPtr<CefV8Context> context)
{
}
void ClientApp::OnContextReleased(CefRefPtr<CefBrowser> browser, CefRefPtr<CefFrame> frame, CefRefPtr<CefV8Context> context)
{
render_js_bridge_->RemoveCallbackFuncWithFrame(frame);
render_js_bridge_->UnRegisterJSFuncWithFrame(frame);
}
void ClientApp::OnUncaughtException(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefV8Context> context,
CefRefPtr<CefV8Exception> exception,
CefRefPtr<CefV8StackTrace> stackTrace)
{
}
void ClientApp::OnFocusedNodeChanged(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefDOMNode> node)
{
bool is_editable = (node.get() && node->IsEditable());
if (is_editable != last_node_is_editable_)
{
// Notify the browser of the change in focused element type.
last_node_is_editable_ = is_editable;
CefRefPtr<CefProcessMessage> message = CefProcessMessage::Create(kFocusedNodeChangedMessage);
message->GetArgumentList()->SetBool(0, is_editable);
browser->SendProcessMessage(PID_BROWSER, message);
}
}
bool ClientApp::OnProcessMessageReceived(
CefRefPtr<CefBrowser> browser,
CefProcessId source_process,
CefRefPtr<CefProcessMessage> message)
{
ASSERT(source_process == PID_BROWSER);
// 收到 browser 的消息回复
const CefString& message_name = message->GetName();
if (message_name == kExecuteJsCallbackMessage)
{
int callback_id = message->GetArgumentList()->GetInt(0);
bool has_error = message->GetArgumentList()->GetBool(1);
CefString json_string = message->GetArgumentList()->GetString(2);
// 将收到的参数经过管理器传递给调用时传递的回调函数
render_js_bridge_->ExecuteJSCallbackFunc(callback_id, has_error, json_string);
}
else if (message_name == kCallJsFunctionMessage)
{
CefString function_name = message->GetArgumentList()->GetString(0);
CefString json_string = message->GetArgumentList()->GetString(1);
int cpp_callback_id = message->GetArgumentList()->GetInt(2);
int64 frame_id = message->GetArgumentList()->GetInt(3);
// 经过 C++ 执行一个已经注册过的 JS 方法
// frame_id 小于 0 则多是 browser 进程的 browser 是无效的，因此这里为了不出现错误就获取一个顶层 frame 执行代码
render_js_bridge_->ExecuteJSFunc(function_name, json_string, frame_id < 0 ? browser->GetMainFrame() : browser->GetFrame(frame_id), cpp_callback_id);
}
return false;
}
2 继承CefV8Handler ，重载Execute方法，以便执行注册的V8/extern扩展的的JS方法，该方法调用C++方法github
class CefJSHandler : public CefV8Handler
{
public:
CefJSHandler() {}
virtual bool Execute(const CefString& name, CefRefPtr<CefV8Value> object, const CefV8ValueList& arguments, CefRefPtr<CefV8Value>& retval, CefString& exception) OVERRIDE;
void AttachJSBridge(std::shared_ptr<CefJSBridge> js_bridge) { js_bridge_ = js_bridge; }
IMPLEMENT_REFCOUNTING(CefJSHandler);
private:
std::shared_ptr<CefJSBridge> js_bridge_;
};
bool CefJSHandler::Execute(const CefString& name, CefRefPtr<CefV8Value> object, const CefV8ValueList& arguments, CefRefPtr<CefV8Value>& retval, CefString& exception)
{
// 当Web中调用了"NimCefWebFunction"函数后，会触发到这里，而后把参数保存，转发到Broswer进程
// Broswer进程的BrowserHandler类在OnProcessMessageReceived接口中处理kJsCallbackMessage消息，就能够收到这个消息
if (arguments.size() < 2)
{
exception = "Invalid arguments.";
return false;
}
CefRefPtr<CefV8Context> context = CefV8Context::GetCurrentContext();
CefRefPtr<CefFrame> frame = context->GetFrame();
CefRefPtr<CefBrowser> browser = context->GetBrowser();
int64_t browser_id = browser->GetIdentifier();
int64_t frame_id = frame->GetIdentifier();
if (name == "call")
{
// 容许没有参数列表的调用，第二个参数为回调
// 若是传递了参数列表，那么回调是第三个参数
CefString function_name = arguments[0]->GetStringValue();
CefString params = "{}";
CefRefPtr<CefV8Value> callback;
if (arguments[0]->IsString() && arguments[1]->IsFunction())
{
callback = arguments[1];
}
else if (arguments[0]->IsString() && arguments[1]->IsString() && arguments[2]->IsFunction())
{
params = arguments[1]->GetStringValue();
callback = arguments[2];
}
else
{
exception = "Invalid arguments.";
return false;
}
// 执行 C++ 方法
if (!js_bridge_->CallCppFunction(function_name, params, callback))
{
exception = nbase::StringPrintf("Failed to call function %s.", function_name).c_str();
return false;
}
return true;
}
else if (name == "register")
{
if (arguments[0]->IsString() && arguments[1]->IsFunction())
{
std::string function_name = arguments[0]->GetStringValue();
CefRefPtr<CefV8Value> callback = arguments[1];
if (!js_bridge_->RegisterJSFunc(function_name, callback))
{
exception = "Failed to register function.";
return false;
}
return true;
}
else
{
exception = "Invalid arguments.";
return false;
}
}
return false;
}