// Copyright (c) 2014 Marshall A. Greenblatt. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the name Chromium Embedded
// Framework nor the names of its contributors may be used to endorse
// or promote products derived from this software without specific prior
// written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// ---------------------------------------------------------------------------
//
// The contents of this file are only available to applications that link
// against the libcef_dll_wrapper target.
//
#ifndef CEF_INCLUDE_WRAPPER_CEF_MESSAGE_ROUTER_H_
#define CEF_INCLUDE_WRAPPER_CEF_MESSAGE_ROUTER_H_
#pragma once
#include "include/base/cef_ref_counted.h"
#include "include/cef_base.h"
#include "include/cef_browser.h"
#include "include/cef_process_message.h"
#include "include/cef_v8.h"
// The below classes implement support for routing aynchronous messages between
// JavaScript running in the renderer process and C++ running in the browser
// process. An application interacts with the router by passing it data from
// standard CEF C++ callbacks (OnBeforeBrowse, OnProcessMessageRecieved,
// OnContextCreated, etc). The renderer-side router supports generic JavaScript
// callback registration and execution while the browser-side router supports
// application-specific logic via one or more application-provided Handler
// instances.
//
// The renderer-side router implementation exposes a query function and a cancel
// function via the JavaScript 'window' object:
//
// // Create and send a new query.
// var request_id = window.cefQuery({
// request: 'my_request',
// persistent: false,
// onSuccess: function(response) {},
// onFailure: function(error_code, error_message) {}
// });
//
// // Optionally cancel the query.
// window.cefQueryCancel(request_id);
//
// When |window.cefQuery| is executed the request is sent asynchronously to one
// or more C++ Handler objects registered in the browser process. Each C++
// Handler can choose to either handle or ignore the query in the
// Handler::OnQuery callback. If a Handler chooses to handle the query then it
// should execute Callback::Success when a response is available or
// Callback::Failure if an error occurs. This will result in asynchronous
// execution of the associated JavaScript callback in the renderer process. Any
// queries unhandled by C++ code in the browser process will be automatically
// canceled and the associated JavaScript onFailure callback will be executed
// with an error code of -1.
//
// Queries can be either persistent or non-persistent. If the query is
// persistent than the callbacks will remain registered until one of the
// following conditions are met:
//
// A. The query is canceled in JavaScript using the |window.cefQueryCancel|
// function.
// B. The query is canceled in C++ code using the Callback::Failure function.
// C. The context associated with the query is released due to browser
// destruction, navigation or renderer process termination.
//
// If the query is non-persistent then the registration will be removed after
// the JavaScript callback is executed a single time. If a query is canceled for
// a reason other than Callback::Failure being executed then the associated
// Handler's OnQueryCanceled method will be called.
//
// Some possible usage patterns include:
//
// One-time Request. Use a non-persistent query to send a JavaScript request.
// The Handler evaluates the request and returns the response. The query is
// then discarded.
//
// Broadcast. Use a persistent query to register as a JavaScript broadcast
// receiver. The Handler keeps track of all registered Callbacks and executes
// them sequentially to deliver the broadcast message.
//
// Subscription. Use a persistent query to register as a JavaScript subscription
// receiver. The Handler initiates the subscription feed on the first request
// and delivers responses to all registered subscribers as they become
// available. The Handler cancels the subscription feed when there are no
// longer any registered JavaScript receivers.
//
// Message routing occurs on a per-browser and per-context basis. Consequently,
// additional application logic can be applied by restricting which browser or
// context instances are passed into the router. If you choose to use this
// approach do so cautiously. In order for the router to function correctly any
// browser or context instance passed into a single router callback must then
// be passed into all router callbacks.
//
// There is generally no need to have multiple renderer-side routers unless you
// wish to have multiple bindings with different JavaScript function names. It
// can be useful to have multiple browser-side routers with different client-
// provided Handler instances when implementing different behaviors on a per-
// browser basis.
//
// This implementation places no formatting restrictions on payload content.
// An application may choose to exchange anything from simple formatted
// strings to serialized XML or JSON data.
//
//
// EXAMPLE USAGE
//
// 1. Define the router configuration. You can optionally specify settings
// like the JavaScript function names. The configuration must be the same in
// both the browser and renderer processes. If using multiple routers in the
// same application make sure to specify unique function names for each
// router configuration.
//
// // Example config object showing the default values.
// CefMessageRouterConfig config;
// config.js_query_function = "cefQuery";
// config.js_cancel_function = "cefQueryCancel";
//
// 2. Create an instance of CefMessageRouterBrowserSide in the browser process.
// You might choose to make it a member of your CefClient implementation,
// for example.
//
// browser_side_router_ = CefMessageRouterBrowserSide::Create(config);
//
// 3. Register one or more Handlers. The Handler instances must either outlive
// the router or be removed from the router before they're deleted.
//
// browser_side_router_->AddHandler(my_handler);
//
// 4. Call all required CefMessageRouterBrowserSide methods from other callbacks
// in your CefClient implementation (OnBeforeClose, etc). See the
// CefMessageRouterBrowserSide class documentation for the complete list of
// methods.
//
// 5. Create an instance of CefMessageRouterRendererSide in the renderer
// process.
// You might choose to make it a member of your CefApp implementation, for
// example.
//
// renderer_side_router_ = CefMessageRouterRendererSide::Create(config);
//
// 6. Call all required CefMessageRouterRendererSide methods from other
// callbacks in your CefRenderProcessHandler implementation
// (OnContextCreated, etc). See the CefMessageRouterRendererSide class
// documentation for the complete list of methods.
//
// 7. Execute the query function from JavaScript code.
//
// window.cefQuery({request: 'my_request',
// persistent: false,
// onSuccess: function(response) { print(response); },
// onFailure: function(error_code, error_message) {} });
//
// 8. Handle the query in your Handler::OnQuery implementation and execute the
// appropriate callback either immediately or asynchronously.
//
// void MyHandler::OnQuery(int64 query_id,
// CefRefPtr<CefBrowser> browser,
// CefRefPtr<CefFrame> frame,
// const CefString& request,
// bool persistent,
// CefRefPtr<Callback> callback) {
// if (request == "my_request") {
// callback->Continue("my_response");
// return true;
// }
// return false; // Not handled.
// }
//
// 9. Notice that the onSuccess callback is executed in JavaScript.
///
// Used to configure the query router. The same values must be passed to both
// CefMessageRouterBrowserSide and CefMessageRouterRendererSide. If using
// multiple router pairs make sure to choose values that do not conflict.
///
struct CefMessageRouterConfig {
CefMessageRouterConfig();
// Name of the JavaScript function that will be added to the 'window' object
// for sending a query. The default value is "cefQuery".
CefString js_query_function;
// Name of the JavaScript function that will be added to the 'window' object
// for canceling a pending query. The default value is "cefQueryCancel".
CefString js_cancel_function;
};
///
// Implements the browser side of query routing. The methods of this class may
// be called on any browser process thread unless otherwise indicated.
///
class CefMessageRouterBrowserSide
: public base::RefCountedThreadSafe<CefMessageRouterBrowserSide> {
public:
///
// Callback associated with a single pending asynchronous query. Execute the
// Success or Failure method to send an asynchronous response to the
// associated JavaScript handler. It is a runtime error to destroy a Callback
// object associated with an uncanceled query without first executing one of
// the callback methods. The methods of this class may be called on any
// browser process thread.
///
class Callback : public CefBaseRefCounted {
public:
///
// Notify the associated JavaScript onSuccess callback that the query has
// completed successfully with the specified |response|.
///
virtual void Success(const CefString& response) = 0;
///
// Notify the associated JavaScript onFailure callback that the query has
// failed with the specified |error_code| and |error_message|.
///
virtual void Failure(int error_code, const CefString& error_message) = 0;
};
///
// Implement this interface to handle queries. All methods will be executed on
// the browser process UI thread.
///
class Handler {
public:
typedef CefMessageRouterBrowserSide::Callback Callback;
///
// Executed when a new query is received. |query_id| uniquely identifies the
// query for the life span of the router. Return true to handle the query
// or false to propagate the query to other registered handlers, if any. If
// no handlers return true from this method then the query will be
// automatically canceled with an error code of -1 delivered to the
// JavaScript onFailure callback. If this method returns true then a
// Callback method must be executed either in this method or asynchronously
// to complete the query.
///
virtual bool OnQuery(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
int64 query_id,
const CefString& request,
bool persistent,
CefRefPtr<Callback> callback) {
return false;
}
///
// Executed when a query has been canceled either explicitly using the
// JavaScript cancel function or implicitly due to browser destruction,
// navigation or renderer process termination. It will only be called for
// the single handler that returned true from OnQuery for the same
// |query_id|. No references to the associated Callback object should be
// kept after this method is called, nor should any Callback methods be
// executed.
///
virtual void OnQueryCanceled(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
int64 query_id) {}
virtual ~Handler() {}
};
///
// Create a new router with the specified configuration.
///
static CefRefPtr<CefMessageRouterBrowserSide> Create(
const CefMessageRouterConfig& config);
///
// Add a new query handler. If |first| is true it will be added as the first
// handler, otherwise it will be added as the last handler. Returns true if
// the handler is added successfully or false if the handler has already been
// added. Must be called on the browser process UI thread. The Handler object
// must either outlive the router or be removed before deletion.
///
virtual bool AddHandler(Handler* handler, bool first) = 0;
///
// Remove an existing query handler. Any pending queries associated with the
// handler will be canceled. Handler::OnQueryCanceled will be called and the
// associated JavaScript onFailure callback will be executed with an error
// code of -1. Returns true if the handler is removed successfully or false
// if the handler is not found. Must be called on the browser process UI
// thread.
///
virtual bool RemoveHandler(Handler* handler) = 0;
///
// Cancel all pending queries associated with either |browser| or |handler|.
// If both |browser| and |handler| are NULL all pending queries will be
// canceled. Handler::OnQueryCanceled will be called and the associated
// JavaScript onFailure callback will be executed in all cases with an error
// code of -1.
///
virtual void CancelPending(CefRefPtr<CefBrowser> browser,
Handler* handler) = 0;
///
// Returns the number of queries currently pending for the specified |browser|
// and/or |handler|. Either or both values may be empty. Must be called on the
// browser process UI thread.
///
virtual int GetPendingCount(CefRefPtr<CefBrowser> browser,
Handler* handler) = 0;
// The below methods should be called from other CEF handlers. They must be
// called exactly as documented for the router to function correctly.
///
// Call from CefLifeSpanHandler::OnBeforeClose. Any pending queries associated
// with |browser| will be canceled and Handler::OnQueryCanceled will be
// called. No JavaScript callbacks will be executed since this indicates
// destruction of the browser.
///
virtual void OnBeforeClose(CefRefPtr<CefBrowser> browser) = 0;
///
// Call from CefRequestHandler::OnRenderProcessTerminated. Any pending queries
// associated with |browser| will be canceled and Handler::OnQueryCanceled
// will be called. No JavaScript callbacks will be executed since this
// indicates destruction of the context.
///
virtual void OnRenderProcessTerminated(CefRefPtr<CefBrowser> browser) = 0;
///
// Call from CefRequestHandler::OnBeforeBrowse only if the navigation is
// allowed to proceed. If |frame| is the main frame then any pending queries
// associated with |browser| will be canceled and Handler::OnQueryCanceled
// will be called. No JavaScript callbacks will be executed since this
// indicates destruction of the context.
///
virtual void OnBeforeBrowse(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame) = 0;
///
// Call from CefClient::OnProcessMessageReceived. Returns true if the message
// is handled by this router or false otherwise.
///
virtual bool OnProcessMessageReceived(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefProcessId source_process,
CefRefPtr<CefProcessMessage> message) = 0;
protected:
// Protect against accidental deletion of this object.
friend class base::RefCountedThreadSafe<CefMessageRouterBrowserSide>;
virtual ~CefMessageRouterBrowserSide() {}
};
///
// Implements the renderer side of query routing. The methods of this class must
// be called on the render process main thread.
///
class CefMessageRouterRendererSide
: public base::RefCountedThreadSafe<CefMessageRouterRendererSide> {
public:
///
// Create a new router with the specified configuration.
///
static CefRefPtr<CefMessageRouterRendererSide> Create(
const CefMessageRouterConfig& config);
///
// Returns the number of queries currently pending for the specified |browser|
// and/or |context|. Either or both values may be empty.
///
virtual int GetPendingCount(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefV8Context> context) = 0;
// The below methods should be called from other CEF handlers. They must be
// called exactly as documented for the router to function correctly.
///
// Call from CefRenderProcessHandler::OnContextCreated. Registers the
// JavaScripts functions with the new context.
///
virtual void OnContextCreated(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefV8Context> context) = 0;
///
// Call from CefRenderProcessHandler::OnContextReleased. Any pending queries
// associated with the released context will be canceled and
// Handler::OnQueryCanceled will be called in the browser process.
///
virtual void OnContextReleased(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefV8Context> context) = 0;
///
// Call from CefRenderProcessHandler::OnProcessMessageReceived. Returns true
// if the message is handled by this router or false otherwise.
///
virtual bool OnProcessMessageReceived(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefProcessId source_process,
CefRefPtr<CefProcessMessage> message) = 0;
protected:
// Protect against accidental deletion of this object.
friend class base::RefCountedThreadSafe<CefMessageRouterRendererSide>;
virtual ~CefMessageRouterRendererSide() {}
};
#endif // CEF_INCLUDE_WRAPPER_CEF_MESSAGE_ROUTER_H_