2 Cef常用接口类介绍
2.1 CefClient
2.2 CefContextMenuHandler右键菜单处理类
2.3 CefDisplayHandler网页显示处理类
2.4 CefDownloadHandler网页下载处理类
2.5 CefDragHandler鼠标拖动到网页处理类
2.6 CefKeyboardHandler键盘事件响应处理类
2.7 CefLifeSpanHandler生命周期处理类
2.7.1 DoClose标准关闭处理
2.7.2 DoClose非标准关闭处理
2.8 CefLoadHandler网页加载处理类
2.9 CefRequestHandler网络请求处理类
Cef是一个网页嵌入外壳，要获取网页的响应，拦截网页中的事件消息，CEF提供了一系列的接口回调类，提供各种事件回调函数，例如拦截获取键盘、鼠标、加载、显示、右键菜单、提示消息、状态变化、窗口打开关闭等，CEF都可以从网页上拦截捕捉消息事件，并通过回调函数传给应用程序进行处理。
2.1 CefClient
CefClient提供了获取各种handler的接口，例如上下文菜单handler、对话框handler、显示状态handler，下载事件handler、拖动事件handler、查找事件handler、键盘handler、生命周期事件handler、加载页面事件handler、离屏render进程handler、请求事件handler等。但是只是返回事件的handle。每个handler的具体的回调函数不在CefClient类中，需要继承各个handler类，才可以实现回调。CefClient类只有一个回调函数OnProcessMessageReceived用来处理进程间的通讯消息。CefClient的定义如下：
class CefClient : public virtual CefBaseRefCounted {
public:
///
// Return the handler for context menus. If no handler is provided the default
// implementation will be used.
///
/*--cef()--*/
virtual CefRefPtr<CefContextMenuHandler> GetContextMenuHandler() {
return NULL;
}
///
// Return the handler for dialogs. If no handler is provided the default
// implementation will be used.
///
/*--cef()--*/
virtual CefRefPtr<CefDialogHandler> GetDialogHandler() { return NULL; }
///
// Return the handler for browser display state events.
///
/*--cef()--*/
virtual CefRefPtr<CefDisplayHandler> GetDisplayHandler() { return NULL; }
///
// Return the handler for download events. If no handler is returned downloads
// will not be allowed.
///
/*--cef()--*/
virtual CefRefPtr<CefDownloadHandler> GetDownloadHandler() { return NULL; }
///
// Return the handler for drag events.
///
/*--cef()--*/
virtual CefRefPtr<CefDragHandler> GetDragHandler() { return NULL; }
///
// Return the handler for find result events.
///
/*--cef()--*/
virtual CefRefPtr<CefFindHandler> GetFindHandler() { return NULL; }
///
// Return the handler for focus events.
///
/*--cef()--*/
virtual CefRefPtr<CefFocusHandler> GetFocusHandler() { return NULL; }
///
// Return the handler for JavaScript dialogs. If no handler is provided the
// default implementation will be used.
///
/*--cef()--*/
virtual CefRefPtr<CefJSDialogHandler> GetJSDialogHandler() { return NULL; }
///
// Return the handler for keyboard events.
///
/*--cef()--*/
virtual CefRefPtr<CefKeyboardHandler> GetKeyboardHandler() { return NULL; }
///
// Return the handler for browser life span events.
///
/*--cef()--*/
virtual CefRefPtr<CefLifeSpanHandler> GetLifeSpanHandler() { return NULL; }
///
// Return the handler for browser load status events.
///
/*--cef()--*/
virtual CefRefPtr<CefLoadHandler> GetLoadHandler() { return NULL; }
///
// Return the handler for off-screen rendering events.
///
/*--cef()--*/
virtual CefRefPtr<CefRenderHandler> GetRenderHandler() { return NULL; }
///
// Return the handler for browser request events.
///
/*--cef()--*/
virtual CefRefPtr<CefRequestHandler> GetRequestHandler() { return NULL; }
///
// Called when a new message is received from a different process. Return true
// if the message was handled or false otherwise. Do not keep a reference to
// or attempt to access the message outside of this callback.
///
/*--cef()--*/
virtual bool OnProcessMessageReceived(CefRefPtr<CefBrowser> browser,
CefProcessId source_process,
CefRefPtr<CefProcessMessage> message) {
return false;
}
};
2.2 CefContextMenuHandler右键菜单处理类
CefContextMenuHandler是网页上的右键菜单事件回调函数类，提供OnBeforeContextMenu回调函数，在右键菜单弹出之前修改或者禁用右键菜单。右键菜单按钮响应回调RunContextMenu、右键菜单命令回调OnContextMenuCommand菜单禁用回调函数OnContextMenuDismissed等。可以拦截右键菜单响应，进行自定义的处理。
class CefContextMenuHandler : public virtual CefBaseRefCounted {
public:
typedef cef_event_flags_t EventFlags;
///
// Called before a context menu is displayed. |params| provides information
// about the context menu state. |model| initially contains the default
// context menu. The |model| can be cleared to show no context menu or
// modified to show a custom menu. Do not keep references to |params| or
// |model| outside of this callback.
///
/*--cef()--*/
virtual void OnBeforeContextMenu(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefContextMenuParams> params,
CefRefPtr<CefMenuModel> model) {}
///
// Called to allow custom display of the context menu. |params| provides
// information about the context menu state. |model| contains the context menu
// model resulting from OnBeforeContextMenu. For custom display return true
// and execute |callback| either synchronously or asynchronously with the
// selected command ID. For default display return false. Do not keep
// references to |params| or |model| outside of this callback.
///
/*--cef()--*/
virtual bool RunContextMenu(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefContextMenuParams> params,
CefRefPtr<CefMenuModel> model,
CefRefPtr<CefRunContextMenuCallback> callback) {
return false;
}
///
// Called to execute a command selected from the context menu. Return true if
// the command was handled or false for the default implementation. See
// cef_menu_id_t for the command ids that have default implementations. All
// user-defined command ids should be between MENU_ID_USER_FIRST and
// MENU_ID_USER_LAST. |params| will have the same values as what was passed to
// OnBeforeContextMenu(). Do not keep a reference to |params| outside of this
// callback.
///
/*--cef()--*/
virtual bool OnContextMenuCommand(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefContextMenuParams> params,
int command_id,
EventFlags event_flags) {
return false;
}
///
// Called when the context menu is dismissed irregardless of whether the menu
// was empty or a command was selected.
///
/*--cef()--*/
virtual void OnContextMenuDismissed(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame) {}
};
2.3 CefDisplayHandler网页显示处理类
CefDisplayHandler提供了一些页面显示回调函数，例如网址发送变化OnAddressChange，网页标题OnTitleChange发生变化，网页图标发生变化OnFaviconURLChange，全屏变化OnFullscreenModeChange，显示提示消息OnTooltip，状态栏消息显示OnStatusMessage，控制台消息回调OnConsoleMessage，设置了自动调整大小回调OnAutoResize，加载进程变化回调OnLoadingProgressChange，CefDisplayHandler类定义如下
class CefDisplayHandler : public virtual CefBaseRefCounted {
public:
///
// Called when a frame's address has changed.
///
/*--cef()--*/
virtual void OnAddressChange(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
const CefString& url) {}
///
// Called when the page title changes.
///
/*--cef(optional_param=title)--*/
virtual void OnTitleChange(CefRefPtr<CefBrowser> browser,
const CefString& title) {}
///
// Called when the page icon changes.
///
/*--cef(optional_param=icon_urls)--*/
virtual void OnFaviconURLChange(CefRefPtr<CefBrowser> browser,
const std::vector<CefString>& icon_urls) {}
///
// Called when web content in the page has toggled fullscreen mode. If
// |fullscreen| is true the content will automatically be sized to fill the
// browser content area. If |fullscreen| is false the content will
// automatically return to its original size and position. The client is
// responsible for resizing the browser if desired.
///
/*--cef()--*/
virtual void OnFullscreenModeChange(CefRefPtr<CefBrowser> browser,
bool fullscreen) {}
///
// Called when the browser is about to display a tooltip. |text| contains the
// text that will be displayed in the tooltip. To handle the display of the
// tooltip yourself return true. Otherwise, you can optionally modify |text|
// and then return false to allow the browser to display the tooltip.
// When window rendering is disabled the application is responsible for
// drawing tooltips and the return value is ignored.
///
/*--cef(optional_param=text)--*/
virtual bool OnTooltip(CefRefPtr<CefBrowser> browser, CefString& text) {
return false;
}
///
// Called when the browser receives a status message. |value| contains the
// text that will be displayed in the status message.
///
/*--cef(optional_param=value)--*/
virtual void OnStatusMessage(CefRefPtr<CefBrowser> browser,
const CefString& value) {}
///
// Called to display a console message. Return true to stop the message from
// being output to the console.
///
/*--cef(optional_param=message,optional_param=source)--*/
virtual bool OnConsoleMessage(CefRefPtr<CefBrowser> browser,
cef_log_severity_t level,
const CefString& message,
const CefString& source,
int line) {
return false;
}
///
// Called when auto-resize is enabled via CefBrowserHost::SetAutoResizeEnabled
// and the contents have auto-resized. |new_size| will be the desired size in
// view coordinates. Return true if the resize was handled or false for
// default handling.
///
/*--cef()--*/
virtual bool OnAutoResize(CefRefPtr<CefBrowser> browser,
const CefSize& new_size) {
return false;
}
///
// Called when the overall page loading progress has changed. |progress|
// ranges from 0.0 to 1.0.
///
/*--cef()--*/
virtual void onl oadingProgressChange(CefRefPtr<CefBrowser> browser,
double progress) {}
};
2.4 CefDownloadHandler网页下载处理类
CefDownloadHandler网页上下载文件类，提供开始从网页下载文件回调函数OnBeforeDownload，下载文件进度更新回调函数OnDownloadUpdated。
class CefDownloadHandler : public virtual CefBaseRefCounted {
public:
///
// Called before a download begins. |suggested_name| is the suggested name for
// the download file. By default the download will be canceled. Execute
// |callback| either asynchronously or in this method to continue the download
// if desired. Do not keep a reference to |download_item| outside of this
// method.
///
/*--cef()--*/
virtual void OnBeforeDownload(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefDownloadItem> download_item,
const CefString& suggested_name,
CefRefPtr<CefBeforeDownloadCallback> callback) = 0;
///
// Called when a download's status or progress information has been updated.
// This may be called multiple times before and after OnBeforeDownload().
// Execute |callback| either asynchronously or in this method to cancel the
// download if desired. Do not keep a reference to |download_item| outside of
// this method.
///
/*--cef()--*/
virtual void OnDownloadUpdated(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefDownloadItem> download_item,
CefRefPtr<CefDownloadItemCallback> callback) {}
};
2.5 CefDragHandler鼠标拖动到网页处理类
CefDragHandler处理鼠标拖动事件，提供鼠标拖动进入网页回调函数OnDragEnter，网页中可以拖动放入的区域发生变化回调函数OnDraggableRegionsChanged。
// Implement this interface to handle events related to dragging. The methods of
// this class will be called on the UI thread.
///
/*--cef(source=client)--*/
class CefDragHandler : public virtual CefBaseRefCounted {
public:
typedef cef_drag_operations_mask_t DragOperationsMask;
///
// Called when an external drag event enters the browser window. |dragData|
// contains the drag event data and |mask| represents the type of drag
// operation. Return false for default drag handling behavior or true to
// cancel the drag event.
///
/*--cef()--*/
virtual bool OnDragEnter(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefDragData> dragData,
DragOperationsMask mask) {
return false;
}
///
// Called whenever draggable regions for the browser window change. These can
// be specified using the '-webkit-app-region: drag/no-drag' CSS-property. If
// draggable regions are never defined in a document this method will also
// never be called. If the last draggable region is removed from a document
// this method will be called with an empty vector.
///
/*--cef()--*/
virtual void OnDraggableRegionsChanged(
CefRefPtr<CefBrowser> browser,
const std::vector<CefDraggableRegion>& regions) {}
};
2.6 CefKeyboardHandler键盘事件响应处理类
CefKeyboardHandler处理键盘响应事件，提供键盘按键响应回调函数。拦截键盘消息。
// Implement this interface to handle events related to keyboard input. The
// methods of this class will be called on the UI thread.
///
/*--cef(source=client)--*/
class CefKeyboardHandler : public virtual CefBaseRefCounted {
public:
///
// Called before a keyboard event is sent to the renderer. |event| contains
// information about the keyboard event. |os_event| is the operating system
// event message, if any. Return true if the event was handled or false
// otherwise. If the event will be handled in OnKeyEvent() as a keyboard
// shortcut set |is_keyboard_shortcut| to true and return false.
///
/*--cef()--*/
virtual bool OnPreKeyEvent(CefRefPtr<CefBrowser> browser,
const CefKeyEvent& event,
CefEventHandle os_event,
bool* is_keyboard_shortcut) {
return false;
}
///
// Called after the renderer and JavaScript in the page has had a chance to
// handle the event. |event| contains information about the keyboard event.
// |os_event| is the operating system event message, if any. Return true if
// the keyboard event was handled or false otherwise.
///
/*--cef()--*/
virtual bool OnKeyEvent(CefRefPtr<CefBrowser> browser,
const CefKeyEvent& event,
CefEventHandle os_event) {
return false;
}
};
2.7 CefLifeSpanHandler生命周期处理类
CefLifeSpanHandler是生命周期处理类，新打开一个网页或者关闭一个网页时，会触发回调函数。OnBeforePopup这个只能在创建一个新的弹出式网页时，才会触发，如果是在一个网页中打开一个子网页，回调函数是拦截不到消息的。OnAfterCreated网页创建完成后的回调函数。browser销毁之前会触发回调函数OnBeforeClose。还有一个关闭回调函数DoClose有点复杂，当调用CefBrowserHost::*CloseBrowser()函数关闭browser，或者browser是CEF创建的顶层窗口的子窗口，当顶层窗口关闭时，也会触发关闭DoClose回调函数。点击网页的关闭按钮后，网页不会立刻关闭，而是会调用两次CloseBrowser()或TryCloseBrowser()，提供了一个让CEF处理JS的onbeforeunload事件和选择性取消关闭网页的机会。CefLifeSpanHandler类定义如下：
// Implement this interface to handle events related to browser life span. The
// methods of this class will be called on the UI thread unless otherwise
// indicated.
///
/*--cef(source=client)--*/
class CefLifeSpanHandler : public virtual CefBaseRefCounted {
public:
typedef cef_window_open_disposition_t WindowOpenDisposition;
///
// Called on the UI thread before a new popup browser is created. The
// |browser| and |frame| values represent the source of the popup request. The
// |target_url| and |target_frame_name| values indicate where the popup
// browser should navigate and may be empty if not specified with the request.
// The |target_disposition| value indicates where the user intended to open
// the popup (e.g. current tab, new tab, etc). The |user_gesture| value will
// be true if the popup was opened via explicit user gesture (e.g. clicking a
// link) or false if the popup opened automatically (e.g. via the
// DomContentLoaded event). The |popupFeatures| structure contains additional
// information about the requested popup window. To allow creation of the
// popup browser optionally modify |windowInfo|, |client|, |settings| and
// |no_javascript_access| and return false. To cancel creation of the popup
// browser return true. The |client| and |settings| values will default to the
// source browser's values. If the |no_javascript_access| value is set to
// false the new browser will not be scriptable and may not be hosted in the
// same renderer process as the source browser. Any modifications to
// |windowInfo| will be ignored if the parent browser is wrapped in a
// CefBrowserView. Popup browser creation will be canceled if the parent
// browser is destroyed before the popup browser creation completes (indicated
// by a call to OnAfterCreated for the popup browser).
///
/*--cef(optional_param=target_url,optional_param=target_frame_name)--*/
virtual bool OnBeforePopup(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
const CefString& target_url,
const CefString& target_frame_name,
WindowOpenDisposition target_disposition,
bool user_gesture,
const CefPopupFeatures& popupFeatures,
CefWindowInfo& windowInfo,
CefRefPtr<CefClient>& client,
CefBrowserSettings& settings,
bool* no_javascript_access) {
return false;
}
///
// Called after a new browser is created. This callback will be the first
// notification that references |browser|.
///
/*--cef()--*/
virtual void OnAfterCreated(CefRefPtr<CefBrowser> browser) {}
///
// Called when a browser has recieved a request to close. This may result
// directly from a call to CefBrowserHost::*CloseBrowser() or indirectly if
// the browser is parented to a top-level window created by CEF and the user
// attempts to close that window (by clicking the 'X', for example). The
// DoClose() method will be called after the JavaScript 'onunload' event has
// been fired.
//
// An application should handle top-level owner window close notifications by
// calling CefBrowserHost::TryCloseBrowser() or
// CefBrowserHost::CloseBrowser(false) instead of allowing the window to close
// immediately (see the examples below). This gives CEF an opportunity to
// process the 'onbeforeunload' event and optionally cancel the close before
// DoClose() is called.
//
// When windowed rendering is enabled CEF will internally create a window or
// view to host the browser. In that case returning false from DoClose() will
// send the standard close notification to the browser's top-level owner
// window (e.g. WM_CLOSE on Windows, performClose: on OS X, "delete_event" on
// Linux or CefWindowDelegate::CanClose() callback from Views). If the
// browser's host window/view has already been destroyed (via view hierarchy
// tear-down, for example) then DoClose() will not be called for that browser
// since is no longer possible to cancel the close.
//
// When windowed rendering is disabled returning false from DoClose() will
// cause the browser object to be destroyed immediately.
//
// If the browser's top-level owner window requires a non-standard close
// notification then send that notification from DoClose() and return true.
//
// The CefLifeSpanHandler::OnBeforeClose() method will be called after
// DoClose() (if DoClose() is called) and immediately before the browser
// object is destroyed. The application should only exit after OnBeforeClose()
// has been called for all existing browsers.
//
// The below examples describe what should happen during window close when the
// browser is parented to an application-provided top-level window.
//
// Example 1: Using CefBrowserHost::TryCloseBrowser(). This is recommended for
// clients using standard close handling and windows created on the browser
// process UI thread.
// 1. User clicks the window close button which sends a close notification to
// the application's top-level window.
// 2. Application's top-level window receives the close notification and
// calls TryCloseBrowser() (which internally calls CloseBrowser(false)).
// TryCloseBrowser() returns false so the client cancels the window close.
// 3. JavaScript 'onbeforeunload' handler executes and shows the close
// confirmation dialog (which can be overridden via
// CefJSDialogHandler::OnBeforeUnloadDialog()).
// 4. User approves the close.
// 5. JavaScript 'onunload' handler executes.
// 6. CEF sends a close notification to the application's top-level window
// (because DoClose() returned false by default).
// 7. Application's top-level window receives the close notification and
// calls TryCloseBrowser(). TryCloseBrowser() returns true so the client
// allows the window close.
// 8. Application's top-level window is destroyed.
// 9. Application's OnBeforeClose() handler is called and the browser object
// is destroyed.
// 10. Application exits by calling CefQuitMessageLoop() if no other browsers
// exist.
//
// Example 2: Using CefBrowserHost::CloseBrowser(false) and implementing the
// DoClose() callback. This is recommended for clients using non-standard
// close handling or windows that were not created on the browser process UI
// thread.
// 1. User clicks the window close button which sends a close notification to
// the application's top-level window.
// 2. Application's top-level window receives the close notification and:
// A. Calls CefBrowserHost::CloseBrowser(false).
// B. Cancels the window close.
// 3. JavaScript 'onbeforeunload' handler executes and shows the close
// confirmation dialog (which can be overridden via
// CefJSDialogHandler::OnBeforeUnloadDialog()).
// 4. User approves the close.
// 5. JavaScript 'onunload' handler executes.
// 6. Application's DoClose() handler is called. Application will:
// A. Set a flag to indicate that the next close attempt will be allowed.
// B. Return false.
// 7. CEF sends an close notification to the application's top-level window.
// 8. Application's top-level window receives the close notification and
// allows the window to close based on the flag from #6B.
// 9. Application's top-level window is destroyed.
// 10. Application's OnBeforeClose() handler is called and the browser object
// is destroyed.
// 11. Application exits by calling CefQuitMessageLoop() if no other browsers
// exist.
///
/*--cef()--*/
virtual bool DoClose(CefRefPtr<CefBrowser> browser) { return false; }
///
// Called just before a browser is destroyed. Release all references to the
// browser object and do not attempt to execute any methods on the browser
// object after this callback returns. This callback will be the last
// notification that references |browser|. See DoClose() documentation for
// additional usage information.
///
/*--cef()--*/
virtual void OnBeforeClose(CefRefPtr<CefBrowser> browser) {}
};
2.7.1 DoClose标准关闭处理
当窗口创建是在browser进程的UI线程创建时，采用标准的关闭处理，使用CefBrowserHost::TryCloseBrowser()。不实现DoClose回调，默认返回false。具体步骤：
（1） 点击窗口的关闭按钮，发送一个关闭通知给顶层窗口。
（2） 顶层窗口接收到关闭通知，调用TryCloseBrowser()函数，返回false；
（3） JS的onbeforeunload处理句柄执行显示关闭确认对话框。
（4） 用户点击按钮同意关闭；
（5） JS的onunload处理句柄执行；
（6） CEF发送一个close通知给顶层窗口；
（7） 定鞥窗口接收到关闭通知，调用TryCloseBrowser，返回true，表示允许关闭。
（8） 顶层窗口销毁
（9） 程序的OnBeforeClose处理回调函数执行，browser销毁.
（10）如果不存在其他browser，则调用CefQuitMessageLoop退出程序。
2.7.2 DoClose非标准关闭处理
当窗口不是在browser进程的UI线程中创建时，采用非标准的关闭处理，使用函数CefBrowserHost::CloseBrowser(false)，并且实现DoClose函数。
（1） 用户点击窗口的关闭按钮，发送一个关闭通知给顶层窗口。
（2） 顶层窗口接收到关闭通知，调用CefBrowserHost::CloseBrowser(false)函数，取消关闭；
（3） JS的onbeforeunload处理句柄执行显示关闭确认对话框。
（4） 用户点击按钮同意关闭；
（5） JS的onunload处理句柄执行；
（6） 程序的DoClose（）回调函数被调用，设置一个flag表明下次关闭尝试会被允许，返回false；
（7） CEF发送一个close通知给顶层窗口；
（8） 顶层窗口接收到关闭通知，根据之前设置的flag判断是否关闭窗口。
（9） 顶层窗口销毁；
（10）程序的OnBeforeClose处理回调函数执行，browser销毁.
（11）如果不存在其他browser，则调用CefQuitMessageLoop退出程序。
2.8 CefLoadHandler网页加载处理类
在一个网页中加载内容，或者在网页中打开一个子frame，都可以拦截到iframe打开时的消息以及url等信息。可以拦截子网页url
（1） 开始加载OnLoadStart，navigation执行网之后，开始加载内容之前，回调此函数，多frame的进程会同时加载。同页面巡航不会调用。
（2） 加载结束OnLoadEnd，加载结束时回调，sub-frame在主frame加载结束后， 会继续开始加载或继续进行加载，同页面巡航不会调用。
（3） 加载错误OnLoadError，navigation失败或者取消是回调。
（4） 加载状态发生变化OnLoadingStateChange，加载初始化和加载结束时各调用一次，在OnLoadStart之前调用一次，OnLoadEnd或OnLoadError之后调用一次。
// Implement this interface to handle events related to browser load status. The
// methods of this class will be called on the browser process UI thread or
// render process main thread (TID_RENDERER).
///
/*--cef(source=client)--*/
class CefLoadHandler : public virtual CefBaseRefCounted {
public:
typedef cef_errorcode_t ErrorCode;
typedef cef_transition_type_t TransitionType;
///
// Called when the loading state has changed. This callback will be executed
// twice -- once when loading is initiated either programmatically or by user
// action, and once when loading is terminated due to completion, cancellation
// of failure. It will be called before any calls to onl oadStart and after all
// calls to onl oadError and/or onl oadEnd.
///
/*--cef()--*/
virtual void onl oadingStateChange(CefRefPtr<CefBrowser> browser,
bool isLoading,
bool canGoBack,
bool canGoForward) {}
///
// Called after a navigation has been committed and before the browser begins
// loading contents in the frame. The |frame| value will never be empty --
// call the IsMain() method to check if this frame is the main frame.
// |transition_type| provides information about the source of the navigation
// and an accurate value is only available in the browser process. Multiple
// frames may be loading at the same time. Sub-frames may start or continue
// loading after the main frame load has ended. This method will not be called
// for same page navigations (fragments, history state, etc.) or for
// navigations that fail or are canceled before commit. For notification of
// overall browser load status use onl oadingStateChange instead.
///
/*--cef()--*/
virtual void onl oadStart(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
TransitionType transition_type) {}
///
// Called when the browser is done loading a frame. The |frame| value will
// never be empty -- call the IsMain() method to check if this frame is the
// main frame. Multiple frames may be loading at the same time. Sub-frames may
// start or continue loading after the main frame load has ended. This method
// will not be called for same page navigations (fragments, history state,
// etc.) or for navigations that fail or are canceled before commit. For
// notification of overall browser load status use onl oadingStateChange
// instead.
///
/*--cef()--*/
virtual void onl oadEnd(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
int httpStatusCode) {}
///
// Called when a navigation fails or is canceled. This method may be called
// by itself if before commit or in combination with onl oadStart/OnLoadEnd if
// after commit. |errorCode| is the error code number, |errorText| is the
// error text and |failedUrl| is the URL that failed to load.
// See net\base\net_error_list.h for complete descriptions of the error codes.
///
/*--cef(optional_param=errorText)--*/
virtual void onl oadError(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
ErrorCode errorCode,
const CefString& errorText,
const CefString& failedUrl) {}
};
2.9 CefRequestHandler网络请求处理类
当打开一个网页， CefRequestHandler的OnBeforeBrowser可以拦截网络请求，只有在新打开网页的时候，才会触发，如果网页已经打开，在网页内部点击查询按钮，查询内容，虽然也有request请求，但是OnBeforeBrowser拦截不到获取请求的URL，post请求的参数都可以获取到。OnResourceRedirect还可以拦截重定向请求。CefLoadHandler也可以拦截request请求，而且页面加载中调用很多的GET和POST请求都可以拦截到。测试发现CefRequestHandler页面内部的加载变化是获取不到的，只有打开页面的请求能获取到。而另外一个函数OnBeforeResourceLoad则可以拦截所有的请求，在浏览器中F12显示的所有请求，包括图片下载等请求都能一一获取。所以CefLoadHandler拦截的请求更详细一些，点击查询查询，OnLoadStart和OnLoadEnd 拦截不到，但是OnLoadingStateChange 可以拦截的到请求。
|
OnBeforeBrowser |
打开新的网页可以拦截，页面内容变化，或者页面内部调用请求拦截不到。 |
|
OnBeforeResourceLoad |
拦截一切请求，最详细。 |
|
OnResourceResponse |
拦截一切请求，最详细。 |
|
|
|
|
OnLoadStart和OnLoadEnd |
新打开页面可以拦截 |
|
OnLoadingStateChange |
打开新页面， 页面内容重新加载，查询，按钮响应可以拦截。像一些图片加载，CSS加载是拦截不到的。第二详细。 |
各回调函的调用的先后顺序是
OnLoadingStateChange->OnBeforeBrowser->OnLoadStart->OnLoadEnd->OnLoadingStateChange。
// Implement this interface to handle events related to browser requests. The
// methods of this class will be called on the thread indicated.
///
/*--cef(source=client)--*/
class CefRequestHandler : public virtual CefBaseRefCounted {
public:
typedef cef_return_value_t ReturnValue;
typedef cef_termination_status_t TerminationStatus;
typedef cef_urlrequest_status_t URLRequestStatus;
typedef cef_window_open_disposition_t WindowOpenDisposition;
typedef std::vector<CefRefPtr<CefX509Certificate>> X509CertificateList;
///
// Called on the UI thread before browser navigation. Return true to cancel
// the navigation or false to allow the navigation to proceed. The |request|
// object cannot be modified in this callback.
// CefLoadHandler::OnLoadingStateChange will be called twice in all cases.
// If the navigation is allowed CefLoadHandler::OnLoadStart and
// CefLoadHandler::OnLoadEnd will be called. If the navigation is canceled
// CefLoadHandler::OnLoadError will be called with an |errorCode| value of
// ERR_ABORTED. The |user_gesture| value will be true if the browser
// navigated via explicit user gesture (e.g. clicking a link) or false if it
// navigated automatically (e.g. via the DomContentLoaded event).
///
/*--cef()--*/
（1）OnBeforeBrowse，在浏览器巡航前调用。
virtual bool OnBeforeBrowse(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
bool user_gesture,
bool is_redirect) {
return false;
}
///
// Called on the UI thread before OnBeforeBrowse in certain limited cases
// where navigating a new or different browser might be desirable. This
// includes user-initiated navigation that might open in a special way (e.g.
// links clicked via middle-click or ctrl + left-click) and certain types of
// cross-origin navigation initiated from the renderer process (e.g.
// navigating the top-level frame to/from a file URL). The |browser| and
// |frame| values represent the source of the navigation. The
// |target_disposition| value indicates where the user intended to navigate
// the browser based on standard Chromium behaviors (e.g. current tab,
// new tab, etc). The |user_gesture| value will be true if the browser
// navigated via explicit user gesture (e.g. clicking a link) or false if it
// navigated automatically (e.g. via the DomContentLoaded event). Return true
// to cancel the navigation or false to allow the navigation to proceed in the
// source browser's top-level frame.
///
/*--cef()--*/
（2）OnOpenURLFromTab，以特殊的方式打开的网页，例如鼠标中间按钮，快捷键等，一些很少的应用场景。
virtual bool OnOpenURLFromTab(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
const CefString& target_url,
WindowOpenDisposition target_disposition,
bool user_gesture) {
return false;
}
///
// Called on the IO thread before a resource request is loaded. The |request|
// object may be modified. Return RV_CONTINUE to continue the request
// immediately. Return RV_CONTINUE_ASYNC and call CefRequestCallback::
// Continue() at a later time to continue or cancel the request
// asynchronously. Return RV_CANCEL to cancel the request immediately.
//
///
/*--cef(default_retval=RV_CONTINUE)--*/
（3）OnBeforeResourceLoad网页开始加载资源时调用，可以拦截所有的请求，最为详细。
virtual ReturnValue OnBeforeResourceLoad(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
CefRefPtr<CefRequestCallback> callback) {
return RV_CONTINUE;
}
};
///
// Called on the IO thread before a resource is loaded. To allow the resource
// to load normally return NULL. To specify a handler for the resource return
// a CefResourceHandler object. The |request| object should not be modified in
// this callback.
///
/*--cef()--*/
virtual CefRefPtr<CefResourceHandler> GetResourceHandler(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request) {
return NULL;
}
///
// Called on the IO thread when a resource load is redirected. The |request|
// parameter will contain the old URL and other request-related information.
// The |response| parameter will contain the response that resulted in the
// redirect. The |new_url| parameter will contain the new URL and can be
// changed if desired. The |request| object cannot be modified in this
// callback.
///
/*--cef()--*/
（4）OnResourceRedirect重定向请求拦截
virtual void OnResourceRedirect(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
CefRefPtr<CefResponse> response,
CefString& new_url) {}
///
// Called on the IO thread when a resource response is received. To allow the
// resource to load normally return false. To redirect or retry the resource
// modify |request| (url, headers or post body) and return true. The
// |response| object cannot be modified in this callback.
///
/*--cef()--*/
（5）OnResourceResponse请求响应后的回调函数
virtual bool OnResourceResponse(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
CefRefPtr<CefResponse> response) {
return false;
}
///
// Called on the IO thread to optionally filter resource response content.
// |request| and |response| represent the request and response respectively
// and cannot be modified in this callback.
///
/*--cef()--*/
virtual CefRefPtr<CefResponseFilter> GetResourceResponseFilter(
CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
CefRefPtr<CefResponse> response) {
return NULL;
}
///
// Called on the IO thread when a resource load has completed. |request| and
// |response| represent the request and response respectively and cannot be
// modified in this callback. |status| indicates the load completion status.
// |received_content_length| is the number of response bytes actually read.
///
/*--cef()--*/
（6）OnResourceLoadComplete资源加载结束时的回调
virtual void OnResourceLoadComplete(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
CefRefPtr<CefResponse> response,
URLRequestStatus status,
int64 received_content_length) {}
///
// Called on the IO thread when the browser needs credentials from the user.
// |isProxy| indicates whether the host is a proxy server. |host| contains the
// hostname and |port| contains the port number. |realm| is the realm of the
// challenge and may be empty. |scheme| is the authentication scheme used,
// such as "basic" or "digest", and will be empty if the source of the request
// is an FTP server. Return true to continue the request and call
// CefAuthCallback::Continue() either in this method or at a later time when
// the authentication information is available. Return false to cancel the
// request immediately.
///
/*--cef(optional_param=realm,optional_param=scheme)--*/
virtual bool GetAuthCredentials(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
bool isProxy,
const CefString& host,
int port,
const CefString& realm,
const CefString& scheme,
CefRefPtr<CefAuthCallback> callback) {
return false;
}
///
// Called on the IO thread before sending a network request with a "Cookie"
// request header. Return true to allow cookies to be included in the network
// request or false to block cookies. The |request| object should not be
// modified in this callback.
///
/*--cef()--*/
virtual bool CanGetCookies(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request) {
return true;
}
///
// Called on the IO thread when receiving a network request with a
// "Set-Cookie" response header value represented by |cookie|. Return true to
// allow the cookie to be stored or false to block the cookie. The |request|
// object should not be modified in this callback.
///
/*--cef()--*/
virtual bool CanSetCookie(CefRefPtr<CefBrowser> browser,
CefRefPtr<CefFrame> frame,
CefRefPtr<CefRequest> request,
const CefCookie& cookie) {
return true;
}
///
// Called on the IO thread when JavaScript requests a specific storage quota
// size via the webkitStorageInfo.requestQuota function. |origin_url| is the
// origin of the page making the request. |new_size| is the requested quota
// size in bytes. Return true to continue the request and call
// CefRequestCallback::Continue() either in this method or at a later time to
// grant or deny the request. Return false to cancel the request immediately.
///
/*--cef()--*/
virtual bool OnQuotaRequest(CefRefPtr<CefBrowser> browser,
const CefString& origin_url,
int64 new_size,
CefRefPtr<CefRequestCallback> callback) {
return false;
}
///
// Called on the UI thread to handle requests for URLs with an unknown
// protocol component. Set |allow_os_execution| to true to attempt execution
// via the registered OS protocol handler, if any.
// SECURITY WARNING: YOU SHOULD USE THIS METHOD TO ENFORCE RESTRICTIONS BASED
// ON SCHEME, HOST OR OTHER URL ANALYSIS BEFORE ALLOWING OS EXECUTION.
///
/*--cef()--*/
virtual void OnProtocolExecution(CefRefPtr<CefBrowser> browser,
const CefString& url,
bool& allow_os_execution) {}
///
// Called on the UI thread to handle requests for URLs with an invalid
// SSL certificate. Return true and call CefRequestCallback::Continue() either
// in this method or at a later time to continue or cancel the request. Return
// false to cancel the request immediately. If
// CefSettings.ignore_certificate_errors is set all invalid certificates will
// be accepted without calling this method.
///
/*--cef()--*/
virtual bool OnCertificateError(CefRefPtr<CefBrowser> browser,
cef_errorcode_t cert_error,
const CefString& request_url,
CefRefPtr<CefSSLInfo> ssl_info,
CefRefPtr<CefRequestCallback> callback) {
return false;
}
///
// Called on the UI thread when a client certificate is being requested for
// authentication. Return false to use the default behavior and automatically
// select the first certificate available. Return true and call
// CefSelectClientCertificateCallback::Select either in this method or at a
// later time to select a certificate. Do not call Select or call it with NULL
// to continue without using any certificate. |isProxy| indicates whether the
// host is an HTTPS proxy or the origin server. |host| and |port| contains the
// hostname and port of the SSL server. |certificates| is the list of
// certificates to choose from; this list has already been pruned by Chromium
// so that it only contains certificates from issuers that the server trusts.
///
/*--cef()--*/
virtual bool OnSelectClientCertificate(
CefRefPtr<CefBrowser> browser,
bool isProxy,
const CefString& host,
int port,
const X509CertificateList& certificates,
CefRefPtr<CefSelectClientCertificateCallback> callback) {
return false;
}
///
// Called on the browser process UI thread when a plugin has crashed.
// |plugin_path| is the path of the plugin that crashed.
///
/*--cef()--*/
virtual void OnPluginCrashed(CefRefPtr<CefBrowser> browser,
const CefString& plugin_path) {}
///
// Called on the browser process UI thread when the render view associated
// with |browser| is ready to receive/handle IPC messages in the render
// process.
///
/*--cef()--*/
virtual void OnRenderViewReady(CefRefPtr<CefBrowser> browser) {}
///
// Called on the browser process UI thread when the render process
// terminates unexpectedly. |status| indicates how the process
// terminated.
///
/*--cef()--*/
virtual void OnRenderProcessTerminated(CefRefPtr<CefBrowser> browser,
TerminationStatus status) {}
};
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