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Implement this interface to handle events related to browser requests.

For an example of how to implement handler see cefpython.CreateBrowserSync(). For a list of all handler interfaces see API > Client handlers.

The RequestHandler tests can be found in the old wxpython.py script (v31).

Not yet exposed in CEF Python:

• OnOpenURLFromTab
• OnSelectClientCertificate

Table of contents:

• Callbacks
  • OnBeforeBrowse
  • OnBeforeResourceLoad
  • GetResourceHandler
  • OnResourceRedirect
  • OnResourceResponse
  • GetAuthCredentials
  • OnQuotaRequest
  • GetCookieManager
  • OnProtocolExecution
  • _OnBeforePluginLoad
  • _OnCertificateError
  • OnRendererProcessTerminated
  • OnPluginCrashed

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. DisplayHandler.OnLoadingStateChange will be called twice in all cases. If the navigation is allowed LoadHandler.OnLoadStart and OnLoadEnd will be called. If the navigation is canceled LoadHandler.OnLoadError will be called with an |error_code| value of ERR_ABORTED.

Called on the IO thread before a resource request is loaded. The |request| object may be modified. To cancel the request return true otherwise return false.

Called on the IO thread before a resource is loaded. To allow the resource to load normally return None. To specify a handler for the resource return a ResourceHandler object. The |request| object should not be modified in this callback.

The ResourceHandler object is a python class that implements the ResourceHandler callbacks. Remember to keep a strong reference to this object while resource is being loaded.

The GetResourceHandler example can be found in the old v31 "wxpython-response.py" script on Linux.

Description from upstream CEF:

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.

Available in upstream CEF, but not yet exposed to CEF Python. See Issue #229.

You can implement this functionality by using ResourceHandler and WebRequest / WebRequestClient. For an example see the _OnResourceResponse() method in the old v31 [wxpython-response.py] example.

Called on the IO thread when the browser needs credentials from the user. |is_proxy| 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.

The AuthCallback object methods:

• void Continue(string username, string password)
• void Cancel()

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.

The RequestCallback object methods:

• void Continue(bool allow)
• void Cancel()

Called on the IO thread to retrieve the cookie manager. |main_url| is the URL of the top-level frame. Cookies managers can be unique per browser or shared across multiple browsers. The global cookie manager will be used if this method returns None.

To successfully implement separate cookie manager per browser session, you have to set ApplicationSettings.unique_request_context_per_browser to True. Otherwise the browser param passed to this callback will always be the same first browser that was created using cefpython.CreateBrowserSync.

Popup browsers created javascript's window.open share the same renderer process and request context. If you want to have separate cookie managers for popups created using window.open then you have to implement the LifespanHandler.OnBeforePopup callback. Return True in that callback to cancel popup creation and instead create the window on your own and embed browser in it. The CreateAnotherBrowser function from the old v31 wxpython example does that.

IMPORTANT: in an exceptional case the browser parameter could be None, so you should handle such case. During testing this issue did not occur, but it may happen in some yet unknown scenarios.

Called on the UI thread to handle requests for URLs with an unknown protocol component. Set |allow_execution_out[0]| to True to attempt execution via the registered OS protocol handler, if any.

SECURITY NOTE: You should use this callback to enforce restrictions based on scheme, host or other url analysis before allowing OS execution.

There's no default implementation for OnProtocolExecution on Linux,