WebPolicyDelegate Protocol Reference

Instance Methods

webView:decidePolicyForMIMEType:request:frame:decisionListener:

Decides whether to display content with a given MIME type. (required)

- (void)webView:(WebView *)webView decidePolicyForMIMEType:(NSString *)type request:(NSURLRequest *)request frame:(WebFrame *)frame decisionListener:(id < WebPolicyDecisionListener >)listener

Parameters

webView

The associated web view.

type

The MIME type of the content.

request

The request to load the content.

frame

The frame for displaying the content.

listener

The object that receives the policy decision.

Discussion

This method is invoked during the process of loading content for request after the webView:didStartProvisionalLoadForFrame: method in the WebFrameLoadDelegate informal protocol is called by the WebView object. The web view implements a policy decision by sending one of the WebPolicyDecisionListener protocol messages to listener.

If you do not implement this method, the default behavior is used. The listener is told to ignore the MIME type unless webView specifies it can handle the type in its canShowMIMEType: method.

In some rare cases, multiple responses may be received for a single resource. This happens in the case of multipart/x-mixed-replace, also known as a “server push.” In this case, this method will be invoked multiple times.

webView:decidePolicyForNavigationAction:request:frame:decisionListener:

Routes a navigation action internally or to an external viewer. (required)

- (void)webView:(WebView *)webView decidePolicyForNavigationAction:(NSDictionary *)actionInformation request:(NSURLRequest *)request frame:(WebFrame *)frame decisionListener:(id < WebPolicyDecisionListener >)listener

Parameters

webView

The WebView object for which this object is the policy delegate.

actionInformation

A description of the action that triggered the navigation request. The possible key-value pairs in this dictionary are defined in “Action Dictionary Keys.”

request

The request for which the navigation is made.

frame

The WebFrame object in which the action occurred.

listener

The WebPolicyDecisionListener object that receives the policy decision.

Discussion

This method is invoked when a navigation decision needs to be made. The web view implements a policy decision by sending one of the WebPolicyDecisionListener protocol messages to listener. This method is invoked whenever a server redirect is encountered, and before loading starts.

If you do not implement this method, the default behavior is used. The listener handles the navigation internally if the request is for an error page or if the canHandleRequest: method of the NSURLConnection class returns YES when passed request. Otherwise, the listener ignores the navigation, and it is handled externally.

webView:decidePolicyForNewWindowAction:request:newFrameName:decisionListener:

Decides whether to allow a targeted navigation event, such as opening a link in a new window. (required)

- (void)webView:(WebView *)webView decidePolicyForNewWindowAction:(NSDictionary *)actionInformation request:(NSURLRequest *)request newFrameName:(NSString *)frameName decisionListener:(id < WebPolicyDecisionListener >)listener

Parameters

webView

The WebView object for which this object is the policy delegate.

actionInformation

A description of the action that triggered the navigation request. The possible key-value pairs in this dictionary are defined in “Making content decisions.”

request

The request for which the new window action is performed.

frameName

The name of the new frame that contains the content returned from the request.

listener

The WebPolicyDecisionListener object that receives the policy decision.

Discussion

This method is invoked when a targeted navigation decision needs to be made. A targeted navigation typically opens a new window to display content. The receiver implements a policy decision by sending one of the WebPolicyDecisionListener protocol messages to listener. This method allows delegates to modify the behavior of targeted links which normally open a new window. Delegates might do something else, such as download or present the content in a special way. If this method sends use to listener then the new window will be opened, and webView:decidePolicyForNavigationAction:request:frame:decisionListener: will be invoked with a WebNavigationTypeOther as the value for the WebActionNavigationTypeKey key in the action dictionary.

The default behavior sends use to listener.

webView:unableToImplementPolicyWithError:frame:

Handles or drops events that were rejected by a policy maker. (required)

- (void)webView:(WebView *)webView unableToImplementPolicyWithError:(NSError *)error frame:(WebFrame *)frame

Parameters

webView

The WebView object for which this object is the policy delegate.

error

The error that occurred.

frame

The frame in which the error occurred.

Discussion

Delegates might implement this method to display or log an error message. If you do not implement this method, no action is taken.