Embedded Webkit - script callbacks how?

Question

On windows, when the \"Shell.Explorer\" ActiveX control is embedded in an application it is possible to register an \"external\" handler - on object that implements IDispatc

Answer 1

This is very easy to do with the WebScriptObject API in combination with the JavaScriptCore framework.

Answer 2

You need to implement the various WebScripting protocol methods. Here is a basic example:

@interface WebController : NSObject
{
    IBOutlet WebView* webView;
}

@end

@implementation WebController

//this returns a nice name for the method in the JavaScript environment
+(NSString*)webScriptNameForSelector:(SEL)sel
{
    if(sel == @selector(logJavaScriptString:))
        return @"log";
    return nil;
}

//this allows JavaScript to call the -logJavaScriptString: method
+ (BOOL)isSelectorExcludedFromWebScript:(SEL)sel
{
    if(sel == @selector(logJavaScriptString:))
        return NO;
    return YES;
}

//called when the nib objects are available, so do initial setup
- (void)awakeFromNib
{
    //set this class as the web view's frame load delegate 
    //we will then be notified when the scripting environment 
    //becomes available in the page
    [webView setFrameLoadDelegate:self];

    //load a file called 'page.html' from the app bundle into the WebView
    NSString* pagePath = [[NSBundle mainBundle] pathForResource:@"page" ofType:@"html"];
    NSURL* pageURL = [NSURL fileURLWithPath:pagePath];
    [[webView mainFrame] loadRequest:[NSURLRequest requestWithURL:pageURL]];
}


//this is a simple log command
- (void)logJavaScriptString:(NSString*) logText
{
    NSLog(@"JavaScript: %@",logText);
}

//this is called as soon as the script environment is ready in the webview
- (void)webView:(WebView *)sender didClearWindowObject:(WebScriptObject *)windowScriptObject forFrame:(WebFrame *)frame
{
    //add the controller to the script environment
    //the "Cocoa" object will now be available to JavaScript
    [windowScriptObject setValue:self forKey:@"Cocoa"];
}

@end

After implementing this code in your controller, you can now call Cocoa.log('foo'); from the JavaScript environment and the logJavaScriptString: method will be called.