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Re: Object does not allow calls



You need <invokeDefaultMethodWithArguments:>, not <invokeUndefinedMethodFromWebScript:withArguments:>. The latter gets called if you try to invoke a method that has not been exposed by isSelectorExcludedFromWebScript (and is therefore undefined). The former gets called if you try to invoke an exposed object as a method.

As for the exception you mention, that's a symptom of invoking a bridged method incorrectly. It probably resulted from the fact that you didn't define <invokeDefaultMethodWithArguments:>. It can also result from passing an incorrect number of arguments.

Geoff

On Dec 8, 2005, at 2:35 PM, Michael Hanna wrote:

yeah, alert(logMessage); returns me the object <LDataTypeManager: 0x34fff0>

OK, so taking what you have to say literally, I could very well do in:

- (void)webView:(WebView *)sender windowScriptObjectAvailable: (WebScriptObject *)wso
...
[wso setValue:self forKey:@"logMessage"];
...


however this seems to produce the runtime exception:

*** Exception handlers were not properly removed. Some code has jumped or returned out of an NS_DURING...NS_HANDLER region without using the NS_VOIDRETURN or NS_VALUERETURN macros. Clearly I'm doing something wrong here..

I'm not sure if I totally understand the role of invokeUndefinedMethodFromWebScript:withArguments:

It doesn't seem to get called at all whether or not [wso setValue:self forKey:@"logMessage"]; is present(I had it just print an NSLog() message). Is it meant to be used as such:

- (id)invokeUndefinedMethodFromWebScript:(NSString *)name withArguments:(NSArray *)args
{
if([name isEqualToString:@"logMessage"])
return [self doTheActualLogMessage:args];


	return nil;
}

Michael

--
Michael Hanna
email@hidden
iChat: michaelkhanna(AIM)



On 8-Dec-05, at 11:20 AM, Geoffrey Garen wrote:

Hi Michael. My comments are enclosed below.

I've been getting the error:

2005-12-07 16:19:18.587 DataTypeRoot01[4369] /SourceCache/ JavaScriptCore/JavaScriptCore-416.13/bindings/objc/ WebScriptObject.mm:211:[4369] JavaScript exception: Object (result of expression logMessage) does not allow calls.

I'm not sure what this means..why would it expect an object that does allow calls?

Because your code calls logMessage as a function, JavaScript expects the logMessage 'object' to allow '[function] calls'. It looks like logMessage is undefined, though. You can confirm this by calling 'alert(logMessage)' and seeing if you get a function or undefined.


Anyway,

on the call:

var lang = logMessage(strLang);

In the calling class(which contains these delegates:

- (void)webView:(WebView *)sender windowScriptObjectAvailable: (WebScriptObject *)wso
+(NSString*)webScriptNameForSelector:(SEL)aSel
+(BOOL)isSelectorExcludedFromWebScript:(SEL)aSel
and
+(BOOL)isKeyExcludedFromWebScript:(const char*)k


in webScriptNameForSelector:

	if (aSel == @selector(logMessage:)) {
		retval = @"logMessage";
	}

in isSelectorExcludedFromWebScript:

	if ( aSel == @selector(logMessage:)) {
		return NO;
	}



Can I access a selector without a namespace(such as this case)?

webScriptNameForSelector and isSelectorExcludedFromWebScript are appropriate methods to implement if your object exposes member functions to JavaScript. What you've done would enable calling plugin.logMessage() if your object were defined in the page as 'plugin'.


In this case, your object doesn't expose member functions. Rather, you want to expose an object that itself can be called as a function. That requires constructing an object that implements invokeDefaultMethodWithArguments:. You can read about that in the WebKit Objective-C docs @ <http://developer.apple.com/ documentation/Cocoa/Reference/WebKit/ObjC_classic/Protocols/ WebScripting.html>

I will say that the note there is a little tricky. It says "Invoked when a script attempts to invoke a method on an exposed object directly." I would say instead, "Invoked when a script attempts to call an exposed object as a function."

Remember, to expose an object that isn't defined in the page as a plugin, you need to call setValue:forKey: on the windowScriptObject, passing in a valid object as the value and @"logMessage" as the key.

You can find a good example of setValue:forKey: in the Dashboard docs @ <http://developer.apple.com/documentation/AppleApplications/ Reference/Dashboard_Ref/Plugin/chapter_5_section_1.html>.

Cheers.

Geoff


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References: 
 >Object does not allow calls (From: Michael Hanna <email@hidden>)
 >Re: Object does not allow calls (From: Geoffrey Garen <email@hidden>)
 >Re: Object does not allow calls (From: Michael Hanna <email@hidden>)



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