DRY Authenticated Tasks in Cocoa (with distributed objects)

Posted by arbales on Stack Overflow See other posts from Stack Overflow or by arbales
Published on 2010-05-26T07:26:07Z Indexed on 2010/05/26 7:31 UTC
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I'm kind of surprise/infuriated that the only way for me to run an authenticated task, like perhaps sudo gem install shi*t, is to make a tool with pre-written code.

I'm writing a MacRuby application, which doesn't seem to expose the KAuthorization* constants/methods. So.. I learned Cocoa and Objective-C.

My application creates a object, serves it and calls the a tool that elevates itself and then performs a selector on a distributed object (in the tool's thread). I hoped that the distributed object's methods would evaluated inside the tool, so I could use delegation to create "privileged" tasks. If this won't work, don't try to save it, I just want a DRY/cocoa solution.

AuthHelper.m

    //AuthorizationExecuteWithPrivileges of this.
    AuthResponder* my_responder = [AuthResponder sharedResponder]; // Gets the proxy object (and it's delegate)
    NSString *selector = [NSString stringWithUTF8String:argv[3]];
    NSLog(@"Performing selector: %@", selector);
    setuid(0);    
    if ([[my_responder delegate] respondsToSelector:NSSelectorFromString(selector)]){
        [[my_responder delegate] performSelectorOnMainThread:NSSelectorFromString(selector) withObject:nil waitUntilDone:YES];
    }

RandomController.m

- (void)awakeFromNib
{
    helperToolPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingString:@"/AuthHelper"];
    delegatePath = [[[NSBundle mainBundle] resourcePath] stringByAppendingString:@"/ABExtensions.rb"];
    AuthResponder* my_responder = [AuthResponder initAsService];
    [my_responder setDelegate:self];

}

-(oneway void)install_gems{
    NSArray *args = [NSArray arrayWithObjects: @"gem", @"install", @"sinatra", nil];
    [NSTask launchedTaskWithLaunchPath:@"/usr/bin/sudo" arguments:args];
    NSLog(@"Ran AuthResponder.delegate.install_gems"); // This prints.
}

... other privileges tasks. "sudo gem update --system" for one.

I'm guessing the proxy object is performing the selector in it's own thread, but I want the current (privileged thread) to do it so I can use sudo.

Can I force the distributed object to evaluate the selector on the tool's thread?

How else can I accomplish this dryly/cocoaly?

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