Closures Can't Be Serialized, How To Do Callbacks Via Ajax To Php?

Question How can i implement a PHP callback being passed over AJAX with the PHP callback being called by the page requested by AJAX? The Setup Comments are posted via AJAX and the

Solution 1:

Create a function that is the callback, then pass the function name via ajax, and call it like this:

$callback = 'callback_function_name'; $callback($params...);

Solution 2:

Maybe I don't get what you're trying to do, but could you do something like:

window.myappstuff={}

window.myappstuff.onSuccess=function(){
   //Do some stuff here.
}

window.myappstuff.onFailure=function(){
   //Do some different stuff here.
}

Your php callback could then call window.myappstuff.onSuccess or window.myappstuff.onFailure. You could also use random function names instead.

Solution 3:

On the whole, I'd have to recommend a rethink. It's considered bad practice to send anything even remotely code-like via ajax, for security reasons. I could, for example, "intercept" the reply using firebug or something, change whatever to my code.If you send a function name and arguments, I can change them. Suppose your script validates user input, I could just make it so that an ajax call returns a non-existing function. Your script will fail, and with it all form of input validation is gone.If you send a full function definition as string, I can go even further.

You might have seen people do something like this:

echo'function(argument){ console.log(argument);}("something"));';

This is just plain text, no JSON. Then, in JS they'll do something that should be considered a crime against humanity:

//readystatechange callback:if (this.readyState === 4 && this.status === 200)
{
    return eval(this.responseText);//<=== EVIL - EVIL - EVIL
}

This is insane it's EVIL don't even look at thisWhat you can do as some sort of quick fix is write a generic onreadystatechange function:

//readystatechangeif (this.readyState === 4 && this.status === 200)
{
    var returnObj = JSON.parse(this.responseText);
    switch(returnObj.actionType)
    {
        case 'DomAction':
            return domSwitch(returnObject.data);//<-- based on data domSwitch will decide what to do
        case 'setVar':
            return varSwitch(returnObjcet.data);
        default:
            return educatedGuess(returnObject);//<-- desperate
    }
}

But again, when you send a request, you generally have a certain expectation as to what kind of data you'll get back, and what you want to do with it, so you could create a readystatechange handler on the fly for each ajax request, to deal with that particular call.

Solution 4:

Instead of passing callbacks, create the functions in advance on the server and pass the name of the function to execute, with list of arguments to pass it.

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Besides, here is the place where you start using angular.js. This way you'll have a client side model of the forum topic with a field of posts_count which you'll update on on the client side and angluar's bindings will update the view wherever you use data from this model.