Async custom validation

[TimoRuetten]

Is there any way to add a custom attribute with async validation ?

Something like this:

Validator.attributes.asyncFunction = function () {
  var self = this;
  someAsync(function(){
    self.validate(true);
  });
};

[tdegrunt]

Not that I'm aware of ... what would be the use-case?

[TimoRuetten]

Sorry if you read the first comment - I made a mistake by writing this @tdegrunt . I am using jsonschema for writing a package for form validation. In this package (its designed for meteorjs) I want to make it possible defining a custom function which is also async but will return a valid jsonschema error for better error handling. Its possible for me to do a "work around" but it would be more awesome if there is still some functionality - if not I will add a work around for my case.

[awwright]

The primary purpose of JSON Schema is to provide structural validation, only requiring simple computation to verify. This necessarily means no blocking or asynchronous calls.

Of course, JSON Schema can do other stuff, too, like extracting link relationships from an instance. The only thing is this would be outside the scope of the validate() function of most implementations. But there should be some mechanism so so that a JSON Schema keyword can pass back a value about the instance -- including a deferred value like a Promise, that your application could wait on.

Maybe more like this:

Validator.attributes.someKeyword = function (instance, schema) {
  var self = this;
  return self.instanceData('verifyReference', function(db, cb){
    db.get(instance.id, function(err, record){ cb(null, !!record); });
  });
};

So here, the keyword isn't blocking at all, but it's passing back a value that annotates something about the instance. In this case, an asynchronous function call that accepts a database connection to make the lookup with.

[xfg]

+1 how to do it?