async Validation doesn't support caching of responses

[fbuchinger]

async validation seems to have problems when a caching mechanism is implemented in the validation handler (use case: prevent unnecessary server requests for repeated inputs). the validation message isn't shown when the remote validation message comes from the cache and not from the async request.

demo:
http://jsfiddle.net/fbuchinger/KVxNN/6/

[fbuchinger]

Caching seems to work if you invoke the "cached callback" with a zero-timeout:

http://jsfiddle.net/fbuchinger/KVxNN/8/

[jhsowter]

Hi

I had the same issue where my validation callback would occur immediately if certain data was already cached. The reason is because "validateObservable" in the knockout-validation source code sets the current "valid" value to true after the async call returns (it expects the async call to return some time later, and set the value correctly then).

Your linked fiddler fixes the issue, but it could be included in the knockout-validation source code. Have you issued a pull request to that effect?

[crissdev]

The fix for this seems pretty straightforward. validateAsync should execute async - ko.validation.utils.async. @jhsowter Would you like to submit a PR for this?

Updated fiddle http://jsfiddle.net/mk9bxnLr/

[jhsowter]

I'd love to make a PR. Just need time to fork. Probably be done within 24hr.

[crissdev]

No need to rush. This is for the 2.1.0 release. Consider writing some unit tests too. If you need any help just leave a comment here. Thanks.
👍