restrict a catalog item to just one time request per user

[levino]

Hi there

i have a requirement to restrict a catalog item to just one time request per user, that is once its requested and state pending or completed it cannot be requested again.

This is requested via the servicenow portal.

the attached script does not seem to work it always comes up with the message  when i change user  'duplicate request cannot be submitted'

Thanks

Levino

function onChange(control, oldValue, newValue, isLoading, isTemplate) {
    if (isLoading || newValue === '') {
        return;
    }
  
    var ga = new GlideAjax('restrictduplicateitem');
    ga.addParam('sysparm_name', 'restrictduplication');
    ga.addParam('sysparm_reqfor', newValue);
    ga.getXML(alertUser);

    function alertUser(response) {
        var answer = response.responseXML.documentElement.getAttribute("answer");
        if (answer) {
            g_form.showFieldMsg('requested_for', 'Duplicate request can not be submitted', 'Error');
            g_form.setValue('hidden_variable', true);
        } else {
            g_form.hideFieldMsg('hidden_variable', true);
        }
    }

}


var restrictduplicateitem = Class.create();
restrictduplicateitem.prototype = Object.extendsObject(AbstractAjaxProcessor, {
restrictduplication: function() {
       var user = this.getParameter('sysparm_user');
		var cat_item_id = this.getParameter('sysparm_catitem');
        
        var gr = new GlideRecord('sc_req_item');
        gr.addEncodedQuery('cat_item=' + cat_item_id + '^stateNOT IN3,4,7^request.requested_for=' + req_for);
        gr.query();
        if (gr.next())
            return true;
        else
            return false;
    },
    type: 'restrictduplicateitem'
});


function onSubmit() {
    //Type appropriate comment here, and begin script below
    if (g_form.getValue('hidden_variable') == 'true') {
        return false;
    }
}

Thanks

Levino

[levino]

thank You Hitoshi

all the answers provided were helpful, but Ankur solution was the one i implemented

not sure if there is way to mark 2 answers as correct?