Detecting server-side error when editing or creating Kendo Grid entries

Question

I have an editable Kendo Grid to manage (create/modify) user accounts. Editing is done in a popup (versus inline or batch). I have client-side validation to help ensure that valid data is provided to the server, however I cannot figure out how to handle the response from the server in the event that the create/update fails server-side. I'm not talking 'failed' as in the request failed with a HTTP 404 or 500, for example; I'm talking failed as in the script on the server didn't like something about the data and refuses to oblige.

Can someone please show me how I can accomplish this? What I would like to be able to do is after the update is sent to the server, wait for the response. If the response says everything is OK, then great. If the response says something didn't go so well, I'd like to be able to (A) keep the popup editing window open and populated and (B) provide feedback to the user regarding the reason for the rejection. The data should not be committed to the grid unless the response says everything is OK. Likewise, the edit popup should remain open until the server says OK.

I'm flexible with how the server's response should be formatted, as long as I can accomplish what I want.

Before you direct me to the Kendo official API documentation, I am already well aware of it and refer to it daily. However, to say the least, it is incomplete and I cannot find anything relating to this topic. If you have found something in the documentation that you think could help me then by all means point me to the documentation =)

As requested, below is the code I have for creating the grid.

$("#kendo_user_grid").kendoGrid({
    columns: [{
        title: "Last name",
        field: "lName"
    },{
        title: "First name",
        field: "fName"
    },{
        title: "Business unit",
        field: "businessUnit"
    },{
        title: "Username",
        field: "loginId"
    },{
        title: "Email address",
        field: "email"
    },{
        title: "Phone",
        field: "phone"
    },{
        title: "Address",
        field: "address"
    },{
        title: "City",
        field: "city"
    },{
        title: "State",
        field: "state"
    },{
        title: "Zip code",
        field: "zipcode"
    },{
        title: "Country",
        field: "country"
    },{
        title: "Time zone",
        field: "timezone"
    },{
        title: "Privileges",
        field: "privs"
    },{
        command: ["edit","destroy"],
        title: " "
    }],
    scrollable: false,
    dataSource: {
        transport: {
            read: {
                url: "manageUsers.phtml",
                data: { mode: "fetch" },
                dataType: "json",
                type: "POST"
            },
            update: {
                url: "manageUsers.phtml",
                data: { mode: "update" },
                type: "POST"
            },
            destroy: {
                url: "manageUsers.phtml",
                data: { mode: "destroy" },
                type: "POST"
            },
            create: {
                url: "manageUsers.phtml",
                data: { mode: "create" },
                type: "POST"
            },
            batch: false
        },
        schema: {
            data: "records",
            total: "total",
            model: {
                id: "userId",
                fields: {
                    userId: { editable: false, nullable: true },
                    lName: { type: "string", editable: true, validation: { required: true } },
                    fName: { type: "string", editable: true, validation: { required: true } },
                    businessUnit: { type: "string", editable: true, validation: { required: true } },
                    loginId: { type: "string", validation: { required: true } },
                    email: { type: "string", validation: { required: true } },
                    phone: { type: "string" },
                    address: { type: "string" },
                    city: { type: "string" },
                    state: { type: "string" },
                    zipcode: { type: "string" },
                    country: { type: "string" },
                    timezone: { type: "string" },
                    privs: { type: "string" }
                }
            }
        },
        pageSize: 20,
        serverPaging: false,
        serverFiltering: false,
        serverSorting: false
    },
    filterable: true,
    sortable: true,
    pageable: true,
    editable: {
        mode: "popup",
        template: kendo.template($("#kendo_edit_user_template").html())
    },
    toolbar: ["create","save","cancel"]
});

Answer 1

There are two point to keep in mind:

1. Schema.errors The field from the server response which contains server-side errors.
2. error is an event that will be fired if there was an error.

Basically you need to:

1. add to your schema an errors definition that provides access to the status sent back from the server.
2. Implement error event handler that, for example, restore previous value.

If your server returns the error message in a field called myError then you would have something like:

schema: {
    errors: "myError", 
    data: "records",
    total: "total",
    model: {
        id: "userId",
        fields: {
            userId: { editable: false, nullable: true },
            lName: { type: "string", editable: true, validation: { required: true } },
            fName: { type: "string", editable: true, validation: { required: true } },
    ...

or:

schema: {
    errors: function(response) {
        if (response.myError && response.myError !== "OK") {
            return response.myError;
        }
        return false;
    }, 
    data: "records",
    total: "total",
    model: {
        id: "userId",
        fields: {
            userId: { editable: false, nullable: true },
            lName: { type: "string", editable: true, validation: { required: true } },
            fName: { type: "string", editable: true, validation: { required: true } },
    ...

and the event would be:

dataSource: {
    error : function (e) {
        if (e.errors !== false) {
            alert("Error: " + e.errors);
            // This will cancel any change done
            this.cancelChanges();
        }
    },
    transport: {
        read: {
            url: "manageUsers.phtml",
            data: { mode: "fetch" },
            dataType: "json",
            type: "POST"
        },

EDIT : If what you want is to keep the popup open you should do:

dataSource: {
    error : function (e) {
        if (e.errors !== false) {
            alert("Error: " + e.errors);
            // This will keep the popup open
            grid.one("dataBinding", function (e) {
                e.preventDefault();   // cancel grid rebind
            });
        }
    },
    transport: {
        read: {
            url: "manageUsers.phtml",
            data: { mode: "fetch" },
            dataType: "json",
            type: "POST"
        },

Where I bind to databinding event just once using jQuery.one