Question

I’m working on implementing a uniform error handler for remote cfc methods following Ben Nadel’s model. Before getting to this point, I was just returning the data object to jqGrid in the form that it expects. Now, I’m returning a response object that looks like so:

RESPONSE.SUCCESS = "true/false"
RESPONSE.ERRORS = [array of errors]
RESPONSE.DATA = {normal data object that jqGrid expects}

So, I now need to massage the response object when it returns so that I have a

RESPONSE.SUCCESS == "true" 

handler that, at the very least, maps RESPONSE.DATA to the data object that jqGrid expects, and also a

RESPONSE.SUCCESS == "false"

handler that does something else. My first thought was to try to implement the beforeProcessing option. However, if I add this to my initialization code:

beforeProcessing: function(data, status, xhr) {
    console.log(data + ' beforeProcessing was called');
},...

nothing ever gets logged, either on initialization or on subsequent calls. Also, if I revert to my original code and successfully reload the grid, nothing ever runs inside

beforeProcessing: function(){
    alert('hi');
    console.log('hi there');
},...

which would seem to indicate that beforeProcessing is broken.

If I can’t get this to work, I’m going to try to implement ajaxGridOptions{} but can’t figure out exactly what needs to be set in there – I haven’t found the documentation to be much help.

Answer 1

I think there are a misunderstanding about the usage of Ajax and loading of grid from the server. The Ajax use HTTP protocol internally which divide clear successful responds from the error responds. If the server detect any kind of error it should set error HTTP status (see here or here). In
case of HTTP status code 400 and higher the loadError callback will be called instead of loadComplete. The format of the error response can be absolutely another as the format of successful response.

So I see no reason the has all SUCCESS, DATA and ERRORS blocks. Boolean SUCCESS will be clear from the context: it’s equal to false inside of loadError and it’s to true inside of loadComplete. RESPONSE.DATA can be directly the body of the response. and the RESPONSE.ERRORS can be the body of the error response.

It’s the reason why both loadError and loadComplete callbacks exists.

The beforeProcessing will be called only in case of successful response. The statement console.log(data); will don’t display the needed information because data will be object and the text like LOG: [object Object] beforeProcessing was called which will be produced by console.log(data + ' beforeProcessing was called'); get not much information.

UPDATED: I don’t know ColdFusion and it’s restriction in the error handling. If you really can only to return in success case the data like

{
    "SUCCESS": true,
    "ERRORS": [],
    "DATA": {
        "TOTAL": xxx, 
        "PAGE": "yyy", 
        "RECORDS": "zzz",
        "ROWS": [
            {"ID": "id1", "CELL": ["cell11", "cell12", "cell13"]},
            {"ID": "id2", "CELL": ["cell21", "cell22", "cell23"]},
            ...
        ]
    }
}

and in the case of an error

{
    "SUCCESS": true,
    "ERRORS": ["Any error description"],
    "DATA": {
    }
}

then you can do the following.

First of all you should define jsonReader option of jqGrid which corresponds to successful data:

jsonReader: {
    root: "DATA.ROWS",
    page: "DATA.PAGE",
    total: "DATA.TOTAL",
    records: "DATA.RECORDS",
    id: "ID"
}

To be able to read the error response you can place empty "DATA" part in the response inside of beforeProcessing:

beforeProcessing: function (data) {
    if (!data.SUCCESS) {
        // error response. we set empty "DATA"
        data.DATA = {TOTAL: 0, PAGE: 0, ROWS: []};

        // now the data.ERRORS should be processed
        alert (data.ERRORS.join(','));
    }
}

In the real world you should display the error messages from data.ERRORS in some div or dialog instead of usage of alert, but the general schema described above should work.