Question

I have a basic collection that does a fetch on document ready: ie:

message_list.fetch({

            success: function(){
                console.log('success');
                //render
                grid_view.render();
            },
            error: function(xhr, text, ajax){
                //set a column limit and retru
                console.log('retrying');
                urlParams.colLimit = true;
                $.ajax(this);
                return;
            },
            data: urlParams,
            processData:true
        });

This grabs a json from the server, which is querying an hbase table with thrift. With certain accounts the dataset in hbase is too large and it runs out of memory and returns a 500 response. So I want to refire the same ajax call on error after I add a new query param. Looking at the jquery .ajax documentation it says to call $.ajax(this), but this is the window object. Also the xhr variable has empty success function. How do I refire the same ajax call with the same properties and success/error functions?

Answer 1

It’s pretty easy — make an object that you store and can pass back in:

var success_cb = function(){
    console.log('success');
    //render
    grid_view.render();
};

var error_cb = function(xhr, text, ajax){
    //set a column limit and retru
    console.log('retrying');
    urlParams.colLimit = true;
    $.ajax(this);
    return;
};

var fetch_options = {
        success: success_cb, 
        error: error_cb,
        data: urlParams,
        processData:true
}

message_list.fetch(fetch_options);

As long as the fetch_options is defined in the same scope as the two callback functions, and fetch_options is accessible outside of that scope, anything that can access fetch_options can use it as it’s arguments to .fetch.