使用Codeigniter处理ajax响应

Question

I've been handling success/error messages by returning json encoded arrays as a response, but it suddenly occurred to me that this probably isn't the correct way of handling notifications.

For example, my controller will look like this:

public function controller_name() {
    //validate form input
    $this->form_validation->set_rules('id', 'id', 'required|is_natural_no_zero');

    // if validation was successful with no errors
    if ($this->form_validation->run() && $this->model_name->method()) {

        $this->data['status'] = 'success';
        $this->data['message'] = 'This is the success message';
        echo json_encode($this->data);

    } else {
        $this->data['status'] = 'error';
        $this->data['message'] = validation_errors();
        echo json_encode($this->data);
    }
}

Then the jQuery:

$.ajax({
    url: url,
    type: 'POST',
    data: data,
    success: function (r) {

        json = $.parseJSON(r);

        if (json.status == 'success') {
            if (json.message == 'added') {
                $this.addClass('success');
            } else {
                $this.removeClass('success');
            }
        } else {
            console.log('There was an error')
        }

What's the best practice way to do this? Can I throw exceptions to use the ajax error?

Answer 1

Sending erroneous http status code should trigger the jQuery ajax error handler:

public function controller_name() {
    //validate form input
    $this->form_validation->set_rules('id', 'id', 'required|is_natural_no_zero');

    // if validation was successful with no errors
    if ($this->form_validation->run() && $this->model_name->method()) {
        $this->data['message'] = 'This is the success message';
    } else {
        $this->output->set_status_header('400'); //Triggers the jQuery error callback
        $this->data['message'] = validation_errors();

    }
    echo json_encode($this->data);
}

JS:

$.ajax({
    url: url,
    type: 'POST',
    data: data,
    success: function (r) {
        var json = $.parseJSON(r);

    },

    error: function( jqXhr ) {
        if( jqXhr.status == 400 ) { //Validation error or other reason for Bad Request 400
            var json = $.parseJSON( jqXhr.responseText );
        }
    }
});