Rails JSON Errors

Easily parse and handle standard json error packets from a Rails API

Installation

Installation is easy. Simply bower install rails-json-errors and include public/rails_json_errors.js in your document.

Usage

RJE.displayJSONErrors( rawJSON, [displayMethod] )

rawJSON

type: String

The JSON returned from the server. If there is an errors key, it will parse the Rails errors returned. Otherwise it will do nothing.

displayMethod

type: Function( Array messages )

The method that receives an array of error messages of the form errorType: errorMessage. Unless this is passed, the default is to join these with new lines and give them to alert.

Rails

In your controller if you want to return an error have something like the following

render json: { errors: my_model.errors }, status: 409 # or some other appropriate 40X

Front End

These can either be set as global ajax error event handlers

CoffeeScript (yay)

$(document).ajaxError (event, jqXHR) ->
  RJS.displayJSONErrors jqXHR.responseText

JavaScript (meh, alright)

$(document).ajaxError(function(event, jqXHR) {
  RJS.displayJSONErrors(jqXHR.responseText);
});

Or given to a promise

CoffeeScript

somePromiseReturningCall.fail (jqXHR) ->
  RJS.displayJSONErrors jqXHR.responseText

JavaScript

somePromiseReturningCall.fail(function(jqXHR) {
  return RJS.displayJSONErrors(jqXHR.responseText);
});