Handle 403s gracefully

- When a list 403s, treat it as if it were empty
- When a single resource 403s, redirect to an application error page
  that has a backdoor link to the tokens page

ui/app/adapters/application.js

@@ -1,5 +1,6 @@
 import Ember from 'ember';
 import RESTAdapter from 'ember-data/adapters/rest';
+import codesForError from '../utils/codes-for-error';
 
 const { get, computed, inject } = Ember;
 
@@ -21,8 +22,12 @@ export default RESTAdapter.extend({
 
   findAll() {
     return this._super(...arguments).catch(error => {
-      if (error.code === '501' || (error.errors && error.errors.findBy('status', '501'))) {
-        // Feature is not implemented in this version of Nomad
+      const errorCodes = codesForError(error);
+
+      const isNotAuthorized = errorCodes.includes('403');
+      const isNotImplemented = errorCodes.includes('501');
+
+      if (isNotAuthorized || isNotImplemented) {
         return [];
       }
 

ui/app/controllers/application.js

@@ -1,4 +1,5 @@
 import Ember from 'ember';
+import codesForError from '../utils/codes-for-error';
 
 const { Controller, computed, inject, run, observer } = Ember;
 
@@ -12,19 +13,7 @@ export default Controller.extend({
   }),
 
   errorCodes: computed('error', function() {
-    const error = this.get('error');
-    const codes = [error.code];
-
-    if (error.errors) {
-      error.errors.forEach(err => {
-        codes.push(err.status);
-      });
-    }
-
-    return codes
-      .compact()
-      .uniq()
-      .map(code => '' + code);
+    return codesForError(this.get('error'));
   }),
 
   is403: computed('errorCodes.[]', function() {

ui/app/utils/codes-for-error.js

@@ -0,0 +1,15 @@
+// Returns an array of error codes as strings for an Ember error object
+export default function codesForError(error) {
+  const codes = [error.code];
+
+  if (error.errors) {
+    error.errors.forEach(err => {
+      codes.push(err.status);
+    });
+  }
+
+  return codes
+    .compact()
+    .uniq()
+    .map(code => '' + code);
+}