Question

Why would a record persisted successfully with a rest proxy calling the POST/Create action, and then on subsequent saves, call the same POST/Create method and not the the PUT/Update one?

POSTS

var ref = beginQuestionnaireControl.getPegfileRef();
var Pegfile = Ext.create('Pegfect.model.Pegfile', {
  Id: 0,
  Reference: ref
});
Pegfile.save({
  scope: this,
  success: function (pegfile, operation) {
    this.activePegfile = pegfile;
    this.startQuestions();
  },
  failure: function () {
    alert('That ref is not unique');
  }
});

also POSTS (expecting a PUT)

this.activePegfile.save({
      success: function () {
        successCallback();
      },
      failure: function () {
        alert('oops, error saving Pegfile');
      }
    });

proxy

proxy:
  {
    type: 'rest',
    url: 'Pegfile',
    timeout: 120000,
    noCache: false,

    reader:
    {
        type: 'json',
        root: 'data',
        successProperty: 'success'
    },

    writer:
    {
        type: 'json',
        writeAllFields: true
    }
  }

Answer 1

The trick is to define an ‘Id‘ property on the Model:

idProperty: 'Id'

Crying out for some convention over config on this one…