Configurable submitFormat on date fields in JsonStore

[Springvar]

I use an editorgrid to edit elements from a JsonStore. The JsonStore uses a HttpProxy to update the backend database.
My problem is that the backend API expects fromTs and toTs to be unix timestamps, but when a record is updated, the resulting http post contains a date formatted like this: Wed Oct 20 00:00:00 UTC+0200 2010

I've searched the API documentation for a parameter to control the post format, but I've not been able to find anything. Is there a simple way to do this?

 myJsonStore = new Ext.data.JsonStore({
 autoLoad: true,
 autoSave: true,
 proxy: new Ext.data.HttpProxy({
  api: {
   create: '/create/',
   read: '/read/',
   update: '/update/',
   destroy:'/destroy/'
  }
 }),
 writer: new Ext.data.JsonWriter({
  encode: true,
  writeAllFields: true
 }),
 idProperty: 'id',
 fields: [
  {name: 'id',  type: 'int'},
  {name: 'fromTs', type: 'date', dateFormat:'timestamp'},
  {name: 'toTs',  type: 'date', dateFormat:'timestamp'}
 ]
 });

The editorgrid is configured like this:

 {
  xtype: 'editorgrid',
  clicksToEdit: 1,
  columns: [
   {header: "Id", dataIndex: 'id', editable: false},
   {header: "From", dataIndex: 'fromTs', editor: new Ext.form.DateField({format: 'd.m.Y', startDay: 1}), xtype: 'datecolumn', format: 'd.m.Y'},     
   {header: "To", dataIndex: 'toTs', editor: new Ext.form.DateField({format: 'd.m.Y', startDay: 1}), xtype: 'datecolumn', format: 'd.m.Y'}
  ],
  store: myJsonStore
 }

Also posted on StackOverflow: http://stackoverflow.com/questions/3...unix-timestamp

[Springvar]

I know this case is old, but I found a solution to this problem that I never came around to post here.

I added a listener to the proxy's beforewrite event, and manipulated the post params there

 proxy: new Ext.data.HttpProxy({
  api: {
   create: '/create/',
   read:   '/read/',
   update: '/update/',
   destroy:'/destroy/'
  },
  listeners: {
   beforewrite: function(proxy, action, record, params) {
    var fromTs = record.data.fromTs;
    var toTs = record.data.toTs;

    if(record.data.fromTs) record.data.fromTs = fromTs.format('U');
    if(record.data.toTs) record.data.toTs = toTs.format('U');

                // Update record to be sent
    // root = store.reader.root
    params.root = Ext.util.JSON.encode(record.data);

    // Restore record
    record.data.fromTs = fromTs;
    record.data.toTs = toTs;
   }
  }
})