tree_store = new Ext.data.TreeStore({ autoLoad: 'true', proxy: { type: 'ajax', url: "{{ base_local_server_url() }}/generic", extraParams: { project_name: '{{ name }}', command: 'get_indexed_metadata' }, headers: { 'Content-Type' : 'application/json; charset=UTF-8', 'Accept' : 'application/json, text/javascript' }, actionMethods: { create : 'POST', read : 'POST', update : 'POST', destroy: 'POST' }, doRequest: function(operation, callback, scope) { var writer = this.getWriter(); var request = this.buildRequest(operation, callback, scope); if (operation.allowWrite()) { request = writer.write(request); } Ext.apply(request, { headers : this.headers, timeout : this.timeout, scope : this, callback : this.createRequestCallback(request, operation, callback, scope), method : this.getMethod(request), jsonData : this.extraParams, disableCaching : false // explicitly set it to false, ServerProxy handles caching }); Ext.Ajax.request(request); return request; }, writer: { type: 'json' } } })