Django ExtJs 6:上传文件错误

我在Django框架中使用ExtJs6。我想从上传带有文本的文件。当我提交表单时，它总是给我错误的无效csrf令牌。

禁止（403）CSRF验证失败。请求中止。

这是我的代码：

//document upload form
Ext.define('MyApp.view.UploadDocumentView', {
    extend: 'Ext.form.Panel',
    title : 'Upload Document',
    id : 'documentUploadForm',
    height: 500,
    width: 400,
    floating : true,
    closable : true,
    modal : true,
    fileUpload: true,
    method : 'POST',
    fieldDefaults: {
        labelAlign: 'top',
        labelWidth: 125,
        labelCls : 'formfield-input-label',
        style : 'border-radius : 4px;',
        inputCls : 'textfield-default',
        focusCls:'textfield-default-active',
        //msgTarget: 'side',
        flex : 1 ,
    },
    
    items: [{
        xtype: 'fieldset',
        //title: 'User Info',
        border : 0,
        //layout: 'column',
        defaultType: 'textfield',
        defaults: {
        	//layout: 'form',
        	xtype: 'container',
        	defaultType: 'textfield',
        	cls : 'rounded',
        	style: 'width: 100%;',
    	},
        
       	items : [
       		{ xtype: 'textfield', allowBlank:false, fieldLabel: 'Doc Title', name: 'doctitle',},
		   { xtype: 'filefield', allowBlank:false, fieldLabel: 'Select file', name: 'docfile'},
		],
    }],
    
    buttons:[{
	    text: 'Upload',
	    handler: function(b,e){
	        var form = Ext.getCmp('documentUploadForm').getForm();
	        var token = Ext.util.Cookies.get('csrftoken');
	        form.submit({
	          	url: '/document/upload/',
	          	//headers: {'Content-Type':'multipart/form-data; charset=UTF-8', 'X-CSRFToken' : token},
	          	headers: {'X-CSRFToken' : token},
	          	success: function (formPanel, action) {
                    var data = Ext.decode(action.response.responseText);
                    alert("Success: " + data.msg);
                },
                failure: function (formPanel, action) {
                    var data = Ext.decode(action.response.responseText);
                    alert("Failure: " + data.msg);
                }
	        });
	    }
	}],
    initComponent: function(){
	    this.callParent();
	},
});