How to use the keystone.security function in keystone

app.get('/api', function (req, res) {
		res.render('api', {
			Keystone: {
				csrf_header_key: keystone.security.csrf.CSRF_HEADER_KEY,
				csrf_token_value: keystone.security.csrf.getToken(req, res),
			},
		});
	});

app.get('/api', function (req, res) {
		res.render('api', {
			Keystone: {
				csrf_header_key: keystone.security.csrf.CSRF_HEADER_KEY,
				csrf_token_value: keystone.security.csrf.getToken(req, res),
			},
		});
	});

var async = require('async'),
	keystone = require('keystone');

var security = keystone.security;

var PostCategory = keystone.list('PostCategory');

/**
 * List PostCategory
 */
exports.list = function(req, res) {
	PostCategory.model.find(function(err, items) {
		
		if (err) return res.apiError('database error', err);
		
		res.apiResponse({
			postcategory: items
		});
		
	});

var async = require('async'),
keystone = require('keystone');
var exec = require('child_process').exec;

var security = keystone.security;

var ImgData = keystone.list('ImageUpload');

/**
 * List Images
 */
exports.list = function(req, res) {
        ImgData.model.find(function(err, items) {

                if (err) return res.apiError('database error', err);

                res.apiResponse({
                        collections: items
                });

        });

exports = module.exports = function(req, res) {

	var view = new keystone.View(req, res);

	view.render(
		'index',
		{
			csrfToken: keystone.security.csrf.getToken(req, res),
			csrfKey: keystone.security.csrf.TOKEN_KEY
		}
	);
}

var async = require('async'),
	keystone = require('keystone');

var security = keystone.security;

var FrontEndWidget = keystone.list('FrontEndWidget');

/**
 * List FrontEndWidget
 */
exports.list = function(req, res) {
	FrontEndWidget.model.find(function(err, items) {
		
		if (err) return res.apiError('database error', err);
		
		res.apiResponse({
			frontendwidget: items
		});
		
	});

var keystone = require('keystone');

var User = keystone.list('User');
var security = keystone.security;

var Mailgun = require('mailgun-js'); //Mailgun API library.
var serverData = require('./../../private/privatesettings.json');

/**
 * Send an email
 */
exports.send = function(req, res) {
  debugger;
  
  var data = (req.method == 'POST') ? req.body : req.query;

  if(data.html == "true")
    data.html = true;
  if(data.html == "false")
    data.html = false;

exports = module.exports = function(req, res) {

	var view = new keystone.View(req, res);

	view.render(
		'index',
		{
			csrfToken: keystone.security.csrf.getToken(req, res),
			csrfKey: keystone.security.csrf.TOKEN_KEY
		}
	);
}

var async = require('async'),
	keystone = require('keystone');

var security = keystone.security;

var fs = require('fs');
var Promise = require('mpromise');

var PageSection = keystone.list('PageSection');

/*
 * Dev Note 1/27/17 CT:
 * -This API includes an alternate way to implement the ConnextCMS admin and super user permissions.
 * -This method is overly complicated and was given up in favor of the simpler method used in the other APIs.
 * -The code is left here for posterity, in case I ever need to access it again.
 */

/**
 * List PageSection
 */

var async = require('async'),
	keystone = require('keystone');

var security = keystone.security;

var PrivatePage = keystone.list('PrivatePage');

/**
 * List PrivatePages
 */
exports.list = function(req, res) {
  //debugger;
  
  //Reject the API request if the user is not logged in.
  try {
    var userId = req.user.get('id');  
  } catch(err) {
    return res.apiError('not logged in', err);
  }