is it possible to value store cookies in Flash or Flex?

Question

In PHP there is a setcookie function based to store it. In Flash is it possible ?. If it is possible then how? I want to store value.

Answer 1

First off: PHP runs on the server and therefore can send the necessary HTTP header to set a cookie, Flash runs in the client's browser and thus can not do the same.

However, there is a way to access and store cookies from flash/flex by using the flash.external.ExternalInterface and calling JavaScript functions to get and set cookies.

I've developed a class for doing this very easily:

package de.slashslash.util {

    import flash.external.ExternalInterface;

    /**
     * The Cookie class provides a simple way to create or access
     * cookies in the embedding HTML document of the application.
     * 
     */
    public class Cookie {

        /**
         * Flag if the class was properly initialized.
         */
        private static var _initialized:Boolean = false;

        /**
         * Name of the cookie.
         */
        private var _name:String;

        /**
         * Contents of the cookie.
         */
        private var _value:String;

        /**
         * Flag indicating if a cookie was just created. It is <code>true</code>
         * when the cookie did not exist before and <code>false</code> otherwise.
         */
        private var _isNew:Boolean;

        /**
         * Name of the external javascript function used for getting
         * cookie information.
         */
        private static const GET_COOKIE:String = "cookieGetCookie";

        /**
         * Name of the external javascript function used for setting
         * cookie information.
         */
        private static const SET_COOKIE:String = "cookieSetCookie";

        /**
         * Javascript code to define the GET_COOKIE function.
         */
        private static var FUNCTION_GET_COOKIE:String =
            "function () { " +
                "if (document." + GET_COOKIE + " == null) {" +
                    GET_COOKIE + " = function (name) { " + 
                        "if (document.cookie) {" + 
                            "cookies = document.cookie.split('; ');" + 
                            "for (i = 0; i < cookies.length; i++) {" + 
                                "param = cookies[i].split('=', 2);" + 
                                "if (decodeURIComponent(param[0]) == name) {" + 
                                    "value = decodeURIComponent(param[1]);" + 
                                    "return value;" + 
                                "}" + 
                            "}" + 
                        "}" + 
                        "return null;" + 
                    "};" +
                "}" +
            "}";

        /**
         * Javascript code to define the SET_COOKIE function.
         */
        private static var FUNCTION_SET_COOKIE:String =
            "function () { " +
                "if (document." + SET_COOKIE + " == null) {" +
                    SET_COOKIE + " = function (name, value) { " + 
                        "document.cookie = name + '=' + value;" + 
                    "};" +
                "}" +
            "}";

        /**
         * Initializes the class by injecting javascript code into
         * the embedding document. If the class was already initialized
         * before, this method does nothing.
         */
        private static function initialize():void {
            if (Cookie._initialized) {
                return;
            }

            if (!ExternalInterface.available) {
                throw new Error("ExternalInterface is not available in this container. Internet Explorer ActiveX, Firefox, Mozilla 1.7.5 and greater, or other browsers that support NPRuntime are required.");
            }

            // Add functions to DOM if they aren't already there
            ExternalInterface.call(FUNCTION_GET_COOKIE);
            ExternalInterface.call(FUNCTION_SET_COOKIE);

            Cookie._initialized = true;
        }

        /**
         * Creates a new Cookie object. If a cookie with the specified
         * name already exists, the existing value is used. Otherwise
         * a new cookie is created as soon as a value is assigned to it.
         * 
         * @param name The name of the cookie
         */
        public function Cookie(name:String) {
            Cookie.initialize();

            this._name = name;
            this._value = ExternalInterface.call(GET_COOKIE, name) as String;

            this._isNew = this._value == null;
        }

        /**
         * The name of the cookie.
         */
        public function get name():String {
            return this._name;
        }

        /**
         * The value of the cookie. If it is a new cookie, it is not
         * made persistent until a value is assigned to it.
         */
        public function get value():String {
            return this._value;
        }

        /**
         * @private
         */
        public function set value(value:String):void {
            this._value = value;

            ExternalInterface.call(SET_COOKIE, this._name, this._value);
        }

        /**
         * The <code>isNew</code> property indicates if the cookie
         * already exists or not.
         */
        public function get isNew():Boolean {
            return this._isNew;
        }
    }
}

Answer 2

Yes. Flash applications can store up to 100kb of data (by default) on a user's computer. This is stored in Flash cookies (Separate from browser cookies). Users can adjust how much applications can store by right clicking on a flash application and going to settings.

Here is the SharedObject API for AS3: http://livedocs.adobe.com/flash/9.0/ActionScriptLangRefV3/flash/net/SharedObject.html

You can get more info by googling "Flash SharedObject"

Make sure to be prepared to handle cases where a user does not let you put data into SharedObjects. This is becoming a popular trend among tech-savy users that are concerned about their privacy.

Good luck!

Answer 3

for an actual code example:

import flash.net.SharedObject;

// get/create the shared object with a unique name.
// If the shared object exists this grab it, if not
// then it will create a new one
var so: SharedObject = SharedObject.getLocal("UniqueName");

// the shared object has a propery named data, it's
// an object on which you can create, read, or modify
// properties (you can't set the data property itself!)
// you can check to see if it already has something set
// using hasOwnProperty, so we'll check if it has a var
// use it if it does, or set it to a default if it doesn't
if (so.data.hasOwnProperty("theProp"))
{
    trace("already has data! It reads: " + so.data.theProp);
}
else
{
    so.data.theProp = "default value";
    so.flush(); // flush saves the data
    trace("It didn't have a value, so we set it.");
}

Paste this in flash, publish it twice and see how it stored the data :)