Manipulating Cookies in Flash via ASP
Written by: Günter Hoffellner
Setting or reading cookies in Flash may be necessary for example to extend the personalization of a web site to the Flash file.
The Flash File
In the following the Flash file which can read and set cookies at the client is described. The file calls the ASP Scripts testCookies.asp, setCookies.asp and getCookies.asp to gain access to the browser's cookies via ASP.
The Flash file tests for the permission to set client side cookies and allows entering data that is to be stored in a cookie. The file also reads the cookie content and displays it on screen.
There are two files in the download: one .fla in English, and a second one in German. The compiled .swf is available in German only.
The User Interface
The user interface is divided into three parts which are described in the following sections.
The user clicks the 'START TEST' button to trigger the test on the server to determine whether the browser of the page visitor accepts cookies. The status message indicates whether the browser accepts cookies or not.
In the case of cookies being accepted, the Flash movie runs on to the second part and waits for data to be saved in a cookie. With a click on the 'SEND DATA' button, the data is transmitted to the server.
In the last part, the server passes the cookie data back to the Flash file where they are written into the text fields.
The Scripts of the Flash File
The graphic part of the Flash file is built according to standard procedure and is not described in detail for this reason.
The layer with the name 'Sourcecode' is important, as this contains the source code of the Flash file. We will go into the details of this now.
//Frame 1 Set Variable: "cookies" = "false" stop
The variable 'cookies' is initialised with the string 'false'. 'false' is used as the server does not return the boolean values true and false, but a string with the value of "true" or "false". Flash waits for the button click for starting the cookie test.
//Frame 2, Label step1 Load Variables ("/testcookies.asp", 0)
The file 'testcookies.asp' is called and returns 'true' or 'false' (Cookies accepted - Cookies not accepted).
//Frame10 If (cookies eq "true") Set Variable: "cookietest" = "Cookies can be set" Stop Else Set Variable: "cookietest" = "Cookies not allowed. Please enable." Go to and Stop ("nocookies") End If
In Frame 10 a different message is displayed in the status field depending on the result of the cookie test.
If cookies are not accepted, Flash jumps to the label 'nocookies', stops there and will not accept any input but another cookie test. In the if-condition cookies eq "true" is set in quotes as the server does not really return the boolean values of true or false, but a string which is immediately tested as such. Also note that the string comparison requires 'eq' instead of '='.
The 'stop' command forces Flash to wait for a click event of the 'SEND DATA' button. Sending the cookie data to the server happens as follows:
//Frame11, Label step2 Load Variables ("/setcookies.asp?cookiename="&name&"&"& "cookiemail="&email&"&"&"cookietelephone="&telephone, 0)
In this script, a query string containing the user entries is sent to the file ' setcookies.asp'. For the composition of the query string, refer to the article 'Data Exchange between ASP and Flash' (German only).
//Frame19, Label step3 Load Variables ("/getcookies.asp", 0)
The data read from a cookie by ASP is loaded into the Flash file.
//Frame 28 Stop
The loaded data is displayed in the text fields after a short animation of a line.
//Frame 35, Label nocookies stop
If the test in frame 10 determines that no cookies are allowed, the Flash time line branches to this frame and the user has the opportunity to perform another test.
The Scripts of the ASP files
The 3 files testcookies.asp, setcookies.asp and getcookies.asp are called by Flash for the following actions: Checking whether the browser accepts cookies (testcookies.asp), setting cookies (setcookies.asp), reading cookies(getcookies.asp).
Checking whether the browser accepts cookies
The file testcookies.asp checks whether the browser permits cookies. The technique is the same as in the article "Simple Browser Cookie Test" (German only). The variation of this script used here is as follows:
<% strTest = Request.QueryString("CookieTest") If UCase(strTest) <> Ucase("true") Then ' First call ' Set session variable Session("__FlashCookieTest") = True ' Redirect with QueryString strURL = Request.ServerVariables("SCRIPT_NAME") strQueryString = "?CookieTest=true" Response.Redirect(strURL & strQueryString) Response.End Else ' Redirect already happened ' Check whether the session variable contains the value If Session("__FlashCookieTest") = True Then ' Session variable contains value ' Thus browser accepts cookies strOut = "Cookies=true" Else ' Session variable is empty ' Thus browser does not accept cookies strOut = "Cookies=false" End If End If ' Output to Flash: Response.Write(strOut) %>
Simply put, the script sets a session variable, performs a redirect onto itself and then checks whether the value still is set in the session variable. For this value to stay saved, the browser must have accepted the session cookie of the Internet Information Server (IIS) which is automatically sent to the browser by ASP. This means that the browser accepts cookies when the value in the session variable is still present after a redirect.
The file returns the text 'Cookies=true' if the browser accepts cookies or 'Cookies=false' if the browser does not accept cookies.
When Flash calls the file testcookies.asp via the Flash command Load Variables, the ASP file returns either the string "Cookies=true" or "Cookies=false" to the Flash file which automatically sets the variable Cookies to "true" or "false" in Flash.
In ASP, cookies can be set easily using the Response.Cookies collection. In our example, the Flash file calls the file setcookies.asp and passes the variables for the cookies (names and values) in the Querystring to the ASP Script.
The ASP Script reads all values out of the Querystring collection sends the corresponding cookies via Response.Cookies to the browser. The complete ASP script consists of only three lines:
<% For each item in Request.QueryString Response.Cookies(item) = Request.Querystring(item) Next %>
Reading the cookies and writing them to the Flash File is about as easy as setting the cookies. When the Flash file calls the file getcookies.asp, it returns all the names and values of the cookies as URL-encoded text. This way, the values of the cookes are written to variables of the same names in Flash when Flash calls the filegetcookies.asp.
The ASP file getcookies.asp is as follows:
<% For each cookie in Request.Cookies strOut = strOut & Server.URLEncode(cookie) & "=" strOut = strOut & Server.URLEncode(Request.Cookies(cookie)) strOut = strOut & "&" Next Response.Write strOut %>
The Flash based part of this article was created using Flash 4. The systematics are the same for the newly published Version 5 of the Macromedia software.
The ASP part runs on IIS 4.0 as well as on IIS 5.0 and with slight modifications also under ASP.NET.
After having described setting and reading of cookies in Flash in conjunction with ASP in this article, one of the next articles will further develop this by using the present base for simple personalization of a Flash file using cookies.
Downloading the Code
Click here to start the download.