Hi!

I have read (at aspfaq.com amongst others) that it's not recommended to
store objects in ASP application variables. However, they seem to be
refering to COM-objects, not JScript Object()s.

I want to cache some data (to avoid having to read it from a datafile or
database everytime a page is accesses) in a JScript object (or an array of
objects). Is it safe and/or good practice to do so? It's only a few KBs...

Best regards
Tomas Eklund, Sweden

IIRC, JScript objects won't go into application or session scope.
someone should confirm or deny this for me, but I believe they don't
have the correct threading model. Put it this way, I never do it.

function String.prototype.r(){// Javascript rot13 en/decipherment. run
me for Atrax's signature
        var a='nopqrstuvwxyz';var b='abcdefghijklm';var j='/:.'+a+b;var
k='/:.'+b+a;var l='';
        for(var
x=0;x<this.length;x++){l+=k.charAt(j.indexOf(this.charAt(x)));}return l;

2002.

*** Sent via Developersdex http://www.developersdex.com ***
Don't just participate in USENET...get rewarded for it!

That's a major disappointment...

So, the workaround would be to convert JScript arrays to strings using the
join method before storing them in application variables, and then split
them when needed? Or would it be better to build a lot of application
variables, where each array item goes into one application variable? Or are
there even better chaching alternatives? Perhaps generating an include file
with the neccesary code to regenerate the data structure?

I must also mention that I have some very complex data structures that I
would like to chache. For example a tree data structure with arrays of
objects containinig arrays of objects containing arrays of ...

Comments on this, please?

Best regards
Tomas Eklund, Sweden

P.S. This is how I mean:

If I have a simple array of objects like:

    aTest[1].header = '<h1>Hello application</h1>';
    aTest[1].body = '<p>This is a test.</p>';
    aTest[1].image = '/images/test.gif';
    aTest[1].number = 5;
    aText[2].header = '<h1>Will this work?</h1>';
    ... etc

I could either store them in one big application variable like this

    // build a long joined string of the entire array
    // must be splitted i two steps afterwards
    // data must not contain the separator characters
    var aTemp = new Array();
    for ( i in aTest )
    {
        aTemp[i] = "";
        for ( j in aTest[i] )
        {
            aTemp[i] += aTest[i][j] + "|";
        }
        aTemp[i] = aTemp[i].slice(0,-1);
    }
    Application("aTest") = aTemp.join("");

Or in several smalll application variables like this

    // making many small application variables
    // of course one must add a few metadata variables as well
    // not doing that here
    for ( i in aTest )
        for ( j in aTest[i] )
            Application('aTest['+i+'].'+j) = aTest[i][j];

Or I could skip application variables alltogether and generate an include
file vith JScript code that regenerates the data structure. Of course, this
would be a challenging task if not done at the same point as where the
original data structure is built. The generated include file would looke
something like this (using the simple example above):

<%
    var aTest = new Array();
    aTest[1].header = '<h1>Hello application</h1>';
    aTest[1].body = '<p>This is a test.</p>';
    aTest[1].image = '/images/test.gif';
    aTest[1].number = 5;
    aText[2].header = '<h1>Will this work?</h1>';
    ... etc
%>

Hi

Thats what I usually do ( Store arrays as string and re-create )
but I try to avoid doing this...
If this data does not change that much just use an include else
stick with the DB... perhaps re-create the include when the DB gets updated

--
Best Regards
  Vidar Petursson
 ==============================
Microsoft Internet Client & Controls MVP
 ==============================
 http://www.icysoft.com/


 ==============================
  No matter where you go there you are
 ==============================

Actually, you *can* persist simple JScript arrays and objects at session level.  It works for data only.  You can't call methods on a array or an object (if it had defined methods) retrieved from the Session collection.

<html>
<body>
<script runat=server language="jscript">
var myarr = Session("myarr");
var myobj = Session("myobj");
if(!myarr){
  Session("myarr") = new Array("a","b","c");
  var o = new Object();
  o.name = "my name";
  o.foobar = "my foobar property";
  Session("myobj") = o;
  Response.Write("myarr/myobj saved. refresh the page to see them.");

  for(var i in myarr){
    Response.Write(i+"="+myarr[i]+"<br>");
  }
  for(var x in myobj){
    Response.Write(x+"="+myobj[x]+"<br>");
  }
  // the following would throw a catastrophic error ;-)...
  // sortedarr = myarr.sort();
</script>
</body>
</html>

--
Michael Harris
Microsoft.MVP.Scripting
Seattle WA US

But it only works for session variables, right? I can't get it to work with
application variables... It is really a shame. I only want to cache small
amounts of data (but a pretty complex structure that takes some time to query
and construct)... Now, I can't

Best regards
Tomas Eklund, Sweden

Michael Harris (MVP) wrote