Best way to persist data locally for a user on a webpage?

I have a search box on the page (webservice-fed results) and I'd like to save the search TERMS for the user in a UL\LI list on the page. So the next time they come back to the page, the resul开发者_运维技巧ts are still there....but if they clear their cache then it gets reset.

What's the best way to go about that?...I can persist between postbacks easily, but this is a new one for me.

Thanks, Steve

Probably use a cookie, but remember you're limited to 4kb of data.

Otherwise, store the session in a database. Then save that records ID to a cookie. That way you can load the data from the database based on the ID in the cookie. Then just flush any entries in DB older than say, 30 days or something.

Due to lack of sleep, I have given you an answer in PHP. Sorry about that, I'll leave it because the information is still correct, just the syntax will be slightly different in asp.net

You have two options for data-persistence in php; cookies and sessions.

Sessions are server-side, and last as long as the browser window stays open.

Cookies are client-side, and last until the user clears their cache.

So it sounds like you want a cookie option. So in your search query processor, add the line

setcookie('search_' . time(), $_POST['search_query'], (time() + 10368000));

This will create a cookie on the client machine, with the name search_xxxx where xxxx is a timestamp (each cookie has to have a unique name otherwise they will overwrite eachother).

The weird looking calculation at the end is an expire time, which is set to 120 days in the future.

Then in your php document that displays your search page, you need to spit out all these cookie values.

foreach($_COOKIES as $k => $v) {
   if(substr($k, 0, 7) == 'search_') echo($v . '<br />');
}

This will spit out each of the search terms found on the clients machine. The if statement is to make sure it only displays search term cookies, and no others.

Use a cookie. Assuming you start with a List<string> of search terms called terms, do:

var sb = new StringBuilder();
foreach (var t in terms) sb.Append(t).Append(";")
var c = new HttpCookie("terms");
c.Value = sb.ToString().TrimEnd(';');
c.Expires = DateTime.Now.AddDays(30);
Response.Cookies.Add(aCookie);

Then when you need to access those terms again (to databind to a Repeater, or process in some other way for display on your page):

if (Request.Cookies["terms"] != null) {
  var terms = new List<string>();
  foreach (var t in Request.Cookies["terms"].Value.Split(';')) list.Add(t);
}

A Cookie is probably your solution for today, but HTML5 localStorage will eventually be the best bet. Only supported by modern browser versions right now, depends on your users.