Is there a Session-unique identifier that can be used as a cache key name?-CodePudding

I'm porting a legacy ASP.NET WebForms app to Razor. It had stored an object in the Session collection. Session storage is now limited to byte[] or string. One technique is to serialize objects and store as a string, but there are caveats. Another article suggested using one of the alternative caching options, so I'm trying to use MemoryCache.

For this to work as a Session replacement, I need a key name that's unique to the user and their session.

I thought I'd use Session.Id for this, like so:

ObjectCache _cache = System.Runtime.Caching.MemoryCache.Default;

string _keyName = HttpContext.Session.Id   "$searchResults";

//(PROBLEM: Session.Id changes per refresh)


//hit a database for set of un-paged results
List<Foo> results = GetSearchResults(query);

if (results.Count > 0)
{
    //add to cache
    _cache.Set(_keyName, results, DateTimeOffset.Now.AddMinutes(20));

    BindResults();
}


//Called from multiple places, wish to use cached copy of results
private void BindResults()
{
    CacheItem cacheItem = _cache.GetCacheItem(_keyName);

    if (cacheItem != null) //in cache
    {
        List<Foo> results = (List<Foo>)cacheItem.Value;

        DrawResults(results);
    }
}

...but when testing, I see any browser refresh, or page link click, generates a new Session.Id. That's problematic.

Is there another built-in property somewhere I can use to identify the user's session and use for this key name purpose? One that will stay static through browser refreshes and clicks within the web app?

Thanks!

CodePudding user response：

The answer Yiyi You linked to explains it -- the Session.Id won't be static until you first put something into the Session collection. Like so:

HttpContext.Session.Set("Foo", new byte[] { 1, 2, 3, 4, 5 });

_keyName = HttpContext.Session.Id   "_searchResults";

ASP.NET Core: Session Id Always Changes