[Help wanted] Update expiration date

[seyfeb]

Is there a way to update expiration dates of existing cached items, preferably without reading the object from a disk cache into memory and rewriting it back to the disk (think of large data objects)?

Use case: I query the server for updates of the object and get a NotModified response, so I simply want to update the expiration date of the already cached item.

[Sewer56]

I'm surprised this (overwriting expiration time) isn't a feature of Akavache personally.

There's some good use cases for this, as you can effectively set up a maximum lifetime for a given object but keep extending it for as long as you need it.

In my case, for example, I can determine I can keep an object for longer from a result of another API call; getting and then re-inserting it sounds silly and inefficient.

In any case, you can use a raw SQL query in the meantime; it's the only reflection-free method I can think of:

/// <summary>
/// Refreshes the expiration date of a given key.
/// </summary>
/// <param name="key">The key to be refreshed.</param>
/// <param name="newExpiration">New timespam of expiration relative to current.</param>
public void Refresh(string key, TimeSpan newExpiration)
{
    var expiration = _cache.Scheduler.Now + newExpiration;
    _cache.Connection.Execute($"UPDATE CacheElement SET Expiration='{expiration.Ticks}' WHERE Key='{key}'");
}

[anaisbetts]

This would be a good feature to add

[cristhian-zarate]

I would like to add a use case. Similar to @Sewer56, I need to refresh the TTL of records when being accessed, but assign them the same expiration period they had before. Unfortunately, I haven't been able to find a workaround while using the BlobCache.Secure location, because it does not expose the Connection property. (I opened a discussion thread asking if there is a way to find the expiration of a record when using BlobCache.Secure) So, for me it would be useful to have a method like GetObjectAndRefresh<T>(string) and not have to potentially look up the Expiration of a record while reading its value and then inserting the record with its TTL again.