/// <inheritdoc />
public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
{
var key = GenerateKey(context);
TagHelperContent result;
if (!MemoryCache.TryGetValue(key, out result))
{
// Create an EntryLink and flow it so that it is accessible via the ambient EntryLinkHelpers.ContentLink
// for user code.
var entryLink = new EntryLink();
using (entryLink.FlowContext())
{
result = await context.GetChildContentAsync();
}
MemoryCache.Set(key, cacheSetContext =>
{
UpdateCacheContext(cacheSetContext, entryLink);
return result;
});
}
// Clear the contents of the "cache" element since we don't want to render it.
output.SuppressOutput();
output.Content.SetContent(result);
}
public void Main()
{
IMemoryCache cache = new MemoryCache(new MemoryCacheOptions());
object result;
string key = "Key";
object newObject = new object();
object state = new object();
// Basic CRUD operations:
// Create / Overwrite
result = cache.Set(key, newObject);
result = cache.Set(key, context => new object());
result = cache.Set(key, state, context => new object());
// Retrieve, null if not found
result = cache.Get(key);
// Retrieve
bool found = cache.TryGetValue(key, out result);
// Delete
cache.Remove(key);
// Conditional operations:
// Retrieve / Create when we want to lazily create the object.
result = cache.GetOrSet(key, context => new object());
// Retrieve / Create when we want to lazily create the object.
result = cache.GetOrSet(key, state, context => new object());
// Cache entry configuration:
// Stays in the cache as long as possible
result = cache.GetOrSet(key, state, context =>
{
context.SetPriority(CachePreservationPriority.NeverRemove);
return new object();
});
// Automatically remove if not accessed in the given time
result = cache.GetOrSet(key, state, context =>
{
context.SetSlidingExpiration(TimeSpan.FromMinutes(5));
return new object();
});
// Automatically remove at a certain time
result = cache.GetOrSet(key, state, context =>
{
context.SetAbsoluteExpiration(new DateTime(2014, 12, 31));
// or relative:
// context.SetAbsoluteExpiration(TimeSpan.FromMinutes(5));
return new object();
});
// Automatically remove if not accessed in the given time
// Automatically remove at a certain time (if it lives that long)
result = cache.GetOrSet(key, state, context =>
{
context.SetSlidingExpiration(TimeSpan.FromMinutes(5));
context.SetAbsoluteExpiration(new DateTime(2014, 12, 31));
// or relative:
// context.SetAbsoluteExpiration(TimeSpan.FromMinutes(5));
return new object();
});
// Callback when evicted
result = cache.GetOrSet(key, state, context =>
{
context.RegisterPostEvictionCallback((echoKey, value, reason, substate) =>
Console.WriteLine(echoKey + ": '" + value + "' was evicted due to " + reason), state: null);
return new object();
});
// Remove on trigger
var cts = new CancellationTokenSource();
result = cache.GetOrSet(key, state, context =>
{
context.AddExpirationTrigger(new CancellationTokenTrigger(cts.Token));
return new object();
});
result = cache.GetOrSet(key, context =>
{
var link = new EntryLink();
var inner1 = cache.GetOrSet("subkey1", link, subContext =>
{
return "SubValue1";
});
string inner2;
using (link.FlowContext())
{
inner2 = cache.GetOrSet("subkey2", subContext =>
{
return "SubValue2";
});
}
context.AddEntryLink(link);
return inner1 + inner2;
});
}