/// <summary>
/// Gets the <see cref="CachedImage"/> associated with the specified key.
/// </summary>
/// <param name="cachedPath">
/// The cached path of the value to get.
/// </param>
/// <returns>
/// The <see cref="CachedImage"/> matching the given key if the <see cref="CacheIndexer"/> contains an element with
/// the specified key; otherwise, null.
/// </returns>
public static CachedImage GetValue(string cachedPath)
{
string key = Path.GetFileNameWithoutExtension(cachedPath);
CachedImage cachedImage = (CachedImage)MemCache.GetItem(key);
if (cachedImage == null)
{
// FileInfo is thread safe.
FileInfo fileInfo = new FileInfo(cachedPath);
if (!fileInfo.Exists)
{
return(null);
}
// Pull the latest info.
fileInfo.Refresh();
cachedImage = new CachedImage
{
Key = Path.GetFileNameWithoutExtension(cachedPath),
Path = cachedPath,
CreationTimeUtc = fileInfo.CreationTimeUtc
};
Add(cachedImage);
}
return(cachedImage);
}
/// <summary>
/// Gets the <see cref="CachedImage"/> associated with the specified key.
/// </summary>
/// <param name="cachedPath">
/// The cached path of the value to get.
/// </param>
/// <returns>
/// The <see cref="CachedImage"/> matching the given key if the <see cref="CacheIndexer"/> contains an element with
/// the specified key; otherwise, null.
/// </returns>
public static CachedImage Get(string cachedPath)
{
string key = Path.GetFileNameWithoutExtension(cachedPath);
CachedImage cachedImage = (CachedImage)MemCache.GetItem(key);
return(cachedImage);
}
/// <summary>
/// Adds the specified key and value to the dictionary or returns the value if it exists.
/// </summary>
/// <param name="cachedImage">
/// The cached image to add.
/// </param>
/// <returns>
/// The value of the item to add or get.
/// </returns>
public static CachedImage Add(CachedImage cachedImage)
{
// Add the CachedImage.
CacheItemPolicy policy = new CacheItemPolicy();
policy.ChangeMonitors.Add(new HostFileChangeMonitor(new List <string> {
cachedImage.Path
}));
MemCache.AddItem(cachedImage.Key, cachedImage, policy);
return(cachedImage);
}
/// <summary>
/// Gets the <see cref="CachedImage"/> associated with the specified key.
/// </summary>
/// <param name="cachedPath">
/// The cached path of the value to get.
/// </param>
/// <returns>
/// The <see cref="CachedImage"/> matching the given key if the <see cref="CacheIndexer"/> contains an element with
/// the specified key; otherwise, null.
/// </returns>
public static async Task <CachedImage> GetValueAsync(string cachedPath)
{
string key = Path.GetFileNameWithoutExtension(cachedPath);
CachedImage cachedImage = (CachedImage)MemCache.GetItem(key);
if (cachedImage == null)
{
cachedImage = await TaskHelpers.Run(() => GetCachedImage(cachedPath));
if (cachedImage != null)
{
Add(cachedImage);
}
}
return(cachedImage);
}
/// <summary>
/// Adds a <see cref="CachedImage"/> to the cache.
/// </summary>
/// <param name="cachedImage">
/// The cached image to add.
/// </param>
/// <param name="expiration">
/// A <see cref="TimeSpan"/> defining the sliding expiration duration, defaults to zero
/// </param>
/// <returns>
/// The value of the item to add or get.
/// </returns>
public static CachedImage Add(CachedImage cachedImage, TimeSpan expiration = default(TimeSpan))
{
if (expiration == default(TimeSpan) || expiration == TimeSpan.Zero)
{
expiration = new TimeSpan(0, 1, 0);
}
// Add the CachedImage with a sliding expiration of `expiry` minutes.
var policy = new CacheItemPolicy {
SlidingExpiration = expiration
};
if (new Uri(cachedImage.Path).IsFile)
{
if (ImageProcessorConfiguration.Instance.UseFileChangeMonitors)
{
// When adding a file to monitor this increases the number of files that ASP.Net will actively monitoring
// which directly relates to FCN in ASP.Net. If there are too many monitors then the FCN buffer could overflow
// resulting in ASP.Net app domain restarts.
// If change monitoring is enabled, we should only monitor the folder, not every individual file. This will
// reduce the amount of file monitors, however since there are still a lot of folders generated by IP this number could
// still be rather large.
// Further to this is that by default ASP.Net will actively monitor these paths anyways so by creating a file change monitor
// here and the IP cache is within the web root, there will most likely be duplicate file change monitors created.
// If we want to add a monitor per file:
policy.ChangeMonitors.Add(new HostFileChangeMonitor(new List <string> {
cachedImage.Path
}));
// If we want to add a monitor per folder, we'd need to create our own implementation of `FileChangeMonitor` (i.e. DirectoryChangeMonitor)
// to pass in a folder to be watched and override the correct members
// policy.ChangeMonitors.Add(new DirectoryChangeMonitor(new List<string> { Path.GetDirectoryName(cachedImage.Path) }));
}
MemCache.AddItem(Path.GetFileNameWithoutExtension(cachedImage.Key), cachedImage, policy);
}
else
{
MemCache.AddItem(Path.GetFileNameWithoutExtension(cachedImage.Key), cachedImage, policy);
}
return(cachedImage);
}
/// <summary>
/// Adds the specified key and value to the dictionary or returns the value if it exists.
/// </summary>
/// <param name="cachedImage">
/// The cached image to add.
/// </param>
/// <returns>
/// The value of the item to add or get.
/// </returns>
public static CachedImage Add(CachedImage cachedImage)
{
// Add the CachedImage with a sliding expiration of 10 minutes.
CacheItemPolicy policy = new CacheItemPolicy {
SlidingExpiration = new TimeSpan(0, 10, 0)
};
if (new Uri(cachedImage.Path).IsFile)
{
policy.ChangeMonitors.Add(new HostFileChangeMonitor(new List <string> {
cachedImage.Path
}));
MemCache.AddItem(Path.GetFileNameWithoutExtension(cachedImage.Key), cachedImage, policy);
}
else
{
MemCache.AddItem(Path.GetFileNameWithoutExtension(cachedImage.Key), cachedImage, policy);
}
return(cachedImage);
}
/// <summary>
/// Removes the value associated with the specified key.
/// </summary>
/// <param name="cachedPath">
/// The key of the item to remove.
/// </param>
/// <returns>
/// true if the <see cref="CacheIndexer"/> removes an element with
/// the specified key; otherwise, false.
/// </returns>
public static bool Remove(string cachedPath)
{
string key = Path.GetFileNameWithoutExtension(cachedPath);
return(MemCache.RemoveItem(key));
}
