#pragma warning disable IDE1006 // Naming Styles
/// <summary>
/// Performs operations upon the current request.
/// </summary>
/// <param name="context">The current HTTP request context.</param>
/// <returns>The <see cref="Task"/>.</returns>
public async Task Invoke(HttpContext context)
#pragma warning restore IDE1006 // Naming Styles
{
IDictionary <string, string> commands = this.requestParser.ParseRequestCommands(context);
if (commands.Count > 0)
{
// Strip out any unknown commands.
foreach (string command in new List <string>(commands.Keys))
{
if (!this.knownCommands.Contains(command))
{
commands.Remove(command);
}
}
}
await this.options.OnParseCommandsAsync.Invoke(
new ImageCommandContext(context, commands, this.commandParser, this.parserCulture));
// Get the correct service for the request.
IImageProvider provider = null;
foreach (IImageProvider resolver in this.providers)
{
if (resolver.Match(context))
{
provider = resolver;
break;
}
}
if ((commands.Count == 0 && provider?.ProcessingBehavior != ProcessingBehavior.All) ||
provider?.IsValidRequest(context) != true)
{
// Nothing to do. call the next delegate/middleware in the pipeline
await this.next(context);
return;
}
IImageResolver sourceImageResolver = await provider.GetAsync(context);
if (sourceImageResolver is null)
{
// Log the error but let the pipeline handle the 404
// by calling the next delegate/middleware in the pipeline.
var imageContext = new ImageContext(context, this.options);
this.logger.LogImageResolveFailed(imageContext.GetDisplayUrl());
await this.next(context);
return;
}
await this.ProcessRequestAsync(
context,
sourceImageResolver,
new ImageContext(context, this.options),
commands);
}
#pragma warning disable IDE1006 // Naming Styles
/// <summary>
/// Performs operations upon the current request.
/// </summary>
/// <param name="context">The current HTTP request context.</param>
/// <returns>The <see cref="Task"/>.</returns>
public async Task Invoke(HttpContext context)
#pragma warning restore IDE1006 // Naming Styles
{
IDictionary <string, string> commands = this.requestParser.ParseRequestCommands(context);
if (commands.Count > 0)
{
List <string> commandKeys = new List <string>(commands.Keys);
foreach (string command in commandKeys)
{
if (!this.knownCommands.Contains(command))
{
commands.Remove(command);
}
}
}
this.options.OnParseCommands?.Invoke(new ImageCommandContext(context, commands, CommandParser.Instance));
if (commands.Count == 0)
{
// Nothing to do. call the next delegate/middleware in the pipeline
await this.next(context).ConfigureAwait(false);
return;
}
// Get the correct service for the request.
IImageProvider provider = null;
foreach (IImageProvider resolver in this.providers)
{
if (resolver.Match(context))
{
provider = resolver;
break;
}
}
if (provider?.IsValidRequest(context) != true)
{
// Nothing to do. call the next delegate/middleware in the pipeline
await this.next(context).ConfigureAwait(false);
return;
}
bool processRequest = true;
IImageResolver sourceImageResolver = await provider.GetAsync(context).ConfigureAwait(false);
if (sourceImageResolver == null)
{
// Log the error but let the pipeline handle the 404
var imageContext = new ImageContext(context, this.options);
this.logger.LogImageResolveFailed(imageContext.GetDisplayUrl());
processRequest = false;
}
if (!processRequest)
{
// Call the next delegate/middleware in the pipeline
await this.next(context).ConfigureAwait(false);
return;
}
await this.ProcessRequestAsync(context, processRequest, sourceImageResolver, new ImageContext(context, this.options), commands)
.ConfigureAwait(false);
}
/// <summary>
/// Performs operations upon the current request.
/// </summary>
/// <param name="context">The current HTTP request context.</param>
/// <returns>The <see cref="Task"/>.</returns>
public async Task Invoke(HttpContext context)
{
IDictionary <string, string> commands = this.requestParser.ParseRequestCommands(context)
.Where(kvp => this.knownCommands.Contains(kvp.Key))
.ToDictionary(p => p.Key, p => p.Value);
this.options.OnParseCommands?.Invoke(new ImageCommandContext(context, commands, CommandParser.Instance));
// Get the correct service for the request.
IImageProvider provider = this.resolvers.FirstOrDefault(r => r.Match(context));
if (provider?.IsValidRequest(context) != true)
{
// Nothing to do. call the next delegate/middleware in the pipeline
await this.next(context).ConfigureAwait(false);
return;
}
// Create a cache key based on all the components of the requested url
string uri = GetUri(context, commands);
string key = this.cacheHash.Create(uri, this.options.CachedNameLength);
bool processRequest = true;
var imageContext = new ImageContext(context, this.options);
IImageResolver sourceImageResolver = await provider.GetAsync(context).ConfigureAwait(false);
if (sourceImageResolver == null)
{
// Log the error but let the pipeline handle the 404
this.logger.LogImageResolveFailed(imageContext.GetDisplayUrl());
processRequest = false;
}
ImageMetaData sourceImageMetadata = default;
if (processRequest)
{
// Lock any reads when a write is being done for the same key to prevent potential file locks.
using (await AsyncLock.ReaderLockAsync(key).ConfigureAwait(false))
{
// Check to see if the cache contains this image
sourceImageMetadata = await sourceImageResolver.GetMetaDataAsync().ConfigureAwait(false);
IImageResolver cachedImageResolver = await this.cache.GetAsync(key).ConfigureAwait(false);
if (cachedImageResolver != null)
{
ImageMetaData cachedImageMetadata = await cachedImageResolver.GetMetaDataAsync().ConfigureAwait(false);
if (cachedImageMetadata != default)
{
// Has the cached image expired or has the source image been updated?
if (cachedImageMetadata.LastWriteTimeUtc > sourceImageMetadata.LastWriteTimeUtc &&
cachedImageMetadata.LastWriteTimeUtc > DateTimeOffset.Now.AddDays(-this.options.MaxCacheDays))
{
// We're pulling the image from the cache.
using (Stream cachedBuffer = await cachedImageResolver.OpenReadAsync().ConfigureAwait(false))
{
await this.SendResponse(imageContext, key, cachedBuffer, cachedImageMetadata).ConfigureAwait(false);
}
return;
}
}
}
}
// Not cached? Let's get it from the image resolver.
ChunkedMemoryStream outStream = null;
try
{
if (processRequest)
{
// Enter a write lock which locks writing and any reads for the same request.
// This reduces the overheads of unnecessary processing plus avoids file locks.
using (await AsyncLock.WriterLockAsync(key).ConfigureAwait(false))
{
// No allocations here for inStream since we are passing the raw input stream.
// outStream allocation depends on the memory allocator used.
ImageMetaData cachedImageMetadata = default;
outStream = new ChunkedMemoryStream(this.memoryAllocator);
using (Stream inStream = await sourceImageResolver.OpenReadAsync().ConfigureAwait(false))
using (var image = FormattedImage.Load(this.options.Configuration, inStream))
{
image.Process(this.logger, this.processors, commands);
this.options.OnBeforeSave?.Invoke(image);
image.Save(outStream);
// Check to see if the source metadata has a cachecontrol max-age value and use it to
// override the default max age from our options.
var maxAge = TimeSpan.FromDays(this.options.MaxBrowserCacheDays);
if (!sourceImageMetadata.CacheControlMaxAge.Equals(TimeSpan.MinValue))
{
maxAge = sourceImageMetadata.CacheControlMaxAge;
}
cachedImageMetadata = new ImageMetaData(DateTime.UtcNow, image.Format.DefaultMimeType, maxAge);
}
// Allow for any further optimization of the image. Always reset the position just in case.
outStream.Position = 0;
string contentType = cachedImageMetadata.ContentType;
string extension = this.formatUtilities.GetExtensionFromContentType(contentType);
this.options.OnProcessed?.Invoke(new ImageProcessingContext(context, outStream, commands, contentType, extension));
outStream.Position = 0;
// Save the image to the cache and send the response to the caller.
await this.cache.SetAsync(key, outStream, cachedImageMetadata).ConfigureAwait(false);
await this.SendResponse(imageContext, key, outStream, cachedImageMetadata).ConfigureAwait(false);
}
}
}
catch (Exception ex)
{
// Log the error internally then rethrow.
// We don't call next here, the pipeline will automatically handle it
this.logger.LogImageProcessingFailed(imageContext.GetDisplayUrl(), ex);
throw;
}
finally
{
outStream?.Dispose();
}
}
if (!processRequest)
{
// Call the next delegate/middleware in the pipeline
await this.next(context).ConfigureAwait(false);
}
}