private async Task ProcessWithNoCache(HttpContext context, ImageJobInfo info)
{
// If we're not caching, we should always use the modified date from source blobs as part of the etag
var betterCacheKey = await info.GetExactCacheKey();
if (context.Request.Headers.TryGetValue(HeaderNames.IfNoneMatch, out var etag) && betterCacheKey == etag)
{
context.Response.StatusCode = StatusCodes.Status304NotModified;
context.Response.ContentLength = 0;
context.Response.ContentType = null;
return;
}
if (info.HasParams)
{
logger?.LogInformation($"Processing image {info.FinalVirtualPath} with params {info.CommandString}");
var imageData = await info.ProcessUncached();
var imageBytes = imageData.ResultBytes;
var contentType = imageData.ContentType;
// write to stream
context.Response.ContentType = contentType;
context.Response.ContentLength = imageBytes.Count;
SetCachingHeaders(context, betterCacheKey);
await context.Response.Body.WriteAsync(imageBytes.Array, imageBytes.Offset, imageBytes.Count);
}
else
{
logger?.LogInformation($"Proxying image {info.FinalVirtualPath} with params {info.CommandString}");
var contentType = PathHelpers.ContentTypeForImageExtension(info.EstimatedFileExtension);
await using var sourceStream = (await info.GetPrimaryBlob()).OpenRead();
if (sourceStream.CanSeek)
{
if (sourceStream.Length == 0)
{
throw new InvalidOperationException("Source blob has zero bytes.");
}
context.Response.ContentType = contentType;
context.Response.ContentLength = sourceStream.Length;
SetCachingHeaders(context, betterCacheKey);
await sourceStream.CopyToAsync(context.Response.Body);
}
else
{
context.Response.ContentType = contentType;
SetCachingHeaders(context, betterCacheKey);
await sourceStream.CopyToAsync(context.Response.Body);
}
}
}
private async Task ProcessWithMemoryCache(HttpContext context, string cacheKey, ImageJobInfo info)
{
var isCached = memoryCache.TryGetValue(cacheKey, out ArraySegment <byte> imageBytes);
var isContentTypeCached = memoryCache.TryGetValue(cacheKey + ".contentType", out string contentType);
if (isCached && isContentTypeCached)
{
logger?.LogInformation("Serving {0}?{1} from memory cache", info.FinalVirtualPath, info.CommandString);
}
else
{
if (info.HasParams)
{
logger?.LogInformation($"Memory Cache Miss: Processing image {info.FinalVirtualPath}?{info.CommandString}");
var imageData = await info.ProcessUncached();
imageBytes = imageData.ResultBytes;
contentType = imageData.ContentType;
}
else
{
logger?.LogInformation($"Memory Cache Miss: Proxying image {info.FinalVirtualPath}?{info.CommandString}");
contentType = PathHelpers.ContentTypeForImageExtension(info.EstimatedFileExtension);
imageBytes = new ArraySegment <byte>(await info.GetPrimaryBlobBytesAsync());
}
// Set cache options.
var cacheEntryOptions = new MemoryCacheEntryOptions()
.SetSize(imageBytes.Count)
.SetSlidingExpiration(options.MemoryCacheSlidingExpiration);
var cacheEntryMetaOptions = new MemoryCacheEntryOptions()
.SetSize(contentType.Length * 2)
.SetSlidingExpiration(options.MemoryCacheSlidingExpiration);
memoryCache.Set(cacheKey, imageBytes, cacheEntryOptions);
memoryCache.Set(cacheKey + ".contentType", contentType, cacheEntryMetaOptions);
}
// write to stream
context.Response.ContentType = contentType;
context.Response.ContentLength = imageBytes.Count;
SetCachingHeaders(context, cacheKey);
await context.Response.Body.WriteAsync(imageBytes.Array, imageBytes.Offset, imageBytes.Count);
}
private async Task ProcessWithDistributedCache(HttpContext context, string cacheKey, ImageJobInfo info)
{
var imageBytes = await distributedCache.GetAsync(cacheKey);
var contentType = await distributedCache.GetStringAsync(cacheKey + ".contentType");
if (imageBytes != null && contentType != null)
{
logger?.LogInformation("Serving {0}?{1} from distributed cache", info.FinalVirtualPath, info.CommandString);
}
else
{
if (info.HasParams)
{
logger?.LogInformation($"Distributed Cache Miss: Processing image {info.FinalVirtualPath}?{info.CommandString}");
var imageData = await info.ProcessUncached();
imageBytes = imageData.ResultBytes.Count != imageData.ResultBytes.Array?.Length
? imageData.ResultBytes.ToArray()
: imageData.ResultBytes.Array;
contentType = imageData.ContentType;
}
else
{
logger?.LogInformation($"Distributed Cache Miss: Proxying image {info.FinalVirtualPath}?{info.CommandString}");
contentType = PathHelpers.ContentTypeForImageExtension(info.EstimatedFileExtension);
imageBytes = await info.GetPrimaryBlobBytesAsync();
}
// Set cache options.
var cacheEntryOptions = new DistributedCacheEntryOptions()
.SetSlidingExpiration(options.DistributedCacheSlidingExpiration);
await distributedCache.SetAsync(cacheKey, imageBytes, cacheEntryOptions);
await distributedCache.SetStringAsync(cacheKey + ".contentType", contentType, cacheEntryOptions);
}
// write to stream
context.Response.ContentType = contentType;
context.Response.ContentLength = imageBytes.Length;
SetCachingHeaders(context, cacheKey);
await context.Response.Body.WriteAsync(imageBytes, 0, imageBytes.Length);
}
private async Task ProcessWithDiskCache(HttpContext context, string cacheKey, ImageJobInfo info)
{
var cacheResult = await diskCache.GetOrCreate(cacheKey, info.EstimatedFileExtension, async (stream) =>
{
if (info.HasParams)
{
logger?.LogInformation($"DiskCache Miss: Processing image {info.FinalVirtualPath}?{info}");
var result = await info.ProcessUncached();
await stream.WriteAsync(result.ResultBytes.Array, result.ResultBytes.Offset,
result.ResultBytes.Count,
CancellationToken.None);
await stream.FlushAsync();
}
else
{
logger?.LogInformation($"DiskCache Miss: Proxying image {info.FinalVirtualPath}");
await info.CopyPrimaryBlobToAsync(stream);
}
});
// Note that using estimated file extension instead of parsing magic bytes will lead to incorrect content-type
// values when the source file has a mismatched extension.
if (cacheResult.Data != null)
{
if (cacheResult.Data.Length < 1)
{
throw new InvalidOperationException("DiskCache returned cache entry with zero bytes");
}
context.Response.ContentType = PathHelpers.ContentTypeForImageExtension(info.EstimatedFileExtension);
context.Response.ContentLength = cacheResult.Data.Length; //ReadOnlyMemoryStream, so it supports seeking
SetCachingHeaders(context, cacheKey);
await cacheResult.Data.CopyToAsync(context.Response.Body);
}
else
{
logger?.LogInformation("Serving {0}?{1} from disk cache {2}", info.FinalVirtualPath, info.CommandString, cacheResult.RelativePath);
await ServeFileFromDisk(context, cacheResult.PhysicalPath, cacheKey,
PathHelpers.ContentTypeForImageExtension(info.EstimatedFileExtension));
}
}
private async Task ProcessWithSqliteCache(HttpContext context, string cacheKey, ImageJobInfo info)
{
var cacheResult = await sqliteCache.GetOrCreate(cacheKey, async() =>
{
if (info.HasParams)
{
logger?.LogInformation($"Sqlite Cache Miss: Processing image {info.FinalVirtualPath}?{info.CommandString}");
var imageData = await info.ProcessUncached();
var imageBytes = imageData.ResultBytes.Count != imageData.ResultBytes.Array?.Length
? imageData.ResultBytes.ToArray()
: imageData.ResultBytes.Array;
var contentType = imageData.ContentType;
return(new SqliteCacheEntry()
{
ContentType = contentType,
Data = imageBytes
});
}
else
{
logger?.LogInformation($"Sqlite Cache Miss: Proxying image {info.FinalVirtualPath}?{info.CommandString}");
var contentType = PathHelpers.ContentTypeForImageExtension(info.EstimatedFileExtension);
return(new SqliteCacheEntry()
{
ContentType = contentType,
Data = await info.GetPrimaryBlobBytesAsync()
});
}
});
// write to stream
context.Response.ContentType = cacheResult.ContentType;
context.Response.ContentLength = cacheResult.Data.Length;
SetCachingHeaders(context, cacheKey);
await context.Response.Body.WriteAsync(cacheResult.Data, 0, cacheResult.Data.Length);
}