public async Task Invoke(HttpContext context)
{
var path = context.Request.Path;
// Delegate to the diagnostics page if it is requested
if (diagnosticsPage.MatchesPath(path.Value))
{
await diagnosticsPage.Invoke(context);
return;
}
// We only handle requests with an image extension, period.
if (!PathHelpers.IsImagePath(path))
{
await next.Invoke(context);
return;
}
var imageJobInfo = new ImageJobInfo(context, options, blobProvider);
if (!imageJobInfo.Authorized)
{
await NotAuthorized(context);
return;
}
// If the file is definitely missing hand to the next middleware
// Remote providers will fail late rather than make 2 requests
if (!imageJobInfo.PrimaryBlobMayExist())
{
await next.Invoke(context);
return;
}
var memoryCacheEnabled = memoryCache != null && options.AllowMemoryCaching && imageJobInfo.NeedsCaching();
var diskCacheEnabled = diskCache != null && options.AllowDiskCaching && imageJobInfo.NeedsCaching();
var distributedCacheEnabled = distributedCache != null && options.AllowDistributedCaching && imageJobInfo.NeedsCaching();
var sqliteCacheEnabled = sqliteCache != null && options.AllowSqliteCaching && imageJobInfo.NeedsCaching();
string cacheKey = null;
if (memoryCacheEnabled || diskCacheEnabled || distributedCacheEnabled | sqliteCacheEnabled)
{
cacheKey = await imageJobInfo.GetFastCacheKey();
if (context.Request.Headers.TryGetValue(HeaderNames.IfNoneMatch, out var etag) && cacheKey == etag)
{
context.Response.StatusCode = StatusCodes.Status304NotModified;
context.Response.ContentLength = 0;
context.Response.ContentType = null;
return;
}
}
try
{
if (sqliteCacheEnabled)
{
await ProcessWithSqliteCache(context, cacheKey, imageJobInfo);
}
else if (diskCacheEnabled)
{
await ProcessWithDiskCache(context, cacheKey, imageJobInfo);
}
else if (memoryCacheEnabled)
{
await ProcessWithMemoryCache(context, cacheKey, imageJobInfo);
// ReSharper disable once ConditionIsAlwaysTrueOrFalse
}
else if (distributedCacheEnabled)
{
await ProcessWithDistributedCache(context, cacheKey, imageJobInfo);
}
else
{
await ProcessWithNoCache(context, imageJobInfo);
}
}
catch (BlobMissingException e)
{
await NotFound(context, e);
}
}
private bool ProcessRewritesAndAuthorization(HttpContext context, ImageflowMiddlewareOptions options)
{
var path = context.Request.Path.Value;
var args = new UrlEventArgs(context, context.Request.Path.Value, PathHelpers.ToQueryDictionary(context.Request.Query));
foreach (var handler in options.PreRewriteAuthorization)
{
var matches = string.IsNullOrEmpty(handler.PathPrefix) ||
path.StartsWith(handler.PathPrefix, StringComparison.OrdinalIgnoreCase);
if (matches && !handler.Handler(args))
{
return(false);
}
}
if (options.UsePresetsExclusively)
{
var firstKey = args.Query.FirstOrDefault().Key;
if (args.Query.Count > 1 || (firstKey != null && firstKey != "preset"))
{
return(false);
}
}
// Parse and apply presets before rewriting
if (args.Query.TryGetValue("preset", out var presetNames))
{
var presetNamesList = presetNames
.Split(new char[] { ',' }, StringSplitOptions.RemoveEmptyEntries);
foreach (var presetName in presetNamesList)
{
if (options.Presets.TryGetValue(presetName, out var presetOptions))
{
foreach (var pair in presetOptions.pairs)
{
if (presetOptions.Priority == PresetPriority.OverrideQuery ||
!args.Query.ContainsKey(pair.Key))
{
args.Query[pair.Key] = pair.Value;
}
}
}
else
{
throw new InvalidOperationException($"The image preset {presetName} was referenced from the querystring but is not registered.");
}
}
}
// Apply rewrite handlers
foreach (var handler in options.Rewrite)
{
var matches = string.IsNullOrEmpty(handler.PathPrefix) ||
path.StartsWith(handler.PathPrefix, StringComparison.OrdinalIgnoreCase);
if (matches)
{
handler.Handler(args);
path = args.VirtualPath;
}
}
// Set defaults if keys are missing, but at least 1 supported key is present
if (PathHelpers.SupportedQuerystringKeys.Any(args.Query.ContainsKey))
{
foreach (var pair in options.CommandDefaults)
{
if (!args.Query.ContainsKey(pair.Key))
{
args.Query[pair.Key] = pair.Value;
}
}
}
// Run post-rewrite authorization
foreach (var handler in options.PostRewriteAuthorization)
{
var matches = string.IsNullOrEmpty(handler.PathPrefix) ||
path.StartsWith(handler.PathPrefix, StringComparison.OrdinalIgnoreCase);
if (matches && !handler.Handler(args))
{
return(false);
}
}
FinalVirtualPath = args.VirtualPath;
FinalQuery = args.Query;
return(true);
}
private string HashStrings(IEnumerable <string> strings)
{
return(PathHelpers.Base64Hash(string.Join('|', strings)));
}
public ImageJobInfo(HttpContext context, ImageflowMiddlewareOptions options, BlobProvider blobProvider)
{
this.options = options;
Authorized = ProcessRewritesAndAuthorization(context, options);
if (!Authorized)
{
return;
}
HasParams = PathHelpers.SupportedQuerystringKeys.Any(FinalQuery.ContainsKey);
var extension = Path.GetExtension(FinalVirtualPath);
if (FinalQuery.TryGetValue("format", out var newExtension))
{
extension = newExtension;
}
EstimatedFileExtension = PathHelpers.SanitizeImageExtension(extension) ?? "jpg";
primaryBlob = new BlobFetchCache(FinalVirtualPath, blobProvider);
allBlobs = new List <BlobFetchCache>(1)
{
primaryBlob
};
appliedWatermarks = new List <NamedWatermark>();
if (HasParams)
{
CommandString = PathHelpers.SerializeCommandString(FinalQuery);
// Look up watermark names
if (FinalQuery.TryGetValue("watermark", out var watermarkValues))
{
var watermarkNames = watermarkValues.Split(",").Select(s => s.Trim(' '));
foreach (var name in watermarkNames)
{
var watermark = options.NamedWatermarks.FirstOrDefault(w =>
w.Name.Equals(name, StringComparison.OrdinalIgnoreCase));
if (watermark == null)
{
throw new InvalidOperationException(
$"watermark {name} was referenced from the querystring but no watermark by that name is registered with the middleware");
}
appliedWatermarks.Add(watermark);
}
}
}
// After we've populated the defaults, run the event handlers for custom watermarking logic
var args = new WatermarkingEventArgs(context, FinalVirtualPath, FinalQuery, appliedWatermarks);
foreach (var handler in options.Watermarking)
{
var matches = string.IsNullOrEmpty(handler.PathPrefix) ||
FinalVirtualPath.StartsWith(handler.PathPrefix, StringComparison.OrdinalIgnoreCase);
if (matches)
{
handler.Handler(args);
}
}
appliedWatermarks = args.AppliedWatermarks;
// Add the watermark source files
foreach (var w in appliedWatermarks)
{
allBlobs.Add(new BlobFetchCache(w.VirtualPath, blobProvider));
}
provider = blobProvider;
}
// ReSharper disable once UnusedMember.Global
public async Task Invoke(HttpContext context)
{
// For instrumentation
globalInfoProvider.CopyHttpContextInfo(context);
var path = context.Request.Path;
// Delegate to the diagnostics page if it is requested
if (DiagnosticsPage.MatchesPath(path.Value))
{
await diagnosticsPage.Invoke(context);
return;
}
// Delegate to licenses page if requested
if (licensePage.MatchesPath(path.Value))
{
await licensePage.Invoke(context);
return;
}
// Respond to /imageflow.ready
if ("/imageflow.ready".Equals(path.Value, StringComparison.Ordinal))
{
options.Licensing.FireHeartbeat();
using (new JobContext())
{
await StringResponseNoCache(context, 200, "Imageflow.Server is ready to accept requests.");
}
return;
}
// Respond to /imageflow.health
if ("/imageflow.health".Equals(path.Value, StringComparison.Ordinal))
{
options.Licensing.FireHeartbeat();
await StringResponseNoCache(context, 200, "Imageflow.Server is healthy.");
return;
}
// We only handle requests with an image extension or if we configured a path prefix for which to handle
// extensionless requests
if (!ImageJobInfo.ShouldHandleRequest(context, options))
{
await next.Invoke(context);
return;
}
options.Licensing.FireHeartbeat();
var imageJobInfo = new ImageJobInfo(context, options, blobProvider);
if (!imageJobInfo.Authorized)
{
await NotAuthorized(context, imageJobInfo.AuthorizedMessage);
return;
}
if (imageJobInfo.LicenseError)
{
if (options.EnforcementMethod == EnforceLicenseWith.Http422Error)
{
await StringResponseNoCache(context, 422, options.Licensing.InvalidLicenseMessage);
return;
}
if (options.EnforcementMethod == EnforceLicenseWith.Http402Error)
{
await StringResponseNoCache(context, 402, options.Licensing.InvalidLicenseMessage);
return;
}
}
// If the file is definitely missing hand to the next middleware
// Remote providers will fail late rather than make 2 requests
if (!imageJobInfo.PrimaryBlobMayExist())
{
await next.Invoke(context);
return;
}
string cacheKey = null;
var cachingPath = imageJobInfo.NeedsCaching() ? options.ActiveCacheBackend : CacheBackend.NoCache;
if (cachingPath != CacheBackend.NoCache)
{
cacheKey = await imageJobInfo.GetFastCacheKey();
if (context.Request.Headers.TryGetValue(HeaderNames.IfNoneMatch, out var etag) && cacheKey == etag)
{
GlobalPerf.Singleton.IncrementCounter("etag_hit");
context.Response.StatusCode = StatusCodes.Status304NotModified;
context.Response.ContentLength = 0;
context.Response.ContentType = null;
return;
}
GlobalPerf.Singleton.IncrementCounter("etag_miss");
}
try
{
switch (cachingPath)
{
case CacheBackend.ClassicDiskCache:
await ProcessWithDiskCache(context, cacheKey, imageJobInfo);
break;
case CacheBackend.NoCache:
await ProcessWithNoCache(context, imageJobInfo);
break;
case CacheBackend.StreamCache:
await ProcessWithStreamCache(context, cacheKey, imageJobInfo);
break;
default:
throw new ArgumentOutOfRangeException();
}
GlobalPerf.Singleton.IncrementCounter("middleware_ok");
}
catch (BlobMissingException e)
{
await NotFound(context, e);
}
catch (Exception e)
{
var errorName = e.GetType().Name;
var errorCounter = "middleware_" + errorName;
GlobalPerf.Singleton.IncrementCounter(errorCounter);
GlobalPerf.Singleton.IncrementCounter("middleware_errors");
throw;
}
finally
{
// Increment counter for type of file served
var imageExtension = PathHelpers.GetImageExtensionFromContentType(context.Response.ContentType);
if (imageExtension != null)
{
GlobalPerf.Singleton.IncrementCounter("module_response_ext_" + imageExtension);
}
}
}
public ImageJobInfo(HttpContext context, ImageflowMiddlewareOptions options, BlobProvider blobProvider)
{
this.options = options;
Authorized = ProcessRewritesAndAuthorization(context, options);
if (!Authorized)
{
return;
}
HasParams = PathHelpers.SupportedQuerystringKeys.Any(FinalQuery.ContainsKey);
// Get the image and page domains
ImageDomain = context.Request.Host.Host;
var referer = context.Request.Headers["Referer"].ToString();
if (!string.IsNullOrEmpty(referer) && Uri.TryCreate(referer, UriKind.Absolute, out var result))
{
PageDomain = result.DnsSafeHost;
}
var extension = Path.GetExtension(FinalVirtualPath);
if (FinalQuery.TryGetValue("format", out var newExtension))
{
extension = newExtension;
}
EstimatedFileExtension = PathHelpers.SanitizeImageExtension(extension) ?? "jpg";
primaryBlob = new BlobFetchCache(FinalVirtualPath, blobProvider);
allBlobs = new List <BlobFetchCache>(1)
{
primaryBlob
};
appliedWatermarks = new List <NamedWatermark>();
if (HasParams)
{
if (options.Licensing.RequestNeedsEnforcementAction(context.Request))
{
if (options.EnforcementMethod == EnforceLicenseWith.RedDotWatermark)
{
FinalQuery["watermark_red_dot"] = "true";
}
LicenseError = true;
}
CommandString = PathHelpers.SerializeCommandString(FinalQuery);
// Look up watermark names
if (FinalQuery.TryGetValue("watermark", out var watermarkValues))
{
var watermarkNames = watermarkValues.Split(",").Select(s => s.Trim(' '));
foreach (var name in watermarkNames)
{
var watermark = options.NamedWatermarks.FirstOrDefault(w =>
w.Name.Equals(name, StringComparison.OrdinalIgnoreCase));
if (watermark == null)
{
throw new InvalidOperationException(
$"watermark {name} was referenced from the querystring but no watermark by that name is registered with the middleware");
}
appliedWatermarks.Add(watermark);
}
}
}
// After we've populated the defaults, run the event handlers for custom watermarking logic
var args = new WatermarkingEventArgs(context, FinalVirtualPath, FinalQuery, appliedWatermarks);
foreach (var handler in options.Watermarking)
{
var matches = string.IsNullOrEmpty(handler.PathPrefix) ||
(FinalVirtualPath != null &&
FinalVirtualPath.StartsWith(handler.PathPrefix, StringComparison.OrdinalIgnoreCase));
if (matches)
{
handler.Handler(args);
}
}
appliedWatermarks = args.AppliedWatermarks;
if (appliedWatermarks.Count > 0)
{
HasParams = true;
}
// Add the watermark source files
foreach (var w in appliedWatermarks)
{
allBlobs.Add(new BlobFetchCache(w.VirtualPath, blobProvider));
}
}