/// <summary>
/// Returns an IVirtualFileAsync instance if the specified file can be provided by an async provider
/// </summary>
/// <param name="virtualPath"></param>
/// <param name="queryString"></param>
/// <returns></returns>
public async Task <IVirtualFileAsync> GetFileAsync(string virtualPath, NameValueCollection queryString)
{
IVirtualFileAsync f = null;
foreach (IVirtualImageProviderAsync p in c.Plugins.GetAll <IVirtualImageProviderAsync>())
{
if (await p.FileExistsAsync(virtualPath, queryString))
{
f = await p.GetFileAsync(virtualPath, queryString);
break;
}
}
if (f == null)
{
return(null);
}
try
{
//Now we have a reference to the real virtual file, let's see if it is source-cached.
IVirtualFileAsync cached = null;
foreach (IVirtualFileCacheAsync p in c.Plugins.GetAll <IVirtualFileCacheAsync>())
{
cached = await p.GetFileIfCachedAsync(virtualPath, queryString, f);
if (cached != null)
{
return(cached);
}
}
}catch (FileNotFoundException)
{
//IVirtualFileCache instances will .Open() and read the original IVirtualFile instance.
return(null);
}
return(f);
}
protected async Task CheckRequest_PostAuthorizeRequest_Async(object sender, EventArgs e)
{
//Skip requests if the Request object isn't populated
HttpApplication app = sender as HttpApplication;
if (app == null || app.Context == null || app.Context.Request == null)
{
return;
}
var ra = new HttpModuleRequestAssistant(app.Context, conf, this);
var result = ra.PostAuthorize();
if (result == HttpModuleRequestAssistant.PostAuthorizeResult.UnrelatedFileType)
{
return; //Exit early, not our scene
}
if (result == HttpModuleRequestAssistant.PostAuthorizeResult.AccessDenied403)
{
ra.FireAccessDenied();
throw new ImageProcessingException(403, "Access denied", "Access denied");
}
if (result == HttpModuleRequestAssistant.PostAuthorizeResult.Complete)
{
//Does the file exist physically? (false if VppUsage=always or file is missing)
bool existsPhysically = (conf.VppUsage != VppUsageOption.Always);
if (existsPhysically)
{
existsPhysically = File.Exists(ra.RewrittenMappedPath);
}
//If not present physically (and VppUsage!=never), try to get the virtual file. Null indicates a missing file
IVirtualFileAsync vf = null;
if (conf.VppUsage != VppUsageOption.Never && !existsPhysically)
{
vf = await conf.GetFileAsync(ra.RewrittenVirtualPath, ra.RewrittenQuery);
}
//Only process files that exist
if (!existsPhysically && vf == null)
{
ra.FireMissing();
return;
}
try
{
await HandleRequest(app.Context, ra, vf);
//Catch not found exceptions
ra.FirePostAuthorizeSuccess();
}
catch (System.IO.FileNotFoundException notFound)
{ //Some VPPs are optimistic, or could be a race condition
if (notFound.Message.Contains(" assembly "))
{
throw; //If an assembly is missing, it should be a 500, not a 404
}
ra.FireMissing();
throw new ImageMissingException("The specified resource could not be located", "File not found", notFound);
}
catch (System.IO.DirectoryNotFoundException notFound)
{
ra.FireMissing();
throw new ImageMissingException("The specified resource could not be located", "File not found", notFound);
}
catch (Exception ex)
{
ra.FirePostAuthorizeRequestException(ex);
throw;
}
}
}
/// <summary>
/// Generates the resized image to disk (if needed), then rewrites the request to that location.
/// Perform 404 checking before calling this method. Assumes file exists.
/// Called during PostAuthorizeRequest
/// </summary>
/// <param name="context"></param>
/// <param name="ra"></param>
/// <param name="vf"></param>
protected virtual async Task HandleRequest(HttpContext context, HttpModuleRequestAssistant ra, IVirtualFileAsync vf)
{
if (!ra.CachingIndicated && !ra.ProcessingIndicated)
{
ra.ApplyRewrittenPath(); //This is needed for both physical and virtual files; only makes changes if needed.
if (vf != null)
{
ra.AssignSFH(); //Virtual files are not served in .NET 4.
}
return;
}
//Communicate to the MVC plugin this request should not be affected by the UrlRoutingModule.
context.Items[conf.StopRoutingKey] = true;
context.Items[conf.ResponseArgsKey] = ""; //We are handling the request
ra.EstimateResponseInfo();
//Build CacheEventArgs
var e = new AsyncResponsePlan();
var modDate = (vf == null) ? System.IO.File.GetLastWriteTimeUtc(ra.RewrittenMappedPath) :
(vf is IVirtualFileWithModifiedDateAsync ? await((IVirtualFileWithModifiedDateAsync)vf).GetModifiedDateUTCAsync() : DateTime.MinValue);
e.RequestCachingKey = ra.GenerateRequestCachingKey(modDate);
var settings = new ResizeSettings(ra.RewrittenInstructions);
e.RewrittenQuerystring = settings;
e.EstimatedContentType = ra.EstimatedContentType;
e.EstimatedFileExtension = ra.EstimatedFileExtension;
//A delegate for accessing the source file
e.OpenSourceStreamAsync = async delegate()
{
return((vf != null) ? await vf.OpenAsync() : File.Open(ra.RewrittenMappedPath, FileMode.Open, FileAccess.Read, FileShare.Read));
};
//Add delegate for writing the data stream
e.CreateAndWriteResultAsync = async delegate(System.IO.Stream stream, IAsyncResponsePlan plan)
{
//This runs on a cache miss or cache invalid. This delegate is preventing from running in more
//than one thread at a time for the specified cache key
try
{
if (!ra.ProcessingIndicated)
{
//Just duplicate the data
using (Stream source = await e.OpenSourceStreamAsync())
await source.CopyToAsync(stream); //4KiB buffer
}
else
{
MemoryStream inBuffer = null;
using (var sourceStream = vf != null ? await vf.OpenAsync() : File.Open(ra.RewrittenMappedPath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
inBuffer = new MemoryStream(sourceStream.CanSeek ? (int)sourceStream.Length : 128 * 1024);
await sourceStream.CopyToAsync(inBuffer);
}
inBuffer.Seek(0, SeekOrigin.Begin);
var outBuffer = new MemoryStream(32 * 1024);
//Handle I/O portions of work asynchronously.
var j = new ImageJob
{
Instructions = new Instructions(settings),
SourcePathData = vf != null ? vf.VirtualPath : ra.RewrittenVirtualPath,
Dest = outBuffer,
Source = inBuffer
};
await conf.GetImageBuilder().BuildAsync(j, int.MaxValue, CancellationToken.None);
outBuffer.Seek(0, SeekOrigin.Begin);
await outBuffer.CopyToAsync(stream);
}
ra.FireJobSuccess();
//Catch not found exceptions
}
catch (System.IO.FileNotFoundException notFound)
{
if (notFound.Message.Contains(" assembly "))
{
throw; //If an assembly is missing, it should be a 500, not a 404
}
//This will be called later, if at all.
ra.FireMissing();
throw new ImageMissingException("The specified resource could not be located", "File not found", notFound);
}
catch (System.IO.DirectoryNotFoundException notFound)
{
ra.FireMissing();
throw new ImageMissingException("The specified resource could not be located", "File not found", notFound);
}
catch (Exception ex)
{
ra.FireJobException(ex);
throw;
}
};
//All bad from here down....
context.Items[conf.ResponseArgsKey] = e; //store in context items
//Fire events (for client-side caching plugins)
conf.FirePreHandleImageAsync(this, context, e);
//Pass the rest of the work off to the caching module. It will handle rewriting/redirecting and everything.
//We handle request headers based on what is found in context.Items
IAsyncTyrantCache cache = conf.GetAsyncCacheFor(context, e);
//Verify we have a caching system
if (cache == null)
{
throw new ImageProcessingException("Image Resizer: No async caching plugin was found for the request");
}
await cache.ProcessAsync(context, e);
}
public async Task <IVirtualFileAsync> GetFileIfCachedAsync(string virtualPath, NameValueCollection queryString, IVirtualFileAsync original)
{
//Use alternate cache key if provided
string key = original is IVirtualFileSourceCacheKey ? ((IVirtualFileSourceCacheKey)original).GetCacheKey(true) : original.VirtualPath;
//If cached, serve it.
CachedVirtualFile c = cache.Get(key);
if (c != null)
{
return(c);
}
//If not, let's cache it.
if ("mem".Equals(queryString["scache"], StringComparison.OrdinalIgnoreCase))
{
await asyncLocks.TryExecuteAsync(key, 3000, async delegate()
{
c = cache.Get(key);
if (c == null)
{
using (Stream data = await original.OpenAsync())
{//Very long-running call
c = new CachedVirtualFile(original.VirtualPath, await data.CopyToBytesAsync(true, 0x1000));
}
cache.Set(key, c);//Save to cache (may trigger cleanup)
}
});
return(c);
}
return(null);
}
public Task <IVirtualFileAsync> GetFileAsync(string virtualPath, NameValueCollection queryString)
{
IVirtualFileAsync blobImage = GetBlobFile(virtualPath, queryString);
return(Task.FromResult(blobImage));
}
public async Task <IVirtualFileAsync> GetFileIfCachedAsync(string virtualPath, NameValueCollection queryString, IVirtualFileAsync original)
{
if (!"disk".Equals(queryString["scache"], StringComparison.OrdinalIgnoreCase))
{
return(null);
}
if (!this.AsyncModuleMode)
{
throw new InvalidOperationException("SourceDiskCache cannot be used in asynchronous mode if AsyncModuleMode=false");
}
//Verify web.config exists in the cache folder.
writer.CheckWebConfigEvery5();
//Use alternate cache key if provided
string key = original is IVirtualFileSourceCacheKey ? ((IVirtualFileSourceCacheKey)original).GetCacheKey(false) : original.VirtualPath;
//If cached, serve it.
var r = await asyncCache.GetCachedFile(key, ".cache", async delegate(Stream target)
{
using (Stream data = await original.OpenAsync())
{//Very long-running call
await data.CopyToAsync(target);
}
}, 15 * 1000, true);
if (r.Result == CacheQueryResult.Failed)
{
return(null);
}
if (r.Result == CacheQueryResult.Hit && cleaner != null)
{
cleaner.UsedFile(r.RelativePath, r.PhysicalPath);
}
return(new SourceVirtualFileAsync(original.VirtualPath, delegate()
{
return Task.FromResult(r.Data ?? File.Open(r.PhysicalPath, FileMode.Open, FileAccess.Read, FileShare.Read));
}));
}
