Error on Publishing ECL Items

Question

To publish ECL Items we have placed a custom build TBB to add external binary to our file system.

On publishing ECL Items we're getting error as Cannot access a closed Stream.

Error:

The number of render failures has exceeded its specified failure limit of 0. Cannot access a closed Stream.

Component: Tridion.ContentManager.Publishing Errorcode: 854 User: NT AUTHORITY\SYSTEM

StackTrace Information Details: at System.IO.Stream.CopyTo(Stream destination) at System.IO.Stream.CopyTo(Stream destination) at ECLItems.Templating.PublishingECLItems.Transform(Engine engine, Package package) at Tridion.ContentManager.Templating.Assembly.AssemblyMediator.Transform(Engine engine, Template template, Package package) at Tridion.ContentManager.Templating.Assembly.CSharpSourceCodeMediator.RunTemplate(Engine engine, Package package, String templateUri, String className) at Tridion.Templating.CSharpTemplate.CSharpSourceTemplate.Transform(Engine __engine, Package __package) at Tridion.ContentManager.Templating.Assembly.CSharpSourceCodeMediator.Transform(Engine engine, Template template, Package package) at Tridion.ContentManager.Templating.Engine.ExecuteTemplate(Template template, Package package) at Tridion.ContentManager.Templating.Engine.InvokeTemplate(Package package, TemplateInvocation templateInvocation, Template template)
at Tridion.ContentManager.Templating.Compound.CompoundTemplateMediator.Transform(Engine engine, Template templateToTransform, Package package) at Tridion.ContentManager.Templating.Engine.ExecuteTemplate(Template template, Package package) at Tridion.ContentManager.Templating.Engine.InvokeTemplate(Package package, TemplateInvocation templateInvocation, Template template)
at Tridion.ContentManager.Templating.Engine.TransformPackage(Template template, Package package) at Tridion.ContentManager.Templating.Engine.TransformItem(Template template, IdentifiableObject itemToRender) at Tridion.ContentManager.Templating.TemplatingRenderer.Render(ResolvedItem resolvedItem, PublishInstruction instruction, PublicationTarget target, RenderedItem renderedItem, RenderContext renderContext) at Tridion.ContentManager.Publishing.Rendering.RenderEngine.Render(ResolvedItem resolvedItem, PublishInstruction instruction, PublicationTarget target, RenderContext context) at Tridion.ContentManager.Publishing.Handling.DefaultPublishTransactionHandler.RenderAndPackage(ResolvedItem resolvedItem, PublishInstruction instruction, PublicationTarget target, List1 processedItems, PublishTransaction publishTransaction, TransportPackage transportPackage) at Tridion.ContentManager.Publishing.Handling.DefaultPublishTransactionHandler.RenderAndPackage(ResolvedItem resolvedItem, PublishInstruction instruction, PublicationTarget target, List1 processedItems, PublishTransaction publishTransaction, TransportPackage transportPackage) at Tridion.ContentManager.Publishing.Handling.DefaultPublishTransactionHandler.HandlePublishRequest(PublishTransaction publishTransaction) at Tridion.ContentManager.Publishing.Handling.DefaultPublishTransactionHandler.ProcessPublishTransaction(PublishTransaction publishTransaction) at Tridion.ContentManager.Publishing.Publisher.QueueMessageHandler.HandleMessage()

TBB Logic :

IContentResult contentResult = eclItem.GetContent(null);
if (contentResult != null)
 {
    using (Stream stream = new MemoryStream())
    {
         contentResult.Stream.CopyTo(stream);
         _engine.PublishingContext.RenderedItem.AddBinary(stream, fileName, "ECL_Default", component, contentType);
    }
  }

ECL Provider : GetContent logic

  public IContentResult GetContent(IList<ITemplateAttribute> attributes)
        {
            string JsessionId = string.Empty;
            if (this.Info.url == null) return null;

            string url = Image.GetPhotoUrl(this.Info.url, out JsessionId);
            using (WebClient webClient = new WebClient())
            {
                webClient.Headers.Add(HttpRequestHeader.Cookie, "JSESSIONID=" + JsessionId);
                using (Stream stream = new MemoryStream(webClient.DownloadData(url)))
                {
                    return Provider.HostServices.CreateContentResult(stream, stream.Length, this.Info.MimeType);
                }
            }
        }

Though GetContent method successfully return IcontentResult,but however we're Unable to add IcontentResult.Stream to AddBinary method.

Update

When we use IContentResult stream directly in AddBinary method,getting similar error Cannot access a closed Stream.

Component: Tridion.ContentManager.Publishing Errorcode: 854 User: NT AUTHORITY\SYSTEM

StackTrace Information Details: at

System.IO.__Error.StreamIsClosed() at

System.IO.MemoryStream.set_Position(Int64 value) at

System.IO.Stream.set_Position(Int64 value) at

Tridion.ContentManager.Publishing.Rendering.Binary..ctor(Stream content, String filename, IdentifiableObject location, String variantId, Component relatedComponent, String mimeType,RenderInstruction renderInstruction) at

Tridion.ContentManager.Publishing.Rendering.RenderedItem.AddBinary(Stream content, String filename, String variantId, Component relatedComponent, String mimeType)

Answer 1

The error you are getting is a .NET error in the CopyTo() method, that tries to copy a closed stream. I'm wondering if it wouldn't be easier to use the IContentResult stream object directly inside your AddBinary call.

_engine.PublishingContext.RenderedItem.AddBinary(contentResult.Stream, fileName, "ECL_Default", component, contentType);

UPDATE

As you get the same issue when using the stream directly, this is caused by your using statement here

 using (Stream stream = new MemoryStream(webClient.DownloadData(url)))
 {
       return Provider.HostServices.CreateContentResult(stream, stream.Length, this.Info.MimeType);
 }

the 'using' will dispose the stream when you return the content result, so the stream is no longer accessible.

I think you can safely change this to

Stream stream = new MemoryStream(webClient.DownloadData(url);
return Provider.HostServices.CreateContentResult(stream, stream.Length, this.Info.MimeType);