Trick to make PDF files automatically download using the Digizuite integration to Optimizely (Episerver) CMS

DownloadableDocument.cs

    //Register the PDF's as a specific content type in Optimizely. Ensure Guid is unique. 
    //Connect to Digizuite asset-types using the DigizuiteType attribute.
    [ContentType(DisplayName = "Downloadable Digizuite File", GUID = "a4ca5288-35ce-4ee5-b094-72f76ca8e07b", Description = "", AvailableInEditMode = false)]
    [DigizuiteType(AssetTypeIds = new[] { Digizuite.Optimizely.Constants.GlobalConstants.AssetTypes.PDF })]
    public class DownloadableDocument : DigizuiteFile
    {
    }

DownloadableDocumentBlobHttpHandler.cs

    //Create a custom HTTP Handler for the blobs of these types - but just inherit from the DigizuiteBlobHttpHandler. 
    //Just make sure you override the "IsDownloadingRequest". The default behavior here would be for it to check if the url ends with "/download".
    [ServiceConfiguration]
    public class DownloadableDocumentBlobHttpHandler : Digizuite.Optimizely.BlobHandling.DigizuiteBlobHttpHandler
    {
        public DownloadableDocumentBlobHttpHandler(HttpClient httpClient, IOptions<DAMIntegrationConfiguration> options) : base(httpClient, options)
        {
        }

        public override bool IsDownloadingRequest(HttpContext httpContext)
        {
            return true;
        }
    }

DownloadableFileMediaEndpoint.cs

//Make a custom Media Endpoint that connects the new content type with the new BlobHttpHandler.
[TemplateDescriptor(Inherited = false, AvailableWithoutTag = true, TemplateTypeCategory = TemplateTypeCategories.HttpHandler)]
    public class DownloadableFileMediaEndpoint : Endpoint, IRenderTemplate<DownloadableDocument>, IRenderTemplate
    {
        private static ContentActionDescriptor _mediaContentActionDescriptor = new ContentActionDescriptor()
        {
            Inherited = false,
            ModelType = typeof(DownloadableDocument)
        };
        private static AuthorizeAttribute _authorizeAttribute = new AuthorizeAttribute("episerver:read");
        private static AuthorizeAttribute _previewAttribute = new AuthorizeAttribute("episerver:preview");

        public DownloadableFileMediaEndpoint(DownloadableDocumentBlobHttpHandler dblobhandler) : base(new RequestDelegate(dblobhandler.Invoke), new EndpointMetadataCollection(new object[3] {
            (object) DownloadableFileMediaEndpoint._mediaContentActionDescriptor,
            (object) DownloadableFileMediaEndpoint._authorizeAttribute,
            (object) DownloadableFileMediaEndpoint._previewAttribute
        }), nameof(DownloadableFileMediaEndpoint))
        {
        }
    }