public static IActionResult Run( [HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)] HttpRequest req, ILogger log) { log.LogInformation("C# HTTP trigger function processed a request."); var invoiceBuilder = new InvoiceBuilder { Init = () => { }, GetRequestStream = () => new MemoryStream(Properties.Resources.Request), GetTemplateStream = (template) => new MemoryStream(Properties.Resources.Invoice), Output = (pdf) => { using (var stream = new MemoryStream()) { stream.Write(pdf, 0, pdf.Length); } } }; invoiceBuilder.Build(); return(new OkObjectResult(invoiceBuilder.ToString())); }