Convert Excel to PDF with Azure function in .NET Standard application.

using System.IO;
using Syncfusion.XlsIO;
using Syncfusion.XlsIORenderer;
using Syncfusion.Pdf;
using System.Net.Http.Headers;

[FunctionName("Function1")]
public static async Task<HttpResponseMessage> Run([HttpTrigger(AuthorizationLevel.Function, "get", "post", Route = null)]HttpRequestMessage req, TraceWriter log)
{
    Stream stream = req.Content.ReadAsStreamAsync().Result;
    //Instantiate the spreadsheet creation engine
    using (ExcelEngine excelEngine = new ExcelEngine())
    {
        //Instantiate the Excel application object
        IApplication application = excelEngine.Excel;
 
        //Assigns default application version
        application.DefaultVersion = ExcelVersion.Excel2013;
 
        IWorkbook workbook = application.Workbooks.Open(stream);
 
        //Access a worksheet from workbook
        IWorksheet worksheet = workbook.Worksheets[0];
 
        //Open the Excel document to Convert
        XlsIORenderer renderer = new XlsIORenderer();
 
        //Initialize PDF document
        PdfDocument pdfDocument = new PdfDocument();
 
        //Convert Excel document into PDF document
        pdfDocument = renderer.ConvertToPDF(workbook);
 
        MemoryStream memoryStream = new MemoryStream();
 
        //Save the PDF file
        pdfDocument.Save(memoryStream);
 
        //Create the response to return
        HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
 
        //Set the PDF document content response
        response.Content = new ByteArrayContent(memoryStream.ToArray());
 
        //Set the contentDisposition as attachment
        response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
        {
            FileName = "Output.pdf"
        };
        //Set the content type as PDF format mime type
        response.Content.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue("application/pdf");
 
        //Return the response with output PDF stream
        return response;
    }
}

//Open the required template Excel file
Stream fileStream = File.Open(@"../../Data/Input.xlsx", FileMode.Open);
 
//Create memory stream to save the template
MemoryStream inputStream = new MemoryStream();
 
//Copy the file stream into memory stream
fileStream.CopyTo(inputStream);
 
//Dispose the file stream
fileStream.Dispose();
try
{
    //Create HttpWebRequest with hosted azure function URL
    HttpWebRequest req = (HttpWebRequest)WebRequest.Create("Your Azure function url");
 
    //Set request method as POST
    req.Method = "POST";
 
    //Get the request stream to strore the Excel document stream
    Stream stream = req.GetRequestStream();
 
    //Write the Excel document stream into request stream
    stream.Write(inputStream.ToArray(), 0, inputStream.ToArray().Length);
 
    //Gets the responce from the Azure Function request
    HttpWebResponse res = (HttpWebResponse)req.GetResponse();
 
    //Create file stream to save the output PDF file
    FileStream outStream = File.Create("Sample.pdf");
 
    //Copy the responce stream into file stream
    res.GetResponseStream().CopyTo(outStream);
 
    //Dispose the input stream
    inputStream.Dispose();
 
    //Dispose the file stream
    outStream.Dispose();
}
catch (Exception ex)
{
    throw;
}
 
//Launch the output document
System.Diagnostics.Process.Start("Sample.pdf");