Timeout Mechanism in Document Processing Libraries
Environment
| Version | Product | Author |
|---|---|---|
| Q4 2024 | Document Processing Libraries | Desislava Yordanova |
Description
After upgrading to Q4 2024 (or a later version) of Telerik Document Processing Libraries, one of the following warning messages may occur when you build a project that contains any logic for importing or exporting documents:
The Compiler Warning (level 2) CS0618 indicates that an obsolete Import or Export method is used:
Solution
Starting with Q4 2024, Telerik Document Processing Libraries introduce a new timeout mechanism for importing and exporting documents. The Import and Export methods of the format providers have a mandatory TimeSpan? timeout parameter. After the specified interval elapses, the operation is canceled and an OperationCanceledException is thrown:
This is valid for WordsProcessing, PdfProcessing and SpreadProcessing.
Import XLSX (Excel Workbook) File
using (Stream input = new FileStream("input-file.xlsx", FileMode.Open))
{
XlsxFormatProvider formatProvider = new XlsxFormatProvider();
TimeSpan timeoutInterval = TimeSpan.FromSeconds(10);
Workbook workbook = formatProvider.Import(input, timeoutInterval);
}The TimeSpan interval depends on the developer and must account for environment-specific configurations. When developing a web application, set a timeout interval value that is safe enough to protect the application from potential DDoS attacks. If the application is delivered directly to end-users, you can use
TimeSpan=nullas well.
There is a Visual Studio setting that controls whether the warnings are treated as errors:
Make sure that this setting is not toggled. Otherwise, the application does not compile due to the obsolete API.
Handling the OperationCanceledException
static void Main(string[] args)
{
string outputFilePath = "output.xlsx";
File.Delete(outputFilePath);
IWorkbookFormatProvider formatProvider = new Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx.XlsxFormatProvider();
bool exceptionThrown = false;
string exceptionStack = string.Empty;
try
{
using (Stream output = new FileStream(outputFilePath, FileMode.Create))
{
formatProvider.Export(workbook, output, TimeSpan.FromMilliseconds(1));
}
Process.Start(new ProcessStartInfo() { FileName = outputFilePath, UseShellExecute = true });
}
catch (OperationCanceledException ex)
{
exceptionThrown = true;
exceptionStack = ex.StackTrace;
}
catch (Exception ex)
{
Exception inner = FindInnermostException(ex);
if (!(inner is OperationCanceledException))
{
throw;
}
else
{
exceptionThrown = true;
exceptionStack = inner.StackTrace;
}
}
}
private static Exception FindInnermostException(Exception ex)
{
while (ex.InnerException != null)
{
ex = ex.InnerException;
}
return ex;
}