Hi,

I get the following error on trying to convert HTML string to PDF


Server Error in '/test' Application.
This session is no longer valid. If you wish to reuse the session later, please consider calling GetCookies to retain the session cookies, then reuse these cookies through HtmlToPdfOptions.Cookies with another session. (6)
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: EO.Pdf.Internal.k1: This session is no longer valid. If you wish to reuse the session later, please consider calling GetCookies to retain the session cookies, then reuse these cookies through HtmlToPdfOptions.Cookies with another session. (6)

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[k1: This session is no longer valid. If you wish to reuse the session later, please consider calling GetCookies to retain the session cookies, then reuse these cookies through HtmlToPdfOptions.Cookies with another session. (6)]
EO.Pdf.Internal.lo.l() +89
EO.Pdf.Internal.lo.a(a A_0) +139
EO.Pdf.Internal.lo.a(cm A_0) +38
EO.Pdf.HtmlToPdfSession.Dispose() +100
EO.Pdf.HtmlToPdf.ConvertHtml(String html, PdfDocument doc, HtmlToPdfOptions options) +240
EO.Pdf.HtmlToPdf.ConvertHtml(String html, PdfDocument doc) +7
[.....]


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.272



The version of EO.Pdf dll being used is - 4.0.41.2
There are no images used in the HTML. The HTML string itself is dynamically generated. The above error doesn't happen all the time and there doesn't seem to be a regular pattern, but happens generally when the HTML size starts to get bigger. The HTML wouldn't be bigger than few KBs.


Below is the code that is being used

SetEoHtmlToPdfLicense();
HtmlToPdf.Options.BaseUrl = HttpContextFactory.Current.Request.Url.GetLeftPart(UriPartial.Authority) +
VirtualPathUtility.ToAbsolute("~/");
HtmlToPdf.Options.PageSize = PdfPageSizes.A4;
HtmlToPdf.Options.MaxLoadWaitTime = 120000;

//Convert the Url to PdfDocument
var doc = new PdfDocument();

HtmlToPdf.ConvertHtml(html, doc);
HttpContextFactory.Current.Response.Clear();
HttpContextFactory.Current.Response.ClearHeaders();
HttpContextFactory.Current.Response.ContentType = "Application/pdf";
HttpContextFactory.Current.Response.AddHeader("Content-Disposition",
string.Format("Attachment;Filename=export_{0}.pdf",
DateTime.Now));
doc.Save(HttpContextFactory.Current.Response.OutputStream);
HttpContextFactory.Current.Response.End();


I have seen other posts in the forum, suggesting the usage of the latest build. But my version seems to be much latest than what is seen in those posts.

Appreciate your help in fixing the issue as soon as possible.

Thanks for the reply.

I guess, I cannot use ASPXToPDF since the documentation says, "ASPXToPDF is an ASP.NET server control that allows you to render the current page as PDF". In my scenario, it is not the current page which needs to be converted. It is more like exporting search results to PDF. The user has an option to select how much ever search results to export to PDF. When the number of results is 10-15, the conversion works most of the time, but I have seen it fail. On other times, the conversion works fine when the number of results is 150 odd. The HTML has mere text, nothing else.

What do you mean by trying to find out which part inside the HTML triggers the problem? You mean to look out for a certain tag? What inside the HTML is likely to cause such an error?

Hi,

"This session is no longer valid error" usually occurs when you create a HtmlToPdfSession object, but didn't use it for a while and then try to use it. This can also occur if one conversion takes a long time.

What I meant is by "trying to find out which part inside the HTML triggers the problem", I meant that there maybe something in your HTML that triggers certain request on your server that can cause problem for you. One example is, if you have something like this in your HTML:



Then the converter will request that page, which runs the code associated to that page on the server and (presumably) cause you to log yourself out. Obviously if you have another request in the HTML block that requires user to be logged in, then you will have trouble. So the idea is to first find out what triggered the problem first.

As to the “buffer can not be null” problem, we do not know what’s causing it. If you can reproduce it and send us a test project, we will be very happy to take a look.

Thanks!

Great. Glad to hear that it worked for you!