HTML-to-PDF Generator for .NET C# WkHtmlToPdf wrapper

PdfGenerator renders web page like a web browser and can load external resources like images, CSS and js files (javascript code is executed just before PDF rendering).

PdfGenerator executes WkHtmlToPdf command line tool (x86 windows build) in the separate process with System.Diagnostics.Process and your project environment/platform should allow that.
Component cannot be used (does not work) in the following cases:

• partial-trust environments where starting new processes is prohibited (shared ASP.NET hostings)
• Windows Server configurations with restricted access to GDI API: Azure Apps (Free, Shared plans) are NOT supported!
  Azure Apps VM-based plans (Basic, Standard, Premium) can use NReco.PdfGenerator with some limitations (avoid usage of custom fonts).
• .NET platforms where System.Diagnostics.Process API is not available (UWP/Univeral Apps)

PdfGenerator works fine with usual Azure VM instances (Web Role, Worker Role) and Azure Service Fabric.
Both .NET 2.0 and 4.0 runtimes are supported.

Linux + MONO, legacy windows versions (XP/2003 Server)
NReco.PdfGenerator assembly embeds windows build of wkhtmltopdf.exe (MSVC 2013) and it can work only under windows (Vista/2008 Server or later).
It is possible to overcome this limitation with special "light" PdfGenerator build (NReco.PdfGenerator.LT.dll). LT assembly doesn't include wkhtmltopdf.exe and can be used with non-windows wkhtmltopdf builds (OS X, Linux or MinGW build for legacy versions of windows).

.NET Core
NReco.PdfGenerator.LT nuget package includes build for .NET Standards 1.5 that can be used from .NET Core apps.
Note that you should deploy wkhtmltopdf binaries for your target platform(s) (Windows, Linux or OS X) with your .NET Core app.

LT build usage
The following C# code snippet illustrates how to initialize LT build:

var htmlToPdfConv = new NReco.PdfGenerator.HtmlToPdfConverter();
htmlToPdfConv.License.SetLicenseKey(
	"your_id", "your_license_key");
// for Linux/OS-X: "wkhtmltopdf"
htmlToPdfConv.WkHtmlToPdfExeName = "wkhtmltopdf.exe";
// path where wkhtmltopdf binaries are installed/deployed
htmlToPdfConv.PdfToolPath = "<path_to_wkhtmltopdf_folder>";
htmlToPdfConv.GeneratePdfFromFile(
	"http://www.google.com", null, "google.pdf");

It is possible to specify custom header/footer in the following way:

var htmlToPdf = new NReco.PdfGenerator.HtmlToPdfConverter();
htmlToPdf.PageHeaderHtml = "<div style='text-align:right;'>HEADER <span class='page'></span> of <span class='topage'></span> </div>";

If PDF is produced from several HTML inputs header/footer may be specified individually for each HTML:

htmlToPdf.GeneratePdfFromFiles(
  new [] {
    new WkHtmlInput("https://wkhtmltopdf.org/") {
      PageHeaderHtml = "HEADER 1"
    },
    new WkHtmlInput("https://www.google.com") {
      PageHeaderHtml = "HEADER 2"
    },
  },
  null,
  "multi_header.pdf"
);

Note that this GeneratePdfFromFiles overload can be used only with a license key.

Starting from PdfGenerator v.1.1. (based on wkhtmltopdf 0.12.x) it is possible to render table headers on each page and get correct page breaks with long tables.
Note: wkhtmltopdf still has several open issues related to rendering long tables (for example, if table cells contain a lot of content).

In some cases PDF generation fails with one of the following errors:

• Exit with code 1 due to network error: ContentNotFoundError
• Exit with code 1 due to network error: ProtocolUnknownError
• Exit with code 1 due to network error: HostNotFoundError

This error means that input HTML has external js/css/image URL reference(s) that cannot be loaded by WkHtmlToPdf. In most cases PDF can be generated by specifying additional WkHtmlToPdf parameter:

var htmlToPdf = new HtmlToPdfConverter();
htmlToPdf.CustomWkHtmlArgs = " --load-media-error-handling ignore ";

PdfGenerator can be used for converting Word documents (docx, Word 2007+) to PDF in the following way:

• convert docx (OpenXML) to HTML using OpenXmlPowerTools library (open source). It correctly handles embedded images, styles, tables etc.
• convert intermediate HTML file to PDF with PdfGenerator

This approach is illustrated by Word-To-Pdf C# example (included into commercial package).

There are 2 ways how ASPX page can be exported to PDF:

1. use GeneratePdfFromFile method and specify absolute URL to ASPX page as input file path (simplest solution if ASPX page is doesn't require authentication).
2. Override System.Web.UI.Page.Render method in the following way:

   protected override void Render(HtmlTextWriter writer) {
    if (Request["export"]=="pdf") {
     var strWr = new StringWriter();
     var htmlWr = new HtmlTextWriter(); 		
     base.Render(htmlWr);
     var htmlToPdf = new HtmlToPdfConverter();
     Response.ContentType = "application/pdf";
     htmlToPdf.GeneratePdf(strWr.ToString(), null, Response.OutputStream);
     Response.End();
    }
   }

   As result you can download PDF version of the ASPX page by adding "?export=pdf" query parameter.

You can force wkhtmltopdf to use print media type by specifying the following option:

var pdfGen = new HtmlToPdfConverter();
pdfGen.CustomWkHtmlArgs ="  --print-media-type ";

Note that in some cases (esp. when page has complex javascript - for example, that renders dynamic SVG charts) this option may cause wkhtmltopdf crush. As alternative to "--print-media-type" you may use extra CSS file that applied only when PDF is generated.