DinkToPdf including image in HtmlContent

Question

I have a pdf invoice created using .Net Core 3 Web API and DinkToPdf library.

Now I need to insert into pdf an image as signature. I created the Resource folder of my project and add the image with the Copy to Output Directory set to allways . But I don't know how to use it in my string value which contain all the pdf data.

 var htmlDoc = new StringBuilder();
 ...
 htmlDoc.AppendLine("<td>");

 // here I need to insert the image
 Stream imgStream = Assembly.GetExecutingAssembly()
  .GetManifestResourceStream("Project.Resources.signature.jpeg"); // is allways null
 or
 htmlDoc.AppendLine("<img src=\"Project.Resources.signature.jpeg\" />");

 htmlDoc.AppendLine("</td>");

 var doc = new HtmlToPdfDocument()
 {
     GlobalSettings = {
         ColorMode = ColorMode.Color,
         Orientation = Orientation.Landscape,
         PaperSize = PaperKind.A4Plus,
         Margins = new MarginSettings() { Top = 10, Left = 30, Right = 30 }
     },
     Objects = {
         new ObjectSettings() {
             PagesCount = true,
             HtmlContent = htmlDoc.ToString(),
             WebSettings = { DefaultEncoding = "utf-8" }
         }
     }
 };

 var pdf = converter.Convert(doc);
 var stream = new MemoryStream(pdf);
 var contentType = @"application/pdf";
 var fileName = $"Invoice_{entity.Id}.pdf";
 stream.Seek(0, SeekOrigin.Begin);
 
 return File(stream, contentType, fileName);

Startup.cs:

services.AddSingleton(typeof(IConverter), new SynchronizedConverter(new PdfTools()));

edit: I found absolute path works

 htmlDoc.AppendLine("<img src=\"C/User/Application/Project/Resources/signature.jpeg\" />");

But, this is not an optimal solution because the absolute path of local environment is different of production environment .

any other idea? thanks

Answer 1

The working directory of Asp.net Core is different from the web directory. You need to add the folder in the project root directory. 。 It is the root directory of the web.

In controller, get the project root directory through IWebHostEnvironment. Here is the example.

[ApiController]
[Route("dink/")]
public class DinkController:ControllerBase
{
    IConverter converter;
    public IConfiguration Configuration;
    IWebHostEnvironment webHostEnvironment;
    public DinkController(IConverter _converter,IConfiguration configuration,IWebHostEnvironment environment)
    {
        converter = _converter;
        Configuration = configuration;
        webHostEnvironment = environment;
    }
    //[Route("get")]
    public IActionResult get()
    {
        var htmlDoc = new StringBuilder();
        htmlDoc.AppendLine("<td>");
        var path = webHostEnvironment.WebRootPath+"\\1.png";//It fetches files under wwwroot
        htmlDoc.AppendLine($"<img src=\"{path}\" />");
        htmlDoc.AppendLine("</td>");

        var doc = new HtmlToPdfDocument()
        {
            GlobalSettings = {
                 ColorMode = ColorMode.Color,
                 Orientation = Orientation.Landscape,
                 PaperSize = PaperKind.A4Plus,
                 Margins = new MarginSettings() { Top = 10, Left = 30, Right = 30 }
             },
             Objects = {
                 new ObjectSettings() {
                     PagesCount = true,
                     HtmlContent = htmlDoc.ToString(),
                     WebSettings = { DefaultEncoding = "utf-8" }
                 }
             }
        };

        var pdf = converter.Convert(doc);
        var stream = new MemoryStream(pdf);
        var contentType = @"application/pdf";
        var fileName = $"Invoice_Id.pdf";
        stream.Seek(0, SeekOrigin.Begin);

        return File(stream, contentType, fileName);
    }
}