Azure static files System.IO.DirectoryNotFoundException

Question

I have an ASP.NET Core application running on Azure. The application sends various emails - both in plaintext and HTML formats. I have created a subfolder in our Resources folder, called EmailTemplates, where I store all the HTML and TXT templates. An example path could be:

\src\WebProject\Resources\EmailTemplates\Welcome.html

I access the file in my EmailService.cs class in the following manner:

var filePath = Path.Combine(Directory.GetCurrentDirectory(), "Resources", "EmailTemplates", "Welcome.html");
var htmlTemplate = await File.ReadAllTextAsync(filePath);

This works great when running on local environment both on IIS and Kestrel. However, when deployed to Azure, I get an IO error message:

System.IO.DirectoryNotFoundException
An unhandled exception has occurred: Could not find a part of the path 'D:\home\site\wwwroot\Resources\EmailTemplates\Welcome.html'.

I have found a similar question on StackOverflow, but the answer is almost 6 years old. I am not sure, whether it still applies since Azure has changed significantly in the past couple of years. I was also looking at official documentation (1) (2), but I did not find anything special about Azure.

What is the correct way to store and retrieve email templates (and other static files) in ASP.NET Core and Azure?

Answer 1

Make sure your static files are part of your project.

And mark them explicitly as content and Copy to output folder -> always.