Implemented customizable email templates

Wave/Dockerfile

@@ -1,11 +1,12 @@
 #See https://aka.ms/customizecontainer to learn how to customize your debug container and how Visual Studio uses this Dockerfile to build your images for faster debugging.
 
 FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
+RUN mkdir -p /app/files && chown app /app/files
+RUN mkdir -p /configuration && chown app /configuration
 USER app
-WORKDIR /app
-RUN mkdir ./files && chown app ./files
 VOLUME /app/files
 VOLUME /configuration
+WORKDIR /app
 EXPOSE 8080
 
 FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build

Wave/Program.cs

@@ -20,11 +20,11 @@
 
 var builder = WebApplication.CreateBuilder(args);
 builder.Configuration
-	.AddJsonFile("/configuration/config.json", true, false)
+	.AddJsonFile(Path.Combine(FileSystemService.ConfigurationDirectory, "config.json"), true, false)
-	.AddYamlFile("/configuration/config.yml", true, false)
+	.AddYamlFile(Path.Combine(FileSystemService.ConfigurationDirectory, "config.yml"), true, false)
-	.AddTomlFile("/configuration/config.toml", true, false)
+	.AddTomlFile(Path.Combine(FileSystemService.ConfigurationDirectory, "config.toml"), true, false)
-	.AddIniFile( "/configuration/config.ini", true, false)
+	.AddIniFile( Path.Combine(FileSystemService.ConfigurationDirectory, "config.ini"), true, false)
-	.AddXmlFile( "/configuration/config.xml", true, false)
+	.AddXmlFile( Path.Combine(FileSystemService.ConfigurationDirectory, "config.xml"), true, false)
 	.AddEnvironmentVariables("WAVE_");
 
 builder.Services.AddRazorComponents().AddInteractiveServerComponents();
@@ -128,6 +128,7 @@
 	logMessages.Add("No Email provider configured.");
 }
 
+builder.Services.AddSingleton<FileSystemService>();
 builder.Services.AddSingleton<EmailTemplateService>();
 builder.Services.AddHostedService<EmailBackgroundWorker>();
 

Wave/Services/EmailBackgroundWorker.cs

@@ -4,7 +4,6 @@
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Options;
 using MimeKit;
-using Mjml.Net;
 using Wave.Data;
 using Wave.Utilities;
 
@@ -33,6 +32,8 @@ public class EmailBackgroundWorker(ILogger<EmailBackgroundWorker> logger, IDbCon
 			waitTime, now.AddMinutes(waitTime).LocalDateTime.ToString("u"));
 		Timer = new Timer(DoWork, null, TimeSpan.FromMinutes(waitTime), TimeSpan.FromMinutes(15));
 
+		TemplateService.TryCreateDefaultTemplates();
+
 		return Task.CompletedTask;
 	}
 
@@ -84,7 +85,10 @@ public class EmailBackgroundWorker(ILogger<EmailBackgroundWorker> logger, IDbCon
 					newsletter.Article, new Uri(Customizations.AppUrl, UriKind.Absolute));
 				string template = TemplateService.Process("newsletter", new Dictionary<EmailTemplateService.Constants, object?>{
 					{EmailTemplateService.Constants.BrowserLink, articleLink},
-					{EmailTemplateService.Constants.ContentLogo, "https://blog.winter-software.com/img/logo.png"},
+					{EmailTemplateService.Constants.ContentLogo, (!string.IsNullOrWhiteSpace(Customizations.LogoLink) ? 
+						new Uri(Customizations.LogoLink) : 
+						new Uri(host, "/img/logo.png"))
+						.AbsoluteUri},
 					{EmailTemplateService.Constants.ContentTitle, newsletter.Article.Title},
 					{EmailTemplateService.Constants.ContentBody, newsletter.Article.BodyHtml},
 					{EmailTemplateService.Constants.EmailUnsubscribeLink, "[[<__UNSUBSCRIBE__>]]"}

Wave/Services/EmailTemplateService.cs

@@ -4,14 +4,15 @@
 
 namespace Wave.Services;
 
-public partial class EmailTemplateService(ILogger<EmailTemplateService> logger, IDistributedCache tokenCache) {
+public partial class EmailTemplateService(ILogger<EmailTemplateService> logger, IDistributedCache tokenCache, FileSystemService fileSystem) {
 	public enum Constants {
 		BrowserLink, HomeLink, ContentLogo, ContentTitle, ContentBody, EmailUnsubscribeLink
 	}
 
 	private ILogger<EmailTemplateService> Logger { get; } = logger;
-	private IMjmlRenderer Renderer { get; } = new MjmlRenderer();
+	private MjmlRenderer Renderer { get; } = new();
 	private IDistributedCache TokenCache { get; } = tokenCache;
+	private FileSystemService FileSystem { get; } = fileSystem;
 
 	private Regex TokenMatcher { get; } = MyRegex();
 
@@ -50,58 +51,19 @@ public enum Constants {
 		});
 	}
 
+	public void TryCreateDefaultTemplates() {
+		FileSystem.GetEmailTemplate("default", DefaultTemplates["default"]);
+		FileSystem.GetEmailTemplate("newsletter", DefaultTemplates["newsletter"]);
+	}
+
 	public string Process(string templateName, Dictionary<Constants, object?> data) {
 		var options = new MjmlOptions {
 			Beautify = false
 		};
 
-		string template = $"""
+		string template = FileSystem.GetEmailTemplate(templateName, 
-		                    <mjml>
+			                  DefaultTemplates.TryGetValue(templateName, out string? s) ? s : null)
-		                      <mj-head>
+			?? throw new ApplicationException("Failed to retrieve mail template " + templateName + ".");
-		                        <mj-preview/>
-		                      </mj-head>
-		                      <mj-body>
-		                        <mj-section>
-		                        	<mj-column>
-		                          	<mj-text align="center" font-size="13px" font-family="Ubuntu,Verdana">
-		                              <a href="[[{Constants.BrowserLink}]]">Read in Browser</a></mj-text>
-		                          </mj-column>
-		                        </mj-section>
-		                        <mj-section direction="rtl" padding-bottom="15px" padding-left="0px" padding-right="0px" padding-top="15px" padding="15px 0px 15px 0px">
-		                          <mj-column vertical-align="middle" width="33%">
-		                            <mj-image align="center" alt="" border-radius="0" border="none" container-background-color="transparent" height="auto" padding-bottom="5px" padding-left="5px" padding-right="5px" padding-top="5px" padding="5px 5px 5px 5px" href="[[{Constants.HomeLink}]]" src="[[{Constants.ContentLogo}]]"></mj-image>
-		                          </mj-column>
-		                          <mj-column vertical-align="middle" width="67%">
-		                            <mj-text font-size="13px" font-family="Ubuntu,Verdana">
-		                              <h1>[[{Constants.ContentTitle}]]</h1>
-		                            </mj-text>
-		                          </mj-column>
-		                        </mj-section>
-		                        <mj-section>
-		                        	<mj-column>
-		                          	<mj-divider border-width="1px"></mj-divider>
-		                          </mj-column>
-		                        </mj-section>
-		                        <mj-section>
-		                          <mj-column>
-		                            <mj-text color="#55575d" font-size="13px" font-family="Ubuntu,Verdana">[[{Constants.ContentBody}]]</mj-text>
-		                          </mj-column>
-		                        </mj-section>
-		                        <mj-section>
-		                        	<mj-column>
-		                          	<mj-divider border-width="1px"></mj-divider>
-		                          </mj-column>
-		                        </mj-section>
-		                        <mj-section>
-		                        	<mj-column>
-		                            <mj-text align="center" font-size="13px" font-family="Ubuntu,Verdana">
-		                              <a href="[[{Constants.EmailUnsubscribeLink}]]">Unsubscribe</a>
-		                            </mj-text>
-		                          </mj-column>
-		                        </mj-section>
-		                      </mj-body>
-		                    </mjml>
-		                    """;
 		
 		template = TokenMatcher.Replace(template, t => 
 			data.TryGetValue(Enum.Parse<Constants>(t.Value[2..^2], true), out object? v) ? 
@@ -121,4 +83,96 @@ public enum Constants {
 	[GeneratedRegex(@"(\[\[.*?\]\])", 
 		RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Singleline | RegexOptions.CultureInvariant)]
 	private static partial Regex MyRegex();
+
+
+	private Dictionary<string, string> DefaultTemplates { get; } = new() {
+		{
+			"default",
+			$"""
+			 <mjml>
+			   <mj-head>
+			     <mj-preview />
+			   </mj-head>
+			   <mj-body>
+			     <mj-section direction="rtl" padding-bottom="5px" padding-left="0px" padding-right="0px" padding-top="15px" padding="15px 0px 5px 0px">
+			       <mj-column vertical-align="middle" width="33%">
+			         <mj-image align="center" alt="" border-radius="0" border="none" container-background-color="transparent" height="auto" padding-bottom="5px" padding-left="5px" padding-right="5px" padding-top="5px" padding="5px 5px 5px 5px" href="[[{Constants.HomeLink}]]" src="[[{Constants.ContentLogo}]]"></mj-image>
+			       </mj-column>
+			       <mj-column vertical-align="middle" width="67%">
+			         <mj-text font-size="13px" font-family="Ubuntu,Verdana">
+			           <h1>[[{Constants.ContentTitle}]]</h1>
+			         </mj-text>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section padding-top="5px" padding-bottom="5px" padding="5px 0 5px 0">
+			       <mj-column>
+			         <mj-divider border-color="#9f9f9f" border-width="1px"></mj-divider>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section>
+			       <mj-column>
+			         <mj-text color="#55575d" font-size="13px" font-family="Ubuntu,Verdana">[[{Constants.ContentBody}]]</mj-text>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section padding-top="5px" padding-bottom="5px" padding="5px 0 5px 0">
+			       <mj-column>
+			         <mj-divider border-color="#9f9f9f" border-width="1px"></mj-divider>
+			       </mj-column>
+			     </mj-section>
+			   </mj-body>
+			 </mjml>
+			 """
+		},
+		{
+			"newsletter",
+			$"""
+			 <mjml>
+			   <mj-head>
+			     <mj-preview />
+			   </mj-head>
+			   <mj-body>
+			     <mj-section>
+			       <mj-column>
+			         <mj-text align="center" font-size="13px" font-family="Ubuntu,Verdana">
+			           <a href="[[{Constants.BrowserLink}]]">Read in Browser</a>
+			         </mj-text>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section direction="rtl" padding-bottom="5px" padding-left="0px" padding-right="0px" padding-top="15px" padding="15px 0px 5px 0px">
+			       <mj-column vertical-align="middle" width="33%">
+			         <mj-image align="center" alt="" border-radius="0" border="none" container-background-color="transparent" height="auto" padding-bottom="5px" padding-left="5px" padding-right="5px" padding-top="5px" padding="5px 5px 5px 5px" href="[[{Constants.HomeLink}]]" src="[[{Constants.ContentLogo}]]"></mj-image>
+			       </mj-column>
+			       <mj-column vertical-align="middle" width="67%">
+			         <mj-text font-size="13px" font-family="Ubuntu,Verdana">
+			           <h1>[[{Constants.ContentTitle}]]</h1>
+			         </mj-text>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section padding-top="5px" padding-bottom="5px" padding="5px 0 5px 0">
+			       <mj-column>
+			         <mj-divider border-color="#9f9f9f" border-width="1px"></mj-divider>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section>
+			       <mj-column>
+			         <mj-text color="#55575d" font-size="13px" font-family="Ubuntu,Verdana">[[{Constants.ContentBody}]]</mj-text>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section padding-top="5px" padding-bottom="5px" padding="5px 0 5px 0">
+			       <mj-column>
+			         <mj-divider border-color="#9f9f9f" border-width="1px"></mj-divider>
+			       </mj-column>
+			     </mj-section>
+			     <mj-section>
+			       <mj-column>
+			         <mj-text align="center" font-size="13px" font-family="Ubuntu,Verdana">
+			           <a href="[[{Constants.EmailUnsubscribeLink}]]">Unsubscribe</a>
+			         </mj-text>
+			       </mj-column>
+			     </mj-section>
+			   </mj-body>
+			 </mjml>
+			 """
+		}
+	};
 }

Wave/Services/FileSystemService.cs

@@ -0,0 +1,55 @@
+using System.Text;
+
+namespace Wave.Services;
+
+public class FileSystemService(ILogger<FileSystemService> logger) {
+	public const string ConfigurationDirectory = "/configuration";
+
+	private ILogger<FileSystemService> Logger { get; } = logger;
+
+	public async Task<string?> GetEmailTemplateAsync(string name, string? defaultTemplate = null) {
+		string path = Path.Combine(ConfigurationDirectory, "templates", "email", name + ".mjml");
+
+		if (!File.Exists(path)) {
+			try {
+				Directory.CreateDirectory(Path.GetDirectoryName(path)!);
+				if (!string.IsNullOrWhiteSpace(defaultTemplate)) {
+					await File.WriteAllTextAsync(path, defaultTemplate, Encoding.UTF8);
+				}
+			} catch (Exception ex) {
+				Logger.LogError(ex, "File system access failed trying write default E-Mail template '{template}'", name);
+				return defaultTemplate;
+			}
+		}
+
+		try {
+			return await File.ReadAllTextAsync(path, Encoding.UTF8);
+		} catch (Exception ex) {
+			Logger.LogError(ex, "File system access failed trying to retrieve E-Mail template '{template}'", name);
+			return defaultTemplate;
+		}
+	}
+	
+	public string? GetEmailTemplate(string name, string? defaultTemplate = null) {
+		string path = Path.Combine(ConfigurationDirectory, "templates", "email", name + ".mjml");
+
+		if (!File.Exists(path)) {
+			try {
+				Directory.CreateDirectory(Path.GetDirectoryName(path)!);
+				if (!string.IsNullOrWhiteSpace(defaultTemplate)) {
+					File.WriteAllText(path, defaultTemplate, Encoding.UTF8);
+				}
+			} catch (Exception ex) {
+				Logger.LogError(ex, "File system access failed trying write default E-Mail template '{template}'", name);
+				return defaultTemplate;
+			}
+		}
+
+		try {
+			return File.ReadAllText(path, Encoding.UTF8);
+		} catch (Exception ex) {
+			Logger.LogError(ex, "File system access failed trying to retrieve E-Mail template '{template}'", name);
+			return defaultTemplate;
+		}
+	}
+}