Refactor overhaul, data extensions & Resend.com support

4 files changed, 278 insertions, 0 deletions

diff --git a/lib/Emails.Transactional.Plugin/src/Templates/EmailTemplateStore.cs b/lib/Emails.Transactional.Plugin/src/Templates/EmailTemplateStore.cs
new file mode 100644
index 0000000..d589262
--- /dev/null
+++ b/lib/Emails.Transactional.Plugin/src/Templates/EmailTemplateStore.cs
@@ -0,0 +1,148 @@
+/*
+* Copyright (c) 2023 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: Emails.Transactional
+* File: EmailTemplateStore.cs 
+*
+* EmailTemplateStore.cs is part of Emails.Transactional which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* Emails.Transactional is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* Emails.Transactional is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with Emails.Transactional. If not, see http://www.gnu.org/licenses/.
+*/
+
+
+using System;
+using System.IO;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Collections.Generic;
+
+using Fluid;
+
+using VNLib.Utils.IO;
+using VNLib.Utils.Extensions;
+using VNLib.Utils.Memory.Caching;
+using VNLib.Plugins;
+using VNLib.Plugins.Extensions.Loading;
+using VNLib.Plugins.Extensions.Data.Storage;
+
+using Emails.Transactional.Mta;
+
+namespace Emails.Transactional.Templates
+{
+    [ConfigurationName("templates")]
+    internal sealed class EmailTemplateStore : ITemplateStorage
+    {
+        private readonly FluidParser _parser;
+        private readonly Dictionary<string, EmailTemplate> _templateCache;
+        private readonly ISimpleFilesystem _filesystem;
+        private readonly TimeSpan _cacheValidFor;
+
+        public EmailTemplateStore(PluginBase plugin, IConfigScope config)
+        {
+            _parser = new();
+            _templateCache = new(StringComparer.OrdinalIgnoreCase);
+
+            _cacheValidFor = config["cache_valid_for_sec"].GetTimeSpan(TimeParseType.Seconds);
+            string fsPath = config.GetRequiredProperty("template_path", e => e.GetString()!);
+
+            //Get the filesystem
+            ISimpleFilesystem baseFs = plugin.GetOrCreateSingleton<MinioStorage>();
+
+            //Create a new scope for the base path
+            _filesystem = baseFs.CreateNewScope(fsPath);
+        }
+
+        public Task<IEmailTemplate> GetTemplateAsync(string templateId, CancellationToken cancellation)
+        {
+            //try to get the template from the cache
+            if (_templateCache.TryGetOrEvictRecord(templateId, out EmailTemplate? template) > 0)
+            {
+                return Task.FromResult<IEmailTemplate>(template!);
+            }
+
+            //Load the template from the store
+            return GetTemplateFromStoreAsync(templateId, cancellation);
+        }
+
+        private async Task<IEmailTemplate> GetTemplateFromStoreAsync(string templateId, CancellationToken cancellation)
+        {
+            //memory stream for template data
+            using VnMemoryStream templateData = new();
+
+            //remove leading slash
+            if (templateId.StartsWith('/'))
+            {
+                templateId = templateId[1..];
+            }
+
+            //Recover template data
+            long read = await _filesystem.ReadFileAsync(templateId, templateData, cancellation);
+
+            if(read <= 0)
+            {
+                throw new TemplateLookupFailedException($"Template {templateId} not found");
+            }
+
+            //Rewind the stream
+            templateData.Seek(0, SeekOrigin.Begin);
+
+            //To string
+            string templateString = Encoding.UTF8.GetString(templateData.AsSpan());
+
+            //Try to parse the template and raise exception if it fails
+            if (!_parser.TryParse(templateString, out IFluidTemplate template, out string error))
+            {
+                throw new TemplateLookupFailedException($"A template parse error occured: {error}");
+            }
+
+            //Create new email template
+            EmailTemplate et = new(template);
+
+            //Store template in cache
+            _templateCache.StoreRecord(templateId, et, _cacheValidFor);
+
+            return et;
+        }
+
+        private sealed record class EmailTemplate(IFluidTemplate Template) : IEmailTemplate, ICacheable
+        {
+            ///<inheritdoc/>
+            public DateTime Expires { get; set; }
+
+            ///<inheritdoc/>
+            public bool Equals(ICacheable? other) => ReferenceEquals(this, other);
+
+            ///<inheritdoc/>
+            public void Evicted()
+            { }
+
+            ///<inheritdoc/>
+            public IEmailMessageData RenderTemplate(object variables)
+            {
+                //Create a template model
+                TemplateContext ctx = new(variables);
+                string html = Template.Render(ctx);
+                return new EmailMessageData(html);
+            }
+
+            private sealed record class EmailMessageData(string Rendered) : IEmailMessageData
+            {
+                public string GetHtml() => Rendered;
+            }
+        }
+    }
+}
diff --git a/lib/Emails.Transactional.Plugin/src/Templates/IEmailTemplate.cs b/lib/Emails.Transactional.Plugin/src/Templates/IEmailTemplate.cs
new file mode 100644
index 0000000..3ee12cb
--- /dev/null
+++ b/lib/Emails.Transactional.Plugin/src/Templates/IEmailTemplate.cs
@@ -0,0 +1,42 @@
+/*
+* Copyright (c) 2023 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: Emails.Transactional
+* File: IEmailTemplate.cs 
+*
+* IEmailTemplate.cs is part of Emails.Transactional which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* Emails.Transactional is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* Emails.Transactional is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with Emails.Transactional. If not, see http://www.gnu.org/licenses/.
+*/
+
+
+using Emails.Transactional.Mta;
+
+namespace Emails.Transactional.Templates
+{
+    /// <summary>
+    /// An abstraction that defines a template for an email
+    /// </summary>
+    internal interface IEmailTemplate
+    {
+        /// <summary>
+        /// Renders a new copy of the template with the specified variables
+        /// </summary>
+        /// <param name="variables">The variable model to compile with the template</param>
+        /// <returns>A new <see cref="IEmailMessageData"/> instance to capture html data from</returns>
+        IEmailMessageData RenderTemplate(object variables);
+    }
+}
diff --git a/lib/Emails.Transactional.Plugin/src/Templates/ITemplateStorage.cs b/lib/Emails.Transactional.Plugin/src/Templates/ITemplateStorage.cs
new file mode 100644
index 0000000..e17e24a
--- /dev/null
+++ b/lib/Emails.Transactional.Plugin/src/Templates/ITemplateStorage.cs
@@ -0,0 +1,45 @@
+/*
+* Copyright (c) 2023 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: Emails.Transactional
+* File: ITemplateStorage.cs 
+*
+* ITemplateStorage.cs is part of Emails.Transactional which is part of the larger 
+* VNLib collection of libraries and utilities.
+*
+* Emails.Transactional is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* Emails.Transactional is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with Emails.Transactional. If not, see http://www.gnu.org/licenses/.
+*/
+
+
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Emails.Transactional.Templates
+{
+    /// <summary>
+    /// An abstraction that defines a storage for email templates
+    /// </summary>
+    internal interface ITemplateStorage
+    {
+        /// <summary>
+        /// Gets an email template from its id
+        /// </summary>
+        /// <param name="templateId">The id of the template to fetch</param>
+        /// <param name="cancellation">A token to cancel the fetch operation</param>
+        /// <returns>A task that completes with the template model instance</returns>
+        /// <exception cref="TemplateLookupFailedException"></exception>
+        Task<IEmailTemplate> GetTemplateAsync(string templateId, CancellationToken cancellation);
+    }
+}
diff --git a/lib/Emails.Transactional.Plugin/src/Templates/TemplateLookupFailedException.cs b/lib/Emails.Transactional.Plugin/src/Templates/TemplateLookupFailedException.cs
new file mode 100644
index 0000000..5e607f3
--- /dev/null
+++ b/lib/Emails.Transactional.Plugin/src/Templates/TemplateLookupFailedException.cs
@@ -0,0 +1,43 @@
+/*
+* Copyright (c) 2023 Vaughn Nugent
+* 
+* Library: VNLib
+* Package: Emails.Transactional
+* File: TemplateLookupFailedException.cs 
+*
+* TemplateLookupFailedException.cs is part of Emails.Transactional which is 
+* part of the larger VNLib collection of libraries and utilities.
+*
+* Emails.Transactional is free software: you can redistribute it and/or modify 
+* it under the terms of the GNU General Public License as published
+* by the Free Software Foundation, either version 2 of the License,
+* or (at your option) any later version.
+*
+* Emails.Transactional is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+* General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License 
+* along with Emails.Transactional. If not, see http://www.gnu.org/licenses/.
+*/
+
+
+using System;
+
+namespace Emails.Transactional.Templates
+{
+    [Serializable]
+    public class TemplateLookupFailedException : Exception
+    {
+        public TemplateLookupFailedException() { }
+
+        public TemplateLookupFailedException(string message) : base(message) { }
+
+        public TemplateLookupFailedException(string message, Exception inner) : base(message, inner) { }
+
+        protected TemplateLookupFailedException(
+          System.Runtime.Serialization.SerializationInfo info,
+          System.Runtime.Serialization.StreamingContext context) : base(info, context) { }
+    }
+}