(GH-391) Add MailSettingsConverter and use it instead of manually ser…

…ializing the mail settings

Source/StrongGrid.UnitTests/Resources/MailTests.cs

@@ -41,8 +41,23 @@ public async Task SendAsync()
 				}
 			};
 
+			var mailSettings = new MailSettings()
+			{
+				BypassBounceManagement = true,
+				BypassListManagement = true,
+				BypassSpamManagement = true,
+				BypassUnsubscribeManagement = true,
+				SandboxModeEnabled = true,
+				Footer = new FooterSettings()
+				{
+					Enabled = true,
+					HtmlContent = "abc123",
+					TextContent = "yzx890"
+				}
+			};
+
 			// Act
-			var result = await mail.SendAsync(personalizations, null, null, null, null, null, null, null, null, null, null, null, null, null, null, null, MailPriority.Normal, CancellationToken.None).ConfigureAwait(false);
+			var result = await mail.SendAsync(personalizations, null, null, null, null, null, null, null, null, null, null, null, null, null, mailSettings, null, MailPriority.Normal, CancellationToken.None).ConfigureAwait(false);
 
 			// Assert
 			mockHttp.VerifyNoOutstandingExpectation();

Source/StrongGrid/Models/MailSettings.cs

@@ -1,8 +1,12 @@
+using Newtonsoft.Json;
+using StrongGrid.Utilities;
+
 namespace StrongGrid.Models
 {
 	/// <summary>
 	/// Mail settings.
 	/// </summary>
+	[JsonConverter(typeof(MailSettingsConverter))]
 	public class MailSettings
 	{
 		/// <summary>

Source/StrongGrid/Resources/Mail.cs

@@ -188,19 +188,18 @@ public async Task<string> SendAsync(
 			numberOfRecipients += personalizationsCopy.Sum(p => p.Bcc?.Count(r => r != null) ?? 0);
 			if (numberOfRecipients >= 1000) throw new ArgumentOutOfRangeException(nameof(numberOfRecipients), numberOfRecipients, "The total number of recipients must be less than 1000");
 
-			var isDynamicTemplate = Template.IsDynamic(templateId);
-			var personalizationConverter = new MailPersonalizationConverter(isDynamicTemplate);
+			// Get the priority headers
+			if (!_priorityHeaders.TryGetValue(priority, out KeyValuePair<string, string>[] priorityHeaders))
+			{
+				throw new Exception($"{priority} is an unknown priority");
+			}
 
-			// Manually serialize the MailSettings object because the shape of the C# class does not match the shape of the desired JSON.
-			// The C# class was intentionaly simplified to improve developers experience.
-			var mailSettingsJsonObject = new JObject();
-			mailSettingsJsonObject.AddPropertyIfValue("bypass_list_management/enable", mailSettings.BypassListManagement);
-			mailSettingsJsonObject.AddPropertyIfValue("bypass_spam_management/enable", mailSettings.BypassSpamManagement);
-			mailSettingsJsonObject.AddPropertyIfValue("bypass_bounce_management/enable", mailSettings.BypassBounceManagement);
-			mailSettingsJsonObject.AddPropertyIfValue("bypass_unsubscribe_management/enable", mailSettings.BypassUnsubscribeManagement);
-			mailSettingsJsonObject.AddPropertyIfValue("footer", mailSettings.Footer);
-			mailSettingsJsonObject.AddPropertyIfValue("sandbox_mode/enable", mailSettings.SandboxModeEnabled);
+			// Combine headers with priority headers making sure not to duplicate priority headers
+			var combinedHeaders = (headers ?? Array.Empty<KeyValuePair<string, string>>())
+				.Where(kvp => !priorityHeaders.Any(p => p.Key.Equals(kvp.Key, StringComparison.OrdinalIgnoreCase)))
+				.Concat(priorityHeaders);
 
+			// Serialize the mail message
 			var data = new JObject();
 			data.AddPropertyIfValue("from", from);
 			data.AddPropertyIfValue("reply_to", replyTo);
@@ -213,52 +212,25 @@ public async Task<string> SendAsync(
 			data.AddPropertyIfValue("batch_id", batchId);
 			data.AddPropertyIfValue("asm", unsubscribeOptions);
 			data.AddPropertyIfValue("ip_pool_name", ipPoolName);
-			data.AddPropertyIfValue("mail_settings", mailSettingsJsonObject);
+			data.AddPropertyIfValue("mail_settings", mailSettings);
 			data.AddPropertyIfValue("tracking_settings", trackingSettings);
-			data.AddPropertyIfValue("personalizations", personalizationsCopy, personalizationConverter);
-
-			if (_priorityHeaders.TryGetValue(priority, out KeyValuePair<string, string>[] priorityHeaders))
-			{
-				headers = (headers ?? Array.Empty<KeyValuePair<string, string>>()).Concat(priorityHeaders);
-			}
-			else
-			{
-				throw new Exception($"{priority} is an unknown priority");
-			}
-
-			if (headers != null && headers.Any())
-			{
-				var hdrs = new JObject();
-				foreach (var header in headers)
-				{
-					hdrs.Add(header.Key, header.Value);
-				}
-
-				data.Add("headers", hdrs);
-			}
-
-			if (customArgs != null && customArgs.Any())
-			{
-				var args = new JObject();
-				foreach (var customArg in customArgs)
-				{
-					args.Add(customArg.Key, customArg.Value);
-				}
-
-				data.Add("custom_args", args);
-			}
+			data.AddPropertyIfValue("personalizations", personalizationsCopy, new MailPersonalizationConverter(Template.IsDynamic(templateId)));
+			data.AddPropertyIfValue("headers", ConvertEnumerationToJObject(combinedHeaders));
+			data.AddPropertyIfValue("custom_args", ConvertEnumerationToJObject(customArgs));
 
 			// SendGrid does not allow emails that exceed 30MB
 			var contentSize = JsonConvert.SerializeObject(data, Formatting.None).Length;
 			if (contentSize > MAX_EMAIL_SIZE) throw new Exception("Email exceeds the size limit");
 
+			// Send the request
 			var response = await _client
 				.PostAsync($"{_endpoint}/send")
 				.WithJsonBody(data)
 				.WithCancellationToken(cancellationToken)
 				.AsResponse()
 				.ConfigureAwait(false);
 
+			// Get the messageId from the response
 			if (response.Message.Headers.TryGetValues("X-Message-Id", out IEnumerable<string> values))
 			{
 				return values?.FirstOrDefault();
@@ -288,5 +260,18 @@ private static MailAddress[] EnsureRecipientsNamesAreQuoted(MailAddress[] recipi
 				.Union(recipientsWithoutName)
 				.ToArray();
 		}
+
+		private static JObject ConvertEnumerationToJObject(IEnumerable<KeyValuePair<string, string>> items)
+		{
+			if (items == null || !items.Any()) return null;
+
+			var obj = new JObject();
+			foreach (var item in items)
+			{
+				obj.Add(item.Key, item.Value);
+			}
+
+			return obj;
+		}
 	}
 }

Source/StrongGrid/Utilities/MailSettingsConverter.cs

@@ -0,0 +1,120 @@
+using Newtonsoft.Json;
+using StrongGrid.Models;
+using System;
+
+namespace StrongGrid.Utilities
+{
+	/// <summary>
+	/// Converts a MailSettings object to and from JSON.
+	/// </summary>
+	/// <seealso cref="Newtonsoft.Json.JsonConverter" />
+	internal class MailSettingsConverter : JsonConverter
+	{
+		public MailSettingsConverter()
+		{
+		}
+
+		/// <summary>
+		/// Determines whether this instance can convert the specified object type.
+		/// </summary>
+		/// <param name="objectType">Type of the object.</param>
+		/// <returns>
+		/// <c>true</c> if this instance can convert the specified object type; otherwise, <c>false</c>.
+		/// </returns>
+		public override bool CanConvert(Type objectType)
+		{
+			return objectType == typeof(MailSettings);
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether this <see cref="T:Newtonsoft.Json.JsonConverter" /> can read JSON.
+		/// </summary>
+		/// <value>
+		/// <c>true</c> if this <see cref="T:Newtonsoft.Json.JsonConverter" /> can read JSON; otherwise, <c>false</c>.
+		/// </value>
+		public override bool CanRead
+		{
+			get { return false; }
+		}
+
+		/// <summary>
+		/// Gets a value indicating whether this <see cref="T:Newtonsoft.Json.JsonConverter" /> can write JSON.
+		/// </summary>
+		/// <value>
+		/// <c>true</c> if this <see cref="T:Newtonsoft.Json.JsonConverter" /> can write JSON; otherwise, <c>false</c>.
+		/// </value>
+		public override bool CanWrite
+		{
+			get { return true; }
+		}
+
+		/// <summary>
+		/// Writes the JSON representation of the object.
+		/// </summary>
+		/// <param name="writer">The <see cref="T:Newtonsoft.Json.JsonWriter" /> to write to.</param>
+		/// <param name="value">The value.</param>
+		/// <param name="serializer">The calling serializer.</param>
+		public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
+		{
+			if (value == null) return;
+
+			writer.WriteStartObject();
+
+			var mailSettings = (MailSettings)value;
+
+			writer.WritePropertyName("bypass_list_management");
+			writer.WriteStartObject();
+			writer.WritePropertyName("enable");
+			serializer.Serialize(writer, mailSettings.BypassListManagement);
+			writer.WriteEndObject();
+
+			writer.WritePropertyName("bypass_spam_management");
+			writer.WriteStartObject();
+			writer.WritePropertyName("enable");
+			serializer.Serialize(writer, mailSettings.BypassSpamManagement);
+			writer.WriteEndObject();
+
+			writer.WritePropertyName("bypass_bounce_management");
+			writer.WriteStartObject();
+			writer.WritePropertyName("enable");
+			serializer.Serialize(writer, mailSettings.BypassBounceManagement);
+			writer.WriteEndObject();
+
+			writer.WritePropertyName("bypass_unsubscribe_management");
+			writer.WriteStartObject();
+			writer.WritePropertyName("enable");
+			serializer.Serialize(writer, mailSettings.BypassUnsubscribeManagement);
+			writer.WriteEndObject();
+
+			if (mailSettings.Footer != null)
+			{
+				writer.WritePropertyName("footer");
+				serializer.Serialize(writer, mailSettings.Footer);
+			}
+
+			writer.WritePropertyName("sandbox_mode");
+			writer.WriteStartObject();
+			writer.WritePropertyName("enable");
+			serializer.Serialize(writer, mailSettings.SandboxModeEnabled);
+			writer.WriteEndObject();
+
+			// End of JSON serialization
+			writer.WriteEndObject();
+		}
+
+		/// <summary>
+		/// Reads the JSON representation of the object.
+		/// </summary>
+		/// <param name="reader">The <see cref="T:Newtonsoft.Json.JsonReader" /> to read from.</param>
+		/// <param name="objectType">Type of the object.</param>
+		/// <param name="existingValue">The existing value of object being read.</param>
+		/// <param name="serializer">The calling serializer.</param>
+		/// <returns>
+		/// The object value.
+		/// </returns>
+		public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
+		{
+			throw new NotSupportedException("The MailSettingsConverter can only be used to write JSON");
+		}
+	}
+}