fix (Email Handler) properly parse GUID ID properties

Also, refactored some of the code to use the previous interface (to avoid breaking extension that rely on the interface not changing).

See: #185

src/formulate.app/Forms/Handlers/Email/EmailConfiguration.cs

@@ -1,7 +1,12 @@
 namespace formulate.app.Forms.Handlers.Email
 {
+
+    // Namespaces.
+    using formulate.core.Extensions;
+    using Newtonsoft.Json;
     using System;
     using System.Collections.Generic;
+    using System.Linq;
 
     /// <summary>
     /// Configuration used by <see cref="EmailHandler"/>.
@@ -16,12 +21,32 @@ public class EmailConfiguration : IEmailSenderRecipientConfiguration
         /// <summary>
         /// Gets or sets the recipients of the email.
         /// </summary>
-        public IEnumerable<Recipient> Recipients { get; set; }
+        [JsonProperty("recipients")]
+        public IEnumerable<Recipient> RecipientsData { get; set; }
+
+        /// <summary>
+        /// Gets the recipients of the email.
+        /// </summary>
+        /// <remarks>
+        /// This is a duplicate property because this version implements the interface,
+        /// which requires a slightly different data type.
+        /// </remarks>
+        public IEnumerable<string> Recipients => RecipientsData.MakeSafe().Select(x => x.Email).ToArray();
 
         /// <summary>
         /// Gets or sets the fields containing the recipients of the email.
         /// </summary>
-        public IEnumerable<Guid> RecipientFields { get; set; }
+        [JsonProperty("recipientFields")]
+        public IEnumerable<GuidId> RecipientFieldsData { get; set; }
+
+        /// <summary>
+        /// Gets the fields containing the recipients of the email.
+        /// </summary>
+        /// <remarks>
+        /// This is a duplicate property because this version implements the interface,
+        /// which requires a slightly different data type.
+        /// </remarks>
+        public IEnumerable<Guid> RecipientFields => RecipientFieldsData.MakeSafe().Select(x => x.Id).ToArray();
 
         /// <summary>
         /// Gets or sets the type of delivery for the recipients (e.g., to, cc, bcc).
@@ -31,7 +56,17 @@ public class EmailConfiguration : IEmailSenderRecipientConfiguration
         /// <summary>
         /// Gets or sets the fields to include.
         /// </summary>
-        public IEnumerable<Guid> FieldsToInclude { get; set; }
+        [JsonProperty("fieldsToInclude")]
+        public IEnumerable<GuidId> FieldsToIncludeData { get; set; }
+
+        /// <summary>
+        /// Gets the fields to include.
+        /// </summary>
+        /// <remarks>
+        /// This is a convenience property that extracts the important data
+        /// from the other version of this property.
+        /// </remarks>
+        public IEnumerable<Guid> FieldsToInclude => FieldsToIncludeData.MakeSafe().Select(x => x.Id).ToArray();
 
         /// <summary>
         /// Gets or sets the message.

src/formulate.app/Forms/Handlers/Email/EmailHandler.cs

@@ -294,7 +294,6 @@ protected MailMessage PrepareEmailMessage(
 
             // Any allowed recipients (if not, abort early)?
             var rawRecipients = config.Recipients
-                .Select(x => x.Email)
                 .Concat(fieldEmails)
                 .Concat(extraEmails);
             var allowedRecipients = FilterEmails(rawRecipients);

src/formulate.app/Forms/Handlers/Email/IEmailSenderRecipientConfiguration.cs

@@ -21,7 +21,7 @@ public interface IEmailSenderRecipientConfiguration
         /// <summary>
         /// Gets the recipients of the email.
         /// </summary>
-        IEnumerable<Recipient> Recipients { get; }
+        IEnumerable<string> Recipients { get; }
 
         /// <summary>
         /// Gets the fields containing the recipients of the email.

src/formulate.app/Forms/Handlers/Email/RecipientField.cs

@@ -0,0 +1,24 @@
+namespace formulate.app.Forms.Handlers.Email
+{
+
+    // Namespaces.
+    using System;
+
+    /// <summary>
+    /// An object that contains an ID that is a GUID.
+    /// </summary>
+    public class GuidId
+    {
+
+        #region Properties
+
+        /// <summary>
+        /// The GUID ID.
+        /// </summary>
+        public Guid Id { get; set; }
+
+        #endregion
+
+    }
+
+}

src/formulate.app/formulate.app.csproj

@@ -350,6 +350,7 @@
     <Compile Include="Forms\Handlers\Email\EmailConfiguration.cs" />
     <Compile Include="Forms\Handlers\Email\EmailHandler.cs" />
     <Compile Include="Forms\Handlers\Email\IEmailSenderRecipientConfiguration.cs" />
+    <Compile Include="Forms\Handlers\Email\RecipientField.cs" />
     <Compile Include="Forms\Handlers\Email\Recipient.cs" />
     <Compile Include="Forms\Handlers\SendData\FieldMapping.cs" />
     <Compile Include="Forms\Handlers\SendData\IHandleSendDataResult.cs" />