Fix #23 - add BeforeSendMail event

Docs/extend.md

@@ -11,6 +11,9 @@ If you need to react to form submissions (e.g. to create your own workflow), you
 
 There's an example of how to use the form submission events in the [samples](../Samples/Event handling/) section.
 
+## Email sending events
+Before any form submission emails are sent (notification and confirmation emails), the `BeforeSendMail` event is invoked so you can manipulate the `MailMessage` as you please. This event is cancelable. If it is cancelled, the email will not be sent.
+
 ## Creating a custom condition for cross field validation
 The cross field validation system can be extended with your own custom conditions. Read more [here](extend_condition.md).
 

Source/Solution/FormEditor/Events/FormEditorMailCancelEventArgs.cs

@@ -0,0 +1,20 @@
+using System.ComponentModel;
+using System.Net.Mail;
+
+namespace FormEditor.Events
+{
+	public class FormEditorMailCancelEventArgs : CancelEventArgs
+	{
+		public FormEditorMailCancelEventArgs(MailMessage mailMessage, string emailType)
+		{
+			MailMessage = mailMessage;
+			EmailType = emailType;
+		}
+
+		// the mail that's being sent
+		public MailMessage MailMessage { get; private set; }
+
+		// the type of mail - "confirmation" or "notification"
+		public string EmailType { get; private set; }
+	}
+}

Source/Solution/FormEditor/Events/FormEditorMailCancelEventHandler.cs

@@ -0,0 +1,4 @@
+namespace FormEditor.Events
+{
+	public delegate void FormEditorMailCancelEventHandler(FormModel sender, FormEditorMailCancelEventArgs e);
+}

Source/Solution/FormEditor/FormEditor.csproj

@@ -263,6 +263,8 @@
     <Compile Include="Events\FormEditorCancelEventHandler.cs" />
     <Compile Include="Events\FormEditorEventArgs.cs" />
     <Compile Include="Events\FormEditorEventHandler.cs" />
+    <Compile Include="Events\FormEditorMailCancelEventArgs.cs" />
+    <Compile Include="Events\FormEditorMailCancelEventHandler.cs" />
     <Compile Include="Fields\CustomFieldFixedValues.cs" />
     <Compile Include="Fields\Statistics\FieldExtensions.cs" />
     <Compile Include="Fields\Statistics\IValueFrequencyStatisticsField.cs" />

Source/Solution/FormEditor/FormModel.cs

@@ -90,6 +90,7 @@ public IEnumerable<Row> Rows
 		// events
 		public static event FormEditorCancelEventHandler BeforeAddToIndex;
 		public static event FormEditorEventHandler AfterAddToIndex;
+		public static event FormEditorMailCancelEventHandler BeforeSendMail;
 
 		public bool CollectSubmittedValues(bool redirect = true)
 		{
@@ -649,10 +650,10 @@ private void SendEmailType(string subject, string senderAddress, string recipien
 			subject = InterpolateSubmittedValues(subject);
 
 			// send emails to the recipients
-			SendEmails(subject, emailBody, senderEmailAddress, addresses, uploadedFiles);
+			SendEmails(subject, emailBody, senderEmailAddress, addresses, uploadedFiles, emailType);
 		}
 
-		private static void SendEmails(string subject, string body, MailAddress from, IEnumerable<MailAddress> to, HttpPostedFile[] uploadedFiles)
+		private void SendEmails(string subject, string body, MailAddress from, IEnumerable<MailAddress> to, HttpPostedFile[] uploadedFiles, string emailType)
 		{
 			if(string.IsNullOrEmpty(body))
 			{
@@ -688,6 +689,26 @@ private static void SendEmails(string subject, string body, MailAddress from, IE
 				attachments.Add(attachment);
 			}
 
+			// #23 - raise an event before sending the mail
+			if(BeforeSendMail != null)
+			{
+				try
+				{
+					var cancelEventArgs = new FormEditorMailCancelEventArgs(mail, emailType.ToLowerInvariant());
+					BeforeSendMail.Invoke(this, cancelEventArgs);
+					if(cancelEventArgs.Cancel)
+					{
+						Log.Info("The {0} email was not sent because an event handler for BeforeSendMail cancelled the mail delivery.", emailType);
+						return;
+					}
+				}
+				catch (Exception ex)
+				{
+					// an event handler failed - log error and continue
+					Log.Error(ex, "An event handler for BeforeSendMail threw an exception.");
+				}
+			}
+
 			// send the mail as fire-and-forget (pass the attachments as state)
 			ThreadPool.QueueUserWorkItem(state =>
 			{