Added bulk-email feature for SMTP

Sources/MailCore/Extensions/Request+Mail.swift

@@ -20,19 +20,22 @@ public struct MailProperty {
         return try mailer.send(message, on: request)
     }
 
+    /// Send email
+    public func send(_ messages: [Mailer.Message]) throws -> EventLoopFuture<[(Mail, Mailer.Result)]> {
+        let mailer = try request.make(MailerService.self)
+        return try mailer.send(messages, on: request)
+    }
+
     /// Send email
     public func send(from: String, to: String, subject: String, text: String) throws -> EventLoopFuture<Mailer.Result> {
         return try send(Mailer.Message(from: from, to: to, subject: subject, text: text))
     }
-
 }
 
-
 extension Request {
 
     /// Mail functionality accessor for request
     public var mail: MailProperty {
         return MailProperty(request: self)
     }
-
 }

Sources/MailCore/MailCore.swift

@@ -15,6 +15,7 @@ import SendGrid
 /// Emailing service
 public protocol MailerService: Service {
     func send(_ message: Mailer.Message, on req: Request) throws -> Future<Mailer.Result>
+    func send(_ messages: [Mailer.Message], on req: Request) throws -> Future<[(Mail, Mailer.Result)]>
 }
 
 
@@ -91,17 +92,17 @@ public class Mailer: MailerService {
             let mailgunClient = try req.make(Mailgun.self)
             return try mailgunClient.send(message.asMailgunContent(), on: req).map(to: Mailer.Result.self) { _ in
                 return Mailer.Result.success
-                }.catchMap({ error in
-                    return Mailer.Result.failure(error: error)
+            }.catchMap({ error in
+                return Mailer.Result.failure(error: error)
                 }
             )
         case .sendGrid(_):
             let email = message.asSendGridContent()
             let sendGridClient = try req.make(SendGridClient.self)
             return try sendGridClient.send([email], on: req.eventLoop).map(to: Mailer.Result.self) { _ in
                 return Mailer.Result.success
-                }.catchMap({ error in
-                    return Mailer.Result.failure(error: error)
+            }.catchMap({ error in
+                return Mailer.Result.failure(error: error)
                 }
             )
         case .smtp(let smtp):
@@ -119,4 +120,23 @@ public class Mailer: MailerService {
         }
     }
 
+    /// Send multiple messages using a provider defined in `config: Config`
+    public func send(_ messages: [Message], on req: Request) throws -> Future<[(Mail, Mailer.Result)]> {
+        switch config {
+        case .mailgun:
+            throw Abort(.notImplemented, reason: "Sending mass email using Mailgun is not currently supported.")
+        case .sendGrid(_):
+            throw Abort(.notImplemented, reason: "Sending mass email using SendGrid is not currently supported.")
+        case .smtp(let smtp):
+            let promise = req.eventLoop.newPromise([(Mail, Mailer.Result)].self)
+            smtp.send(messages.map { $0.asSmtpMail() }, progress: nil) { mails, errors in
+                let errors = errors.map { ($0.0, Mailer.Result.failure(error: $0.1)) }
+                let successes = mails.map { ($0, Mailer.Result.success) }
+                promise.succeed(result: errors + successes)
+            }
+            return promise.futureResult
+        default:
+            throw Abort(.serviceUnavailable, reason: "Mails could not be sent: you need to configure your mail service.")
+        }
+    }
 }