Add SMTP.com email provider

README.md

@@ -96,6 +96,7 @@ Courrier.configure do |config|
   config.providers.cloudflare.account_id = "your-account-id"
   config.providers.loops.transactional_id = "default-template"
   config.providers.mailgun.domain = "notifications.railsdesigner.com"
+  config.providers.smtpcom.channel = "your-sender-channel"
 
   config.providers.ses.region = "us-east-1"
   config.providers.ses.access_key_id = "your-access-key-id"
@@ -202,6 +203,7 @@ Courrier supports these transactional email providers:
 - [Resend](https://resend.com)
 - [SendGrid](https://sendgrid.com)
 - [SMTP2GO](https://www.smtp2go.com/)
+- [SMTP.com](https://www.smtp.com/) — requires a `channel`
 - [SparkPost](https://www.sparkpost.com/)
 - [Userlist](https://userlist.com)
 

lib/courrier/email/provider.rb

@@ -14,6 +14,7 @@
 require "courrier/email/providers/ses"
 require "courrier/email/providers/sendgrid"
 require "courrier/email/providers/smtp2go"
+require "courrier/email/providers/smtpcom"
 require "courrier/email/providers/sparkpost"
 require "courrier/email/providers/userlist"
 
@@ -34,6 +35,7 @@ class Provider
         ses: Courrier::Email::Providers::Ses,
         sendgrid: Courrier::Email::Providers::Sendgrid,
         smtp2go: Courrier::Email::Providers::Smtp2go,
+        smtpcom: Courrier::Email::Providers::Smtpcom,
         sparkpost: Courrier::Email::Providers::Sparkpost,
         userlist: Courrier::Email::Providers::Userlist
       }

lib/courrier/email/providers/smtpcom.rb

@@ -0,0 +1,65 @@
+# frozen_string_literal: true
+
+module Courrier
+  class Email
+    module Providers
+      class Smtpcom < Base
+        def self.config_options = %w[channel]
+
+        ENDPOINT_URL = "https://api.smtp.com/v4/messages"
+
+        def body
+          {
+            "channel" => channel,
+            "recipients" => {
+              "to" => email_addresses(@options.to),
+              "cc" => email_addresses(@options.cc),
+              "bcc" => email_addresses(@options.bcc)
+            }.compact,
+            "originator" => {
+              "from" => email_address(@options.from),
+              "reply_to" => email_address(@options.reply_to)
+            }.compact,
+            "subject" => @options.subject,
+            "body" => {"parts" => parts}
+          }
+        end
+
+        private
+
+        def default_headers
+          {"Authorization" => "Basic #{base64("api:#{@api_key}")}"}
+        end
+
+        def channel
+          @provider_options.channel || raise(Courrier::ArgumentError, "SMTP.com requires a `channel`")
+        end
+
+        def parts
+          [part("text/plain", @options.text), part("text/html", @options.html)].compact
+        end
+
+        def part(type, content)
+          return unless content
+
+          {
+            "type" => type,
+            "charset" => "UTF-8",
+            "encoding" => "base64",
+            "content" => base64(content)
+          }
+        end
+
+        def base64(value) = [value].pack("m0")
+
+        def email_addresses(addresses)
+          addresses&.split(",")&.map { |address| email_address(address) }
+        end
+
+        def email_address(address)
+          {"address" => address.strip} if address
+        end
+      end
+    end
+  end
+end

test/courrier/email/providers/smtpcom_test.rb

@@ -0,0 +1,93 @@
+require "test_helper"
+
+module Courrier::Email::Providers
+  class SmtpcomTest < Minitest::Test
+    def setup
+      email = TestEmail.new(
+        from: "devs@railsdesigner.com",
+        to: "first@example.com, second@example.com",
+        reply_to: "support@railsdesigner.com",
+        cc: "copy@example.com",
+        bcc: "archive@example.com"
+      )
+
+      @provider = provider_for(email)
+    end
+
+    def test_formats_transactional_email
+      assert_equal(
+        {
+          "channel" => "test_channel",
+          "recipients" => {
+            "to" => [{"address" => "first@example.com"}, {"address" => "second@example.com"}],
+            "cc" => [{"address" => "copy@example.com"}],
+            "bcc" => [{"address" => "archive@example.com"}]
+          },
+          "originator" => {
+            "from" => {"address" => "devs@railsdesigner.com"},
+            "reply_to" => {"address" => "support@railsdesigner.com"}
+          },
+          "subject" => "Test Subject",
+          "body" => {
+            "parts" => [
+              {"type" => "text/plain", "charset" => "UTF-8", "encoding" => "base64", "content" => ["Test Body"].pack("m0")},
+              {"type" => "text/html", "charset" => "UTF-8", "encoding" => "base64", "content" => ["<p>Test HTML Body</p>"].pack("m0")}
+            ]
+          }
+        },
+        @provider.body
+      )
+    end
+
+    def test_omits_optional_addresses_when_not_set
+      body = provider_for(TestEmail.new(from: "devs@railsdesigner.com", to: "first@example.com")).body
+
+      refute_includes body["recipients"].keys, "cc"
+      refute_includes body["recipients"].keys, "bcc"
+      refute_includes body["originator"].keys, "reply_to"
+    end
+
+    def test_requires_a_channel
+      provider = Smtpcom.new(
+        api_key: "test_key",
+        options: TestEmail.new(from: "devs@railsdesigner.com", to: "first@example.com").options,
+        provider_options: Courrier::Configuration::ProviderConfig.new
+      )
+
+      error = assert_raises(Courrier::ArgumentError) { provider.body }
+
+      assert_match(/channel/, error.message)
+    end
+
+    def test_authenticates_with_api_key
+      assert_equal(
+        {"Authorization" => "Basic #{["api:test_key"].pack("m0")}"},
+        @provider.send(:default_headers)
+      )
+    end
+
+    def test_is_available_through_provider_registry
+      mock_provider = Minitest::Mock.new
+      mock_provider.expect(:deliver, nil)
+
+      Smtpcom.stub :new, mock_provider do
+        Courrier::Email::Provider.new(
+          provider: "smtpcom",
+          api_key: "test_key",
+          options: @provider.instance_variable_get(:@options)
+        ).deliver
+      end
+
+      mock_provider.verify
+    end
+
+    private
+
+    def provider_for(email)
+      provider_options = Courrier::Configuration::ProviderConfig.new
+      provider_options.channel = "test_channel"
+
+      Smtpcom.new(api_key: "test_key", options: email.options, provider_options: provider_options)
+    end
+  end
+end