From 0daa667b55fd9b948da643d37ec438e341809369 Mon Sep 17 00:00:00 2001
From: Adam Cooke <adam@krystal.io>
Date: Mon, 4 Mar 2024 14:24:24 +0000
Subject: [PATCH] feat: support for additional SMTP client options

---
 config/initializers/smtp.rb         | 15 +++++++++++----
 doc/config/environment-variables.md |  5 +++++
 doc/config/yaml.yml                 | 10 ++++++++++
 lib/postal/config_schema.rb         | 25 +++++++++++++++++++++++++
 4 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/config/initializers/smtp.rb b/config/initializers/smtp.rb
index f6203959..53f2d003 100644
--- a/config/initializers/smtp.rb
+++ b/config/initializers/smtp.rb
@@ -2,10 +2,17 @@
 
 require "postal/config"
 
+config = Postal::Config.smtp
+
 ActionMailer::Base.delivery_method = :smtp
 ActionMailer::Base.smtp_settings = {
-  address: Postal::Config.smtp.host,
-  user_name: Postal::Config.smtp.username,
-  password: Postal::Config.smtp.password,
-  port: Postal::Config.smtp.port
+  address: config.host,
+  user_name: config.username,
+  password: config.password,
+  port: config.port,
+  authentication: config.authentication_type&.to_sym,
+  enable_starttls: config.enable_starttls?,
+  enable_starttls_auto: config.enable_starttls_auto?,
+  openssl_verify_mode: config.openssl_verify_mode,
+  ssl: config.ssl?
 }
diff --git a/doc/config/environment-variables.md b/doc/config/environment-variables.md
index 540a2de3..57873c04 100644
--- a/doc/config/environment-variables.md
+++ b/doc/config/environment-variables.md
@@ -70,6 +70,11 @@ This document contains all the environment variables which are available for thi
 | `SMTP_PORT` | Integer | The port number to send application-level e-mails to | 25 |
 | `SMTP_USERNAME` | String | The username to use when authentication to the SMTP server |  |
 | `SMTP_PASSWORD` | String | The password to use when authentication to the SMTP server |  |
+| `SMTP_AUTHENTICATION_TYPE` | String | The type of authentication to use | login |
+| `SMTP_ENABLE_STARTTLS` | Boolean | Use STARTTLS when connecting to the SMTP server and fail if unsupported | false |
+| `SMTP_ENABLE_STARTTLS_AUTO` | Boolean | Detects if STARTTLS is enabled in the SMTP server and starts to use it | true |
+| `SMTP_OPENSSL_VERIFY_MODE` | String | When using TLS, you can set how OpenSSL checks the certificate. Use 'none' for no certificate checking | peer |
+| `SMTP_SSL` | Boolean | Use an SSL/TLS connection to the SMTP server (SMTPS) | false |
 | `SMTP_FROM_NAME` | String | The name to use as the from name outgoing emails from Postal | Postal |
 | `SMTP_FROM_ADDRESS` | String | The e-mail to use as the from address outgoing emails from Postal | postal@example.com |
 | `RAILS_ENVIRONMENT` | String | The Rails environment to run the application in | production |
diff --git a/doc/config/yaml.yml b/doc/config/yaml.yml
index 9da0c78d..82eb582d 100644
--- a/doc/config/yaml.yml
+++ b/doc/config/yaml.yml
@@ -153,6 +153,16 @@ smtp:
   username: 
   # The password to use when authentication to the SMTP server
   password: 
+  # The type of authentication to use
+  authentication_type: login
+  # Use STARTTLS when connecting to the SMTP server and fail if unsupported
+  enable_starttls: false
+  # Detects if STARTTLS is enabled in the SMTP server and starts to use it
+  enable_starttls_auto: true
+  # When using TLS, you can set how OpenSSL checks the certificate. Use 'none' for no certificate checking
+  openssl_verify_mode: peer
+  # Use an SSL/TLS connection to the SMTP server (SMTPS)
+  ssl: false
   # The name to use as the from name outgoing emails from Postal
   from_name: Postal
   # The e-mail to use as the from address outgoing emails from Postal
diff --git a/lib/postal/config_schema.rb b/lib/postal/config_schema.rb
index 69b4a17e..42a547c5 100644
--- a/lib/postal/config_schema.rb
+++ b/lib/postal/config_schema.rb
@@ -360,6 +360,31 @@ module Postal
         description "The password to use when authentication to the SMTP server"
       end
 
+      string :authentication_type do
+        description "The type of authentication to use"
+        default "login"
+      end
+
+      boolean :enable_starttls do
+        description "Use STARTTLS when connecting to the SMTP server and fail if unsupported"
+        default false
+      end
+
+      boolean :enable_starttls_auto do
+        description "Detects if STARTTLS is enabled in the SMTP server and starts to use it"
+        default true
+      end
+
+      string :openssl_verify_mode do
+        description "When using TLS, you can set how OpenSSL checks the certificate. Use 'none' for no certificate checking"
+        default "peer"
+      end
+
+      boolean :ssl do
+        description "Use an SSL/TLS connection to the SMTP server (SMTPS)"
+        default false
+      end
+
       string :from_name do
         description "The name to use as the from name outgoing emails from Postal"
         default "Postal"