Extends Ruby's URI with support for SMTP-uri's.
This allows for more concise SMTP-config:

# config/environments/production.rb
config.action_mailer.delivery_method = :smtp
- config.action_mailer.smtp_settings = {
-   address:         "smtp.gmail.com",
-   port:            587,
-   domain:          "example.com",
-   user_name:       Rails.application.credentials.dig(:smtp, :user_name),
-   password:        Rails.application.credentials.dig(:smtp, :password),
-   authentication:  "plain",
-   enable_starttls: true,
-   open_timeout:    5,
-   read_timeout:    5
- }
# given ENV["SMPT_URL"]:
# "smtp://user_name:password@smtp.gmail.com?open_timeout=5&read_timeout=5#example.com"
+ config.action_mailer.smtp_settings = URI(ENV.fetch("SMTP_URL")).to_h(format: :am)

Install the gem and add to the application's Gemfile by executing:

bundle add uri-smtp

If bundler is not being used to manage dependencies, install the gem by executing:

gem install uri-smtp

u = URI("smtps+login://user%40gmail.com:p%40ss@smtp.gmail.com#sender.org")

url.scheme           #=> "smtps+login"
url.auth             #=> "login"
url.starttls         #=> false
url.starttls?        #=> false
url.tls?             #=> true
url.userinfo         #=> "user%40gmail.com:p%40ss"
url.decoded_userinfo #=> "user@gmail.com:p@ss"
url.decoded_user     #=> "user@gmail.com"
url.user             #=> "user%40gmail.com"
url.decoded_password #=> "p@ss"
url.password         #=> "p%40ss"
url.host             #=> "smtp.gmail.com"
url.port             #=> 465
url.domain           #=> "sender.org"

URI("smtps+login://user%40gmail.com:p%40ss@smtp.gmail.com?domain=sender.org").to_h
#=>
{auth: "login",
 domain: "sender.org",
 host: "smtp.gmail.com",
 port: 587,
 scheme: "smtps+login",
 starttls: :always,
 tls: false,
 user: "user@gmail.com",
 password: "p@ss"}

For ActionMailer configuration, use format: :action_mailer (or :am):

URI("smtps+login://user%40gmail.com:p%40ss@smtp.gmail.com?domain=sender.org").to_h(format: :am)
#=>
{address: "smtp.gmail.com",
 authentication: "login",
 domain: "sender.org",
 enable_starttls: :always,
 port: 587,
 user_name: "user@gmail.com",
 password: "p@ss"}

Besides renaming some keys, this also works around a quirk in v2.8.1 of the mail-gem (e.g. tls: false skips setting up STARTTLS).

Full Rails config:

    config.action_mailer.delivery_method = :smtp
    # [mailcatcher](https://github.com/sj26/mailcatcher) fallback:
    config.action_mailer.smtp_settings = URI(ENV.fetch("SMTP_URL", "smtp://127.0.0.1:1025")).to_h(format: :am)

There's no official specification for SMTP-URIs. There's some prior work though. This implementation is heavily inspired by aerc.

<scheme>[+<auth>]://[<user>[:<password>]@]<host>[:<port>][?<query>][#<fragment>]

• smtp
  SMTP with STARTTLS (i.e. url.starttls #=> :always).
• smtp+insecure
  SMTP without STARTTLS (i.e. url.starttls #=> false)..
• smtps
  SMTP with TLS.

Any value for auth that passes the URI-parser is acceptable. Though the following values have special meaning:

• none
  No authentication is required.
• plain
  Authenticate with a username and password using AUTH PLAIN. This is the default behavior when no authentication is provided.

Legend

STARTTLS

• ⚡ = :always
  Require STARTTLS (i.e. net-smtp aborts when server doesn't support STARTTLS).
• 🔄 = :auto
  Use STARTTLS if supported by server.
• ❌ = false
  No STARTTLS. This is always the case when using TLS.

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment. Use bin/yard server --reload when working on documentation.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/eval/uri-smtp.

The gem is available as open source under the terms of the MIT License.