Running puma in ssl mode in development environment.

ssl_config.rb

# Ref:- 'https://gist.github.com/tadast/9932075'
# Inside your rails app root directory.
# run "mkdir config/certs && touch config/certs/.keep"
# Add below two lines in .gitignore
# /config/certs/*
# !/config/certs/.keep

# Add below code in config/puma.rb

if Rails.env.development?
  unless File.exist?(Rails.root.join('config', 'certs', 'localhost.key'))
    def generate_root_cert(root_key)
      root_ca = OpenSSL::X509::Certificate.new
      root_ca.version = 2 # cf. RFC 5280 - to make it a "v3" certificate
      root_ca.serial = 0x0
      root_ca.subject = OpenSSL::X509::Name.parse "/C=BE/O=A1/OU=A/CN=localhost"
      root_ca.issuer = root_ca.subject # root CA's are "self-signed"
      root_ca.public_key = root_key.public_key
      root_ca.not_before = Time.now
      root_ca.not_after = root_ca.not_before + 2 * 365 * 24 * 60 * 60 # 2 years validity
      root_ca.sign(root_key, OpenSSL::Digest::SHA256.new)
      root_ca
    end

    root_key = OpenSSL::PKey::RSA.new(2048)
    file = File.new( Rails.root.join('config', 'certs', 'localhost.key'), "wb")
    file.write(root_key)
    file.close

    root_cert = generate_root_cert(root_key)

    file = File.new( Rails.root.join('config','certs', 'localhost.cert'), "wb")
    file.write(root_cert)
    file.close
  end

  ssl_bind '0.0.0.0', '8443', {
      key: Rails.root.join('config','certs', 'localhost.key'),
      cert: Rails.root.join('config','certs', 'localhost.cert')
  }
end