Send emails with Ruby

require "net/http"
require "json"

FLARESEND_URL = "https://mailer.example.com"

class FlaresendError < StandardError
  attr_reader :status, :type, :code, :param

  def initialize(status, error)
    super(error["message"])
    @status = status
    @type = error["type"]
    @code = error["code"]
    @param = error["param"]
  end
end

def flaresend_send(email, idempotency_key: nil)
  uri = URI("#{FLARESEND_URL}/v1/emails")
  req = Net::HTTP::Post.new(uri)
  req["Authorization"] = "Bearer #{ENV.fetch("FLARESEND_API_KEY")}"
  req["Content-Type"] = "application/json"
  req["Idempotency-Key"] = idempotency_key if idempotency_key
  req.body = JSON.generate(email)

  res = Net::HTTP.start(uri.host, uri.port, use_ssl: true, read_timeout: 30) { |http| http.request(req) }
  body = JSON.parse(res.body) rescue {}

  unless res.is_a?(Net::HTTPSuccess)
    error = body["error"] || { "type" => "internal_error", "code" => "http_#{res.code}", "message" => res.body.to_s[0, 200] }
    raise FlaresendError.new(res.code.to_i, error)
  end
  body
end

result = flaresend_send(
  {
    from: "Acme <hello@acme.com>",
    to: "ada@example.com",
    subject: "Hello from Ruby",
    html: "<p>It works.</p>",
    text: "It works."
  },
  idempotency_key: "hello-ruby-1"
)

puts result["id"], result["status"] # email_01K6B2Y4ZP9R3M7T8V5N2QXW4C, queued

{
  "error": {
    "type": "rate_limit_error",
    "code": "daily_limit_exceeded",
    "message": "daily limit of 500 emails reached for this project (resets 00:00 UTC)"
  }
}

begin
  flaresend_send(email, idempotency_key: "welcome-#{user.id}")
rescue FlaresendError => e
  Rails.logger.error("#{e.status} #{e.code}: #{e.message}")
end

class WelcomeEmailJob < ApplicationJob
  def perform(user)
    flaresend_send(
      {
        from: "Acme <hello@acme.com>",
        to: user.email,
        template: "welcome",
        data: { name: user.name, appName: "Acme", loginUrl: "https://acme.com/login" }
      },
      idempotency_key: "welcome-#{user.id}"
    )
  end
end