Add support for storing letters and attachments on AWS s3

README.md

@@ -92,9 +92,58 @@ end
 You might also want to have a look at the sources for the [demo](http://letter-opener-web.herokuapp.com)
 available at https://github.com/fgrehm/letter_opener_web_demo.
 
-**NOTICE: Using this gem on Heroku will only work if your app has just one Dyno
-and does not send emails from background jobs. For updates on this matter please
-subscribe to [GH-35](https://github.com/fgrehm/letter_opener_web/issues/35)**
+### Usage with Amazon S3 to support multiple separated instances
+
+If you are using this gem on Heroku and your application is not using one Dyno or your have containerized setup, the default configuration won't work as the e-mail is saved on the server. You can use S3 bucket instead.
+
+**1. Configure AWS environment:**
+
+* Create new non-public bucket, note the name and the region
+* Create new user using IAM or use existing one for which you already have `aws_access_key_id` and `aws_secret_access_key`
+* Assign proper policy to the user. Replace `your-bucket-name` with the name of the bucket you have created
+
+```json
+{
+  "Version": "2012-10-17",
+  "Statement": [
+    {
+      "Sid": "VisualEditor0",
+      "Effect": "Allow",
+      "Action": [
+          "s3:PutObject",
+          "s3:PutObjectAcl",
+          "s3:GetObject",
+          "s3:DeleteObject*"
+      ],
+      "Resource": "arn:aws:s3:::your-bucket-name/*"
+    },
+    {
+      "Sid": "VisualEditor1",
+      "Effect": "Allow",
+      "Action": [
+          "s3:ListBucket"
+      ],
+      "Resource": "arn:aws:s3:::your-bucket-name"
+    }
+  ]
+}
+```
+
+**2. Update gem configuration:**
+
+Add the following configuration to the initializer (or environment files):
+
+```ruby
+LetterOpenerWeb.configure do |config|
+  config.aws_access_key_id = ENV['AWS_ACCESS_KEY_ID']
+  config.aws_secret_access_key = ENV['AWS_SECRET_ACCESS_KEY']
+  config.aws_region = ENV['AWS_REGION']
+  config.aws_bucket = ENV['AWS_BUCKET']
+  config.letters_location = :s3
+end
+```
+
+When you send e-mail with attachment(s), the presigned link is generated to attachment that is valid for 1 week.
 
 ## Acknowledgements
 

app/controllers/letter_opener_web/letters_controller.rb

@@ -10,7 +10,7 @@ class LettersController < ApplicationController
     before_action :load_letter, only: %i[show attachment destroy]
 
     def index
-      @letters = LetterOpenerWeb::Letter.search
+      @letters = letter_model.search
     end
 
     def show
@@ -26,12 +26,13 @@ def attachment
       file     = @letter.attachments[filename]
 
       return render plain: 'Attachment not found!', status: 404 unless file.present?
+      return redirect_to(file, allow_other_host: true) if LetterOpenerWeb.config.letters_location == :s3
 
       send_file(file, filename: filename, disposition: 'inline')
     end
 
     def clear
-      LetterOpenerWeb::Letter.destroy_all
+      letter_model.destroy_all
       redirect_to routes.letters_path
     end
 
@@ -50,13 +51,19 @@ def check_style
     end
 
     def load_letter
-      @letter = LetterOpenerWeb::Letter.find(params[:id])
+      @letter = letter_model.find(params[:id])
 
       head :not_found unless @letter.valid?
     end
 
     def routes
       LetterOpenerWeb.railtie_routes_url_helpers
     end
+
+    private
+
+    def letter_model
+      LetterOpenerWeb.config.letters_location == :s3 ? LetterOpenerWeb::AwsLetter : LetterOpenerWeb::Letter
+    end
   end
 end

app/models/letter_opener_web/aws_letter.rb

@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+
+module LetterOpenerWeb
+  class AwsLetter < LetterOpenerWeb::Letter
+    def self.search
+      letters = LetterOpenerWeb.aws_client.list_objects_v2(bucket: LetterOpenerWeb.config.aws_bucket, delimiter: '/').common_prefixes.map do |folder|
+        new(id: folder.prefix.gsub('/', ''))
+      end
+
+      letters.reverse
+    end
+
+    def self.destroy_all
+      letters = LetterOpenerWeb.aws_client.list_objects_v2(bucket: LetterOpenerWeb.config.aws_bucket).contents.map(&:key)
+
+      LetterOpenerWeb.aws_client.delete_objects(
+        bucket: LetterOpenerWeb.config.aws_bucket,
+        delete: {
+          objects: letters.map { |key| { key: key } },
+          quiet: false
+        }
+      )
+    end
+
+    def initialize(params)
+      @id = params.fetch(:id)
+    end
+
+    def attachments
+      @attachments ||= LetterOpenerWeb.aws_client.list_objects_v2(
+        bucket: LetterOpenerWeb.config.aws_bucket, prefix: "#{@id}/attachments/"
+      ).contents.each_with_object({}) do |file, hash|
+        hash[File.basename(file.key)] = attachment_url(file.key)
+      end
+    end
+
+    def delete
+      return unless valid?
+
+      letters = LetterOpenerWeb.aws_client.list_objects_v2(bucket: LetterOpenerWeb.config.aws_bucket, prefix: @id).contents.map(&:key)
+
+      LetterOpenerWeb.aws_client.delete_objects(
+        bucket: LetterOpenerWeb.config.aws_bucket,
+        delete: {
+          objects: letters.map { |key| { key: key } },
+          quiet: false
+        }
+      )
+    end
+
+    def valid?
+      LetterOpenerWeb.aws_client.list_objects_v2(bucket: LetterOpenerWeb.config.aws_bucket, prefix: @id).contents.any?
+    end
+
+    private
+
+    def attachment_url(key)
+      bucket = Aws::S3::Bucket.new(
+        name: LetterOpenerWeb.config.aws_bucket, client: LetterOpenerWeb.aws_client
+      )
+
+      obj = bucket.object(key)
+      obj.presigned_url(:get, expires_in: 1.week.to_i)
+    end
+
+    def objects
+      @objects ||= {}
+    end
+
+    def read_file(style)
+      return objects[style] if objects.key?(style)
+
+      response = LetterOpenerWeb.aws_client.get_object(bucket: LetterOpenerWeb.config.aws_bucket, key: "#{@id}/#{style}.html")
+
+      response.body.read.tap do |value|
+        objects[style] = value
+      end
+    rescue Aws::S3::Errors::NoSuchKey
+      ''
+    end
+
+    def style_exists?(style)
+      return !objects[style].empty? if objects.key?(style)
+
+      objects[style] = read_file(style)
+      !objects[style].empty?
+    end
+  end
+end

app/models/letter_opener_web/s3_message.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module LetterOpenerWeb
+  class S3Message < LetterOpener::Message
+    def render
+      mail.attachments.each do |attachment|
+        filename = attachment_filename(attachment)
+
+        LetterOpenerWeb.aws_client.put_object(
+          bucket: LetterOpenerWeb.config.aws_bucket,
+          key: "#{@location}/attachments/#{filename}",
+          body: attachment.body.raw_source
+        )
+
+        @attachments << [attachment.filename, "attachments/#{filename}"]
+      end
+
+      LetterOpenerWeb.aws_client.put_object(
+        bucket: LetterOpenerWeb.config.aws_bucket,
+        key: "#{@location}/#{type}.html",
+        body: ERB.new(template).result(binding)
+      )
+    end
+  end
+end

letter_opener_web.gemspec

@@ -24,6 +24,7 @@ Gem::Specification.new do |gem|
   gem.add_dependency 'letter_opener', '~> 1.7'
   gem.add_dependency 'railties', '>= 5.2'
   gem.add_dependency 'rexml'
+  gem.add_dependency 'aws-sdk-s3', '~> 1.142'
 
   gem.add_development_dependency 'rails', '~> 6.1'
   gem.add_development_dependency 'rspec-rails', '~> 5.0'

lib/letter_opener_web.rb

@@ -3,10 +3,11 @@
 require 'letter_opener_web/version'
 require 'letter_opener_web/engine'
 require 'rexml/document'
+require 'aws-sdk-s3'
 
 module LetterOpenerWeb
   class Config
-    attr_accessor :letters_location
+    attr_accessor :letters_location, :aws_access_key_id, :aws_secret_access_key, :aws_region, :aws_bucket
   end
 
   def self.config
@@ -21,5 +22,14 @@ def self.configure
 
   def self.reset!
     @config = nil
+    @aws_client = nil
+  end
+
+  def self.aws_client
+    @aws_client ||= ::Aws::S3::Client.new(
+      access_key_id: LetterOpenerWeb.config.aws_access_key_id,
+      secret_access_key: LetterOpenerWeb.config.aws_secret_access_key,
+      region: LetterOpenerWeb.config.aws_region
+    )
   end
 end

lib/letter_opener_web/delivery_method.rb

@@ -7,8 +7,15 @@ class DeliveryMethod < LetterOpener::DeliveryMethod
     def deliver!(mail)
       original = ENV['LAUNCHY_DRY_RUN']
       ENV['LAUNCHY_DRY_RUN'] = 'true'
+
+      if LetterOpenerWeb.config.letters_location == :s3
+        validate_mail!(mail)
+        location = "#{Time.now.to_f.to_s.tr('.', '_')}_#{Digest::SHA1.hexdigest(mail.encoded)[0..6]}"
 
-      super
+        messages = LetterOpenerWeb::S3Message.rendered_messages(mail, location: location, message_template: settings[:message_template])
+      else
+        super
+      end
     rescue Launchy::CommandNotFoundError
       # Ignore for non-executable Launchy environment.
     ensure