Send attachment with mail in rails and active storage

 Routes: 

post "/send_email_with_attachment", to: "articles#send_email_with_attachment"

-----------------------------------

Controller:

class ArticlesController < ApplicationController

  def send_email_with_attachment

    email = "arvind@gmail.com"

    attachment = params[:attachment]

    # Save the file temporarily

    file_path = Rails.root.join('tmp', attachment.original_filename)

    File.open(file_path, 'wb') do |file|

      file.write(attachment.read)

    end

    MyMailer.send_email_with_attachment(email, file_path).deliver_now

    # Delete the temporary file after sending the email

    File.delete(file_path) if File.exist?(file_path)

    redirect_to root_path, notice: 'Email sent successfully'

  end

end

--------------------------

Mailer

class MyMailer < ApplicationMailer

  def send_email_with_attachment(email, attachment_path)

    @greeting = "Hi"

    attachments[File.basename(attachment_path)] = File.read(attachment_path)

    mail(to: email, subject: 'Email with Attachment')

  end

end

-------------------------------

View

Form view:

<%= form_tag "/send_email_with_attachment", class: "inline-form", multipart: true do %>

  <%= file_field_tag :attachment %>

  <%= submit_tag 'Send Email' %>

<% end %>

Mailer view:

<h1>My#send_email_with_attachment</h1>

<p>

  <%= @greeting %>, find me in app/views/my_mailer/send_email_with_attachment.html.erb

</p>

----------------------------

Development.rb

config.action_mailer.perform_deliveries = true

  config.action_mailer.raise_delivery_errors = true

  config.action_mailer.default_options = {from: 'localhost:3000'}

  config.action_mailer.delivery_method = :smtp

  config.action_mailer.smtp_settings = {

    address:              'smtp.gmail.com',

    port:                 587,

    domain:               'localhost',

    user_name:            ENV["SMTP_EMAIL"],

    password:             ENV["SMTP_PASSWORD"],

    authentication:       'plain',

    enable_starttls_auto: true

  }

=======================================

With Active storage and with html override

class AnnouncementMailer < ApplicationMailer

  def announcement_created(user, announcement)

    @user = user

    @announcement = announcement

    @association = announcement.custom_association

    # subject = "📢 New Announcement from #{@association.name}"

    subject = "📢 #{announcement.subject}"

    @announcement.announcement_attachments.each do |attachment|

      # next unless attachment.attached? #user this for has_one_attached :announcement_attachment

      # Optional size limit (10MB)

      # next if attachment.byte_size > 10.megabytes

      attachments[attachment.filename.to_s] = {

        mime_type: attachment.content_type,

        content: attachment.download

      }

    rescue StandardError => e

      Rails.logger.info "**********Announcement attachment skipped: #{e.message}"

    end

    template_path = Rails.root.join(

      "app", "views", "announcement_mailer", "announcement_created.html.erb"

    )

    erb_template = File.read(template_path)

    html_body = ERB.new(erb_template).result(binding)

    plain_text = ActionView::Base.full_sanitizer.sanitize(html_body)

    Notification.create(user_id: @user.id, notifiable: announcement, title: subject, message: plain_text, delivery_methods: ["email", "portal"], created_by: announcement.user_id, updated_by: announcement.user_id)

    mail(

      to: @user.email,

      subject: subject,

    ) do |format|

      format.html { render html: html_body.html_safe }

    end

  end

end