Papercut simple replacement = IMAP to print

README.md

Papercut replacement

• imap to print
• use case: on a Raspi oder Office server that hangs in the same LAN like the printer and can print via cups/system using "lp"
• just uses lp under the hood
• uses the awesome mail_room Gem under the hood to handle imap connection, which does most of the lifting

Send Mail as a authorized return-path (via regex matching) to your mailbox, it will print all pdf Attachments.

USAGE

create config.yml

---
:email: "print@mycompany.de"
:password: "securepassword"
:host: 'imap.mycompany.de'
:port: 993
:ssl: true
:start_ssl: false
:delete_after_delivery: true
:expunge_deleted: true
:name: "inbox"
:search_command: 'NEW'
:delivery_method: "print_attachments"
:delivery_options:
  :whitelist_from: ".*@mycompany.de$"
  # Modify lp command to change media format, or address, see lp -h for all options
  :lp_command: "lp -o media=a4 -o sides=two-sided-long-edge"

ruby run.rb

Or wrap with your favourite init tool.

config.yml.example

---
:email: "printing@mycompany.de"
:password: "XXXXX"
:host: 'mail.mycompany.de'
:port: 993
:ssl: true
:start_ssl: false
:delete_after_delivery: true
:expunge_deleted: true
:name: "inbox"
:search_command: 'NEW'
:delivery_method: "print_attachments"
:delivery_options:
  :whitelist_from: ".*@mycompany.de$"
  :lp_command: "lp -o media=a4 -o sides=two-sided-long-edge"

imap-print.service

[Unit]
Description=IMAP Print
After=syslog.target network.target
# DefaultMemoryAccounting=yes

[Service]
WorkingDirectory=/home/pludoni/cli-tools/print_fetcher
ExecStart=/bin/bash -l -c "cd /home/pludoni/cli-tools/print_fetcher/ && ruby run.rb"
CPUAccounting = yes
MemoryAccounting = yes

User=pludoni
Group=pludoni
UMask=0002

# if we crash, restart
RestartSec=20
Restart=always
# StartLimitIntervalSec=0

# output goes to /var/log/syslog
StandardOutput=syslog
StandardError=syslog

# This will default to "bundler" if we don't specify it
SyslogIdentifier=imap-print

[Install]
WantedBy=multi-user.target

run.rb

require 'bundler/inline'
gemfile do
  source "https://rubygems.org"
  gem 'mail'
  gem 'mail_room'
  gem 'pry'
end

require 'open3'

module MailRoom
  module Delivery
    class PrintAttachments
      Options = Class.new do
        def initialize(config)
          @config = config.delivery_options
          @logger = config.logger
          super()
        end

        attr_reader :config
        attr_reader :logger

        def lp_command
          @config[:lp_command] || "lp"
        end

        def whitelisted?(mail)
          return true if @config[:whitelist_from].nil? || @config[:whitelist_from] == ""


          regex = Regexp.new(@config[:whitelist_from])
          mail.return_path[regex]
        end
      end

      # build a new delivery, do nothing
      def initialize(config)
        @config = config
      end

      # accept the delivery, do nothing
      def deliver(*args)
        mail = Mail.new(args.first)
        if @config.whitelisted?(mail)
          print!(mail)
        else
          @config.logger.warn "unpermitted return-path #{mail.return_path} #{mail.message_id}"
        end
        true
      end

      def print!(mail)
        attachments = mail.attachments.select { |i| i.content_type['application/pdf'] }
        if attachments.length == 0
          @config.logger.warn "No pdf attachments found in mail #{mail.message_id}"
          return
        end
        attachments.each do |pdf|
          print_attachment(pdf)
        end
      end

      def print_attachment(pdf)
        save_name = pdf.filename.gsub(/[^\w\.]+/, '-')
        tf = Tempfile.new(['mail_room_print_attachments', save_name])
        tf.binmode
        tf.write pdf.body.decoded
        tf.rewind

        command = "#{@config.lp_command} #{Shellwords.escape(tf.path)}"

        stdout, stderr, status = Open3.capture3(command)
        if status.success?
          @config.logger.info("Printing #{save_name}: #{command}")
        else
          @config.logger.error("Printing failed: #{stderr}")
        end
      end
    end
  end
end

class MailRoom::Mailbox
  def delivery_klass
    MailRoom::Delivery::PrintAttachments
  end
end

mailboxes = [
  mb = MailRoom::Mailbox.new(YAML.load_file('config.yml'))
]
logger = Logger.new(STDOUT)
logger.formatter = proc do |severity, datetime, progname, msg|
  "#{severity} #{datetime.strftime("%Y-%m-%dT%H:%M:%S")}: #{msg}\n"
end
mailboxes.first.instance_variable_set("@logger", logger)
$coordinator = MailRoom::Coordinator.new(mailboxes)

def start
  Signal.trap(:INT) do
    $coordinator.running = false
  end

  Signal.trap(:TERM) do
    exit
  end

  puts "Starting MailRoom Server"
  $coordinator.run
rescue Exception => e # not just Errors, but includes lower-level Exceptions
  p e
  puts e.backtrace
  exit
end

start