Module: InboxBeam::Message

Defined in:
lib/inbox_beam/message.rb

Overview

Builds an RFC 5322 message ready to hand to IMAP APPEND. Zero dependencies — UTF-8 safe via base64 bodies and encoded-word headers.

Constant Summary collapse

CRLF = 
"\r\n"

Class Method Summary collapse

Class Method Details

.ascii?(value) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/inbox_beam/message.rb', line 57

def ascii?(value)
  value.ascii_only?
end

.base64_body(content) ⇒ Object

Base64-encode a body and wrap at 76 columns per RFC 2045.



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# File 'lib/inbox_beam/message.rb', line 80

def base64_body(content)
  Base64.strict_encode64(content.encode("UTF-8")).scan(/.{1,76}/).join(CRLF)
end

.build(from:, to:, subject:, text: nil, html: nil, date: nil) ⇒ String

Returns the raw RFC 5322 message with CRLF line endings.

Parameters:

  • from (String) —

    e.g. “you@example.com” or “Name <you@example.com>”

  • to (String)
  • subject (String)
  • text (String, nil) (defaults to: nil)
  • html (String, nil) (defaults to: nil)
  • date (Time, nil) (defaults to: nil)

Returns:

  • (String) —

    the raw RFC 5322 message with CRLF line endings



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# File 'lib/inbox_beam/message.rb', line 21

def build(from:, to:, subject:, text: nil, html: nil, date: nil)
  date ||= Time.now
  message_id = "<#{SecureRandom.hex(16)}@#{domain_of(from)}>"

  headers = [
    "From: #{encode_header(from)}",
    "To: #{encode_header(to)}",
    "Subject: #{encode_word(subject)}",
    "Date: #{rfc2822_date(date)}",
    "Message-ID: #{message_id}",
    "MIME-Version: 1.0"
  ]

  if html && text
    boundary = "inbox_beam_#{SecureRandom.hex(12)}"
    headers << %(Content-Type: multipart/alternative; boundary="#{boundary}")
    body = [
      "--#{boundary}",
      mime_part("text/plain", text),
      "--#{boundary}",
      mime_part("text/html", html),
      "--#{boundary}--",
      ""
    ].join(CRLF)
  elsif html
    headers << "Content-Type: text/html; charset=UTF-8" << "Content-Transfer-Encoding: base64"
    body = base64_body(html)
  else
    headers << "Content-Type: text/plain; charset=UTF-8" << "Content-Transfer-Encoding: base64"
    body = base64_body(text.to_s)
  end

  raw = headers.join(CRLF) + CRLF + CRLF + body
  raw.gsub(/\r\n|\r|\n/, CRLF)
end

.domain_of(address) ⇒ Object 



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# File 'lib/inbox_beam/message.rb', line 88

def domain_of(address)
  m = address.match(/@([^>\s]+)/)
  m ? m[1] : "localhost"
end

.encode_header(value) ⇒ Object

Encode a header that may contain a display name: ‘名前 <addr>`.



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# File 'lib/inbox_beam/message.rb', line 69

def encode_header(value)
  return value if ascii?(value)

  if (m = value.match(/\A(.*?)\s*<([^>]+)>\s*\z/))
    "#{encode_word(m[1])} <#{m[2]}>"
  else
    encode_word(value)
  end
end

.encode_word(value) ⇒ Object

RFC 2047 encoded-word for non-ASCII header values.



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# File 'lib/inbox_beam/message.rb', line 62

def encode_word(value)
  return value if ascii?(value)

  "=?UTF-8?B?#{Base64.strict_encode64(value.encode("UTF-8"))}?="
end

.mime_part(content_type, content) ⇒ Object 



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# File 'lib/inbox_beam/message.rb', line 93

def mime_part(content_type, content)
  [
    "Content-Type: #{content_type}; charset=UTF-8",
    "Content-Transfer-Encoding: base64",
    "",
    base64_body(content)
  ].join(CRLF)
end

.rfc2822_date(time) ⇒ Object 



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# File 'lib/inbox_beam/message.rb', line 84

def rfc2822_date(time)
  time.getutc.strftime("%a, %d %b %Y %H:%M:%S +0000")
end