Module: Mail::EmbedHTMLImages

Included in:
Message
Defined in:
lib/mail/embed-html-images.rb,
lib/mail/embed-html-images/version.rb

Constant Summary collapse

MIME_TO_EXTENSION = 
{
  'image/png'  => 'png',
  'image/jpeg' => 'jpg',
  'image/gif'  => 'gif',
}
VERSION = 
"1.0.0"

Instance Method Summary collapse

Instance Method Details

#embed_html_images ⇒ Object 



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# File 'lib/mail/embed-html-images.rb', line 13

def embed_html_images
  @_embedded_images ||= {}
  current_images = {}

  # Don't do anything if we don't have an html part
  return unless html_part

  # Find all img tags in the html part
  new_html = html_part.body.to_s.gsub(/<img (.*?)src=((?<![\\])['"])(http(?:.(?!(?<![\\])\2))*.?)\2([^>]*)>/) do |match_string|
    img_src_original = $3
    img_src_hash = Digest::SHA1.hexdigest img_src_original

    # Check to see whether or not we already have this image: if not, attach it
    if !@_embedded_images[img_src_hash]
      response = Net::HTTP.get_response(URI(img_src_original))
      attachment_filename = img_src_hash + '.' + MIME_TO_EXTENSION[response["content-type"]]
      add_file filename: attachment_filename, content: response.body
      @_embedded_images[img_src_hash] = attachment_filename
    end
    current_images[img_src_hash] = @_embedded_images[img_src_hash]

    attached_image = attachments[@_embedded_images[img_src_hash]]

    # Create new src using content id of attachment
    img_src_new = "cid:#{attached_image.cid}"

    # Return substitute with new src
    "<img #{$1}src=\"#{img_src_new}\"#{$4}>"
  end

  # Detach any images that are no longer needed
  @_embedded_images.each do |hash, filename|
    if !current_images[hash]
      self.parts.delete_if { |p| p.filename == filename }
    end
  end
  @_embedded_images = current_images

  html_part.body = new_html
end