discourse/lib/email/sender.rb

247 lines
8.6 KiB
Ruby

#
# A helper class to send an email. It will also handle a nil message, which it considers
# to be "do nothing". This is because some Mailers will decide not to do work for some
# reason. For example, emailing a user too frequently. A nil to address is also considered
# "do nothing"
#
# It also adds an HTML part for the plain text body
#
require_dependency 'email/renderer'
require 'uri'
require 'net/smtp'
SMTP_CLIENT_ERRORS = [Net::SMTPFatalError, Net::SMTPSyntaxError]
module Email
class Sender
def initialize(message, email_type, user = nil)
@message = message
@email_type = email_type
@user = user
end
def send
return if SiteSetting.disable_emails && @email_type.to_s != "admin_login"
return if ActionMailer::Base::NullMail === @message
return if ActionMailer::Base::NullMail === (@message.message rescue nil)
return skip(I18n.t('email_log.message_blank')) if @message.blank?
return skip(I18n.t('email_log.message_to_blank')) if @message.to.blank?
if @message.text_part
return skip(I18n.t('email_log.text_part_body_blank')) if @message.text_part.body.to_s.blank?
else
return skip(I18n.t('email_log.body_blank')) if @message.body.to_s.blank?
end
@message.charset = 'UTF-8'
opts = {}
renderer = Email::Renderer.new(@message, opts)
if @message.html_part
@message.html_part.body = renderer.html
else
@message.html_part = Mail::Part.new do
content_type 'text/html; charset=UTF-8'
body renderer.html
end
end
# Fix relative (ie upload) HTML links in markdown which do not work well in plain text emails.
# These are the links we add when a user uploads a file or image.
# Ideally we would parse general markdown into plain text, but that is almost an intractable problem.
url_prefix = Discourse.base_url
@message.parts[0].body = @message.parts[0].body.to_s.gsub(/<a class="attachment" href="(\/uploads\/default\/[^"]+)">([^<]*)<\/a>/, '[\2](' + url_prefix + '\1)')
@message.parts[0].body = @message.parts[0].body.to_s.gsub(/<img src="(\/uploads\/default\/[^"]+)"([^>]*)>/, '![](' + url_prefix + '\1)')
@message.text_part.content_type = 'text/plain; charset=UTF-8'
# Set up the email log
email_log = EmailLog.new(email_type: @email_type, to_address: to_address, user_id: @user.try(:id))
host = Email::Sender.host_for(Discourse.base_url)
post_id = header_value('X-Discourse-Post-Id')
topic_id = header_value('X-Discourse-Topic-Id')
reply_key = header_value('X-Discourse-Reply-Key')
# always set a default Message ID from the host
@message.header['Message-ID'] = "<#{SecureRandom.uuid}@#{host}>"
if topic_id.present?
email_log.topic_id = topic_id
post = Post.find_by(id: post_id)
topic = Topic.find_by(id: topic_id)
first_post = topic.ordered_posts.first
topic_message_id = first_post.incoming_email&.message_id.present? ?
"<#{first_post.incoming_email.message_id}>" :
"<topic/#{topic_id}@#{host}>"
post_message_id = post.incoming_email&.message_id.present? ?
"<#{post.incoming_email.message_id}>" :
"<topic/#{topic_id}/#{post_id}@#{host}>"
referenced_posts = Post.includes(:incoming_email)
.where(id: PostReply.where(reply_id: post_id).select(:post_id))
.order(id: :desc)
referenced_post_message_ids = referenced_posts.map do |post|
if post.incoming_email&.message_id.present?
"<#{post.incoming_email.message_id}>"
else
if post.post_number == 1
"<topic/#{topic_id}@#{host}>"
else
"<topic/#{topic_id}/#{post.id}@#{host}>"
end
end
end
# https://www.ietf.org/rfc/rfc2822.txt
if post.post_number == 1
@message.header['Message-ID'] = topic_message_id
else
@message.header['Message-ID'] = post_message_id
@message.header['In-Reply-To'] = referenced_post_message_ids[0] || topic_message_id
@message.header['References'] = [referenced_post_message_ids, topic_message_id].flatten.compact.uniq
end
# https://www.ietf.org/rfc/rfc2919.txt
if topic && topic.category && !topic.category.uncategorized?
list_id = "<#{topic.category.name.downcase.tr(' ', '-')}.#{host}>"
# subcategory case
if !topic.category.parent_category_id.nil?
parent_category_name = Category.find_by(id: topic.category.parent_category_id).name
list_id = "<#{topic.category.name.downcase.tr(' ', '-')}.#{parent_category_name.downcase.tr(' ', '-')}.#{host}>"
end
else
list_id = "<#{host}>"
end
# https://www.ietf.org/rfc/rfc3834.txt
@message.header['Precedence'] = 'list'
@message.header['List-ID'] = list_id
if topic
if SiteSetting.private_email?
@message.header['List-Archive'] = "#{Discourse.base_url}#{topic.slugless_url}"
else
@message.header['List-Archive'] = topic.url
end
end
end
if reply_key.present? && @message.header['Reply-To'] =~ /\<([^\>]+)\>/
email = Regexp.last_match[1]
@message.header['List-Post'] = "<mailto:#{email}>"
end
if SiteSetting.reply_by_email_address.present? && SiteSetting.reply_by_email_address["+"]
email_log.bounce_key = SecureRandom.hex
# WARNING: RFC claims you can not set the Return Path header, this is 100% correct
# however Rails has special handling for this header and ends up using this value
# as the Envelope From address so stuff works as expected
@message.header[:return_path] = SiteSetting.reply_by_email_address.sub("%{reply_key}", "verp-#{email_log.bounce_key}")
end
email_log.post_id = post_id if post_id.present?
email_log.reply_key = reply_key if reply_key.present?
# Remove headers we don't need anymore
@message.header['X-Discourse-Topic-Id'] = nil if topic_id.present?
@message.header['X-Discourse-Post-Id'] = nil if post_id.present?
@message.header['X-Discourse-Reply-Key'] = nil if reply_key.present?
# pass the original message_id when using mailjet/mandrill/sparkpost
case ActionMailer::Base.smtp_settings[:address]
when /\.mailjet\.com/
@message.header['X-MJ-CustomID'] = @message.message_id
when "smtp.mandrillapp.com"
merge_json_x_header('X-MC-Metadata', message_id: @message.message_id)
when "smtp.sparkpostmail.com"
merge_json_x_header('X-MSYS-API', metadata: { message_id: @message.message_id })
end
# Suppress images from short emails
if SiteSetting.strip_images_from_short_emails &&
@message.html_part.body.to_s.bytesize <= SiteSetting.short_email_length &&
@message.html_part.body =~ /<img[^>]+>/
style = Email::Styles.new(@message.html_part.body.to_s)
@message.html_part.body = style.strip_avatars_and_emojis
end
email_log.message_id = @message.message_id
begin
@message.deliver_now
rescue *SMTP_CLIENT_ERRORS => e
return skip(e.message)
end
# Save and return the email log
email_log.save!
email_log
end
def to_address
@to_address ||= begin
to = @message.try(:to)
to = to.first if Array === to
to.presence || "no_email_found"
end
end
def self.host_for(base_url)
host = "localhost"
if base_url.present?
begin
uri = URI.parse(base_url)
host = uri.host.downcase if uri.host.present?
rescue URI::InvalidURIError
end
end
host
end
private
def header_value(name)
header = @message.header[name]
return nil unless header
header.value
end
def skip(reason)
EmailLog.create!(
email_type: @email_type,
to_address: to_address,
user_id: @user.try(:id),
skipped: true,
skipped_reason: "[Sender] #{reason}"
)
end
def merge_json_x_header(name, value)
data = JSON.parse(@message.header[name].to_s) rescue nil
data ||= {}
data.merge!(value)
# /!\ @message.header is not a standard ruby hash.
# It can have multiple values attached to the same key...
# In order to remove all the previous keys, we have to "nil" it.
# But for "nil" to work, there must already be a key...
@message.header[name] = ""
@message.header[name] = nil
@message.header[name] = data.to_json
end
end
end