require "digest"
require_dependency "new_post_manager"
require_dependency "post_action_creator"
require_dependency "email/html_cleaner"
module Email
class Receiver
include ActionView::Helpers::NumberHelper
class ProcessingError < StandardError; end
class EmptyEmailError < ProcessingError; end
class ScreenedEmailError < ProcessingError; end
class UserNotFoundError < ProcessingError; end
class AutoGeneratedEmailError < ProcessingError; end
class AutoGeneratedEmailReplyError < ProcessingError; end
class BouncedEmailError < ProcessingError; end
class NoBodyDetectedError < ProcessingError; end
class InactiveUserError < ProcessingError; end
class BlockedUserError < ProcessingError; end
class BadDestinationAddress < ProcessingError; end
class StrangersNotAllowedError < ProcessingError; end
class InsufficientTrustLevelError < ProcessingError; end
class ReplyUserNotMatchingError < ProcessingError; end
class TopicNotFoundError < ProcessingError; end
class TopicClosedError < ProcessingError; end
class InvalidPost < ProcessingError; end
class InvalidPostAction < ProcessingError; end
attr_reader :incoming_email
def initialize(mail_string)
raise EmptyEmailError if mail_string.blank?
@staged_users_created = 0
@raw_email = mail_string
@mail = Mail.new(@raw_email)
@message_id = @mail.message_id.presence || Digest::MD5.hexdigest(mail_string)
end
def process!
return if is_blacklisted?
@from_email, @from_display_name = parse_from_field
@incoming_email = find_or_create_incoming_email
process_internal
rescue => e
@incoming_email.update_columns(error: e.to_s) if @incoming_email
raise
end
def is_blacklisted?
return false if SiteSetting.ignore_by_title.blank?
Regexp.new(SiteSetting.ignore_by_title) =~ @mail.subject
end
def find_or_create_incoming_email
IncomingEmail.find_or_create_by(message_id: @message_id) do |ie|
ie.raw = @raw_email
ie.subject = subject
ie.from_address = @from_email
ie.to_addresses = @mail.to.map(&:downcase).join(";") if @mail.to.present?
ie.cc_addresses = @mail.cc.map(&:downcase).join(";") if @mail.cc.present?
end
end
def process_internal
raise ScreenedEmailError if ScreenedEmail.should_block?(@from_email)
user = find_or_create_user(@from_email, @from_display_name)
raise UserNotFoundError if user.nil?
@incoming_email.update_columns(user_id: user.id)
raise BouncedEmailError if is_bounce?
raise InactiveUserError if !user.active && !user.staged
raise BlockedUserError if user.blocked
body, @elided = select_body
body ||= ""
raise NoBodyDetectedError if body.blank? && !@mail.has_attachments?
if is_auto_generated?
@incoming_email.update_columns(is_auto_generated: true)
raise AutoGeneratedEmailReplyError if check_reply_to_auto_generated_header
raise AutoGeneratedEmailError if SiteSetting.block_auto_generated_emails?
end
if action = subscription_action_for(body, subject)
message = SubscriptionMailer.send(action, user)
Email::Sender.new(message, :subscription).send
elsif post = find_related_post
create_reply(user: user,
raw: body,
post: post,
topic: post.topic,
skip_validations: user.staged?)
else
destination = destinations.first
raise BadDestinationAddress if destination.blank?
case destination[:type]
when :group
group = destination[:obj]
create_topic(user: user,
raw: body,
title: subject,
archetype: Archetype.private_message,
target_group_names: [group.name],
is_group_message: true,
skip_validations: true)
when :category
category = destination[:obj]
raise StrangersNotAllowedError if user.staged? && !category.email_in_allow_strangers
raise InsufficientTrustLevelError if !user.has_trust_level?(SiteSetting.email_in_min_trust)
create_topic(user: user,
raw: body,
title: subject,
category: category.id,
skip_validations: user.staged?)
when :reply
email_log = destination[:obj]
raise ReplyUserNotMatchingError if email_log.user_id != user.id
create_reply(user: user,
raw: body,
post: email_log.post,
topic: email_log.post.topic)
end
end
end
SOFT_BOUNCE_SCORE ||= 1
HARD_BOUNCE_SCORE ||= 2
def is_bounce?
return false unless @mail.bounced? || verp
@incoming_email.update_columns(is_bounce: true)
if verp
bounce_key = verp[/\+verp-(\h{32})@/, 1]
if bounce_key && (email_log = EmailLog.find_by(bounce_key: bounce_key))
email_log.update_columns(bounced: true)
if @mail.error_status.present?
if @mail.error_status.start_with?("4.")
Email::Receiver.update_bounce_score(email_log.user.email, SOFT_BOUNCE_SCORE)
elsif @mail.error_status.start_with?("5.")
Email::Receiver.update_bounce_score(email_log.user.email, HARD_BOUNCE_SCORE)
end
elsif is_auto_generated?
Email::Receiver.update_bounce_score(email_log.user.email, HARD_BOUNCE_SCORE)
end
end
end
true
end
def verp
@verp ||= all_destinations.select { |to| to[/\+verp-\h{32}@/] }.first
end
def self.update_bounce_score(email, score)
# only update bounce score once per day
key = "bounce_score:#{email}:#{Date.today}"
if $redis.setnx(key, "1")
$redis.expire(key, 25.hours)
if user = User.find_by(email: email)
user.user_stat.bounce_score += score
user.user_stat.reset_bounce_score_after = 30.days.from_now
user.user_stat.save
if user.user_stat.bounce_score >= SiteSetting.bounce_score_threshold
StaffActionLogger.new(Discourse.system_user).log_revoke_email(user)
end
end
true
else
false
end
end
def is_auto_generated?
return false if SiteSetting.auto_generated_whitelist.split('|').include?(@from_email)
@mail[:precedence].to_s[/list|junk|bulk|auto_reply/i] ||
@mail[:from].to_s[/(mailer-?daemon|postmaster|noreply)@/i] ||
@mail.header.to_s[/auto[\-_]?(response|submitted|replied|reply|generated|respond)|holidayreply|machinegenerated/i]
end
def select_body
text = nil
html = nil
if @mail.multipart?
text = fix_charset(@mail.text_part)
html = fix_charset(@mail.html_part)
elsif @mail.content_type.to_s["text/html"]
html = fix_charset(@mail)
else
text = fix_charset(@mail)
end
if html.present? && (SiteSetting.incoming_email_prefer_html || text.blank?)
html = Email::HtmlCleaner.new(html).output_html
html = trim_discourse_markers(html)
html, elided = EmailReplyTrimmer.trim(html, true)
return [html, elided]
end
if text.present?
text = trim_discourse_markers(text)
text, elided = EmailReplyTrimmer.trim(text, true)
return [text, elided]
end
end
def fix_charset(mail_part)
return nil if mail_part.blank? || mail_part.body.blank?
string = mail_part.body.decoded rescue nil
return nil if string.blank?
# 1) use the charset provided
if mail_part.charset.present?
fixed = try_to_encode(string, mail_part.charset)
return fixed if fixed.present?
end
# 2) try most used encodings
try_to_encode(string, "UTF-8") || try_to_encode(string, "ISO-8859-1")
end
def try_to_encode(string, encoding)
encoded = string.encode("UTF-8", encoding)
encoded.present? && encoded.valid_encoding? ? encoded : nil
rescue Encoding::InvalidByteSequenceError,
Encoding::UndefinedConversionError,
Encoding::ConverterNotFoundError
nil
end
def previous_replies_regex
@previous_replies_regex ||= /^--[- ]\n\*#{I18n.t("user_notifications.previous_discussion")}\*\n/im
end
def trim_discourse_markers(reply)
reply.split(previous_replies_regex)[0]
end
def parse_from_field
if @mail[:from].errors.blank?
address_field = @mail[:from].address_list.addresses.first
address_field.decoded
from_address = address_field.address
from_display_name = address_field.display_name.try(:to_s)
else
from_address = @mail.from[/<([^>]+)>/, 1]
from_display_name = @mail.from[/^([^<]+)/, 1]
end
[from_address.downcase, from_display_name]
end
def subject
@suject ||= @mail.subject.presence || I18n.t("emails.incoming.default_subject", email: @from_email)
end
def find_or_create_user(email, display_name)
user = nil
User.transaction do
begin
user = User.find_by_email(email)
if user.nil? && SiteSetting.enable_staged_users
username = UserNameSuggester.sanitize_username(display_name) if display_name.present?
user = User.create!(
email: email,
username: UserNameSuggester.suggest(username.presence || email),
name: display_name.presence || User.suggest_name(email),
staged: true
)
@staged_users_created += 1
end
rescue
user = nil
end
end
user
end
def all_destinations
@all_destinations ||= [
@mail.destinations,
[@mail[:x_forwarded_to]].flatten.compact.map(&:decoded),
[@mail[:delivered_to]].flatten.compact.map(&:decoded),
].flatten.select(&:present?).uniq.lazy
end
def destinations
all_destinations
.map { |d| check_address(d) }
.drop_while(&:blank?)
end
def check_address(address)
# only check for a group/category when 'email_in' is enabled
if SiteSetting.email_in
group = Group.find_by_email(address)
return { type: :group, obj: group } if group
category = Category.find_by_email(address)
return { type: :category, obj: category } if category
end
# reply
match = reply_by_email_address_regex.match(address)
if match && match[1].present?
email_log = EmailLog.for(match[1])
return { type: :reply, obj: email_log } if email_log
end
end
def reply_by_email_address_regex
@reply_by_email_address_regex ||= Regexp.new Regexp.escape(SiteSetting.reply_by_email_address)
.gsub(Regexp.escape("%{reply_key}"), "([[:xdigit:]]{32})")
end
def group_incoming_emails_regex
@group_incoming_emails_regex ||= Regexp.union Group.pluck(:incoming_email).select(&:present?).map { |e| e.split("|") }.flatten.uniq
end
def category_email_in_regex
@category_email_in_regex ||= Regexp.union Category.pluck(:email_in).select(&:present?).map { |e| e.split("|") }.flatten.uniq
end
def find_related_post
message_ids = [@mail.in_reply_to, Email::Receiver.extract_references(@mail.references)]
message_ids.flatten!
message_ids.select!(&:present?)
message_ids.uniq!
return if message_ids.empty?
Post.where(id: IncomingEmail.where(message_id: message_ids).select(:post_id))
.order(created_at: :desc)
.first
end
def self.extract_references(references)
if Array === references
references
elsif references.present?
references.split(/[\s,]/).map { |r| r.sub(/^</, "").sub(/>$/, "") }
end
end
def likes
@likes ||= Set.new ["+1", I18n.t('post_action_types.like.title').downcase]
end
def subscription_action_for(body, subject)
return unless SiteSetting.unsubscribe_via_email
if ([subject, body].compact.map(&:to_s).map(&:downcase) & ['unsubscribe']).any?
:confirm_unsubscribe
end
end
def post_action_for(body)
if likes.include?(body.strip.downcase)
PostActionType.types[:like]
end
end
def create_topic(options={})
create_post_with_attachments(options)
end
def create_reply(options={})
raise TopicNotFoundError if options[:topic].nil? || options[:topic].trashed?
raise TopicClosedError if options[:topic].closed?
if post_action_type = post_action_for(options[:raw])
create_post_action(options[:user], options[:post], post_action_type)
else
options[:topic_id] = options[:post].try(:topic_id)
options[:reply_to_post_number] = options[:post].try(:post_number)
options[:is_group_message] = options[:topic].private_message? && options[:topic].allowed_groups.exists?
create_post_with_attachments(options)
end
end
def create_post_action(user, post, type)
PostActionCreator.new(user, post).perform(type)
rescue PostAction::AlreadyActed
# it's cool, don't care
rescue Discourse::InvalidAccess => e
raise InvalidPostAction.new(e)
end
def create_post_with_attachments(options={})
# deal with attachments
@mail.attachments.each do |attachment|
tmp = Tempfile.new("discourse-email-attachment")
begin
# read attachment
File.open(tmp.path, "w+b") { |f| f.write attachment.body.decoded }
# create the upload for the user
opts = { is_attachment_for_group_message: options[:is_group_message] }
upload = Upload.create_for(options[:user].id, tmp, attachment.filename, tmp.size, opts)
if upload && upload.errors.empty?
# try to inline images
if attachment.content_type.start_with?("image/") && options[:raw][/\[image: .+ \d+\]/]
options[:raw].sub!(/\[image: .+ \d+\]/, attachment_markdown(upload))
else
options[:raw] << "\n\n#{attachment_markdown(upload)}\n\n"
end
end
ensure
tmp.try(:close!) rescue nil
end
end
create_post(options)
end
def attachment_markdown(upload)
if FileHelper.is_image?(upload.original_filename)
"<img src='#{upload.url}' width='#{upload.width}' height='#{upload.height}'>"
else
"<a class='attachment' href='#{upload.url}'>#{upload.original_filename}</a> (#{number_to_human_size(upload.filesize)})"
end
end
def create_post(options={})
options[:via_email] = true
options[:raw_email] = @raw_email
# ensure posts aren't created in the future
options[:created_at] = [@mail.date, DateTime.now].min
is_private_message = options[:archetype] == Archetype.private_message ||
options[:topic].try(:private_message?)
# only add elided part in messages
if @elided.present? && is_private_message
options[:raw] << "\n\n" << "<details class='elided'>" << "\n"
options[:raw] << "<summary title='#{I18n.t('emails.incoming.show_trimmed_content')}'>···</summary>" << "\n"
options[:raw] << @elided << "\n"
options[:raw] << "</details>" << "\n"
end
user = options.delete(:user)
manager = NewPostManager.new(user, options)
result = manager.perform
raise InvalidPost, result.errors.full_messages.join("\n") if result.errors.any?
if result.post
@incoming_email.update_columns(topic_id: result.post.topic_id, post_id: result.post.id)
if result.post.topic && result.post.topic.private_message?
add_other_addresses(result.post.topic, user)
end
end
end
def add_other_addresses(topic, sender)
%i(to cc bcc).each do |d|
if @mail[d] && @mail[d].address_list && @mail[d].address_list.addresses
@mail[d].address_list.addresses.each do |address_field|
begin
address_field.decoded
email = address_field.address.downcase
display_name = address_field.display_name.try(:to_s)
if should_invite?(email)
user = find_or_create_user(email, display_name)
if user && can_invite?(topic, user)
topic.topic_allowed_users.create!(user_id: user.id)
topic.add_small_action(sender, "invited_user", user.username)
end
# cap number of staged users created per email
if @staged_users_created > SiteSetting.maximum_staged_users_per_email
topic.add_moderator_post(sender, I18n.t("emails.incoming.maximum_staged_user_per_email_reached"))
return
end
end
rescue ActiveRecord::RecordInvalid
# don't care if user already allowed
end
end
end
end
end
def should_invite?(email)
email !~ reply_by_email_address_regex &&
email !~ group_incoming_emails_regex &&
email !~ category_email_in_regex
end
def can_invite?(topic, user)
!topic.topic_allowed_users.where(user_id: user.id).exists? &&
!topic.topic_allowed_groups.where("group_id IN (SELECT group_id FROM group_users WHERE user_id = ?)", user.id).exists?
end
private
def check_reply_to_auto_generated_header
headers = Mail::Header.new(@mail.body.to_s.gsub("\r\n\r\n", "\r\n")).to_a
index = headers.find_index do |f|
f.name == Email::MessageBuilder::REPLY_TO_AUTO_GENERATED_HEADER_KEY
end
if index
headers[index].value == Email::MessageBuilder::REPLY_TO_AUTO_GENERATED_HEADER_VALUE
end
end
end
end