require "digest" require_dependency "new_post_manager" require_dependency "post_action_creator" require_dependency "html_to_markdown" require_dependency "upload_creator" 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 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 attr_reader :raw_email attr_reader :mail attr_reader :message_id def initialize(mail_string) raise EmptyEmailError if mail_string.blank? @staged_users_created = 0 @raw_email = try_to_encode(mail_string, "UTF-8") || try_to_encode(mail_string, "ISO-8859-1") || 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? DistributedMutex.synchronize(@message_id) do begin return if IncomingEmail.exists?(message_id: @message_id) @from_email, @from_display_name = parse_from_field(@mail) @incoming_email = create_incoming_email process_internal rescue => e @incoming_email.update_columns(error: e.to_s) if @incoming_email raise end end end def is_blacklisted? return false if SiteSetting.ignore_by_title.blank? Regexp.new(SiteSetting.ignore_by_title) =~ @mail.subject end def create_incoming_email IncomingEmail.create( message_id: @message_id, raw: @raw_email, subject: subject, from_address: @from_email, to_addresses: @mail.to&.map(&:downcase)&.join(";"), cc_addresses: @mail.cc&.map(&:downcase)&.join(";"), ) end def process_internal raise BouncedEmailError if is_bounce? 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 InactiveUserError if !user.active && !user.staged raise BlockedUserError if user.blocked body, elided = select_body body ||= "" raise NoBodyDetectedError if body.blank? && attachments.empty? if is_auto_generated? @incoming_email.update_columns(is_auto_generated: true) 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, elided: elided, post: post, topic: post.topic, skip_validations: user.staged?) else first_exception = nil destinations.each do |destination| begin process_destination(destination, user, body, elided) rescue => e first_exception ||= e else return end end raise first_exception || BadDestinationAddress end end 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]) && (email_log = EmailLog.find_by(bounce_key: bounce_key)) email_log.update_columns(bounced: true) email = email_log.user.try(:email).presence end email ||= @from_email if @mail.error_status.present? && @mail.error_status.start_with?("4.") Email::Receiver.update_bounce_score(email, SiteSetting.soft_bounce_score) else Email::Receiver.update_bounce_score(email, SiteSetting.hard_bounce_score) 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 = SiteSetting.reset_bounce_score_after_days.days.from_now user.user_stat.save bounce_score = user.user_stat.bounce_score if user.active && bounce_score >= SiteSetting.bounce_score_threshold_deactivate user.update_columns(active: false) reason = I18n.t("user.deactivated", email: user.email) StaffActionLogger.new(Discourse.system_user).log_user_deactivate(user, reason) elsif bounce_score >= SiteSetting.bounce_score_threshold # NOTE: we check bounce_score before sending emails, nothing to do # here other than log it happened. reason = I18n.t("user.email.revoked", { email: user.email, date: user.user_stat.reset_bounce_score_after }) StaffActionLogger.new(Discourse.system_user).log_revoke_email(user, reason) 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|post[\-_]?master|no[\-_]?reply)@/i] || @mail[:subject].to_s[/^\s*(Auto:|Automatic reply|Autosvar|Automatisk svar|Automatisch antwoord|Abwesenheitsnotiz|Risposta Non al computer|Automatisch antwoord|Auto Response|Respuesta automática|Fuori sede|Out of Office|Frånvaro|Réponse automatique)/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 text, elided_text = if text.present? text = trim_discourse_markers(text) EmailReplyTrimmer.trim(text, true) end markdown, elided_markdown = if html.present? markdown = HtmlToMarkdown.new(html, keep_img_tags: true, keep_cid_imgs: true).to_markdown markdown = trim_discourse_markers(markdown) EmailReplyTrimmer.trim(markdown, true) end if text.blank? || (SiteSetting.incoming_email_prefer_html && markdown.present?) return [markdown, elided_markdown] else return [text, elided_text] 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? # common encodings encodings = ["UTF-8", "ISO-8859-1"] encodings.unshift(mail_part.charset) if mail_part.charset.present? # mail (>=2.5) decodes mails with 8bit transfer encoding to utf-8, so # always try UTF-8 first if mail_part.content_transfer_encoding == "8bit" encodings.delete("UTF-8") encodings.unshift("UTF-8") end encodings.uniq.each do |encoding| fixed = try_to_encode(string, encoding) return fixed if fixed.present? end nil end def try_to_encode(string, encoding) encoded = string.encode("UTF-8", encoding) !encoded.nil? && 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(mail) return unless mail[:from] if mail[:from].errors.blank? mail[:from].address_list.addresses.each do |address_field| address_field.decoded from_address = address_field.address from_display_name = address_field.display_name.try(:to_s) return [from_address&.downcase, from_display_name&.strip] if from_address["@"] end end if mail.from[/<[^>]+>/] from_address = mail.from[/<([^>]+)>/, 1] from_display_name = mail.from[/^([^<]+)/, 1] end if (from_address.blank? || !from_address["@"]) && mail.from[/\[mailto:[^\]]+\]/] from_address = mail.from[/\[mailto:([^\]]+)\]/, 1] from_display_name = mail.from[/^([^\[]+)/, 1] end [from_address&.downcase, from_display_name&.strip] 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| Email::Receiver.check_address(d) } .drop_while(&:blank?) end def self.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 = Email::Receiver.reply_by_email_address_regex.match(address) if match && match.captures match.captures.each do |c| next if c.blank? email_log = EmailLog.for(c) return { type: :reply, obj: email_log } if email_log end end nil end def process_destination(destination, user, body, elided) return if SiteSetting.enable_forwarded_emails && has_been_forwarded? && process_forwarded_email(destination, user) case destination[:type] when :group group = destination[:obj] create_topic(user: user, raw: body, elided: elided, 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, elided: elided, title: subject, category: category.id, skip_validations: user.staged?) when :reply email_log = destination[:obj] if email_log.user_id != user.id raise ReplyUserNotMatchingError, "email_log.user_id => #{email_log.user_id.inspect}, user.id => #{user.id.inspect}" end create_reply(user: user, raw: body, elided: elided, post: email_log.post, topic: email_log.post.topic, skip_validations: user.staged?) end end def has_been_forwarded? subject[/^[[:blank:]]*(fwd?|tr)[[:blank:]]?:/i] && embedded_email_raw.present? end def embedded_email_raw return @embedded_email_raw if @embedded_email_raw text = fix_charset(@mail.multipart? ? @mail.text_part : @mail) @embedded_email_raw, @before_embedded = EmailReplyTrimmer.extract_embedded_email(text) @embedded_email_raw end def process_forwarded_email(destination, user) embedded = Mail.new(embedded_email_raw) email, display_name = parse_from_field(embedded) return false if email.blank? || !email["@"] embedded_user = find_or_create_user(email, display_name) raw = try_to_encode(embedded.decoded, "UTF-8").presence || embedded.to_s title = embedded.subject.presence || subject case destination[:type] when :group group = destination[:obj] post = create_topic(user: embedded_user, raw: raw, title: title, archetype: Archetype.private_message, target_usernames: [user.username], target_group_names: [group.name], is_group_message: true, skip_validations: true, created_at: embedded.date) when :category category = destination[:obj] return false if user.staged? && !category.email_in_allow_strangers return false if !user.has_trust_level?(SiteSetting.email_in_min_trust) post = create_topic(user: embedded_user, raw: raw, title: title, category: category.id, skip_validations: embedded_user.staged?, created_at: embedded.date) else return false end if post&.topic # mark post as seen for the forwarder PostTiming.record_timing(user_id: user.id, topic_id: post.topic_id, post_number: post.post_number, msecs: 5000) # create reply when available if @before_embedded.present? post_type = Post.types[:regular] post_type = Post.types[:whisper] if post.topic.private_message? && group.usernames[user.username] create_reply(user: user, raw: @before_embedded, post: post, topic: post.topic, post_type: post_type, skip_validations: user.staged?) end end true end def self.reply_by_email_address_regex(extract_reply_key=true) reply_addresses = [SiteSetting.reply_by_email_address] reply_addresses << (SiteSetting.alternative_reply_by_email_addresses.presence || "").split("|") reply_addresses.flatten! reply_addresses.select!(&:present?) reply_addresses.map! { |a| Regexp.escape(a) } reply_addresses.map! { |a| a.gsub(Regexp.escape("%{reply_key}"), "(\\h{32})") } /#{reply_addresses.join("|")}/ 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 return if SiteSetting.find_related_post_with_key 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? message_ids = message_ids.first(5) host = Email::Sender.host_for(Discourse.base_url) post_id_regexp = Regexp.new "topic/\\d+/(\\d+)@#{Regexp.escape(host)}" topic_id_regexp = Regexp.new "topic/(\\d+)@#{Regexp.escape(host)}" post_ids = message_ids.map { |message_id| message_id[post_id_regexp, 1] }.compact.map(&:to_i) post_ids << Post.where(topic_id: message_ids.map { |message_id| message_id[topic_id_regexp, 1] }.compact, post_number: 1).pluck(:id) post_ids << EmailLog.where(message_id: message_ids).pluck(:post_id) post_ids << IncomingEmail.where(message_id: message_ids).pluck(:post_id) post_ids.flatten! post_ids.compact! post_ids.uniq! return if post_ids.empty? Post.where(id: post_ids).order(:created_at).last end def self.extract_references(references) if Array === references references elsif references.present? references.split(/[\s,]/).map { |r| r.tr("<>", "") } end end def likes @likes ||= Set.new ["+1", "<3", "❤", 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) PostActionType.types[:like] if likes.include?(body.strip.downcase) end def create_topic(options={}) create_post_with_attachments(options) end def create_reply(options={}) raise TopicNotFoundError if options[:topic].nil? || options[:topic].trashed? if post_action_type = post_action_for(options[:raw]) create_post_action(options[:user], options[:post], post_action_type) else raise TopicClosedError if options[:topic].closed? 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 attachments # strip blacklisted attachments (mostly signatures) @attachments ||= @mail.attachments.select do |attachment| attachment.content_type !~ SiteSetting.attachment_content_type_blacklist_regex && attachment.filename !~ SiteSetting.attachment_filename_blacklist_regex end end def create_post_with_attachments(options={}) # deal with attachments attachments.each do |attachment| tmp = Tempfile.new(["discourse-email-attachment", File.extname(attachment.filename)]) begin # read attachment File.open(tmp.path, "w+b") { |f| f.write attachment.body.decoded } # create the upload for the user opts = { for_group_message: options[:is_group_message] } upload = UploadCreator.new(tmp, attachment.filename, opts).create_for(options[:user].id) if upload && upload.errors.empty? # try to inline images if attachment.content_type.start_with?("image/") if options[:raw][attachment.url] options[:raw].sub!(attachment.url, upload.url) elsif options[:raw][/\[image:.*?\d+[^\]]*\]/i] options[:raw].sub!(/\[image:.*?\d+[^\]]*\]/i, attachment_markdown(upload)) else options[:raw] << "\n\n#{attachment_markdown(upload)}\n\n" end 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) "" else "#{upload.original_filename} (#{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 if options[:created_at].nil? raise InvalidPost, "No post creation date found. Is the e-mail missing a Date: header?" end options[:created_at] = DateTime.now if options[:created_at] > DateTime.now is_private_message = options[:archetype] == Archetype.private_message || options[:topic].try(:private_message?) # only add elided part in messages if options[:elided].present? && (SiteSetting.always_show_trimmed_content || is_private_message) options[:raw] << Email::Receiver.elided_html(options[:elided]) end user = options.delete(:user) result = NewPostManager.new(user, options).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 result.post end def self.elided_html(elided) html = "\n\n" << "
" << "\n" html << "···" << "\n" html << elided << "\n" html << "
" << "\n" html 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) next unless email["@"] 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 !~ Email::Receiver.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 end end