discourse/lib/email/receiver.rb

824 lines
28 KiB
Ruby

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
# If you add a new error, you need to
# * add it to Email::Processor#handle_failure()
# * add text to server.en.yml (parent key: "emails.incoming.errors")
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 NoSenderDetectedError < ProcessingError; end
class InactiveUserError < ProcessingError; end
class SilencedUserError < 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
class UnsubscribeNotAllowed < ProcessingError; end
class EmailNotAllowed < ProcessingError; end
attr_reader :incoming_email
attr_reader :raw_email
attr_reader :mail
attr_reader :message_id
def self.formats
@formats ||= Enum.new(plaintext: 1,
markdown: 2)
end
def initialize(mail_string)
raise EmptyEmailError if mail_string.blank?
@staged_users = []
@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
error = e.to_s
error = e.class.name if error.blank?
@incoming_email.update_columns(error: error) if @incoming_email
delete_staged_users
raise
end
end
end
def is_blacklisted?
return false if SiteSetting.ignore_by_title.blank?
Regexp.new(SiteSetting.ignore_by_title, Regexp::IGNORECASE) =~ @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 NoSenderDetectedError if @from_email.blank?
raise ScreenedEmailError if ScreenedEmail.should_block?(@from_email)
user = find_user(@from_email)
if user.present?
log_and_validate_user(user)
else
raise UserNotFoundError unless SiteSetting.enable_staged_users
end
body, elided = select_body
body ||= ""
raise NoBodyDetectedError if body.blank? && attachments.empty?
if is_auto_generated?
@incoming_email.update_columns(is_auto_generated: true)
if SiteSetting.block_auto_generated_emails? && !sent_to_mailinglist_mirror?
raise AutoGeneratedEmailError
end
end
if action = subscription_action_for(body, subject)
raise UnsubscribeNotAllowed if user.nil?
send_subscription_mail(action, user)
return
end
# Lets create a staged user if there isn't one yet. We will try to
# delete staged users in process!() if something bad happens.
if user.nil?
user = find_or_create_user(@from_email, @from_display_name)
log_and_validate_user(user)
end
if 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 log_and_validate_user(user)
@incoming_email.update_columns(user_id: user.id)
raise InactiveUserError if !user.active && !user.staged
raise SilencedUserError if user.silenced?
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, Receiver::formats[:markdown]]
else
return [text, elided_text, Receiver::formats[:plaintext]]
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
return extract_from_address_and_name(mail.from) if mail.from.is_a? String
if mail.from.is_a? Mail::AddressContainer
mail.from.each do |from|
from_address, from_display_name = extract_from_address_and_name(from)
return [from_address, from_display_name] if from_address
end
end
nil
rescue StandardError
nil
end
def extract_from_address_and_name(value)
if value[/<[^>]+>/]
from_address = value[/<([^>]+)>/, 1]
from_display_name = value[/^([^<]+)/, 1]
end
if (from_address.blank? || !from_address["@"]) && value[/\[mailto:[^\]]+\]/]
from_address = value[/\[mailto:([^\]]+)\]/, 1]
from_display_name = value[/^([^\[]+)/, 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_user(email)
User.find_by_email(email)
end
def find_or_create_user(email, display_name)
user = nil
User.transaction do
user = User.find_by_email(email)
if user.nil? && SiteSetting.enable_staged_users
raise EmailNotAllowed unless EmailValidator.allowed?(email)
begin
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 << user
rescue
user = nil
end
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
@destinations ||= all_destinations
.map { |d| Email::Receiver.check_address(d) }
.reject(&:blank?)
end
def sent_to_mailinglist_mirror?
destinations.each do |destination|
next unless destination[:type] == :category
category = destination[:obj]
return true if category.mailinglist_mirror?
end
false
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 && !forwareded_reply_key?(email_log, user)
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 forwareded_reply_key?(email_log, user)
incoming_emails = IncomingEmail
.joins(:post)
.where('posts.topic_id = ?', email_log.topic_id)
.addressed_to(email_log.reply_key)
.addressed_to(user.email)
incoming_emails.each do |email|
next unless contains_email_address?(email.to_addresses, user.email) ||
contains_email_address?(email.cc_addresses, user.email)
return true if contains_reply_by_email_address(email.to_addresses, email_log.reply_key) ||
contains_reply_by_email_address(email.cc_addresses, email_log.reply_key)
end
false
end
def contains_email_address?(addresses, email)
return false if addresses.blank?
addresses.split(";").include?(email)
end
def contains_reply_by_email_address(addresses, reply_key)
return false if addresses.blank?
addresses.split(";").each do |address|
match = Email::Receiver.reply_by_email_address_regex.match(address)
return true if match && match.captures&.include?(reply_key)
end
false
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 && !sent_to_mailinglist_mirror?
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
options[:raw] = add_attachments(options[:raw], options[:user].id, options)
create_post(options)
end
def add_attachments(raw, user_id, options = {})
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(user_id)
if upload&.valid?
# try to inline images
if attachment.content_type&.start_with?("image/")
if raw[attachment.url]
raw.sub!(attachment.url, upload.url)
elsif raw[/\[image:.*?\d+[^\]]*\]/i]
raw.sub!(/\[image:.*?\d+[^\]]*\]/i, attachment_markdown(upload))
else
raw << "\n\n#{attachment_markdown(upload)}\n\n"
end
else
raw << "\n\n#{attachment_markdown(upload)}\n\n"
end
end
ensure
tmp.try(:close!) rescue nil
end
end
raw
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
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, user)
end
end
result.post
end
def self.elided_html(elided)
html = "\n\n" << "<details class='elided'>" << "\n"
html << "<summary title='#{I18n.t('emails.incoming.show_trimmed_content')}'>&#183;&#183;&#183;</summary>" << "\n"
html << elided << "\n"
html << "</details>" << "\n"
html
end
def add_other_addresses(post, 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?(post.topic, user)
post.topic.topic_allowed_users.create!(user_id: user.id)
TopicUser.auto_notification_for_staging(user.id, post.topic_id, TopicUser.notification_reasons[:auto_watch])
post.topic.add_small_action(sender, "invited_user", user.username)
end
# cap number of staged users created per email
if @staged_users.count > SiteSetting.maximum_staged_users_per_email
post.topic.add_moderator_post(sender, I18n.t("emails.incoming.maximum_staged_user_per_email_reached"))
return
end
end
rescue ActiveRecord::RecordInvalid, EmailNotAllowed
# don't care if user already allowed or the user's email address is not 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
def send_subscription_mail(action, user)
message = SubscriptionMailer.send(action, user)
Email::Sender.new(message, :subscription).send
end
def delete_staged_users
@staged_users.each do |user|
if @incoming_email.user.id == user.id
@incoming_email.update_columns(user_id: nil)
end
if user.posts.count == 0
UserDestroyer.new(Discourse.system_user).destroy(user, quiet: true)
end
end
end
end
end