discourse/lib/email/receiver.rb

262 lines
7.8 KiB
Ruby

require 'email/html_cleaner'
#
# Handles an incoming message
#
module Email
class Receiver
include ActionView::Helpers::NumberHelper
class ProcessingError < StandardError; end
class EmailUnparsableError < ProcessingError; end
class EmptyEmailError < ProcessingError; end
class UserNotFoundError < ProcessingError; end
class UserNotSufficientTrustLevelError < ProcessingError; end
class BadDestinationAddress < ProcessingError; end
class EmailLogNotFound < ProcessingError; end
class InvalidPost < ProcessingError; end
attr_reader :body, :email_log
def initialize(raw)
@raw = raw
end
def process
raise EmptyEmailError if @raw.blank?
message = Mail.new(@raw)
body = parse_body message
dest_info = {type: :invalid, obj: nil}
message.to.each do |to_address|
if dest_info[:type] == :invalid
dest_info = check_address to_address
end
end
raise BadDestinationAddress if dest_info[:type] == :invalid
# TODO get to a state where we can remove this
@message = message
@body = body
if dest_info[:type] == :category
raise BadDestinationAddress unless SiteSetting.email_in
category = dest_info[:obj]
@category_id = category.id
@allow_strangers = category.email_in_allow_strangers
user_email = @message.from.first
@user = User.find_by_email(user_email)
if @user.blank? && @allow_strangers
wrap_body_in_quote user_email
# TODO This is WRONG it should register an account
# and email the user details on how to log in / activate
@user = Discourse.system_user
end
raise UserNotFoundError if @user.blank?
raise UserNotSufficientTrustLevelError.new @user unless @allow_strangers || @user.has_trust_level?(TrustLevel[SiteSetting.email_in_min_trust.to_i])
create_new_topic
else
@email_log = dest_info[:obj]
raise EmailLogNotFound if @email_log.blank?
create_reply
end
rescue Encoding::UndefinedConversionError, Encoding::InvalidByteSequenceError => e
raise EmailUnparsableError.new(e)
end
def check_address(address)
category = Category.find_by_email(address)
return {type: :category, obj: category} if category
regex = Regexp.escape SiteSetting.reply_by_email_address
regex = regex.gsub(Regexp.escape('%{reply_key}'), "(.*)")
regex = Regexp.new regex
match = regex.match address
if match && match[1].present?
reply_key = match[1]
email_log = EmailLog.for(reply_key)
return {type: :reply, obj: email_log}
end
{type: :invalid, obj: nil}
end
def parse_body(message)
body = select_body message
encoding = body.encoding
raise EmptyEmailError if body.strip.blank?
body = discourse_email_trimmer body
raise EmptyEmailError if body.strip.blank?
body = EmailReplyParser.parse_reply body
raise EmptyEmailError if body.strip.blank?
body.force_encoding(encoding).encode("UTF-8")
end
def select_body(message)
html = nil
# If the message is multipart, return that part (favor html)
if message.multipart?
html = fix_charset message.html_part
text = fix_charset message.text_part
# TODO picking text if available may be better
# in case of email reply from MS Outlook client, prefer text
if (text && !html) || (text && message.header.to_s =~ /X-MS-Has-Attach/)
return text
end
elsif message.content_type =~ /text\/html/
html = fix_charset message
end
if html
body = HtmlCleaner.new(html).output_html
else
body = fix_charset message
end
# Certain trigger phrases that means we didn't parse correctly
if body =~ /Content\-Type\:/ || body =~ /multipart\/alternative/ || body =~ /text\/plain/
raise EmptyEmailError
end
body
end
# Force encoding to UTF-8 on a Mail::Message or Mail::Part
def fix_charset(object)
return nil if object.nil?
if object.charset
object.body.decoded.force_encoding(object.charset).encode("UTF-8").to_s
else
object.body.to_s
end
end
REPLYING_HEADER_LABELS = ['From', 'Sent', 'To', 'Subject', 'Reply To']
REPLYING_HEADER_REGEX = Regexp.union(REPLYING_HEADER_LABELS.map { |lbl| "#{lbl}:" })
def discourse_email_trimmer(body)
lines = body.scrub.lines.to_a
range_end = 0
lines.each_with_index do |l, idx|
break if l =~ /\A\s*\-{3,80}\s*\z/ ||
l =~ Regexp.new("\\A\\s*" + I18n.t('user_notifications.previous_discussion') + "\\s*\\Z") ||
(l =~ /via #{SiteSetting.title}(.*)\:$/) ||
# This one might be controversial but so many reply lines have years, times and end with a colon.
# Let's try it and see how well it works.
(l =~ /\d{4}/ && l =~ /\d:\d\d/ && l =~ /\:$/) ||
(l =~ /On \w+ \d+,? \d+,?.*wrote:/)
# Headers on subsequent lines
break if (0..2).all? { |off| lines[idx+off] =~ REPLYING_HEADER_REGEX }
# Headers on the same line
break if REPLYING_HEADER_LABELS.count { |lbl| l.include? lbl } >= 3
range_end = idx
end
lines[0..range_end].join.strip
end
def wrap_body_in_quote(user_email)
@body = "[quote=\"#{user_email}\"]
#{@body}
[/quote]"
end
private
def create_reply
create_post_with_attachments(@email_log.user,
raw: @body,
topic_id: @email_log.topic_id,
reply_to_post_number: @email_log.post.post_number)
end
def create_new_topic
post = create_post_with_attachments(@user,
raw: @body,
title: @message.subject,
category: @category_id)
EmailLog.create(
email_type: "topic_via_incoming_email",
to_address: @message.from.first, # pick from address because we want the user's email
topic_id: post.topic.id,
user_id: @user.id,
)
post
end
def create_post_with_attachments(user, post_opts={})
options = {
cooking_options: { traditional_markdown_linebreaks: true },
}.merge(post_opts)
raw = options[:raw]
# deal with attachments
@message.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
upload = Upload.create_for(user.id, tmp, attachment.filename, File.size(tmp))
if upload && upload.errors.empty?
# TODO: should use the same code as the client to insert attachments
raw << "\n#{attachment_markdown(upload)}\n"
end
ensure
tmp.close!
end
end
options[:raw] = raw
create_post(user, 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(user, options)
# Mark the reply as incoming via email
options[:via_email] = true
options[:raw_email] = @raw
creator = PostCreator.new(user, options)
post = creator.create
if creator.errors.present?
raise InvalidPost, creator.errors.full_messages.join("\n")
end
post
end
end
end