PERF: Move EmailLog#reply_key into new post_reply_keys table.

lib/email/message_builder.rb

@@ -17,6 +17,8 @@ module Email
   class MessageBuilder
     attr_reader :template_args
 
+    ALLOW_REPLY_BY_EMAIL_HEADER = 'X-Discourse-Allow-Reply-By-Email'.freeze
+
     def initialize(to, opts = nil)
       @to = to
       @opts = opts || {}
@@ -147,7 +149,7 @@ module Email
       result['X-Auto-Response-Suppress'] = 'All'
 
       if allow_reply_by_email?
-        result['X-Discourse-Reply-Key'] = reply_key
+        result[ALLOW_REPLY_BY_EMAIL_HEADER] = true
         result['Reply-To'] = reply_by_email_address
       else
         result['Reply-To'] = from_value
@@ -171,10 +173,6 @@ module Email
 
     protected
 
-    def reply_key
-      @reply_key ||= SecureRandom.hex(16)
-    end
-
     def allow_reply_by_email?
       SiteSetting.reply_by_email_enabled? &&
       reply_by_email_address.present? &&
@@ -196,7 +194,6 @@ module Email
       return nil unless SiteSetting.reply_by_email_address.present?
 
       @reply_by_email_address = SiteSetting.reply_by_email_address.dup
-      @reply_by_email_address.gsub!("%{reply_key}", reply_key)
 
       @reply_by_email_address =
         if private_reply?

lib/email/receiver.rb

@@ -548,8 +548,8 @@ module Email
       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
+          post_reply_key = PostReplyKey.find_by(reply_key: c)
+          return { type: :reply, obj: post_reply_key } if post_reply_key
         end
       end
       nil
@@ -580,18 +580,18 @@ module Email
                      skip_validations: user.staged?)
 
       when :reply
-        email_log = destination[:obj]
+        post_reply_key = destination[:obj]
 
-        if email_log.user_id != user.id && !forwarded_reply_key?(email_log, user)
-          raise ReplyUserNotMatchingError, "email_log.user_id => #{email_log.user_id.inspect}, user.id => #{user.id.inspect}"
+        if post_reply_key.user_id != user.id && !forwarded_reply_key?(post_reply_key, user)
+          raise ReplyUserNotMatchingError, "post_reply_key.user_id => #{post_reply_key.user_id.inspect}, user.id => #{user.id.inspect}"
         end
 
         create_reply(user: user,
                      raw: body,
                      elided: elided,
                      hidden_reason_id: hidden_reason_id,
-                     post: email_log.post,
-                     topic: email_log.post.topic,
+                     post: post_reply_key.post,
+                     topic: post_reply_key.post.topic,
                      skip_validations: user.staged?)
       end
     end
@@ -631,11 +631,11 @@ module Email
       end
     end
 
-    def forwarded_reply_key?(email_log, user)
+    def forwarded_reply_key?(post_reply_key, user)
       incoming_emails = IncomingEmail
         .joins(:post)
-        .where('posts.topic_id = ?', email_log.topic.id)
-        .addressed_to(email_log.reply_key)
+        .where('posts.topic_id = ?', post_reply_key.post.topic_id)
+        .addressed_to(post_reply_key.reply_key)
         .addressed_to_user(user)
         .pluck(:to_addresses, :cc_addresses)
 
@@ -643,8 +643,8 @@ module Email
         next unless contains_email_address_of_user?(to_addresses, user) ||
           contains_email_address_of_user?(cc_addresses, user)
 
-        return true if contains_reply_by_email_address(to_addresses, email_log.reply_key) ||
-          contains_reply_by_email_address(cc_addresses, email_log.reply_key)
+        return true if contains_reply_by_email_address(to_addresses, post_reply_key.reply_key) ||
+          contains_reply_by_email_address(cc_addresses, post_reply_key.reply_key)
       end
 
       false

lib/email/sender.rb

@@ -31,8 +31,7 @@ module Email
       return skip(SkippedEmailLog.reason_types[:sender_message_to_blank]) if @message.to.blank?
 
       if SiteSetting.disable_emails == "non-staff"
-        user = User.find_by_email(to_address)
-        return unless user && user.staff?
+        return unless User.find_by_email(to_address)&.staff?
       end
 
       if @message.text_part
@@ -68,15 +67,20 @@ module Email
       @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'
+      user_id = @user&.id
 
       # Set up the email log
-      email_log = EmailLog.new(email_type: @email_type, to_address: to_address, user_id: @user.try(:id))
+      email_log = EmailLog.new(
+        email_type: @email_type,
+        to_address: to_address,
+        user_id: user_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')
+      reply_key = set_reply_key(post_id, user_id)
 
       # always set a default Message ID from the host
       @message.header['Message-ID'] = "<#{SecureRandom.uuid}@#{host}>"
@@ -160,12 +164,14 @@ module Email
       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?
+
+      if reply_key.present?
+        @message.header[Email::MessageBuilder::ALLOW_REPLY_BY_EMAIL_HEADER] = nil
+      end
 
       # pass the original message_id when using mailjet/mandrill/sparkpost
       case ActionMailer::Base.smtp_settings[:address]
@@ -251,5 +257,19 @@ module Email
       @message.header[name] = data.to_json
     end
 
+    def set_reply_key(post_id, user_id)
+      return unless user_id &&
+        post_id &&
+        header_value(Email::MessageBuilder::ALLOW_REPLY_BY_EMAIL_HEADER).present?
+
+      reply_key = PostReplyKey.find_or_create_by!(
+        post_id: post_id,
+        user_id: user_id
+      ).reply_key
+
+      @message.header['Reply-To'] =
+        header_value('Reply-To').gsub!("%{reply_key}", reply_key)
+    end
+
   end
 end