style(rubocop): fix all safe auto correctable offenses

lib/postal/smtp_server/client.rb

@@ -1,11 +1,11 @@
-require 'resolv'
-require 'nifty/utils/random_string'
+require "resolv"
+require "nifty/utils/random_string"
 
 module Postal
   module SMTPServer
     class Client
 
-      CRAM_MD5_DIGEST = OpenSSL::Digest.new('md5')
+      CRAM_MD5_DIGEST = OpenSSL::Digest.new("md5")
       LOG_REDACTION_STRING = "[redacted]".freeze
 
       attr_reader :logging_enabled
@@ -23,9 +23,9 @@ module Postal
       end
 
       def check_ip_address
-        if @ip_address && Postal.config.smtp_server.log_exclude_ips && @ip_address =~ Regexp.new(Postal.config.smtp_server.log_exclude_ips)
-          @logging_enabled = false
-        end
+        return unless @ip_address && Postal.config.smtp_server.log_exclude_ips && @ip_address =~ Regexp.new(Postal.config.smtp_server.log_exclude_ips)
+
+        @logging_enabled = false
       end
 
       def transaction_reset
@@ -36,7 +36,7 @@ module Postal
       end
 
       def id
-        @id ||= Nifty::Utils::RandomString.generate(:length => 6).upcase
+        @id ||= Nifty::Utils::RandomString.generate(length: 6).upcase
       end
 
       def handle(data)
@@ -56,13 +56,13 @@ module Postal
       def sanitize_input_for_log(data)
         if @password_expected_next
           @password_expected_next = false
-          if data =~ /\A[a-z0-9]{3,}\=*\z/i
+          if data =~ /\A[a-z0-9]{3,}=*\z/i
             return LOG_REDACTION_STRING
           end
         end
 
         data = data.dup
-        data.gsub!(/(.*AUTH \w+) (.*)\z/i) { "#{$1} #{LOG_REDACTION_STRING}" }
+        data.gsub!(/(.*AUTH \w+) (.*)\z/i) { "#{::Regexp.last_match(1)} #{LOG_REDACTION_STRING}" }
         data
       end
 
@@ -74,9 +74,7 @@ module Postal
         @start_tls || false
       end
 
-      def start_tls=(value)
-        @start_tls = value
-      end
+      attr_writer :start_tls
 
       def handle_command(data)
         case data
@@ -93,12 +91,13 @@ module Postal
         when /^RCPT TO/i        then rcpt_to(data)
         when /^DATA/i           then data(data)
         else
-          '502 Invalid/unsupported command'
+          "502 Invalid/unsupported command"
         end
       end
 
       def log(text)
         return false unless @logging_enabled
+
         Postal.logger_for(:smtp_server).debug "[#{id}] #{text}"
       end
 
@@ -106,8 +105,12 @@ module Postal
 
       def resolve_hostname
         Resolv::DNS.open do |dns|
-          dns.timeouts = [10,5]
-          @hostname = dns.getname(@ip_address) rescue @ip_address
+          dns.timeouts = [10, 5]
+          @hostname = begin
+            dns.getname(@ip_address)
+          rescue StandardError
+            @ip_address
+          end
         end
       end
 
@@ -120,7 +123,7 @@ module Postal
           "220 #{Postal.config.dns.smtp_server_hostname} ESMTP Postal/#{id}"
         else
           @finished = true
-          '502 Proxy Error'
+          "502 Proxy Error"
         end
       end
 
@@ -141,15 +144,15 @@ module Postal
 
       def ehlo(data)
         resolve_hostname
-        @helo_name = data.strip.split(' ', 2)[1]
+        @helo_name = data.strip.split(" ", 2)[1]
         transaction_reset
         @state = :welcomed
-        ["250-My capabilities are", Postal.config.smtp_server.tls_enabled? && !@tls ? "250-STARTTLS" : nil, "250 AUTH CRAM-MD5 PLAIN LOGIN", ]
+        ["250-My capabilities are", Postal.config.smtp_server.tls_enabled? && !@tls ? "250-STARTTLS" : nil, "250 AUTH CRAM-MD5 PLAIN LOGIN"]
       end
 
       def helo(data)
         resolve_hostname
-        @helo_name = data.strip.split(' ', 2)[1]
+        @helo_name = data.strip.split(" ", 2)[1]
         transaction_reset
         @state = :welcomed
         "250 #{Postal.config.dns.smtp_server_hostname}"
@@ -158,59 +161,61 @@ module Postal
       def rset
         transaction_reset
         @state = :welcomed
-        '250 OK'
+        "250 OK"
       end
 
       def noop
-        '250 OK'
+        "250 OK"
       end
 
       def auth_plain(data)
-        handler = Proc.new do |data|
+        handler = proc do |data|
           @proc = nil
           data = Base64.decode64(data)
           parts = data.split("\0")
-          username, password = parts[-2], parts[-1]
+          username = parts[-2]
+          password = parts[-1]
           unless username && password
-            next '535 Authenticated failed - protocol error'
+            next "535 Authenticated failed - protocol error"
           end
+
           authenticate(password)
         end
 
-        data = data.gsub(/AUTH PLAIN ?/i, '')
-        if data.strip == ''
+        data = data.gsub(/AUTH PLAIN ?/i, "")
+        if data.strip == ""
           @proc = handler
           @password_expected_next = true
-          '334'
+          "334"
         else
           handler.call(data)
         end
       end
 
       def auth_login(data)
-        password_handler = Proc.new do |data|
+        password_handler = proc do |data|
           @proc = nil
           password = Base64.decode64(data)
           authenticate(password)
         end
 
-        username_handler = Proc.new do |data|
+        username_handler = proc do |data|
           @proc = password_handler
           @password_expected_next = true
-          '334 UGFzc3dvcmQ6' # "Password:"
+          "334 UGFzc3dvcmQ6" # "Password:"
         end
 
-        data = data.gsub!(/AUTH LOGIN ?/i, '')
-        if data.strip == ''
+        data = data.gsub!(/AUTH LOGIN ?/i, "")
+        if data.strip == ""
           @proc = username_handler
-          '334 VXNlcm5hbWU6' # "Username:"
+          "334 VXNlcm5hbWU6" # "Username:"
         else
           username_handler.call(nil)
         end
       end
 
       def authenticate(password)
-        if @credential = Credential.where(:type => 'SMTP', :key => password).first
+        if @credential = Credential.where(type: "SMTP", key: password).first
           @credential.use
           "235 Granted for #{@credential.server.organization.permalink}/#{@credential.server.permalink}"
         else
@@ -220,27 +225,27 @@ module Postal
       end
 
       def auth_cram_md5(data)
-        challenge = Digest::SHA1.hexdigest(Time.now.to_i.to_s + rand(100000).to_s)
-        challenge = "<#{challenge[0,20]}@#{Postal.config.dns.smtp_server_hostname}>"
+        challenge = Digest::SHA1.hexdigest(Time.now.to_i.to_s + rand(100_000).to_s)
+        challenge = "<#{challenge[0, 20]}@#{Postal.config.dns.smtp_server_hostname}>"
 
-        handler = Proc.new do |data|
+        handler = proc do |data|
           @proc = nil
-          username, password = Base64.decode64(data).split(' ', 2).map{ |a| a.chomp }
-          org_permlink, server_permalink = username.split(/[\/\_]/, 2)
-          server = ::Server.includes(:organization).where(:organizations => {:permalink => org_permlink}, :permalink => server_permalink).first
+          username, password = Base64.decode64(data).split(" ", 2).map { |a| a.chomp }
+          org_permlink, server_permalink = username.split(/[\/_]/, 2)
+          server = ::Server.includes(:organization).where(organizations: { permalink: org_permlink }, permalink: server_permalink).first
           if server.nil?
             log "\e[33m WARN: AUTH failure for #{@ip_address}\e[0m"
-            next '535 Denied'
+            next "535 Denied"
           end
           grant = nil
-          server.credentials.where(:type => 'SMTP').each do |credential|
+          server.credentials.where(type: "SMTP").each do |credential|
             correct_response = OpenSSL::HMAC.hexdigest(CRAM_MD5_DIGEST, credential.key, challenge)
-            if password == correct_response
-              @credential = credential
-              @credential.use
-              grant = "235 Granted for #{credential.server.organization.permalink}/#{credential.server.permalink}"
-              break
-            end
+            next unless password == correct_response
+
+            @credential = credential
+            @credential.use
+            grant = "235 Granted for #{credential.server.organization.permalink}/#{credential.server.permalink}"
+            break
           end
           if grant.nil?
             log "\e[33m WARN: AUTH failure for #{@ip_address}\e[0m"
@@ -250,12 +255,12 @@ module Postal
         end
 
         @proc = handler
-        "334 " + Base64.encode64(challenge).gsub(/[\r\n]/, '')
+        "334 " + Base64.encode64(challenge).gsub(/[\r\n]/, "")
       end
 
       def mail_from(data)
         unless in_state(:welcomed, :mail_from_received)
-          return '503 EHLO/HELO first please'
+          return "503 EHLO/HELO first please"
         end
 
         @state = :mail_from_received
@@ -263,93 +268,93 @@ module Postal
         if data =~ /AUTH=/
           # Discard AUTH= parameter and anything that follows.
           # We don't need this parameter as we don't trust any client to set it
-          mail_from_line = data.sub(/ *AUTH=.*/, '')
+          mail_from_line = data.sub(/ *AUTH=.*/, "")
         else
           mail_from_line = data
         end
-        @mail_from = mail_from_line.gsub(/MAIL FROM\s*:\s*/i, '').gsub(/.*</, '').gsub(/>.*/, '').strip
-        '250 OK'
+        @mail_from = mail_from_line.gsub(/MAIL FROM\s*:\s*/i, "").gsub(/.*</, "").gsub(/>.*/, "").strip
+        "250 OK"
       end
 
       def rcpt_to(data)
         unless in_state(:mail_from_received, :rcpt_to_received)
-          return '503 EHLO/HELO and MAIL FROM first please'
+          return "503 EHLO/HELO and MAIL FROM first please"
         end
 
-        rcpt_to = data.gsub(/RCPT TO\s*:\s*/i, '').gsub(/.*</, '').gsub(/>.*/, '').strip
+        rcpt_to = data.gsub(/RCPT TO\s*:\s*/i, "").gsub(/.*</, "").gsub(/>.*/, "").strip
 
         if rcpt_to.blank?
-          return '501 RCPT TO should not be empty'
+          return "501 RCPT TO should not be empty"
         end
 
-        uname, domain = rcpt_to.split('@', 2)
+        uname, domain = rcpt_to.split("@", 2)
 
         if domain.blank?
-          return '501 Invalid RCPT TO'
+          return "501 Invalid RCPT TO"
         end
 
-        uname, tag = uname.split('+', 2)
+        uname, tag = uname.split("+", 2)
 
         if domain == Postal.config.dns.return_path || domain =~ /\A#{Regexp.escape(Postal.config.dns.custom_return_path_prefix)}\./
           # This is a return path
           @state = :rcpt_to_received
-          if server = ::Server.where(:token => uname).first
+          if server = ::Server.where(token: uname).first
             if server.suspended?
-              '535 Mail server has been suspended'
+              "535 Mail server has been suspended"
             else
               log "Added bounce on server #{server.id}"
               @recipients << [:bounce, rcpt_to, server]
-              '250 OK'
+              "250 OK"
             end
           else
-            '550 Invalid server token'
+            "550 Invalid server token"
           end
 
         elsif domain == Postal.config.dns.route_domain
           # This is an email direct to a route. This isn't actually supported yet.
           @state = :rcpt_to_received
-          if route = Route.where(:token => uname).first
+          if route = Route.where(token: uname).first
             if route.server.suspended?
-              '535 Mail server has been suspended'
-            elsif route.mode == 'Reject'
-              '550 Route does not accept incoming messages'
+              "535 Mail server has been suspended"
+            elsif route.mode == "Reject"
+              "550 Route does not accept incoming messages"
             else
               log "Added route #{route.id} to recipients (tag: #{tag.inspect})"
               actual_rcpt_to = "#{route.name}" + (tag ? "+#{tag}" : "") + "@#{route.domain.name}"
-              @recipients << [:route, actual_rcpt_to, route.server, :route => route]
-              '250 OK'
+              @recipients << [:route, actual_rcpt_to, route.server, { route: route }]
+              "250 OK"
             end
           else
-            '550 Invalid route token'
+            "550 Invalid route token"
           end
 
         elsif @credential
           # This is outgoing mail for an authenticated user
           @state = :rcpt_to_received
           if @credential.server.suspended?
-            '535 Mail server has been suspended'
+            "535 Mail server has been suspended"
           else
             log "Added external address '#{rcpt_to}'"
             @recipients << [:credential, rcpt_to, @credential.server]
-            '250 OK'
+            "250 OK"
           end
 
         elsif uname && domain && route = Route.find_by_name_and_domain(uname, domain)
           # This is incoming mail for a route
           @state = :rcpt_to_received
           if route.server.suspended?
-            '535 Mail server has been suspended'
-          elsif route.mode == 'Reject'
-            '550 Route does not accept incoming messages'
+            "535 Mail server has been suspended"
+          elsif route.mode == "Reject"
+            "550 Route does not accept incoming messages"
           else
             log "Added route #{route.id} to recipients (tag: #{tag.inspect})"
-            @recipients << [:route, rcpt_to, route.server, :route => route]
-            '250 OK'
+            @recipients << [:route, rcpt_to, route.server, { route: route }]
+            "250 OK"
           end
 
         else
           # User is trying to relay but is not authenticated. Try to authenticate by IP address
-          @credential = Credential.where(:type => 'SMTP-IP').all.sort_by { |c| c.ipaddr&.prefix || 0 }.reverse.find do |credential|
+          @credential = Credential.where(type: "SMTP-IP").all.sort_by { |c| c.ipaddr&.prefix || 0 }.reverse.find do |credential|
             credential.ipaddr.include?(@ip_address)
           end
 
@@ -358,33 +363,33 @@ module Postal
             @credential.use
             rcpt_to(data)
           else
-            '530 Authentication required'
+            "530 Authentication required"
           end
         end
       end
 
       def data(data)
         unless in_state(:rcpt_to_received)
-          return '503 HELO/EHLO, MAIL FROM and RCPT TO before sending data'
+          return "503 HELO/EHLO, MAIL FROM and RCPT TO before sending data"
         end
 
         @data = "".force_encoding("BINARY")
         @headers = {}
         @receiving_headers = true
 
-        received_header_content = "from #{@helo_name} (#{@hostname} [#{@ip_address}]) by #{Postal.config.dns.smtp_server_hostname} with SMTP; #{Time.now.utc.rfc2822.to_s}".force_encoding('BINARY')
-        if !Postal.config.smtp_server.strip_received_headers?
+        received_header_content = "from #{@helo_name} (#{@hostname} [#{@ip_address}]) by #{Postal.config.dns.smtp_server_hostname} with SMTP; #{Time.now.utc.rfc2822}".force_encoding("BINARY")
+        unless Postal.config.smtp_server.strip_received_headers?
           @data << "Received: #{received_header_content}\r\n"
         end
-        @headers['received'] = [received_header_content]
+        @headers["received"] = [received_header_content]
 
-        handler = Proc.new do |data|
-          if data == '.'
+        handler = proc do |data|
+          if data == "."
             @logging_enabled = true
             @proc = nil
             finished
           else
-            data = data.to_s.sub(/\A\.\./, '.')
+            data = data.to_s.sub(/\A\.\./, ".")
 
             if @credential && @credential.server.log_smtp_data?
               # We want to log if enabled
@@ -405,7 +410,7 @@ module Postal
                 # skip the append methods at the bottom of this loop.
                 next if Postal.config.smtp_server.strip_received_headers? && @header_key && @header_key.downcase == "received"
               else
-                @header_key, value = data.split(/\:\s*/, 2)
+                @header_key, value = data.split(/:\s*/, 2)
                 @headers[@header_key.downcase] ||= []
                 @headers[@header_key.downcase] << value
                 # As above
@@ -419,7 +424,7 @@ module Postal
         end
 
         @proc = handler
-        '354 Go ahead'
+        "354 Go ahead"
       end
 
       def finished
@@ -429,10 +434,10 @@ module Postal
           return "552 Message too large (maximum size %dMB)" % Postal.config.smtp_server.max_message_size
         end
 
-        if @headers['received'].select { |r| r =~ /by #{Postal.config.dns.smtp_server_hostname}/ }.count > 4
+        if @headers["received"].select { |r| r =~ /by #{Postal.config.dns.smtp_server_hostname}/ }.count > 4
           transaction_reset
           @state = :welcomed
-          return '550 Loop detected'
+          return "550 Loop detected"
         end
 
         authenticated_domain = nil
@@ -441,7 +446,7 @@ module Postal
           if authenticated_domain.nil?
             transaction_reset
             @state = :welcomed
-            return '530 From/Sender name is not valid'
+            return "530 From/Sender name is not valid"
           end
         end
 
@@ -456,13 +461,13 @@ module Postal
             message.mail_from = @mail_from
             message.raw_message = @data
             message.received_with_ssl = @tls
-            message.scope = 'outgoing'
+            message.scope = "outgoing"
             message.domain_id = authenticated_domain&.id
             message.credential_id = @credential.id
             message.save
 
           when :bounce
-            if rp_route = server.routes.where(:name => "__returnpath__").first
+            if rp_route = server.routes.where(name: "__returnpath__").first
               # If there's a return path route, we can use this to create the message
               rp_route.create_messages do |message|
                 message.rcpt_to = rcpt_to
@@ -478,7 +483,7 @@ module Postal
               message.mail_from = @mail_from
               message.raw_message = @data
               message.received_with_ssl = @tls
-              message.scope = 'incoming'
+              message.scope = "incoming"
               message.bounce = 1
               message.save
             end
@@ -493,7 +498,7 @@ module Postal
         end
         transaction_reset
         @state = :welcomed
-        '250 OK'
+        "250 OK"
       end
 
       def in_state(*states)

lib/postal/smtp_server/server.rb

@@ -1,5 +1,5 @@
-require 'ipaddr'
-require 'nio'
+require "ipaddr"
+require "nio"
 
 module Postal
   module SMTPServer
@@ -18,11 +18,11 @@ module Postal
         trap("USR1") do
           STDOUT.puts "Received USR1 signal, respawning."
           fork do
-            if ENV['APP_ROOT']
-              Dir.chdir(ENV['APP_ROOT'])
+            if ENV["APP_ROOT"]
+              Dir.chdir(ENV["APP_ROOT"])
             end
-            ENV.delete('BUNDLE_GEMFILE')
-            exec("bundle exec --keep-file-descriptors rake postal:smtp_server", :close_others => false)
+            ENV.delete("BUNDLE_GEMFILE")
+            exec("bundle exec --keep-file-descriptors rake postal:smtp_server", close_others: false)
           end
         end
 
@@ -30,7 +30,6 @@ module Postal
           STDOUT.puts "Received TERM signal, shutting down."
           unlisten
         end
-
       end
 
       def ssl_context
@@ -38,7 +37,7 @@ module Postal
           ssl_context      = OpenSSL::SSL::SSLContext.new
           ssl_context.cert = Postal.smtp_certificates[0]
           ssl_context.extra_chain_cert = Postal.smtp_certificates[1..-1]
-          ssl_context.key  = Postal.smtp_private_key
+          ssl_context.key = Postal.smtp_private_key
           ssl_context.ssl_version = Postal.config.smtp_server.ssl_version if Postal.config.smtp_server.ssl_version
           ssl_context.ciphers = Postal.config.smtp_server.tls_ciphers if Postal.config.smtp_server.tls_ciphers
           ssl_context
@@ -46,8 +45,8 @@ module Postal
       end
 
       def listen
-        if ENV['SERVER_FD']
-          @server = TCPServer.for_fd(ENV['SERVER_FD'].to_i)
+        if ENV["SERVER_FD"]
+          @server = TCPServer.for_fd(ENV["SERVER_FD"].to_i)
         else
           @server = TCPServer.open(Postal.config.smtp_server.bind_address, Postal.config.smtp_server.port)
         end
@@ -61,7 +60,7 @@ module Postal
           @server.setsockopt(Socket::SOL_TCP, Socket::TCP_KEEPINTVL, 10)
           @server.setsockopt(Socket::SOL_TCP, Socket::TCP_KEEPCNT, 5)
         end
-        ENV['SERVER_FD'] = @server.to_i.to_s
+        ENV["SERVER_FD"] = @server.to_i.to_s
         logger.info "Listening on  #{Postal.config.smtp_server.bind_address}:#{Postal.config.smtp_server.port}"
       end
 
@@ -72,7 +71,7 @@ module Postal
       end
 
       def kill_parent
-        Process.kill('TERM', Process.ppid)
+        Process.kill("TERM", Process.ppid)
       end
 
       def run_event_loop
@@ -81,7 +80,7 @@ module Postal
         # Register the SMTP listener
         @io_selector.register(@server, :r)
         # Create a hash to contain a buffer for each client.
-        buffers = Hash.new { |h, k| h[k] = String.new.force_encoding('BINARY') }
+        buffers = Hash.new { |h, k| h[k] = String.new.force_encoding("BINARY") }
         loop do
           # Wait for an event to occur
           @io_selector.select do |monitor|
@@ -112,17 +111,25 @@ module Postal
                 # Register the client and its socket with nio4r
                 monitor = @io_selector.register(new_io, :r)
                 monitor.value = client
-              rescue => e
+              rescue StandardError => e
                 # If something goes wrong, log as appropriate and disconnect the client
                 if defined?(Raven)
-                  Raven.capture_exception(e, :extra => {:log_id => (client.id rescue nil)})
+                  Raven.capture_exception(e, extra: { log_id: begin
+                    client.id
+                  rescue StandardError
+                    nil
+                  end })
                 end
                 logger.error "An error occurred while accepting a new client."
                 logger.error "#{e.class}: #{e.message}"
                 e.backtrace.each do |line|
                   logger.error line
                 end
-                new_io.close rescue nil
+                begin
+                  new_io.close
+                rescue StandardError
+                  nil
+                end
               end
             else
               # This event is not an incoming connection so it must be data from a client
@@ -135,7 +142,7 @@ module Postal
                 if client.start_tls?
                   begin
                     # Can we accept the TLS connection at this time?
-                    io.accept_nonblock()
+                    io.accept_nonblock
                     # We were able to accept the connection, the client is no longer handshaking
                     client.start_tls = false
                   rescue IO::WaitReadable, IO::WaitWritable => e
@@ -153,12 +160,10 @@ module Postal
                     # There is an extra step for SSL sockets
                     case io
                     when OpenSSL::SSL::SSLSocket
-                      buffers[io] << io.readpartial(10240)
-                      while(io.pending > 0)
-                        buffers[io] << io.readpartial(10240)
-                      end
+                      buffers[io] << io.readpartial(10_240)
+                      buffers[io] << io.readpartial(10_240) while io.pending > 0
                     else
-                      buffers[io] << io.readpartial(10240)
+                      buffers[io] << io.readpartial(10_240)
                     end
                   rescue EOFError, Errno::ECONNRESET, Errno::ETIMEDOUT
                     # Client went away
@@ -167,7 +172,7 @@ module Postal
 
                   # Normalize all \r\n and \n to \r\n, but ignore only \r.
                   # A \r\n may be split in 2 buffers (\n in one buffer and \r in the other)
-                  buffers[io] = buffers[io].gsub(/\r/,"").encode(buffers[io].encoding, crlf_newline: true)
+                  buffers[io] = buffers[io].gsub(/\r/, "").encode(buffers[io].encoding, crlf_newline: true)
 
                   # We line buffer, so look to see if we have received a newline
                   # and keep doing so until all buffered lines have been processed.
@@ -178,17 +183,17 @@ module Postal
                     # Send the received line to the client object for processing
                     result = client.handle(line)
                     # If the client object returned some data, write it back to the client
-                    unless result.nil?
-                      result = [result] unless result.is_a?(Array)
-                      result.compact.each do |line|
-                        client.log "\e[34m=> #{line.strip}\e[0m"
-                        begin
-                          io.write(line.to_s + "\r\n")
-                          io.flush
-                        rescue Errno::ECONNRESET
-                          # Client disconnected before we could write response
-                          eof = true
-                        end
+                    next if result.nil?
+
+                    result = [result] unless result.is_a?(Array)
+                    result.compact.each do |line|
+                      client.log "\e[34m=> #{line.strip}\e[0m"
+                      begin
+                        io.write(line.to_s + "\r\n")
+                        io.flush
+                      rescue Errno::ECONNRESET
+                        # Client disconnected before we could write response
+                        eof = true
                       end
                     end
                   end
@@ -219,11 +224,15 @@ module Postal
                     Process.exit(0)
                   end
                 end
-              rescue => e
+              rescue StandardError => e
                 # Something went wrong, log as appropriate
-                client_id = client ? client.id : '------'
+                client_id = client ? client.id : "------"
                 if defined?(Raven)
-                  Raven.capture_exception(e, :extra => {:log_id => (client.id rescue nil)})
+                  Raven.capture_exception(e, extra: { log_id: begin
+                    client.id
+                  rescue StandardError
+                    nil
+                  end })
                 end
                 logger.error "[#{client_id}] An error occurred while processing data from a client."
                 logger.error "[#{client_id}] #{e.class}: #{e.message}"
@@ -231,9 +240,17 @@ module Postal
                   logger.error "[#{client_id}] #{line}"
                 end
                 # Close all IO and forget this client
-                @io_selector.deregister(io) rescue nil
+                begin
+                  @io_selector.deregister(io)
+                rescue StandardError
+                  nil
+                end
                 buffers.delete(io)
-                io.close rescue nil
+                begin
+                  io.close
+                rescue StandardError
+                  nil
+                end
                 if @io_selector.empty?
                   Process.exit(0)
                 end
@@ -241,27 +258,27 @@ module Postal
             end
           end
           # If unlisten has been called, stop listening
-          if $unlisten
-            @io_selector.deregister(@server)
-            @server.close
-            # If there's nothing left to do, shut down the process
-            if @io_selector.empty?
-              Process.exit(0)
-            end
-            # Clear the request
-            $unlisten = false
+          next unless $unlisten
+
+          @io_selector.deregister(@server)
+          @server.close
+          # If there's nothing left to do, shut down the process
+          if @io_selector.empty?
+            Process.exit(0)
           end
+          # Clear the request
+          $unlisten = false
         end
       end
 
       def run
         # Write PID to file if path specified
-        if ENV['PID_FILE']
-          File.open(ENV['PID_FILE'], 'w') { |f| f.write(Process.pid.to_s + "\n") }
+        if ENV["PID_FILE"]
+          File.write(ENV["PID_FILE"], Process.pid.to_s + "\n")
         end
         # If we have been spawned to replace an existing processm shut down the
         # parent after listening.
-        if ENV['SERVER_FD']
+        if ENV["SERVER_FD"]
           listen
           kill_parent
         else