pmarreck · August 4, 2023 09:36 · Jan 17, 2014 · Jan 17, 2014
diff --git a/email_header_parser.rb b/email_header_parser.rb
@@ -76,7 +76,7 @@ def clean_header_values_hash(h)
 
 
 headers = <<-HEADERS
-Delivered-To: jtest01@assistly.com
+Delivered-To: jtest01@test.com
 Return-Path: <[email protected]>
 Received: from smtp36.gate.dfw1a (gate36.gate.dfw.mlsrvr.com [172.20.100.36])
        by mail138a.mail.dfw.mlsrvr.com (SMTP Server) with ESMTP id 107434FCCD

diff --git a/email_header_parser.rb b/email_header_parser.rb
@@ -0,0 +1,137 @@
+require 'ap'
+require 'mail'
+
+# String monkeypatch
+# This is one of many possible "encoding problem" solutions. It's actually an intractable problem
+# but you'd have to read "Gödel, Escher, Bach" to understand why...
+class String
+  def clean_utf8
+    # self.force_encoding("UTF-8").encode("UTF-16BE", :invalid=>:replace, :replace=>"?").encode("UTF-8")
+    unpack('C*').pack('U*') if !valid_encoding?
+  end
+end
+
+module Parsing
+  module Email
+    class Header
+      EMAIL_HEADER_PARSER_REGEX = /
+        ([A-Za-z-]+):\s       # Find a header key, which ends in a colon and a space. Capture the hyphenated word portion.
+        (                     # Now start capturing the value.
+          [^\r\n]+            # First, match everything that is not a line ending char.
+          (?:                 # Then start a non-capturing repeating match which first consists of...
+            \r?\n             # A line ending combo...
+            (?![A-Za-z-]+:\s) # But first, do a negative lookahead to make sure the next line does not start with another header-key-looking string
+            [^\r\n]+          # Then match all text that is not a line ending char.
+          )*                  # Repeat this non-capturing group match 0 or more times.
+        )                     # End capturing the value.
+      /mx                     # Allow matches to cross line endings (m) and allow whitespace and comments in this regex (x).
+      EMAIL_MULTILINE_HEADER_VALUE_REGEX = /\r?\n\s*/m
+
+      attr_reader :headers
+      def initialize(opts = {})
+        @headers = (Hash === opts ? opts[:headers] : opts)
+      end
+
+      def call
+        return {} unless @headers
+        clean_header_values_hash(headers_hash)
+      end
+      alias to_h call
+
+      private
+
+      def headers_hash
+        h = {}
+        @headers.scan(EMAIL_HEADER_PARSER_REGEX).map do |k,v|
+          if k && v
+            if h[k]
+              # if this key already has a value, wrap it in an array and append the new value, otherwise just set the key value
+              h[k] = [h[k]] unless Array === h[k]
+              h[k] << v
+            else
+              h[k] = v
+            end
+          end
+        end
+        h
+      end
+
+      # Clean up runs of a newline followed by whitespace in header values by replacing with a space
+      def clean_header_values_hash(h)
+        h.each do |k,v|
+          if Array === v
+            v.map! do |val|
+              val =~ EMAIL_MULTILINE_HEADER_VALUE_REGEX ? val.gsub!(EMAIL_MULTILINE_HEADER_VALUE_REGEX,' ') : val
+            end
+          else
+            v.gsub!(EMAIL_MULTILINE_HEADER_VALUE_REGEX, ' ') if v =~ EMAIL_MULTILINE_HEADER_VALUE_REGEX
+          end
+        end
+        h
+      end
+
+    end
+  end
+end
+
+
+headers = <<-HEADERS
+Delivered-To: [email protected]
+Return-Path: <[email protected]>
+Received: from smtp36.gate.dfw1a (gate36.gate.dfw.mlsrvr.com [172.20.100.36])
+       by mail138a.mail.dfw.mlsrvr.com (SMTP Server) with ESMTP id 107434FCCD
+       for <[email protected]>; Wed, 29 Dec 2010 05:46:02 -0500 (EST)
+X-Spam-Threshold: 95
+X-Spam-Score: 0
+X-Spam-Flag: NO
+X-Virus-Scanned: OK
+X-MessageSniffer-Scan-Result: 0
+X-MessageSniffer-Rules: 0-0-0-32767-c
+X-CMAE-Scan-Result: 0
+X-CNFS-Analysis: v=1.0 c=1 a=410GYZBmXEQA:10 a=8nJEP1OIZ-IA:10 a=jrTSQGAaAAAA:8 a=zr8WG4425YMt8zt5NHsA:9 a=9yu0GlTtA_AyZ2ttE_-TzX-Oml0A:4 a=wPNLvfGTeEIA:10 a=vUvjSO8KtUCdM2_P:21 a=bi41oqnuo1lMp9yW:21
+X-Orig-To: [email protected]
+X-Originating-Ip: [173.203.22.3]
+Received: from [173.203.22.3] ([173.203.22.3:54314] helo=287315-web1.comixology.com)
+       by smtp36.gate.dfw1a.rsapps.net (envelope-from <[email protected]>)
+       (ecelerity 2.2.3.46 r(37554)) with ESMTP
+       id 4A/C8-28011-8611B1D4; Wed, 29 Dec 2010 05:46:01 -0500
+Received: from comixology.com (localhost [127.0.0.1])
+       by 287315-web1.comixology.com (Postfix) with ESMTP id E41991188DCD;
+       Wed, 29 Dec 2010 05:45:59 -0500 (EST)
+Date: Wed, 29 Dec 2010 05:45:59 -0500
+To: [email protected]
+From: comiXology <[email protected]>
+Reply-to: [email protected]
+Subject: Feedback from the Marvel Mobile Comics App
+Message-ID: <[email protected]>
+X-Priority: 3
+X-Mailer: PHPMailer 5.0.2 (phpmailer.codeworxtech.com)
+MIME-Version: 1.0
+Content-Transfer-Encoding: 8bit
+Content-Type: text/plain; charset="ISO-8859-1"
+HEADERS
+
+t = Time.now
+500.times do
+  begin
+    email = Parsing::Email::Header.new(headers)
+    email.call
+  rescue ArgumentError
+    email = Parsing::Email::Header.new(headers.clean_utf8)
+    email.call
+  end
+end
+puts "Time with my regex: #{Time.now - t} seconds"
+
+t = Time.now
+500.times do
+  email = Mail.new(headers)
+  email.received
+end
+puts "Time with Mail gem: #{Time.now - t} seconds"
+
+
+
+# Time with my regex: 0.063965 seconds
+# Time with Mail gem: 16.327161 seconds
+# [Finished in 16.7s]