Land rapid7#19435, Add php minify encoder

This encoder minifies PHP payloads by removing spaces after keywords and
before block openings. It removes comments, empty lines, new lines and
leading and trailing spaces

Author: jheysel-r7

modules/encoders/php/minify.rb

@@ -0,0 +1,42 @@
+##
+# This module requires Metasploit: https://metasploit.com/download
+# Current source: https://github.com/rapid7/metasploit-framework
+##
+
+class MetasploitModule < Msf::Encoder
+  Rank = GreatRanking
+
+  def initialize
+    super(
+      'Name' => 'PHP Minify Encoder',
+      'Description' => %q{
+        This encoder minifies a PHP payload by removing leasing spaces, trailing
+        new lines, comments, …
+      },
+      'Author' => 'Julien Voisin',
+      'License' => BSD_LICENSE,
+      'Arch' => ARCH_PHP)
+  end
+
+  def encode_block(_, buf)
+    # Remove comments
+    buf.gsub!(/^\s*#.*$/, '')
+
+    # Remove spaces after keywords
+    buf.gsub!(/^\s*(if|else|elsif|while|for|foreach)\s*\(/, '\1(')
+
+    # Remove spaces before block opening
+    buf.gsub!(/\s*{$/, '{')
+
+    # Remove empty lines
+    buf.squeeze!("\n")
+
+    # Remove leading/trailing spaces
+    buf.gsub!(/^[ \t]+/, '')
+
+    # Remove new lines
+    buf.gsub!(/([;{}])\n/, '\1')
+
+    return buf
+  end
+end