adding client_encoding method for discovering the encoding set for this...

adding client_encoding method for discovering the encoding set for this client, testing exec_insert on a string

activerecord/lib/active_record/connection_adapters/mysql_adapter.rb

@@ -196,6 +196,7 @@ def initialize(connection, logger, connection_options, config)
         @connection_options, @config = connection_options, config
         @quoted_column_names, @quoted_table_names = {}, {}
         @statements = {}
+        @client_encoding = nil
         connect
       end
 
@@ -330,6 +331,63 @@ def clear_cache!
         @statements.clear
       end
 
+      if "<3".respond_to?(:encode)
+        # Taken from here:
+        #   https://github.com/tmtm/ruby-mysql/blob/master/lib/mysql/charset.rb
+        # Author: TOMITA Masahiro <tommy@tmtm.org>
+        ENCODINGS = {
+          "armscii8" => nil,
+          "ascii"    => Encoding::US_ASCII,
+          "big5"     => Encoding::Big5,
+          "binary"   => Encoding::ASCII_8BIT,
+          "cp1250"   => Encoding::Windows_1250,
+          "cp1251"   => Encoding::Windows_1251,
+          "cp1256"   => Encoding::Windows_1256,
+          "cp1257"   => Encoding::Windows_1257,
+          "cp850"    => Encoding::CP850,
+          "cp852"    => Encoding::CP852,
+          "cp866"    => Encoding::IBM866,
+          "cp932"    => Encoding::Windows_31J,
+          "dec8"     => nil,
+          "eucjpms"  => Encoding::EucJP_ms,
+          "euckr"    => Encoding::EUC_KR,
+          "gb2312"   => Encoding::EUC_CN,
+          "gbk"      => Encoding::GBK,
+          "geostd8"  => nil,
+          "greek"    => Encoding::ISO_8859_7,
+          "hebrew"   => Encoding::ISO_8859_8,
+          "hp8"      => nil,
+          "keybcs2"  => nil,
+          "koi8r"    => Encoding::KOI8_R,
+          "koi8u"    => Encoding::KOI8_U,
+          "latin1"   => Encoding::ISO_8859_1,
+          "latin2"   => Encoding::ISO_8859_2,
+          "latin5"   => Encoding::ISO_8859_9,
+          "latin7"   => Encoding::ISO_8859_13,
+          "macce"    => Encoding::MacCentEuro,
+          "macroman" => Encoding::MacRoman,
+          "sjis"     => Encoding::SHIFT_JIS,
+          "swe7"     => nil,
+          "tis620"   => Encoding::TIS_620,
+          "ucs2"     => Encoding::UTF_16BE,
+          "ujis"     => Encoding::EucJP_ms,
+          "utf8"     => Encoding::UTF_8,
+          "utf8mb4"  => Encoding::UTF_8,
+        }
+      else
+        ENCODINGS = Hash.new { |h,k| h[k] = k }
+      end
+
+      # Get the client encoding for this database
+      def client_encoding
+        return @client_encoding if @client_encoding
+
+        result = exec_query(
+          "SHOW VARIABLES WHERE Variable_name = 'character_set_client'",
+          'SCHEMA')
+        @client_encoding = ENCODINGS[result.rows.last.last]
+      end
+
       def exec_query(sql, name = 'SQL', binds = [])
         log(sql, name, binds) do
           result = nil
@@ -363,6 +421,10 @@ def exec_query(sql, name = 'SQL', binds = [])
         end
       end
 
+      def exec_insert(sql, name, binds)
+        exec_query(sql, name, binds)
+      end
+
       def exec_without_stmt(sql, name = 'SQL') # :nodoc:
         # Some queries, like SHOW CREATE TABLE don't work through the prepared
         # statement API.  For those queries, we need to use this method. :'(