Allow custom escaping mode

People can now use connection config to define an `queryFormat`
function that is used instead of connection.format.

lib/Connection.js

@@ -126,6 +126,9 @@ Connection.prototype.escape = function(value) {
 };
 
 Connection.prototype.format = function(sql, values) {
+  if (typeof this.config.queryFormat == "function") {
+    return this.config.queryFormat(sql, values, this.config.timezone);
+  }
   return SqlString.format(sql, values, this.config.timezone);
 };
 

lib/ConnectionConfig.js

@@ -18,9 +18,11 @@ function ConnectionConfig(options) {
   this.debug        = options.debug;
   this.timezone     = options.timezone || 'local';
   this.flags        = options.flags || '';
+  this.queryFormat  = options.queryFormat;
   this.typeCast     = (options.typeCast === undefined)
     ? true
     : options.typeCast;
+
   if (this.timezone[0] == " ") {
     // "+" is a url encoded char for space so it
     // gets translated to space when giving a

test/integration/connection/test-custom-query-format.js

@@ -0,0 +1,15 @@
+var Mysql      = require('../../../');
+var common     = require('../../common');
+var connection = common.createConnection();
+var assert     = require('assert');
+
+connection.config.queryFormat = function (query, values, tz) {
+  return query.replace(/\:(\w+)/g, function (txt, key) {
+    if (values.hasOwnProperty(key)) {
+      return connection.escape(values[key]);
+    }
+    return txt;
+  });
+};
+
+assert.equal(connection.format("SELECT :a1, :a2", { a1: 1, a2: 'two' }), "SELECT 1, 'two'");