replace unsupported ucs-2 characters in a string with �

Doctrine/DBAL/Driver/PDODblib/Connection.php

@@ -30,6 +30,13 @@ class Connection extends \Doctrine\DBAL\Driver\PDOConnection implements \Doctrin
 
     protected $_pdoTransactionsSupport = null;
     protected $_pdoLastInsertIdSupport = null;
+
+    public function __construct($dsn, $user = null, $password = null, $options = null)
+    {
+        parent::__construct($dsn, $user, $password, $options);
+        $this->setAttribute(\PDO::ATTR_STATEMENT_CLASS, array(__NAMESPACE__ . '\PDOStatement', array()));
+    }
+
     /**
      * @override
      */

Doctrine/DBAL/Driver/PDODblib/PDOStatement.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace Lsw\DoctrinePdoDblib\Doctrine\DBAL\Driver\PDODblib;
+
+class PDOStatement extends \Doctrine\DBAL\Driver\PDOStatement
+{
+    /**
+     * @var string Regex matching freetds non-supported characters.
+     */
+    const FREETDS_INVALID_CHAR_REGEX = '/[^\x{1}-\x{FFFF}]/u';
+
+    /**
+     * {@inheritdoc}
+     *
+     * Freetds communicates with the server using UCS-2 (since v7.0).
+     * Freetds claims to convert from any given client charset to UCS-2 using iconv. Which should strip or replace unsupported chars.
+     * However in my experience, characters like 👍 (THUMBS UP SIGN, \u1F44D) still end up in Sqlsrv shouting '102 incorrect syntax'.
+     * As does the null character \u0000.
+     *
+     * Upon binding a value, this function replaces the unsupported characters.
+     */
+    public function bindValue($param, $value, $type = \PDO::PARAM_STR)
+    {
+        if ($type == \PDO::PARAM_STR) {
+            $value = static::replaceUnsupportedFreetdsChars($value);
+        }
+        return parent::bindValue($param, $value, $type);
+    }
+
+    /**
+     * This function replaces characters in a string unsupported by freetds with the REPLACEMENT CHARACTER.
+     * @param string $val
+     * @return string
+     */
+    public static function replaceUnsupportedFreetdsChars($val)
+    {
+        return is_string($val) ? \preg_replace(static::FREETDS_INVALID_CHAR_REGEX, "�", $val) : $val;
+    }
+}