im trying to extend the mysqli class in php in order to create a wrapper class. I would like this class to manage multiple connections.. I am currently at a very early stage and have hit a problem:
Auth Connected no: 1
1045:Access denied for user 'rootty'#'localhost' (using password: YES)
Segmentation fault
It seems when the second connection has an error a segmentation fault is created however connection one errors correctly..
<?php
class mysqli_ls extends mysqli
{
private $link = array();
private $link_no = 0;
/* ************************************************************ */
public function __construct()
{
}
/* ************************************************************ */
public function open($host='', $user='', $pass='', $port='3306', $database='')
{
if ( empty($host) || empty($user) || empty($pass) || empty($database) )
{
$this->error[] = "Missing required connection variables";
return false;
}
$this->link_no++;
#$this->link[ $linkno ] = $this->connect($host, $user, $pass, $database, $port);
if ($this->connect_errno)
{
$this->error[] = $this->connect_errno .':'. $this->connect_error;
return false;
}
return $this->link_no;
}
######Test script
#!/usr/bin/php
<?php
require_once('mysqli.class.php');
$_mysqli = new mysqli_ls;
$_auth = $_mysqli->open('localhost','root','xx','3306','auth');
if ($_auth === false) print $_mysqli->get_last_error() ."\n";
else print 'Auth Connected no: '. $_auth ."\n";
$_trak = $_mysqli->open('localhost','root','sxx','3306','wlr_tracker');
if ($_trak === false) print $_mysqli->get_last_error() ."\n";
else print 'Trak Connected no: '. $_trak ."\n";
I would report this to the PHP/mysqli devs. A scripting language segfaulting is most likely an internal bug you cannot fix - while it might be possible to create a workaround the proper way is to get it fixed in the C code.
Related
I feel that the PHP static field is static merely throughout a request.
I have this code in my controller class:
static $a = 2;
public function debug()
{
var_dump(self::$a++);
var_dump(self::$a++);
}
No matter how many times I request debug, it outputs:
int 2
int 3
Very different from my knowledge on static in java.
Yes, static in PHP is "real" static.
What you observe is result of different application life cycle in PHP and Java.
In Java, web application run inside WebServer(HTTP server), which after initial class load, on following requests reuse what it already loaded. For this reason class(and static properties) initialization occurs only once in application life cycle.
In case of typical PHP web application it looks a bit different.
HTTP server is independent application which listens for HTTP requests and runs PHP on demand(not all HTTP requests must be passed to PHP).
PHP is run as a separate process, request is passed and after answer is received process is discarded. Every request is handled by completely separate process. Classes(and static properties) are loaded and initialized from scratch every single time.
Below is simple(very) HTTP server written in PHP which will simulate how Java WebServer works.
<?php
class Server {
private $socket;
private $routes = [];
public function __construct($address, $port, $backlog = 5) {
$socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($socket === false) {
throw new Exception("socket_create() failed: reason: " . socket_strerror(socket_last_error($socket)));
}
if (socket_bind($socket, $address, $port) === false) {
throw new Exception("socket_bind() failed: reason: " . socket_strerror(socket_last_error($socket)));
}
if (socket_listen($socket, $backlog) === false) {
throw new Exception("socket_listen() failed: reason: " . socket_strerror(socket_last_error($socket)));
}
$this->socket = $socket;
}
public function listen() {
while( ($requestSocket = socket_accept($this->socket)) !== false ) {
$this->handleRequestSocket($requestSocket);
}
throw new Exception("socket_accept() failed: reason: " . socket_strerror(socket_last_error($this->socket)));
}
public function registerController($url, $controller) {
$this->routes[$url] = $controller;
}
private function handleRequestSocket($socket) {
$buffer = "";
while(false !== ($part = socket_read($socket, 1024, PHP_NORMAL_READ))){
$buffer .= $part;
if(substr($buffer, -4) == "\r\n\r\n") break;
}
$buffer = trim($buffer);
echo "\n======\n$buffer\n======\n";
$response = $this->handleRequest($buffer);
if (null === $response){
socket_write($socket, "HTTP/1.1 404 Not Found\r\nConnection: close\r\n\r\n");
} else {
socket_write($socket, "HTTP/1.1 200 OK\r\nContent-Length: ".strlen($response)."\r\n\r\n$response");
}
socket_close($socket);
}
private function handleRequest($raw) {
$lines = explode("\r\n", $raw);
$req = explode(" ", $lines[0]);
$method = $req[0];
$url = $req[1];
if(isset($this->routes[$url])) {
return (string) (is_callable($this->routes[$url]) ? $this->routes[$url]($raw) : $this->routes[$url]);
}
return null;
}
}
class ControllerWithStatic {
private static $static = 0;
public function handle() {
return "Hello from static: " . (self::$static++) . "\n";
}
}
$server = new Server($argv[1], $argv[2]);
$c = new ControllerWithStatic();
$server->registerController("/", "Hello world\n");
$server->registerController("/closure", function(){return "Hello world from closure\n";});
$server->registerController("/static", [$c, 'handle']);
$server->registerController("/static2", function(){
return (new ControllerWithStatic())->handle();
});
$server->listen();
Run it using
php server.php HOST PORT
e.g.
php server.php 127.0.0.1 8080
Now open in your browser http://127.0.0.1:8080/static or http://127.0.0.1:8080/static2 and you will get
Hello from static: 0
Hello from static: 1
Hello from static: 2
...
Number will be increasing as long as you don't restart server.
I'm coming from Java programming and I'm trying to apply my knowledge in OOP style programming in PHP.
So, I tried to create a utility class to connect to database just like how I usually do it in Java where I create a static method to get the database connection.
However, after spending hours I still can't fix the error.
DBHelper.php
<?php
class DBHelper
{
protected $db_name = 'myDb';
protected $db_user = 'root';
protected $db_pass = '';
protected $db_host = 'localhost';
public function obtainConnection()
{
$mysqli_instance = new mysqli($this->db_host, $this->db_user, $this->db_pass, $this->db_name);
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
return $mysqli_instance;
}
}
?>
There are no errors in this file
Then I tried to use it on another file called login.php
login.php
<?php
if (isset($_POST['submit'])) {
include "/DBUtility/DBHelper.php";
$username = $_POST['username']; //s means string
$password = $_POST['password']; // s means string
echo "<br/> Username value: " . $username;
echo "<br />Password value: " . $password;
}
if (empty($username) || empty($password) ) {
echo "Fill out the fields!";
} else {
//PREPARE THE PreparedStatment or Stored Procedure
$dbHelper = new DBHelper();
$connection = $dbHelper->obtainConnection();
$preparedStatement = $connection->prepare('CALL getUserRoleByLogin(?, ?)'); //getUserRoleByLogin() is the name of stored proc in mysql db
$preparedStatement->bind_param('ss', $username, $password); //assign arguments to ? ?
$preparedStatement->execute();//execute the stored procedure. This will return a result
$userRole = $preparedStatement->store_result();
$countOfRows = $preparedStatement->num_rows;
?>
I read every related question about the Fatal error: Cannot redeclare class CLASSNAME error. I tried following the instructions given by many which is to use require_once("DBHelper.php"); instead of include("DBHelper.php");
but still can't get rid of the error.
I tried making the obtainConnection() static and called it via DBHelper::obtainConnection(); but with no luck. Same error message.
I get the error on opening brace of class DBHelper {
I hope you can help me with this.
Thank you.
A couple tips you should do when doing OOP in PHP:
1) I would maybe rethink about not baking the db credentials into your class directly, it makes it harder/more cumbersome to modify them via UI if you wanted to implement a UI control mechanism down the line. Instead, try making a define or maybe a json pref file or a dynamically-created php file that contains an array, something like that. I will do a define because it's the easiest to demonstrate:
/config.php
# You can create a series of defines including the database
define('DB_HOST','localhost');
define('DB_NAME','dbname');
define('DB_USER','root');
define('DB_PASS','dbpassword');
# To maximize compatibility it's helpful to define fwd/back slash
define('DS',DIRECTORY_SEPARATOR);
# It is helpful to create path defines for easy file inclusion
define('ROOT_DIR',__DIR__);
define('CLASSES',ROOT_DIR.DS.'classes');
# Start session
session_start();
2) Create a class autoloader in the config.php file which then allows you to not have to manually include/require classes in pages. It will automatically include them:
spl_autoload_register(function($class) {
if(class_exists($class))
return;
# This will turn a namespace/class into a path so should turn:
# $db = new \DBUtility\DBHelper();
# into:
# /var/www/domain/httpdocs/classes/DBUtility/DBHelper.php
$path = str_replace(DS.DS,DS,CLASSES.DS.str_replace('\\',DS,$class).'.php');
# If the class file is located in the class folder, it will include it
if(is_file($path))
include_once($path);
});
3) I am going to create a static connection so you don't create a new connection every time (also I will use PDO):
/classes/DBUtility/DBHelper.php
<?php
namespace DBUtility;
class DBHelper
{
protected $query;
private static $con;
public function connection()
{
# This will send back the connection without making a new one
if(self::$con instanceof \PDO)
return self::$con;
# I like to catch any pdo exceptions on connection, just incase.
try {
# Assign the connection
self::$con = new \PDO('mysql:host='.DB_HOST.';dbname='.DB_NAME,DB_USER,DB_PASS);
}
catch(\PDOException $e) {
# Here you can just die with a more user-friendly error.
# It would be helpful to save the actual error to a log file
$msg = $e->getMessage();
# I would put your log outside the root or in a protected folder
$txt = realpath(ROOT_DIR.DS.'..').DS.'errors'.DS.'sql.txt';
# Make a directory if none set
if(!is_dir(pathinfo($txt,PATHINFO_DIRNAME))) {
# Make the directory
if(mkdir(pathinfo($txt,PATHINFO_DIRNAME),0744,true)) {
# Save to log file
file_put_contents($txt,$msg.PHP_EOL);
}
}
else {
# Save to log file
file_put_contents($txt,$msg.PHP_EOL);
}
die("Site is under maintenance.");
}
}
# It would be helpful to create a query that will bind and not bind
public function query($sql,$bind = false)
{
if(is_array($bind)) {
foreach($bind as $key => $value) {
$sKey = ":{$key}";
$bindArr[$sKey] = $value;
}
$this->query = $this->connection()->prepare($sql);
$this->query->execute($bindArr);
}
else {
# The second "query" on this is the method from PDO, not the
# "query" method from this class
$this->query = $this->connection()->query($sql);
}
return $this;
}
public function getResults()
{
if(empty($this->query))
return false;
while($result = $this->query->fetch(\PDO::FETCH_ASSOC)) {
$row[] = $result;
}
return (isset($row))? $row : false;
}
}
# If your page ends with a php tag, you should just remove it. It will
# protect against empty spaces that may cause "header already sent" errors
3a) I use something similar to this to autoload functions:
/classes/Helper.php
class Helper
{
public static function autoload($function)
{
if(function_exists($function))
return;
$path = ROOT_DIR.DS.'functions'.DS.$function.'.php';
if(is_file($path))
include_once($path);
}
}
4) Create useful/reusable functions or class/methods
/functions/getUserRole.php
function getUserRole($username,$password,\DBUtility\DBHelper $DBHelper)
{
return $DBHelper->query('CALL getUserRoleByLogin(:0, :1)',array($username,$password))->getResults();
}
/index.php
# Include the config file
require_once(__DIR__.DIRECTORY_SEPARATOR.'config.php');
if (isset($_POST['submit'])) {
# No need for this line ->> include "/DBUtility/DBHelper.php";
# Use trim to remove empty spaces on the left and right
$username = trim($_POST['username']);
$password = trim($_POST['password']);
}
if (empty($username) || empty($password) ) {
echo "Fill out the fields!";
} else {
# User our function autoloader to include this function
Helper::autoload('getUserRole');
# Use the function and inject the DB class
$userRoles = getUserRole($username,$password,new \DBUtility\DBHelper());
$count = count($userRoles);
echo "Count: {$count}";
echo '<pre>';
print_r($userRoles);
echo '</pre>';
}
I know socket and thread is horrible in php... I'm just trying to connect my php file with socket to my server.
The problem is I got nothing from socket_read (no datas no error just returning an empty string) and I think pthread kill automatically the socket.
For now I don't need thread but I need to keep it to use it later.
My code:
<?php
class test extends Threaded
{
/*
*/
public function __construct($ip, $port, $debug = false)
{
$this->debug = $debug;
$this->ip = $ip;
$this->port = $port;
}
/*
*/
public function __destruct()
{
socket_close($this->connect);
}
/*
*/
public function start()
{
if (!($this->connect = socket_create(AF_INET, SOCK_STREAM, SOL_TCP))) {
throw new Exception('SOCKET_CREATE');
}
if (!socket_set_option($this->connect, SOL_SOCKET, SO_RCVTIMEO, array('sec' => 5, 'usec' => 0))) {
throw new Exception('SOCKET_SET_OPTION');
}
if (!socket_connect($this->connect, $this->ip, $this->port)) {
throw new Exception('SOCKET_CONNECT');
}
$getMsg = socket_read($this->connect, 255);
echo $getMsg;
}
}
Do you know how it can works?
EDIT: I tried again today and my script works, I don't understand sometime it works sometime not ....
EDIT2: I copied my server file script to an other server with much much more traffic and it works ! So why it works on the server 2 and not on server 1 ?
This question already has answers here:
Synchronized functions in PHP
(6 answers)
Closed 9 years ago.
I've got a php application that requires to make a connection to a server which authenticates with a token, this token stays valid until connection is lost.
When another connection is made while the first is still open my application crashes because the token is different from the currently connected one...
public function connect()
{
$Socket = fsockopen("192.168.1.1", 1234);
if ($Socket !== false) {
stream_set_timeout($Socket, static::TIMEOUT_SEC, static::TIMEOUT_USEC);
$this->socket = $Socket;
$this->sendeverything;
}
}
How am I able to run a function like:
function gogogo() {
connect();
}
multiple times without having them running simultaneously
Sorry for my bad english
Most easy solution would be to have a is_connected function:
function connect() {
if(is_already_connected()) {
return;
}
// ... your connect logic
}
In the is_already_connected() you'll have to write some intelligent code to determine if there is an open connection.
You can also create a kind of singleton connection (although this suggestion would probably instantiate a lot of debate about the use of singletons ;))
Try something like this...
<?php
class Connection {
public $Socket = null;
public function connect(){
// Checking if Socket already has a pointer :P
if((bool)$this->Socket){
return true;
}
$this->Socket = fsockopen("192.168.1.1", 1234);
if ($this->Socket !== false) {
stream_set_timeout($this->Socket, static::TIMEOUT_SEC, static::TIMEOUT_USEC);
$this->sendeverything();
}
}
}
$myconnect = new Connection();
$myconnect->connect();
$myconnect->connect();
?>
As mentioned in this question you can use sem_aquire for this. Something like:
function connect(){
$key = "192.168.1.1:1234" ;
try{
$sem = sem_get( $SEMKey);
sem_acquire($sem);
//Do connecty stuff here
sem_release($sem);
}catch(Exception $ex){
//Exception handling
}finally{
//Finally only available in PHP 5.5 place this in catch and try if < 5.5
sem_release($sem);
}
}
Note that this is entirely untested and wont work on windows. If you are on windows you can use flock - again as mentioned in the above question.
A legacy website is exhibiting unexpected behavior with it's database connections. The application connects to several MySQL databases on the same server and the original developer created a "singleton" class that holds connection objects for each of them.
Lately we have been encountering a strange behavior with the class: when a connection to www is created after creating extra, getting the instance of extra returns a connection that has the correct parameters when viewed with var_dump() but is actually connected to the www database.
What could cause this? The code has worked before at some stage. Creating a new connection on each call to getInstance() fixes the problem but I'd like to solve this the right way if possible.
<?php
class DBConnection
{
private static $default;
private static $extra;
private static $intra;
private static $www;
public static function getInstance($dbname = "default")
{
global $db; // This is an array containing database connection parameters
if(!($dbname == "default" || $dbname == "extra" || $dbname == "www" || $dbname == "intra"))
{
$dbname = "default";
}
if (empty(self::$$dbname)) // Making this pass every time fixes the problem
{
try
{
self::$$dbname = ADONewConnection('mysqlt');
if(isset($db[$dbname]))
{
self::$$dbname->connect(DBHOSTNAME, $db[$dbname]["dbusername"], $db[$dbname]["dbpassword"], $db[$dbname]["dbname"]);
}
else
{
// fallback
self::$$dbname->connect(DBHOSTNAME, DBUSERNAME, DBPASSWORD, DBNAME);
}
self::$$dbname->SetFetchMode(ADODB_FETCH_ASSOC);
self::$$dbname->execute("SET NAMES utf8");
return self::$$dbname;
}
catch(Exception $e)
{
exit("DB connection failed");
}
}
else
{
return self::$$dbname;
}
}
}
Here's a simplified example of the class misbehaving:
$cn = DBConnection::getInstance("extra");
$cn->debug = true;
$rs = $cn->execute("SELECT * FROM messages WHERE id = ".$this->id);
The last line fails with the error message "Table www.messages does not exist".
1: You don't need to establish connection in getInstance().
getInstance must not do anything, but return instance of DB class.
2: when you do self::$$dbname->connect(, if (empty(self::$$dbname)) will return you false next time you call it.
Singleton is described here: http://en.wikipedia.org/wiki/Singleton_pattern
What you have - it's just a static method.