Problem:- Create A Message Board Using PHP – PHP App
Solution:-
First of all Make a table in your database here i using testdb as database name and message as table name
Creating Table using SQL Query
CREATE TABLE message(
id INTEGER PRIMARY KEY AUTO_INCREAMENT NOT NULL,
posted_on DATETIME NOT NULL,
author CHAR(255),
subject CHAR(255),
body MEDIUMTEXT,
thread_id INT UNSIGNED NOT NULL,
parent_id INT UNSIGNED NOT NULL,
level INT UNSIGNED NOT NULL,
thread_pos INT UNSIGNED NOT NULL
);
message.php
<?php
//creating a object of messageBoard class
$board = new MessageBoard();
// calling a method inside messageBoard class
$board->go();
class MessageBoard{
protected $db;
protected $form_errors = array();
protected $inTransaction = false;
// setting up the databse connection
public function __construct(){
set_exception_handler(array($this, 'logAndDie'));
$this->db = new PDO("mysql:host=localhost; dbname=testdb", 'root', '');
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
// using superglobal variable we use single page to display all message with view, submit, and save
public function go(){
$cmd = isset($_REQUEST['cmd'])? $_REQUEST['cmd'] : "show";
switch ($cmd) {
case 'read':
$this->read();
break;
case 'post':
$this->post();
break;
case 'save':
if ($this->valid()) {
$this->save();
$this->show();
}else{
$this->post();
}
break;
case 'show':
default:
$this->show();
break;
}
}
// to save and update messsage
protected function save(){
$parent_id = isset($_REQUEST['parent_id']) ? intval($_REQUEST['parent_id']) : 0;
$this->db->beginTransaction();
$this->inTransaction = true;
if ($parent_id) {
$st = $this->db->prepare("SELECT thread_id, level, thread_pos FROM message WHERE id = ?");
$st->execute(array($parent_id));
$parent = $st->fetch();
$level = $parent['level'] + 1;
$st = $this->db->prepare("SELECT MAX(thread_pos) FROM message WHERE thread_id = ? AND parent_id = ?");
$st->execute(array($parent['thread_id'], $parent_id));
$thread_pos = $st->fetchColumn(0);
if ($thread_pos) {
$thread_pos++;
}else{
$thread_pos = $parent['thread_pos'] + 1;
}
$st = $this->db->prepare("UPDATE message SET thread_pos = thread_pos + 1 WHERE thread_id = ? AND thread_pos >= ?");
$st->execute(array($parent['thread_id'], $thread_pos));
$thread_id = $parent['thread_id'];
}else{
$thread_id = $this->db->query("SELECT MAX(thread_id) + 1 FROM message")->fetchColumn(0);
if (!$thread_id) {
$thread_id = 1;
}
$level = 0;
$thread_pos = 0;
}
$st = $this->db->prepare("INSERT INTO message (id, thread_id, parent_id, thread_pos, posted_on, level, author, subject, body) VALUES (?,?,?,?,?,?,?,?,?)");
$st->execute(array(null, $thread_id, $parent_id, $thread_pos, date('c'), $level, $_REQUEST['author'], $_REQUEST['subject'], $_REQUEST['body']));
$this->db->commit();
$this->inTransaction = false;
}
//to show all message
protected function show(){
print "<h2>Message List</h2><p>";
$st = $this->db->query("SELECT id, author, subject, LENGTH(body) AS body_length, posted_on, level FROM message ORDER BY thread_id, thread_pos");
while($row = $st->fetch()){
print str_repeat(" ", 4*$row['level']);
$when = date('Y-m-d h:i', strtotime($row['posted_on']));
print "<a href='".htmlentities($_SERVER['PHP_SELF'])."?cmd=read&id={$row['id']}'>".htmlentities($row['subject']).'</a> by'. htmlentities($row['author']). '@'.
htmlentities($when). "({$row['body_length']} bytes)<br/>";
}
print "<hr/><a href='".htmlentities($_SERVER['PHP_SELF'])."?cmd=post'>Start Messaging</a>";
}
// to read a single person message and reply them.
public function read(){
if (!$_REQUEST['id']) {
throw new Exception("No Message ID Supplied");
}
$id = intval($_REQUEST['id']);
$st = $this->db->prepare("SELECT author, subject, body, posted_on FROM message WHERE id = ?");
$st->execute(array($id));
$msg = $st->fetch();
if (!$msg) {
throw new Exception("Bad Request");
}
$body = nl2br(htmlentities($msg['body']));
$self = htmlentities($_SERVER['PHP_SELF']);
$subject = htmlentities($msg['subject']);
$author = htmlentities($msg['author']);
print "<h2>".$subject."</h2><h3>By ".$author."</h3><p>".$body."</p><hr/>";
print "<a href='".$self."?cmd=post&parent_id=$id'>Reply</a><br><a href='".$self."?cmd=list'>List Message</a>";
}
// for start messaging
public function post(){
$safe = array();
foreach (array('author', 'subject', 'body') as $field) {
if (isset($_POST[$field])) {
$safe[$field] = htmlentities($_POST[$field]);
}else{
$safe[$field] = " ";
}
if (isset($this->form_errors[$field])) {
$this->form_errors[$field] = "<span style='color:red;'>". $this->form_errors[$field]. "</span>";
}else{
$this->form_errors[$field] = " ";
}
}
if (isset($_REQUEST['parent_id']) && $parent_id = intval($_REQUEST['parent_id'])) {
$parent_field = sprintf('<input type="hidden" name="parent_id" value="%d">', $parent_id);
if (!strlen($safe['subject'])) {
$st = $this->db->prepare('SELECT subject FROM message WHERE id=?');
$st->execute(array($parent_id));
$parent_subject = $st->fetchColumn(0);
$safe['subject'] = htmlentities($parent_subject);
if ($parent_subject && (!preg_match('/^re:/i', $parent_subject))) {
$safe['subject'] = "Re: {$safe['subject']}";
}
}
}else{
$parent_field = ' ';
}
$self = htmlentities($_SERVER['PHP_SELF']);
print "<form method = 'post' action = '{$self}'><table border='2'><tr><td>Your Name</td><td>{$this->form_errors['author']}<input type='text' name='author' value='{$safe['author']}'></td></tr>";
print "<tr><td>Subject</td><td>{$this->form_errors['subject']}<input type='text' name='subject' value='{$safe['subject']}'></td></tr>";
print "<tr><td>Message:</td><td>{$this->form_errors['body']}<textarea rows='4' cols='30' name='body'>{$safe['body']}</textarea></td></tr>";
print "<tr><td colspan='2'><input type='submit' value='Post Message'></td></tr></table>";
print $parent_field;
print "<input type='hidden' name='cmd' value='save' /></form>";
}
// checking message box and return any error if something not found or not set
public function valid(){
$this->form_errors = array();
if (!(isset($_POST['author']) && strlen(trim($_POST['author'])))) {
$this->form_errors['author'] = "Please Enter Your Name";
}
if (!(isset($_POST['subject']) && strlen(trim($_POST['subject'])))) {
$this->form_errors['subject'] = "Please Enter Your Message Subject";
}
if (!(isset($_POST['body']) && strlen(trim($_POST['body'])))) {
$this->form_errors['body'] = "Please Write Your Message";
}
return (count($this->form_errors)==0);
}
// to get error message of database...
public function logAndDie(Exception $e){
print 'Error: '.htmlentities($e->getMessage());
if ($this->db && $this->db->inTransaction()) {
$this->db->rollback();
}
exit();
}
}
?>
