Installing Apache Webserver with PHP scripting, and MySQL and PostgreSQL PHP connection driver under Ubuntu 18.04 LTS (Bionic Beaver)

1.  Download and install the Apache webserver software

# apt-get install apache2

If there are errors displayed during the installation, issue the update command before repeating the installation command.

# apt-get update --fix-missing
# apt-get install apache2


2.  Download and install the PHP scripting language

# apt-get install php

If there are errors displayed during the installation, issue the update command before repeating the installation command.

# apt-get update --fix-missing
# apt-get install php libapache2-mod-php

3.  Download and install the MySQL database server PHP connection driver.

# apt-get install php-mysql

If there are errors displayed during the installation, issue the update command before repeating the installation command.

# apt-get update --fix-missing
# apt-get install php-mysql

4.  Download and install the PostgreSQL database server PHP connection driver as follows:

# apt-get install php-pgsql

If there are errors displayed during the installation, issue the update command before repeating the installation command.

# apt-get update --fix-missing
# apt-get install php-pgsql

5.  By default, the Apache webserver should be running after installation.  You should restart the Apache webserver in order to load the PHP, MySQL and PostgreSQL support.  Issue the command:

# systemctl restart apache2.service


6. To check if the Apache process is running, issue the command

# ps ax | grep apache2

This should produce a display similar to this if it is running:

23263 ?        Ss     0:00 /usr/sbin/apache2 -k start
23265 ?        S      0:00 /usr/sbin/apache2 -k start
23266 ?        S      0:00 /usr/sbin/apache2 -k start
23267 ?        S      0:00 /usr/sbin/apache2 -k start
23268 ?        S      0:00 /usr/sbin/apache2 -k start
23269 ?        S      0:00 /usr/sbin/apache2 -k start
25621 pts/0    S+     0:00 grep --color=auto apache2

If the apache2 process is not running, the display should just produce this entry:

6433 pts/0    S+     0:00 grep --color=auto apache2

7.  To test if the Apache webserver is running using an Internet browser, type the address where the webserver is running.  On the local machine, the address is 127.0.0.1 (also known as the loopback address).  This should display a page similar to this.

This is the default page of the Apache web server.


8.  To change the default page of the Apache webserver, remove the "index.html" file in the subdirectory "/var/www/html" and create a sample HTML file called "index.html" as follows:

# cd /var/www/html
# rm index.html
# vi index.html

< html >
< head >
< title > My First HTML Page < /title >
< /head >
< body >
Hello World!< /body >
< /html >

My assumption here is, you are familiar with using the vi text editor in Linux.  You may use your own preferred text editor to create the HTML file.  After refreshing your browser, the display should look like this.

9.  To test if the Apache webserver has PHP scripting support, create the following "test.php" file and place it in the subdirectory "/var/www/html".

# cd /var/www/html
# vi test.php

< ?php 
phpinfo();
? >

Type in the address bar of the browser "http://127.0.0.1/test.php", the browser should display a page similar to this.

10.  To know if the MySQL database PHP connection driver is installed, you should see and entry in the PHP test page similar to this:

11.  Likewise, to know if the PostgreSQL database PHP connection driver is installed, you should see an entry in the PHP test page similar to this:

12.  Should there be a need to uninstall the Apache webserver, shut down the running apache2 process first before uninstalling.

# systemctl stop apache2.service
# apt-get remove apache2

Authentication System Design Pattern

The following are PHP scripts that can serve as design pattern for an application authentication system.

This is the "login.php" file that serves as the HTML login form.

<?php
echo "
<center>
<form method='post' action='authenticate.php'>
<fieldset>
<legend> Login </legend>
<table border='0'>
<tr>
<td rowspan='3'><img src='../img/emblem-keys.png'></td>
<td>Username</td><td><input type='text' name='username'></td>
</tr>
<tr>
<td>Password</td><td><input type='password' name='wordpass'></td>
</tr>
<tr>
<td>   </td><td><input type='submit' value='Login'><input type='reset' value='Reset'</td>
</tr>
</table>
</fieldset>
</form>
";
?>

This is the "authenticate.php" file that is executed after the HTML login form.

<?php
session_start();
include_once('db_postgresql.inc.php');

$sql1 = "SELECT COUNT(*) AS numfound FROM webappuser WHERE username='{$_POST['username']}' AND wordpass='{$_POST['wordpass']}' AND access_level='1' AND record_state='1'";
$result1 = $con->query(''.$sql1.'');

// Login Logic
$my_array1 = $result1->fetch(PDO::FETCH_ASSOC);
if ( $my_array1 ['numfound'] < 1 ) // Login Failed
	{
	$delay = 0;
	$url = "unauthorized.php";
	echo "<meta http-equiv='REFRESH' content='$delay;url=$url'>";
	exit;
	}

// Get the login information from the user	
$sql2 = "SELECT username, wordpass, access_leve, record_state FROM webappuser WHERE username='{$_POST['username']}' AND wordpass='{$_POST['wordpass']}' AND access_level='1' AND record_state='1'";
$result2 = $con->query(''.$sql2.'');
$my_array2 = $result2->fetch(PDO::FETCH_ASSOC);

// Register authentication information in the session
$username = $my_array2['username'];
$wordpass = $my_array2['wordpass'];
$access_level = $my_array2['access_level'];
$_SESSION["u_id"] = $u_id;
$_SESSION["username"] = $username;
$_SESSION["wordpass"] = $wordpass; 
$_SESSION["access_level"] = $access_level;

// Go to the welcome page
$delay = 0;
$url = "welcome.php";
echo "<meta http-equiv='REFRESH' content='$delay;url=$url'>";
?>

This is the "unauthorized.php" file that is called by the authentication system if username and password does not match.

<?php
session_destroy();
echo "
<center>
<form method='post' action='authenticate.php'>
<fieldset>
<legend> Login </legend>
<table border='0'>
<tr>
<td rowspan='3'><img src='../img/emblem-keys.png'></td>
<td>Username</td><td><input type='text' name='username'></td>
</tr>
<tr>
<td>Password</td><td><input type='password' name='wordpass'></td>
</tr>
<tr>
<td>   </td><td><input type='submit' value='Login'><input type='reset' value='Reset'</td>
</tr>
</table>
</fieldset>
</form>
<br>
<font color='red'><blink><b>Unauthorized ...</b></blink></font>
</center>
";
?>

This is the "logout.php" file that is called when the user clicks on a logout button.

<?php
session_destroy();
echo "
<center>
<form method='post' action='authenticate.php'>
<fieldset>
<legend> Login </legend>
<table border='0'>
<tr>
<td rowspan='3'><img src='../img/emblem-keys.png'></td>
<td>Username</td><td><input type='text' name='username'></td>
</tr>
<tr>
<td>Password</td><td><input type='password' name='wordpass'></td>
</tr>
<tr>
<td>   </td><td><input type='submit' value='Login'><input type='reset' value='Reset'</td>
</tr>
</table>
</fieldset>
</form>
<br>
<font color='red'><blink><b>You have been logged out...</b></blink></font>
</center>
";
?>

This is the "db_postgresql.inc.php" database connection file that is included in PHP page whenever it needs to connect to the database. The assumption here is the application is connected to a PostgreSQL database system. You can change this to whatever database brands you prefer. Furthermore, the database named "mydb" will have a table named "webappuser" with a minimum of four fields, namely: (i) username, (ii) wordpass, (iii) access_level, (iv) record_state. In like manner, you can modify this to suit your needs.

<?php
$host = "localhost";
$user = "postgres";
$pw = "wordpass123";
$db = "mydb";
# Using pg PDO
# Connection Check
try {
    $con = new PDO('pgsql:host='.$host.';dbname='.$db.'', $user, $pw );
    $con->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    #echo "Database Status:  <font color='green'><blink><b>Connected...</b></blink></font><hr />";
} catch(PDOException $e) {
    echo 'ERROR: ' . $e->getMessage();
}
?>

This is the "secure.php" file that can be added at the top of any of the PHP file that you want protected from unauthorized users.

<?php
ini_set( "display_errors", 0);
session_start();
include_once( 'db_postgresql.inc.php' );
$username = $_SESSION["username"];
$wordpass = $_SESSION["wordpass"];

$sql1 = "SELECT COUNT(*) AS numfound FROM webappuser WHERE username='$username' AND wordpass='$wordpass' AND access_level='1' AND record_state='1'";
$result1 = $con->query(''.$sql1.'');
$my_array1 = $result1->fetch(PDO::FETCH_ASSOC);

// Login Logic
if ( $my_array1 ['numfound'] < 1 ) // Login Failed
	{
	$delay = 0;
	$url = "unauthorized.php";
	echo "<meta http-equiv='REFRESH' content='$delay;url=$url'>";	
	exit;
	}
?>

SQL Query Form Design Pattern Using "pg" driver

The following is a PHP Script that can serve as a design pattern for HTML form handling with "pg" connection driver for the PostgreSQL database.

<html>
<head>
<title>Postgresql pg Query Interface</title>
<!--
Clement L. Rasul
copyright (c) 2013
-->
</head>
<body>

<?php
$sql = trim($_POST['sql']);
$host = "localhost";
$user = "postgres";
$pw = "wordpass123";
$db = "testdb";

# Query Form
echo "<h1>PostgreSQL pg Query Interface</h1>";
echo "<form action='postgresql_pg_query.php' method='post'><textarea cols='80' rows='5' name='sql'>";
echo "$sql";
echo "</textarea><br /><input type='submit'></form>";

# Connection Check
$con = pg_connect("host=$host port=5432 dbname=$db user=$user password=$pw") or 
   die ("Database Status: <font color='red'><blink><b>Connection Error!</b></blink></font>");
echo "Database Status:  <font color='green'><blink><b>Connected...</b></blink></font><hr />";

# SQL Query Script
$result = pg_query($con, $sql);
$num_rows = pg_num_rows($result);
$num_cols = pg_num_fields($result);
echo "Rows: ".$num_rows."<br />";
echo "Columns: ".$num_cols."<hr />";
echo "<table border='1'>";

# Table Heading
$f=0;
while ( $col = pg_field_name($result, $f) ) {
	$fn = $col;
	echo "<th>".$fn."</th>";
	$f=$f+1;
    	}

# Table Content
while ( $row = pg_fetch_array($result) ) {
	echo "<tr>";
	$c = 0;
	while ( $c < $num_cols ) {
		echo "<td>".$row[$c]."   </td.>";
		$c = $c+1;
		}
	echo "</tr>";
    	}
echo "</table>";

?>
</body>
</html>

SQL Query Form Design Pattern Using mysqli

The following is a PHP Script that can serve as a design pattern for HTML form handling with "mysqli" connection driver for the MySQL database.

<html>
<head>
<title>MySQL mysqli Query Interface</title>
<!--
Clement L. Rasul
copyright (c) 2013
-->
</head>
<body>

<?php
$sql = trim($_POST['sql']);
$host = "localhost";
$user = "root";
$pw = "wordpass123";
$db = "testdb";

# Query Form
echo "<h1>MySQL mysqli Query Interface</h1>";
echo "<form action='mysql_mysqli_query.php' method='post'><textarea cols='80' rows='5' name='sql'>";
echo "$sql";
echo "</textarea><br /><input type='submit'></form>";

# Connection Check
$testcon = mysqli_connect("$host", "$user", "$pw", "$db") or 
   die ("Database Status: <font color='red'><blink><b>Connection Error!</b></blink></font>");
echo "Database Status:  <font color='green'><blink><b>Connected...</b></blink></font><hr />";

# SQL Query Script
$con = new mysqli("$host", "$user", "$pw", "$db");
$result = $con->query("$sql");
$num_rows = $result->num_rows;
$num_cols = $result->field_count;
echo "Rows: ".$num_rows."<br />";
echo "Columns: ".$num_cols."<hr />";

# Table Heading
echo "<table border='1'>";
while ( $col = $result->fetch_field() ) {
	$fn = $col->name;
	echo "<th>".$fn."</th>";
    	}

# Table Content
while ( $row = $result->fetch_array() ) {
	echo "<tr>";
	$c = 0;
	while ( $c < $num_cols ) {
		echo "<td>".$row[$c]."   </td.>";
		$c = $c+1;
		}
	echo "</tr>";
    	}
echo "</table>";
?>

</body>
</html>

SQL Query Form Design Pattern Using mysql

The following is a PHP Script that can serve as a design pattern for HTML form handling with "mysql" connection driver for the MySQL database.

<html>
<head>
<title>MySQL mysql Query Interface</title>
<!--
Clement L. Rasul
copyright (c) 2013
-->
</head>
<body>

<?php
$sql = trim($_POST['sql']);
$host = "localhost";
$user = "root";
$pw = "wordpass123";
$db = "testdb";

# Query Form
echo "<h1>MySQL mysql Query Interface</h1>";
echo "<form action='mysql_mysql_query.php' method='post'><textarea cols='80' rows='5' name='sql'>";
echo "$sql";
echo "</textarea><br /><input type='submit'></form>";

# Connection Check
$con = mysql_connect( $host, $user, $pw );
mysql_select_db( $db , $con) or 
  die ("Database Status: <font color='red'><blink><b>Connection Error!</b></blink></font>");
echo "Database Status:  <font color='green'><blink><b>Connected...</b></blink></font><hr />";

# SQL Query Script
$result = mysql_query( $sql , $con) or die(mysql_error());
$num_rows = mysql_num_rows($result);
$num_cols = mysql_num_fields($result);
echo "Rows: ".$num_rows."<br />";
echo "Columns: ".$num_cols."<hr />";
echo "<table border='1'>";

# Table Heading
$f=0;
while ( $col = mysql_field_name($result, $f) ) {
	$fn = $col;
	echo "<th>".$fn."</th>";
	$f=$f+1;
    	}

# Table Content
while ( $row = mysql_fetch_array($result) ) {
	echo "<tr>";
	$c = 0;
	while ( $c < $num_cols ) {
		echo "<td>".$row[$c]."   </td.>";
		$c = $c+1;
		}
	echo "</tr>";
    	}
echo "</table>";

?>
</body>
</html>

Installing PHP on Ubuntu

To install PHP on Ubuntu 8.10, issue the following command:

#apt-get install php5
#apt-get install libapache2-mod-php5