Useful PHP Functions

These are three of my favorite PHP functions.

string file_get_contents ( string $filename [, int $flags [, resource $context [, int $offset [, int $maxlen ]]]] ) – Get the contents of a url.

Example:

// following code will display the contents of the web page www.example.com $url = “http://www.example.com”; $contents = file_get_contents($url); echo $contents;

bool mail ( string $to , string $subject , string $message [, string $additional_headers [, string $additional_parameters ]] ) – Requires an email server. This functions programatically sends an email based on the given parameters.
Example:

// send an email to someone@somedomain.com $to=”someone@somedomain.com $subj = “example”; $message=”this is an email”; if(mail($to, $subj, $message)) echo “Email was sent”; else echo “Email sending failed.”;

int fwrite ( resource $handle , string $string [, int $length ] ) - Write something to a file. Note that the file and it’s parent directory should have permissions granted to a user such as “apache” or “www-data”.

Example:

// open a file called test.txt and if it does not exist, attempt to create it; place the pointer at the begining of the file $handle = fopen(“test.txt”, “a+”); $data = “I am programatically written.\n”; fwrite($handle, $data); fclose($handle);

I’ll stick with these 3 functions for the meantime. With this though, you can make programs such as:

• A simple email interface.
• A logging system using just the last function
• A proxy browser or something.

PHP SESSION

This post was originally titled "PHP Developer Essentials" which was what I really wanted to post instead of "PHP Essentials". But as I was at it, I got really bored and I realize, I really just wanted to list all my favorite or let me just say "mostly used" php functions.

But to preserve the efforts, let me just leave what I have already typed here—Creating a session with PHP.

Creating a Session

login.php

<?php $login_name = $_POST['username']; $login_password = $_POST['password']; if($login_name==’admin’ && $login_password==’@dm!n’){    session_start();    session_cache_expire(15);    $_SESSION['user'] = $_POST['username'];    header("Location: ‘home.html’"); } else{    die("Authentication Failed"); } ?>

What this simple program does, is get post data from a form that uses the POST method and defined the URL of this code as the form target. The form will look like:

<form action=’login.php’ method=’post’> Username: <input type=’text’ name=’username’> Password: <input type=’password’ name=’password’> <input type=’submit’ value=’Login’>

After retrieving post data, it will validate the user inputs then start a session and store the login data (username) in a session variable called (user). It will then set the window location to the home page using the header() function.

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PHP Essentials

Learn PHP quick! Here are the php elements and functions which I find essential in developing applications with PHP.

Basic Syntax

<?php echo “hello world”; ?>

The output would be:

hello world

Variables

Variables are represented by a dollar sign ($) and does not require type declaration.

<?php $a = “this is a string”; $b = 1; $c = 2; $d = $b + $c; echo $d . ” is an integer” . “<br>”; echo $a; ?>

The output would be:

3 is an integer this is a string

Basic Conditions

Here are some of the most basic conditions:

<?php $a = 1; $b = 2; if($a==$b){ echo “a is equal to b” . “<br>”; } else if($a!=$b){ echo “a is not equal to b” . “<br>”; } if($a>=$b) or $a==1){ echo “a is greater than or equal to b or a is equal to 1″; } ?>

The output would be:

a is not equal to be a is greater than or equal to b or a is equal to 1

….Anyway, this is supposed to be a reference, not a tutorial. To really learn php, go to this site!