Intro to PHP 2

Dr. Andrew Besmer

Arrays

Arrays

  • PHP Arrays are 0
  • They can be accessed with typical array operators []
  • PHP will index values unless you provide one
<?php
$animal[] = "aardvark";
$animal[] = "bat";
$animal[] = "cat";
$animal[1] = "bug";
$animal[4] = "elephant";

var_dump($animal);

/*
array(4) {
  [0]=>
  string(8) "aardvark"
  [1]=>
  string(3) "bug"
  [2]=>
  string(3) "cat"
  [4]=>
  string(8) "elephant"
}
*/

Associative Arrays

  • Arrays can also have indexes of a string
<?php
$name['first'] = 'Andrew';
$name['last'] = 'Besmer';

echo "Hey there " . $name['first'];

//Hey there Andrew

Looping Through an Array

  • Never loop through a php array with a counter
  • Always use a foreach or direct access to elements you are looking for
<?php
$name['first'] = 'Andrew';
$name['last'] = 'Besmer';

foreach($name as $key => $value)
{
    //echo "Your " . $key . " name is " . $value . ".";
    echo "Your $key name is $value.";
}


//Your first name is Andrew.Your last name is Besmer.

Useful Array Functions

  • is_array($animals) - Is $animals an array true or false
  • count($animals) - Return the number of elements in the array
  • sort($animals) - Sorts the array elements
  • explode(',', 'Blue,Green') - Returns the array ['Blue','Green']
  • unset($animals[0]) - Removes the element at index 0
  • in_array(5, $values) - Is 5 in the array of $values
  • isset($myArray['pos']) - Does an element at position pos exist in $myArray?

String Functions

  • There are many string functions
    • strtoupper('Andrew') - Returns ANDREW
    • strtolower('Andrew') - Returns andrew
    • substr($myString, 1, 5) - Return characters at posistions 1-5
    • substr($myString, -4) - Return the last 4 characters of the string
    • strpos('Andrew Besmer', 'Besmer') - Returns location Besmer is at in the string 7 or false if not found
  • Complete List found in documentation

Forms and Superglobals

Typical Data Access

  • Data is typically passed from the web server process by inserting that data into so called “superglobals”
  • Data may also be inside files or databases

Forms

Forms



Sending Data

  • Lets fill out this form using the following pieces of data
    • Andrew
    • 4825
    • besmera
    • Thurmond 304

 





Sending Data

  • Lets fill out this form using the following pieces of data
    • Andrew
    • 4825
    • besmera
    • Thurmond 304
  • Labeling/naming is neccessary for both the human AND the server

 





Name Value Pairs

  • camelCaseIsUsedForMultipleWords
  • itshardertoreadtextlikethis

Query String

  • Starts with ?
  • Uses name value pairs seperated by =
  • More than one seperated by &
  • URL Encoding
?first=Andrew&last=Besmer

Try it

Form Structure

  • Forms use the form tag and require two attributes
    • action - Where the data will be sent
    • method - How the data will be sent
<form action="http://deltona.birdnest.org/~acc.besmera2/simulators/FormData/echo.php" method="GET">

</form>

Form Methods

  • GET
    • Visible in url
    • Saved in browser history
    • Has size limits
  • POST
    • Sent as part of message body
    • Not stored in browser history
    • No practical size limits

GET Form



<form action="http://deltona.birdnest.org/~acc.besmera2/simulators/FormData/echo.php" method="GET">
  <label>First: <input type="text" name="first"></label><br>
  <label>Last: <input type="text" name="last"></label><br>
  <button type="submit">Submit</button>
</form>

POST Form



<form action="http://deltona.birdnest.org/~acc.besmera2/simulators/FormData/echo.php" method="POST">
  <label>First: <input type="text" name="first"></label><br>
  <label>Last: <input type="text" name="last"></label><br>
  <button type="submit">Submit</button>
</form>

$_GET/$_POST

  • The superglobals $_GET and $_POST contain the name value pairs sent as part of a GET/POST request from your form1
  • $_SERVER contains information relevant to the execution environment ['REQUEST_METHOD'] is of particular interest.

$_GET/$_POST

<!DOCTYPE html>
<html>
<head>
    <title>Hello There</title>
</head>
<body> 
<?php
        if($_SERVER['REQUEST_METHOD'] == 'GET')
        {
            ?>
                <form method="POST" action="index.php"> 
                    <label>First Name: <input type="text" name="firstName"></input></label><br /> 
                    <label>Last Name: <input type="text" name="lastName"></input></label>
                    <input type="submit" value="Submit" name="submit">
                </form>
            <?php
        } 
        else {
            if(isset($_POST['firstName']) && isset($_POST['lastName']))
            {
                $firstName = "Somebody";
                $lastName = "Cool";
    
                if($_POST['firstName'] != '')
                {
                    $firstName = $_POST['firstName'];
                }
    
                if($_POST['lastName'] != '')
                {
                    $lastName = $_POST['lastName'];
                }
    
                echo "Hello there $firstName $lastName.";
            }
            else
            {
                echo "Sorry you must access this page by filling out the form.";
            }
        }
        ?>
    </body>
</html>

  1. XSS has been left in example for simplicity.↩