IT350: Web & Internet Programming JavaScript Dynamic HTML CGI - - PowerPoint PPT Presentation

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IT350: Web & Internet Programming JavaScript Dynamic HTML CGI - - PowerPoint PPT Presentation

Aug 16, 2022 171 likes •365 views

Things well learn and do HTML5 basics, tables, forms Cascading Style Sheets IT350: Web & Internet Programming JavaScript Dynamic HTML CGI / PHP Set 12: CGI and PHP 1 Outline The Three-Tier Architecture

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IT350: Web & Internet Programming

Set 12: CGI and PHP

Things we’ll learn and do

  • HTML5 – basics, tables, forms
  • Cascading Style Sheets
  • JavaScript
  • Dynamic HTML
  • CGI / PHP
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Outline

  • Three-tier architecture
  • CGI basics
  • PHP overview
  • PHP classes and functions
  • PHP files
  • PHP arrays

The Three-Tier Architecture

Presentation tier Client Program (Web Browser) Middle tier Application Server Database Management System, File Server Data management tier

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Example 1: Airline reservations Build a system for making airline reservations

  • Database/File System
  • Application Server
  • Client Program

Technologies

Client Program (Web Browser) Application Server Database / File System HTML, Javascript, XSLT C++, Cookies, XML, XPath, web services, Perl, PHP SQL, Triggers, Stored Procedures, Scripts

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PHP

  • PHP: PHP Hypertext Preprocessor
  • Server-side scripting language
  • PHP pages require a web server with PHP support
  • Competitors:

PHP Strengths

  • High performance
  • Interface to many different database systems
  • Built-in libraries
  • Ease of learning and use
  • Object-oriented support
  • Portability
  • Open source
  • Free
  • Availability of support
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PHP References

  • Online tutorials

– http://www.w3schools.com/php/default.asp – https://www.codecademy.com/learn/php

  • Online references

– http://www.php.net

  • IT350 Textbook: Internet & WWW – How to

Program by Deitel, Deitel, and Goldberg. CGI – What does it all look like?

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CGI Script Basics

  • Common Gateway Interface (CGI)

– “Common”: Not specific to any operating system or language

  • Output file generated at runtime:
  • 1. When a program executed as a CGI script, “standard output”

is redirected to web server

  • 2. Web server then redirects output to client's browser

How can CGI get data from user?

Technique #1: Forms

  • User enters data via a form, submits
  • Browser requests the CGI file by name specified on form

__________

  • Web server runs the CGI program with form’s data

passed to it

  • Script receives data in one of two ways:

1. method = “get” 2. method = “post” Use language-specific method to get these inside CGI program

Technique #2: URL with parameters

<a href=“http://www.usna.edu/CS/calendar/view.pl?events=seminars”> Seminars </a>

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PHP and CGI

  • We will use PHP in this class.

– We will not focus on teaching you the language. – You are expected to pick this up on your own.

  • Remember: the goal of a CGI program is to
  • utput HTML

– The web server will run your program. – The web server will pipe the output to your browser. – Your browser only understands HTML 

PHP Overview

  • PHP tags <?php

?>

– Mixed with HTML tags – File extension .php

  • Statements

– Separated by semicolon – if..else.., while, do, for, switch – echo

  • Variables

– $varname – Type determined by content; type not declared, variables not declared – Variable names are case sensitive

  • Strings

– Single quotes – literal string – Double quotes – interpolated string – Use . to concatenate

  • Accessing form variables

– $_POST[‘age’], $_GET[‘age’], $_REQUEST[‘age’]

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Exercise #1

  • Write PHP code that will, given the URL provided below,

generate HTML that looks like the screenshot

http://mope.academy.usna.edu/~adina/it350/ice/set12_ex1.php?maxNumber=5

PHP Objects and Functions

  • PHP objects

– Java-like inheritance – public, private, or protected attributes and methods – __construct(), __destruct(), – __set(), __get()

  • PHP functions

– function myFunction($param1, $param2){…return .. }

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How everything works: Step 1: Input Form – form.html

<!DOCTYPE html> <html><head><title>IT350 PHP test page</title><meta charset = “utf-8”></head> <body>

<form action="processPersonInfo.php" method="post"> <p><label>Enter your name: <input type="text" name="name"/></label></p> <p><label>Enter your age: <input type="text" name="age" /></label></p> <p><input type="submit" name = "submit" value = "Submit"/></p> </form>

</body> </html>

<?php class Page{ public $content; private $title; public function __construct($title){ $this->title = $title; } public function __set($name, $value){ $this->$name = $value; } public function display(){ ?> <!DOCTYPE html> <head><title> <?php echo $this->title; ?> </title></head> <body> <?php echo $this->content; echo "</body></html>"; } } //end class definition ?>

page.inc.php

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Step 1 version 2 – getPersonInfo.php

<?php require('page.inc.php'); $page = new Page("Input person"); $page->content = '<form action = "processPersonInfo.php" method = "post">'. '<p><label>Enter your name: <input type="text” name="name“/></label></p>’. ‘<p><label>Enter your age: <input type="text" name="age"/></label></p>’. '<input type = "submit" value = "submit">'; $page->display(); ?>

Exercise #2

  • Create Person class with method

getPersonAttributesAsHTMLInput() that returns

'<p><label>Enter your name: <input type="text” name="name“/></label></p>’. ‘<p><label>Enter your age: <input type="text" name="age"/></label></p>’

  • Modify getPersonInfo.php to use the

getPersonAttributesAsHTMLInput method in Person class

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<?php /* define a class Person with name and age */ class Person{ private $name; private $age; public function __construct(){} public function __set($varName, $varValue) { $varValue = trim($varValue); $varValue = strip_tags($varValue); $this->$varName = $varValue; } public function __get($varName) { return $this->$varName; }

person.inc.php – part 1

public function processPerson(){ $success = $this->insertToFile(); if ($success){ $confirmation = '<h1>Thank you for registering with our site</h1>'. '<p>The information recorded is as follows: <br />'. "Name: $this->name <br /> Age: $this->age </p>"; } else{ $confirmation = '<h1>Error: we had problems with your registration (probably some file error - permissions??). Please try again.</h1>'; } return $confirmation; }

person.inc.php – part 2

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PHP Files

  • Files

– $handle = fopen($fileName, $mode) – fwrite($handle, $someText) – fclose($handle) – fgets($handle) – feof($handle)

private function insertToFile($fileName="persons.txt") { $fp = @fopen($fileName, 'a'); if (!$fp){ return false; } else{ $text = "$this->name\t$this->age\n"; fwrite($fp, $text); fclose($fp); return true; } }

person.inc.php – part 3

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public static function getAllPersonsInfo($fileName = "persons.txt"){ $fp = @fopen($fileName, 'r'); if (!$fp){ $content = "<p>ERROR! Could not open file $fileName for reading.</p>"; } else{ $content= '<p>Here is the list: <br>'; $line = fgets($fp); while( !feof($fp) ){ $content .= $line . '<br>'; $line = fgets($fp); } $content .= '</p>'; fclose($fp); } return $content; } }?>

person.inc.php – part 4

<?php require('page.inc.php'); require('person.inc.php'); $name = $_POST['name']; $age = $_POST['age']; $page = new Page("Registration confirmation"); if (empty($name) || empty($age)){ $page->content = '<p> Name or age not entered!! Try again</p>'; $page->display(); exit; } $dummy = new Person(); $dummy->name = $name; $dummy->age = $age; $page->content = $dummy->processPerson(); $page->display(); ?>

Step 2: processPersonInfo.php

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<?php

require('page.inc.php'); require('person.inc.php'); if (isset($_GET['filename'])){ $fileName = $_GET['filename']; } else{ $fileName = "persons.txt"; } $page = new Page("Persons list"); $page->content = Person::getAllPersonsInfo($fileName); $page->display(); ?> Step 3: readPearsonsInfo.php

CGI – Review

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Arrays

<?php require_once('page.inc.php'); require_once('arrayFunctions.inc.php'); $myPage = new Page('Array examples'); $myPage->content = '<p>Working with Arrays</p>'; $array = array('thing1', 'thing2'); $array[2] = 'thing3'; $myPage->content .= '<p>'.displayArray($array) . '</p>'; $prices = array('Tires' => 100, 'Oil' => 10); $prices[‘Spark plugs'] = 200; $myPage->content .= '<p>The values in $prices array are <br />’ . displayAssociativeArray($prices) . '</p>'; sort($array); //sort array $myPage->content .= '<p> Sorted array '.displayArray($array) . '</p>'; ksort($prices); //sort associative array by key $myPage->content .= '<p>The values in $prices array sorted by key are <br />' . displayAssociativeArray($prices) . '</p>'; asort($prices); //sort associative array by value $myPage->content .= '<p>The values in $prices array sorted by value are <br />' . displayAssociativeArray($prices) . '</p>'; $myPage->display(); ?>

array_functions.inc.php

<?php //return a string to display an array function displayArray($array){ $result = ‘<p>'; for($i = 0; $i < count($array); $i++){ $result .= "Element at index $i is $array[$i] <br />"; } $result .= ‘</p>'; return $result; } //return a string to display an associative array function displayAssociativeArray($array){ $result = ‘<p>'; foreach($array as $key => $value){ $result .= "Element with key $key has value $value <br />"; } $result .= ‘</p>'; return $result; } ?>

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Exercise #3

  • Create an array containing the following values:

(1900, 2000, 2015, 2016 ).

  • Use the array in a “foreach” loop to test if the

value is a divisible by 4.

  • If it is divisible by 4 print “XXXX is divisible by 4”
  • Else print “XXXX is not divisible by 4”
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Variables Scope

  • Variables used in functions are visible from first

use line to end of function – local variables

  • Variables used outside functions are visible from

first use line to end of file, but not inside functions – global variables

  • Superglobal variables ($_POST, $_SERVER, …) are

visible everywhere

  • Keyword global makes local variables global – not

recommended Variables Scope Example

<?php function fn(){ $x = 'content'; } fn(); echo 'Value of $x is '. $x; ?>

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Variables Scope Example 2

<?php $x = 'content 1 <br/>'; echo 'Content of $x after initialization is '. $x . '<br />'; function fn(){ echo 'Content of $x at start of function is '. $x. '<br />'; $x = 'content 2 <br/>'; echo 'Content of $x at end of function is '. $x. '<br />'; } fn(); echo 'Value of $x after calling fn() is '. $x. ‘<br />'; ?>

PHP Summary

  • PHP tags <?php

?>

– Mixed with HTML tags – File extension .php

  • Statements

– Separated by semicolon – if..else.., while, do, for, switch, echo

  • Variables

– $varname – Type determined by content; variables not declared; case sensitive

  • Strings

– Single quotes – literal string – Double quotes – interpolated string (variables are replaced with their value)

  • Arrays

– Numerically indexed arrays – Associative arrays – count(), foreach($array as $key => $value)…

  • Accessing form variables

– $_POST[‘age’], $_GET[‘age’], $_REQUEST[‘age’]