Web Technologies Course Outline Christian KHOURY
[email protected]
References & Links • • • •
http://www.php.net/ http://www.php.net/manual/en/ http://www.mysql.com/ http://httpd.apache.org/
• Interesting link for website construction by example – http://www.siteduzero.com/tutoriel-3-14668-un-sitedynamique-avec-php.html
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What is PHP ? • • • •
PHP stands for PHP: Hypertext Preprocessor PHP is a server-side scripting language, like ASP PHP scripts are executed on the server PHP supports many databases (MySQL, Informix, Oracle, Sybase, Solid, PostgreSQL, Generic ODBC, etc.) • PHP is an open source software (OSS) • PHP is free to download and use
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What is a PHP file ? • PHP files may contain text, HTML tags and scripts • PHP files are returned to the browser as plain HTML • PHP files have a file extension of ".php", ".php3", or ".phtml"
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What is MySQL ? • MySQL is a database server • MySQL is ideal for both small and large applications • MySQL supports standard SQL • MySQL compiles on a number of platforms • MySQL is free to download and use PHP combined with MySQL are cross-platform
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Where to start ? • Install an Apache server on a Windows or Linux machine • Install PHP on a Windows or Linux machine • Install MySQL on a Windows or Linux machine
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PHP Syntax
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Basic Syntax • A PHP scripting block always starts with • can be placed anywhere in the document • On servers with shorthand support enabled you can start a scripting block with
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Simple Example • Each code line in PHP must end with a semicolon. The semicolon is a separator and is used to distinguish one set of instructions from another 9
Comments in PHP
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PHP Variables • All variables in PHP start with a $ sign symbol – $var_name = value;
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PHP Variables • PHP is a Loosely Typed Language • In PHP a variable does not need to be declared before being set. • In the example above, you see that you do not have to tell PHP which data type the variable is. • PHP automatically converts the variable to the correct data type, depending on how they are set. • In a strongly typed programming language, you have to declare (define) the type and name of the variable before using it. • In PHP the variable is declared automatically when you use it. 12
Naming Rules • A variable name must start with a letter or an underscore "_" • A variable name can only contain alpha-numeric characters and underscores (a-Z, 0-9, and _ ) • A variable name should not contain spaces. If a variable name is more than one word, it should be separated with underscore ($my_string), or with capitalization ($myString)
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Predefined Variables • • • • • • • • • • • • • • •
Superglobals — Superglobals are built-in variables that are always available in all scopes $GLOBALS — References all variables available in global scope $_SERVER — Server and execution environment information $_GET — HTTP GET variables $_POST — HTTP POST variables $_FILES — HTTP File Upload variables $_REQUEST — HTTP Request variables $_SESSION — Session variables $_ENV — Environment variables $_COOKIE — HTTP Cookies $php_errormsg — The previous error message $HTTP_RAW_POST_DATA — Raw POST data $http_response_header — HTTP response headers $argc — The number of arguments passed to script $argv — Array of arguments passed to script
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Variable Scope • Entire php file • Global keyword
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Using $GLOBALS
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Static Variables • C-like
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Strings (1/3) • Concatenation Operator – (.) is used to put two string values together – To concatenate two variables together, use the dot (.) operator
• In double-quoted strings, variable names will be expanded
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Strings (2/3) • strlen() • strpos() – used to search for a string or character within a string – If a match is found in the string, this function will return the position of the first match. If no match is found, it will return FALSE
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Strings (3/3) – Output is 6 – The reason that it is 6, and not 7, is that the first position in the string is 0, and not 1
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PHP Operators (1/4) • Arithmetic operators
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PHP Operators (2/4) • Assignment operators – – – – – – –
= += -= /= *= .= %=
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PHP Operators (3/4) • Comparison operators
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PHP Operators (4/4) • Logical operators
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Conditional Statements (1/3) • if...else statement - use this statement if you want to execute a set of code when a condition is true and another if the condition is not true • elseif statement - is used with the if...else statement to execute a set of code if one of several conditions are true
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Conditional Statements (2/3)
• If more than one line should be executed if a condition is true/false, the lines should be enclosed within curly braces 26
Conditional Statements (3/3)
• The following example will output "Have a nice weekend!" if the current day is Friday, and "Have a nice Sunday!" if the current day is Sunday. Otherwise it will output "Have a nice day!" 27
Switch Statement (1/2) • used to avoid long blocks of if..elseif..else code
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Switch Statement (2/2) • A single expression (most often a variable) is evaluated once • The value of the expression is compared with the values for each case in the structure • If there is a match, the code associated with that case is executed • After a code is executed, break is used to stop the code from running into the next case • The default statement is used if none of the cases are true 29
PHP Arrays There are three different kind of arrays: • Numeric array - An array with a numeric ID key • Associative array - An array where each ID key is associated with a value • Multidimensional array - An array containing one or more arrays
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Numeric Arrays (1/2) • stores each element with a numeric ID key Examples: $names = array("Peter","Quagmire","Joe"); $names[0] = "Peter"; $names[1] = "Quagmire"; $names[2] = "Joe"; 31
Numeric Arrays (2/2)
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Associative Arrays $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34);
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Multidimensional Array
echo "Is " . $families['Griffin'][2] . " a part of the Griffin family?";
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Iterations In PHP we have the following looping statements: • while - loops through a block of code if and as long as a specified condition is true • do...while - loops through a block of code once, and then repeats the loop as long as a special condition is true • for - loops through a block of code a specified number of times • foreach - loops through a block of code for each element in an array 35
While Statement
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do … while
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for
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foreach
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PHP Functions (1/4) • In PHP - there are more than 700 built-in functions available ! • Creating PHP functions: – All functions start with the word "function()" – Name the function - It should be possible to understand what the function does by its name. The name can start with a letter or underscore (not a number) – Add a "{" - The function code starts after the opening curly brace – Insert the function code – Add a "}" - The function is finished by a closing curly brace
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PHP Functions (2/4)
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PHP Functions (3/4)
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PHP Functions (4/4)
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Form Handling (1/3)
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Form Handling (2/3)
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Form Handling (3/3) • Form validation – Client side validation is faster, and will reduce server load – You should always use server side validation for security reasons if the form accesses a database
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PHP $_GET (1/2) • The $_GET variable is used to collect values from a form with method="get" • $_GET variable is an array of variable names and values sent by the HTTP GET method • The HTTP GET method is not suitable on large variable values; the value cannot exceed 100 characters 47
PHP $_GET (2/2)
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PHP $_POST (1/2) • Variables sent with HTTP POST are not shown in the URL • Variables have no length limit • $_POST variable is used to collect values from a form with method="post"
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PHP $_POST (2/2)
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PHP $_REQUEST • $_REQUEST variable can be used to get the result from form data sent with both the GET and POST method
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Date (1/2) • formats a timestamp to a more readable date and time • date(format,timestamp)
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Date (2/2) • Adding a timestamp • mktime(hour,minute,second,month,day,year,is_dst)
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Include (1/4) • Server Side Includes (SSI) are used to create functions, headers, footers, or elements that will be reused on multiple pages • You can insert the content of a file into a PHP file before the server executes it, with the include() or require() function – two functions are identical in every way, except how they handle errors – Include generates a warning – Require generates a fatal error ! 54
Include (2/4) • The include() function takes all the text in a specified file and copies it into the file that uses the include function
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Include (3/4)
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Include (4/4) • include_once • require_once
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File Handling (1/5) • Fopen & cie – C-like library
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File Handling (2/5)
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File Handling (3/5)
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File Handling (4/5) • fclose($file) – Close an opened file
• feof() – Check end of file
• fgets(), fgetc()
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File Handling (5/5)
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Cookies (1/4) • A cookie is often used to identify a user • A cookie is a small file that the server embeds on the user's computer. Each time the same computer requests a page with a browser, it will send the cookie too • With PHP, you can both create and retrieve cookie values 63
How to Create a Cookie (2/4) • The setcookie() function is used to set a cookie – It must appear BEFORE the tag – setcookie(name, value, expire, path, domain);
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How to Retrieve a Cookie (3/4) • $_COOKIE variable is used to retrieve a cookie value
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How to Delete a Cookie (4/4) • When deleting a cookie you should assure that the expiration date is in the past
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Sessions (1/4) • HTTP is stateless ! – the web server does not know who you are and what you do
• A PHP session solves this problem by allowing you to store user information on the server for later use (i.e. username, shopping items, etc). • Sessions work by creating a unique id (UID) for each visitor and store variables based on this UID. The UID is either stored in a cookie or is propagated in the URL
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Sessions (2/4) • Starting a session
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Sessions (3/4) • Storing a session variable
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Sessions (4/4) • Destroying a session
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Email
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OOP (1/5) • Class definition 72
OOP (2/5) • Inheriting a class with a constructor 73
OOP (3/5) • Invocation
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OOP (4/5) • Static method calls 75
OOP (5/5) •
Calling methods in your parent class
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Object References (1/2) 77
Object References (2/2) 78
Object Cloning 79
Constructors and Destructors 80
Constructors and Subclasses • Subclasses should call the parent's constructor within their own constructor 81
Public, Private, Protected (1/2)
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Public, Private, Protected (2/2) •
Object methods can be designated private, public, or protected
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Class Constants
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Indirect Referencing
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Getter and Setter •
PHP 5 objects support special __get() and __set() methods to access "virtual" properties that do not actually exist
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Abstract Classes 89
Interfaces 90
Exceptions 91
Objects as Strings 92
MySQL and PHP
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Querying A Database • Basic steps 1. 2. 3. 4. 5.
Check and filter data coming from the user Set up a connection to the appropriate database Query a database Retrieve the results Present the results back to the user
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Book Search Example (html) Book-O-Rama Catalog Search
Book-O-Rama Catalog Search
Choose Search Type:
Author Title ISBN
Enter Search Term:
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results_generic.php (1/4) Book-O-Rama Search Results
Book-O-Rama Search Results
