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Working With PHP. David Lash Module 1 Getting Started. Objectives. To understand what PHP is What is HTML How PHP compares with CGI Getting Started with PHP Your first script PHP syntax and embedding in HTML Finding out about your PHP configuration Using PHP variables

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Working with php

Working With PHP

David Lash

Module 1

Getting Started


Objectives

Objectives

  • To understand what PHP is

    • What is HTML

    • How PHP compares with CGI

  • Getting Started with PHP

    • Your first script

    • PHP syntax and embedding in HTML

    • Finding out about your PHP configuration

  • Using PHP variables

    • Numerical variables and operators

    • String variables, operators and a few functions

  • Separating PHP from HTML using <?=


Competencies

Competencies

  • At end of unit be able to

    • Understand how PHP compares with other dynamic technologies

    • Create a Web Page with PHP embedded

    • Receive input into PHP script with variables

Competency

Alert:

You need to

know this!

Common

Problem

Area!

People seem to forget this


Ummm what is html used for

Ummm, What is HTML used for?

  • HTML primarily . . .

    • Provides instructions to browser on how file should display.

      • Has a set of markup language commands

      • Can include graphical image files

  • HTML documents are Static.

    • For example, cannot use HTML alone to:

      • have a document display current time

      • receive results of a form, query a database, and display the results

      • Open an input file and based on its contents, display different document content


Accessing html files

Accessing HTML Files

http protocol

Note:

The file is just

retrieved no code is executed on server

Note2:

HTML tags interpreted on client by browser.


Http web servers clients

HTTP, Web Servers, Clients …

  • Hyper Text Transport Protocol – The protocol used to move data between Web server and Web browser.

  • Web Server Machine: A machine that runs web server software that listens for incoming requests on a port.

    • They have Internet IP addresses (e.g., 192.33.23.191) and listen on a specific ports

      • 193.22.12.191:80

  • Web Server Software - an application, that exchanges data between Web server and Web browser.

    • Uses HTTP

    • Excepts a requests (e.g., from browser) in a specific format.

    • Responds to browser in a specific format.

    • For example, a request consist of TOP LINE, HEADER and BODY (BODY is sometimes absent).

    • HEADER and BODY are separated by an empty line.


Working with php

HTML?

  • The Hypertext Markup Language(HTML)

    • used coded HTML tags

    • provide Web browsers display instructions.

  • HTML is

    • It is simple to use and understand

    • It provides ways to include things like text, graphics, sounds, links.

    • It is STANDARD

    • Its creation (and use) is one of the big reasons the WWW became popular


Major server side web technologies

Major Server-Side Web Technologies

  • CGI - Computer Gateway Interface

    • Web Servers enable computer variety of computer languages to dynamically generate HTML

    • E.g. Perl, C, Unix Shell, C++

  • Web Server add-on

    • Builds on to existing web servers – E.g., Cold Fusion

  • Embedded Web server

    • Web server has scripting language built into it.

    • Comprises most modern scripting technologies

      • ASP, JSP, PHP

Competency

Alert:

You need to

know this!


Often the choice depends on web server

Often the Choice Depends on Web Server

  • If running a Microsoft Web Server (e.g., IIS)

    • More likely to use ASP or ASP.net

  • If running UNIX/Linux (e.g., Apache)

    • more likely to use PHP, or JSP.

Source netscrat http://www.netscraft.com


What is php

What Is PHP?

Advantages of Using PHP to enhance Web pages:

  • Easy to use.

  • Open source.

  • Multiple platform.

  • Started around 1996 when

    • Rasmus Lerdorf (a consultant) wanted to know number of people viewing his on-line resume.

    • Developed a CGI/Perl script that counted visitors and logged some visitor information.

    • He received many inquires for his CGI/Perl toolset so started giving it away for free (and called it Personal Home Page).

    • Got so many requests for additions, developed a next release of toolset (called PHP 2.0)

    • PHP 2.0 became popular and PHP moved to open source model.


  • How php pages are accessed and interpreted

    How PHP Pages are Accessed and Interpreted


    Compare with cgi

    Compare with CGI

    On a UNIX server this is a fork operation

    Note this can be shell script, perl script, C program or whatever.


    Objectives1

    Objectives

    • To understand what PHP is

      • What is HTML

      • How PHP compares with CGI

    • Getting Started with PHP

      • Your first script

      • PHP syntax and embedding in HTML

      • Finding out about your PHP configuration

    • Using PHP variables

      • Numerical variables and operators

      • String variables, operators and a few functions

    • Separating PHP from HTML using <?=


    Getting started with php

    Getting Started with PHP

    To develop and publish PHP scripts you need:

    • A Web server with PHP built into it

    • A client machine with a basic text editor and Internet connection

    • FTP or Telnet software

    Its worth noting:

    There are a couple good IDEs for PHP.

    They basically allow you create PHP scripts on PC, syntax check them, see output, and then copy to Web server


    Common php development configurations

    Common PHP Development Configurations

    Windows/

    Apache/IIS

    Linux/Apache

    FTP or telnet

    Development

    PC

    Development

    PC

    PC Running

    Windows

    Apache/IIS

    PC Running

    Linux

    Apache


    Creating a php script file and saving it to a local disk

    Creating a PHP Script File and Saving It to a Local Disk

    You can use a number of different editors to create your PHP script files.

    • The PHP script starts with a <?php tag and ends with ?>.

    • Between these tags is a single PHP print statement.


    Alternative php delimiters

    Alternative PHP Delimiters

    • You can alternatively start your PHP scripts with the <script> tag as follows:

      <script language="PHP">

      print ("A simple initial script");

      </script>

    • If haveshort_open_tagenabled in its configuration file, you can use <? and ?>.

    • If asp_tags is enabled in the PHP configuration file, you can use <% and %> as delimiters.


    On a linux apache web server

    On a Linux/Apache Web Server

    Typically you:

    • Save files with a .php suffix (myfile.php).

    • Place files under public_html (e.g., /home/dlash/public_html/

    Its worth noting:

    Some web hosts allow direct access to servers with SSH telnet. Others only allow you to use FTP to copy files over.


    Php proper syntax

    PHP Proper Syntax

    • Need to be syntactically correct.

    • For example, the print statement syntax:


    If use improper syntax

    If Use Improper Syntax

    • Suppose you use the wrong syntax:

      1. <?php2. print ( “A simple initial script);

      3. ?>


    A little about php s syntax

    A Little About PHP's Syntax

    • Some PHP Syntax Issues:

      • Be careful to use quotation marks, parentheses, and brackets in pairs.

      • Most PHP commands end with a semicolon (;).

      • Be careful of case.

      • PHP ignores blank spaces.


    Embedding php statements within html documents

    Embedding PHP Statements Within HTML Documents

    1.<html>

    2.<head>

    3.<title>HTML With PHP Embedded</title> </head>

    4.<body>

    5.<font size=5 color=”blue”>Welcome To My Page</font>

    6.<?php

    7. print ("<br> Using PHP is not hard<br>");

    8.?>

    9.and you can learn to use it quickly!

    10. </body></html>


    Using backslash to generate html tags with print

    Using Backslash (\) to Generate HTML Tags with print()

    • Sometimes you want to output an HTML tag that also requires double quotation marks.

      • Use the backslash (“\”) character to signal that the double quotation marks themselves should beoutput:print ("<font color=\"blue\">");

      • The above statement would output:

        <font color="blue">

    Note! . . . You could also output the above line using the following PHP line:

    print (‘<font color="blue">“’);

    We will examine the meaning between “ and ‘ later.


    Using comments with php scripts

    Using Comments with PHP Scripts

    • Comment Syntax - Use //

      <?php

      // This is a comment

      ?>

    • Can place on Same line as a statement:

      <?php

      print ("A simple initial script"); //Output a line

      ?>

    Note: Comment lines are ignored when the script runs. They do not slow down the run-time


    Alternative comment syntax

    Alternative Comment Syntax

    PHP allows a couple of additional ways to create comments.

    <?php

    phpinfo(); # This is a built-in function

    ?>

    • Multiple line comments.<?php

      /*

      A script that gets information about the

      PHP version being used.

      */

      <? phpinfo(); ?>


    More on phpinfo

    More on phpinfo()

    • Use a script with the following to find out about your PHP installation:

      • <? phpinfo(); ?>

    The php version

    This build does NOT have mysql!

    Location of PHP main config file

    Other interesting items:

    Apache version & configuration, php config variables, environment.


    More on phpinfo1

    More on phpinfo()

    Allow ASP style tages

    Manual strongly recommends setting to off

    Flag values indicates which errors to display/log


    Error definitions

    Error Definitions . . .


    Overriding php ini settings

    ‘Overriding’ php.ini settings

    <?php

    ini_set('error_reporting', 2047);

    phpinfo();

    ?>

    Global is ’85’ Local is 2047.


    Apache2triad provide config administrator

    Apache2triad provide config administrator

    Show errors in browser

    Include HTML errors

    Note: Has option at bottom to save configuration. Also must restart apache for changes to take effect.


    Setting your own configuration options

    Setting Your own Configuration Options

    <?php

    ini_set('error_reporting', E_ALL);

    $x = $y + 1;

    print " x=$x $y=$y"

    ?>


    How to read error reporting variable

    How to read ‘Error_reporting’ variable

    • How did ‘get’ error_reporting = 85 ?

      • Answer: php.ini has the following line:

    error_reporting = E_COMPILE_ERROR|E_PARSE|E_ERROR|E_CORE_ERROR

    1 + 4 + 16 + + 64 = 85.


    Even more phpinfo

    Even more phpinfo()

    Enable scripts to upload to server

    Defines where to look for includes. (This can be set dynamically in scripts.)

    Send errors to logfile

    Require input variables to use super-global array


    Visit www php net

    Visit www.php.net

    Quick function search

    Function manual


    Objectives2

    Objectives

    • To understand what PHP is

      • What is HTML

      • How PHP compares with CGI

    • Getting Started with PHP

      • Your first script

      • PHP syntax and embedding in HTML

      • Finding out about your PHP configuration

    • Using PHP variables

      • Numerical variables and operators

      • String variables, operators and a few functions

    • Separating PHP from HTML using <?=


    Php allows creating variables on the fly

    PHP allows creating variables on the fly

    • For example,

      <?php

      $days = 3;

      $newdays = 100;

      $days = $newdays;

      ?>

    • A PHP variable names must:

      • Use a dollar sign ($) as the first character

      • Use a letter or an underscore character (_) as the second character.


    Combining variables and the print statement

    Combining Variables and the print Statement

    • Use print statement with double quotes:

      $age=6;

      print ("Bryant is $age years old.");

      print (‘but george is $age years old.’);

    Double quotes output any variable’s value

    Single quotes output any variable’s name.

    Would output:

    Bryant is 6 years old but george is $age years old.


    Using arithmetic operators

    Using Arithmetic Operators

    • PHP supports various arithmetic operators.

    • For example

      <?php

      $apples = 12;

      $oranges = 14;

      $total_fruit = $apples + $oranges;

      print ("The total number of fruit is $total_fruit");

      ?>

    These PHP statements would output

    The total number of fruit is 26.


    Common php numeric operators

    Common PHP Numeric Operators


    Common php combined assignment operators

    Common PHP Combined Assignment Operators


    A full example

    A Full Example

    1. <html>

    2. <head> <title>Variable Example </title> </head>

    3. <body>

    4. <?php

    5. $columns = 20;

    6. $rows = 12;

    7. $total_seats = $rows * $columns;

    8.

    9. $ticket_cost = 3.75;

    10. $total_revenue = $total_seats * $ticket_cost;

    11.

    12. $building_cost = 300;

    13. $profit = $total_revenue - $building_cost;

    14.

    15. print ("Total Seats are $total_seats <br>");

    16. print ("Total Revenue is $total_revenue <br>");

    17. print ("Total Profit is $profit");

    18. ?> </body> </html>


    Warning using variables with undefined values

    WARNING: Using Variables with Undefined Values

    Use a variable without a value assigned will have no value (called a null value).

    PHP will NOT generate an error and will complete the expression.

    For example,

    <?php

    $y = 3;

    $y=$y + $x + 1; // $x has a null value

    print ("x=$x y=$y");

    ?>

    Will output

    x= y=4.


    Php precedence rules

    PHP Precedence Rules

    • PHP follows the precedence rules listed below.

      • First it evaluates operators within parentheses.

      • Next it evaluates multiplication and division

      • Finally it evaluates addition and subtraction

    • For example, the first 2 statements evaluate to 80 while the last to 180.

      • $x = 100 - 10 * 2;

      • $y = 100 - (10 * 2);

      • $z = (100 - 10) * 2;


    Objectives3

    Objectives

    • To understand what PHP is

      • What is HTML

      • How PHP compares with CGI

    • Getting Started with PHP

      • Your first script

      • PHP syntax and embedding in HTML

      • Finding out about your PHP configuration

    • Using PHP variables

      • Numerical variables and operators

      • String variables, operators and a few functions

    • Separating PHP from HTML using <?=


    Working with php string variables

    Working with PHP String Variables

    • Use character strings for data such as customer names, addresses, product names, and descriptions.

    • E.g.,

      • $name="Christopher";

      • $preference="Milk Shake";

    • Note: Technically it is more correct to write:

      • $name=‘Christopher’;

      • $preference=‘Milk Shake’;

      • Since there are no variable values to evaluate.


    Warning be careful not to mix variable types

    WARNING: Be Careful Not to Mix Variable Types

    • Be careful not to mix string and numeric variable types.

      <?php

      $x ="banana";

      $sum = 1 + $x;

      print ("y=$sum");

      ?>

    No error will occur instead will output:

    y=1


    Using the concatenate operator

    Using the Concatenate Operator

    • The concatenate operator combines two separate string variables into one.

    • For example,

      • $fullname = $firstname . $lastname;

    • $fullname will receive the string values of $firstname and $lastname connected together.

    • For example,

      $firstname = "John";

      $lastname = "Smith";

      $fullname = $firstname . $lastname;

      print ("Fullname=$fullname");


    Tip different ways to concatenate strings

    TIP: Different ways to concatenate strings.

    • A couple different ways to concatenate strings:

      • Concatenation operator

        • $Fullname2 = $FirstName . " " . $LastName;

    • Double quotes

      • $Fullname2 = "$FirstName $LastName";

  • Concatenation combination operator

    • $comment = ‘I love this job’;

    • $comment .= ‘but the hours and not that good’;

  • Mix and match:

    • $name = ‘George’;

    • $comment = “$name said: I love this job”;

    • $comment .= ‘but the hours and not that good’;


  • The strlen function

    The strlen() Function

    • Usually use one or more arguments with

      • Arguments are input values that functions

      • Often functions return a value

      • For example

    <?php

    $comments = "Good Job";

    $len = strlen($comments);

    print ("Length=$len");

    ?>

    Would output

    Length=8

    Note: Function output would be one reason to use the concatenate operator

    <?php

    $First = 'George';

    print "$First has " . strlen($First ) . ' characters';

    ?>

    Would output:

    George has 6 characters


    The trim function

    The trim() Function

    • Removes any blank characters from the beginning and end of a string.

    • For example, consider the following script:

      • <?php

      • $in_name = " Joe Jackson ";

      • $name = trim($in_name);

      • print ("name=$name$name");

      • ?>

    Would output

    Lname=“Joe JacksonJoe Jackson”


    The strtolower and strtoupper functions

    The strtolower() and strtoupper() Functions

    • These functions return the input string in all uppercase or all lowercase letters, respectively.

    • For example,

      <?php

      $inquote = "Now Is The Time";

      $lower = strtolower($inquote);

      $upper = strtoupper($inquote);

      print ("upper=$upper lower=$lower");

      ?>

    Would output

    “upper=NOW IS THE TIME lower=now is the time”.


    The substr function

    The substr() Function

    • Substr has the following general format:

    $part = substr( $name, 0, 5);

    Assign results into here

    Extract from here.

    Position to start extracting from.

    Number of characters to extract (If omitted will continue to end of string.)

    • For example:

    • <?php

    • $date = "12/25/2002";

    • $month = substr($date, 0, 2);

    • $day = substr($date, 3, 2);

    • print ("Month=$month Day=$day");

    • ?>

    Would output

    “Month=12 Day=25”.


    Objectives4

    Objectives

    • To understand what PHP is

      • What is HTML

      • How PHP compares with CGI

    • Getting Started with PHP

      • Your first script

      • PHP syntax and embedding in HTML

      • Finding out about your PHP configuration

    • Using PHP variables

      • Numerical variables and operators

      • String variables, operators and a few functions

    • Separating PHP from HTML using <?=


    Evaluation delimiters

    Evaluation delimiters

    1 <?php

    2

    3 $url = '<a href=http://mysite.com> mysite.com </a>';

    4 $store = '<font color=red> toy store </font>';

    5 $special = 'boxed block sets';

    6 ?>

    7 <html>

    8 <head> <title> this is a title </title> </head>

    9 <body> <font color=blue size=4>

    10 Welcome to the <?= $store ?>

    11 our special today is <i> <?= $special ?> </i>

    12 <br> Visit our home page at <?= $url ?>

    13 </font> </body> </html>

    Can separate PHP from HTML and use <?= delimiter. It automatically outputs any PHP variables found.


    Getting input data

    Getting input data

    • To receive data with REGISTER_GOBALS OFF you use a special variable called $_GET.

      • $mynm = $_GET[“name”];

    Enclose in square

    bracket and then quotes

    Name of HTML form CGI

    variable (note do not use $)

    Special PHP Global variable. Technically it is an associative array (covered in chptr 5.)

    PHP variable name that you want to receive the HTML form input.


    Sending input from url

    Sending Input From URL

    • You can send data to your application by:

      • http://www.indelible-learning.com/php/module1/input.php?special=Baseball Bats

    • If needed to send multiple input variables could:

      • http://www.indelible-learning.com/php/module1/input.php?special=Baseball Bats&myname=Dave

    Use & sign


    Objectives5

    Objectives

    • To understand what PHP is

      • What is HTML

      • How PHP compares with CGI

    • Getting Started with PHP

      • Your first script

      • PHP syntax and embedding in HTML

      • Finding out about your PHP configuration

    • Using PHP variables

      • Numerical variables and operators

      • String variables, operators and a few functions

    • Separating PHP from HTML using <?=


    Module 1 hands on assignment

    Module 1 Hands on Assignment

    • Create a php script that calculates the total possible revenue of a theater. Suppose that:

      • The theater charges $5 per seat

      • The theater has with 10 rows and 8 seats per row.

      • Output the total possible revenue.

      • Set the seat cost, rows and seats per row at top of script and separate PHP from HTML code.


    One possible solution

    One possible solution

    1 <?php

    2 $cost = 5; $rows = 10;

    3 $cols = 8; $total = $rows * $cols;

    4 $rev = $cost * $total;

    5 ?>

    6 <html>

    7 <head> <title> Theater Calculation </title> </head>

    8 <body> <font color=blue size=4>

    9 We have <?= $total ?> seats in the house

    10 <br>

    11 At a costs of $<?=$cost ?> our total possible revenue is

    12 <?= $rev ?>.

    13 </font> </body> </html>


    Lab 1 extension exercise

    Lab 1 Extension Exercise

    • Modify that same script to receive the values of $rows and $cols from the Web URL.

      • Send different input values from the web


    One possible solution1

    One Possible Solution

    <?php

    $cost = 5;

    $rows = $_GET[rows];

    $cols = $_GET[cols];

    $total = $rows * $cols;

    $rev = $cost * $total;

    ?>

    <html>

    <head> <title> Theater Calculation </title> </head>

    <body> <font color=blue size=4>

    We have <?= $total ?> seats in the house

    <br>

    At a costs of $<?=$cost ?> our total possible revenue is

    <?= $rev ?>.

    </font> </body> </html>


    Module 1 hands on assignment1

    Module 1 Hands on assignment

    • Write a simple script that outputs the configuration of PHP

    • What are compilation settings of our PHP

      • What version?

      • What apache version?

      • Other interesting settings?


    One possible solution2

    One possible solution

    <? phpinfo() ?>


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