ECA 236

Open Source Server Side Scripting

ECA 236

Open Source Server Side ScriptingIncludes and Dates

Open Source Server Side Scripting 2ECA 236

include( )include( )

include( )include( ‘file_name.inc’ )

PHP includes and evaluates the specified fileif include( ) fails, PHP generates a warninginherits variable scope of line from which it is calledmay contain DTD, HTML, JavaScript, PHP,

variables, other includesmay use any extension: .inc .php


include( ) cont … include( ) cont … header.inc

main document

<html><head><title><?php echo $page_title; ?></title></head><body><?php $name=’Michael’; ?>

<?php$page_title = “Include Test”;include( ‘header.inc’ );

?><p>Hello, <?php echo $name; ?></p></body></html>


require( )require( )

require( )require( ‘file_name.inc’ )

PHP includes and evaluates the specified fileif require( ) fails, PHP generates a fatal errorinherits variable scope of line from which it is calledmay contain DTD, HTML, JavaScript, PHP,

variables, other includesmay use any extension: .inc .php


include_once( )include_once( )

include_once( ‘file_name.inc’ );

similar behaviors to include( )if the file has already been included, it will not be

included againuse to avoid such problems as:

function redefinitionsvariable value reassignment


require_once( )require_once( )

require_once( ‘file_name.inc’ );

similar behaviors to require( )if the file has already been required, it will not be

required againuse to avoid such problems as:

function redefinitionsvariable value reassignment


HTTP HeadersHTTP Headers

header( )used to send raw HTTP headers

header( ) MUST be called before anything else is sent to the browser:

HTMLblank spaces or lines

common use for header( ) is to redirect the user to another URI using the Location header


HTTP Headers cont … HTTP Headers cont …

HTTP requires an absolute URI as an argument to Location

<?php

header( “Location: http://www.headerExample.com” );

?>



You can usually use $_SERVER['HTTP_HOST'], $_SERVER['PHP_SELF'], and dirname( ) to create an absolute URI out of a relative URI.

dirname( ) returns path of directory names

<?php

header( “Location: http://” . $_SERVER[ 'HTTP_HOST‘ ] . dirname( $_SERVER[ 'PHP_SELF‘ ] ) . “/” . $relative_url);

?>



Remember, header( ) must be called before any other output is sent.

The following will generate an error:

<html><?php

// This will give an error. Note the output// above, which is before the header( ) call

header('Location: http://www.example.com/');?>



headers_sent( )checks if headers have been sent

<?phpif( !headers_sent( ) ) {

header( “Location: http://www.headerExample.com” );

}?>


mail( )mail( )mail( ) takes three required parameters, plus additional

optional parametersto

email address of the recipientseparate multiple addresses with commas

subjectsubject line of the email

messagebody of the email


mail( ) cont … mail( ) cont … fourth optional parameter for additional headers

such as from, cc, etc

$to = “[email protected], [email protected]”; $subject = “Test email”; $message = “This is my email message.”; $from = [email protected];

mail( $to, $subject, $message, $from );


dates and timesdates and times

date( )takes two parameters

format stringtime stamp (optional)

returns current date and time in following format:

echo $today = date( “jS F Y” );

13th September 2003


date( )date( )

examples of format stringsj day of month without leading zerosS English ordinalsF month, textual, longY 4 digit year

for complete list of format strings see the PHP Manual ( php.net )


date( ) cont …date( ) cont …

string format can contain literals as well as format code

escape letters to print as literals rather than format code

echo $today = date( “m/d/Y” );

9/13/2003

echo $today = date( “jS F in the year Y” );

13th September 179 3001e 03epmSat, 13 Sep 2003 13:17:19 -0400 2003


date( ) cont …date( ) cont …

2nd parameter is a UNIX time stampnumber of seconds since UNIX Epoch ( midnight 1 Jan 1970 )32 bit integer 2^ 32

holds up to 2,147,483,647 secondswill face UNIX “Y2K” in 2038turned 1 billion on September 08, 2001

if no timestamp is provided, PHP uses current date and time


mktime( )mktime( )

mktime( )converts a date and time to UNIX time stamp

takes 6 arguments

common programming error is to mix up order of arguments, which differs from UNIX mktime( ) function

returns a value of 18001

mktime( hour, minute, second, month, day, year );

mktime( 0, 0, 1, 1, 1, 1970 );


mktime( ) cont …mktime( ) cont …

mktime( )arguments can be left out in order from right to leftleaving out an argument defaults to the timestamp for the

current date or time

negative timestamps are not supported under any version of Windows ( limiting the range from 1970 – 2038 )

$timestamp = mktime( ); // returns current date and time


mktime( ) cont …mktime( ) cont …

mktime( )it is possible to use date( ) and mktime( ) together to

find dates in the future or past

returns the day of the week of the future date, Monday

$ts = mktime( 0, 0, 0, 7, 1, 2005 );

echo "July 1, 2005 is on a " . date("l", $ts ) ;


getdate( )getdate( )

getdate( )takes a time stamp as an optional argument if no time stamp is provided, getdate( ) returns information

on current date and timereturns an associative array with keys and values


getdate( ) cont …getdate( ) cont …

Key Description Example returned values

"seconds" Numeric representation of seconds 0 to 59

"minutes" Numeric representation of minutes 0 to 59

"hours" Numeric representation of hours 0 to 23

"mday" Numeric day of the month 1 to 31

"wday" Numeric day of the week 0 (Sunday) through 6

"mon" Numeric representation of a month 1 through 12

"year" Full numeric representation of year Examples: 1999 or 2003

"yday" Numeric day of the year 0 through 356

"weekday" Full textual representation day Sunday through Saturday

"month" Full textual representation of month January through December

0 Seconds since the Unix Epoch System Dependent


getdate( ) cont …getdate( ) cont …

Array( [seconds] => 40 [minutes] => 58 [hours] => 21 [mday] => 17 [wday] => 2 [mon] => 6 [year] => 2003 [yday] => 167 [weekday] => Tuesday [month] => June [0] => 1055901520

)

$today = getdate( );print_r( $today );

// will print


checkdate( )checkdate( )checkdate( )

checks whether a date is validuseful for checking user inputtakes leap year into considerationworks for date before 1970takes three integer arguments

checkdate( month, day, year );

checkdate( 1, 24, 1956 ); // returns TRUE

checkdate( 2, 30, 2003 ); // returns FALSE


date and time calculationsdate and time calculations

one of the easiest ways to compare dates and times is to compare their time stamps

to calculate the difference between two dates, subtract their timestamps

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ECA 236