Serverside Webscripting [JLW322]

01.php.intro

PHP Introduction

PHP

Short for PHP: Hypertext Preprocessor
Scripting language
- Loose syntax
- Not compiled for distribution (cfr. Java), but interpreted at runtime
  - Therefore it's slower than compiled languages
Very popular on the internet
- One of the first Serverside Scripting Languages (° 1995)
- PHP plugins exist for nearly all web servers and OSes
- e.g. Wordpress, Facebook, Wikipedia, etc.
Suffers from historical cruft & syntax inconsistencies

PHP Versions

Current versions:
- 5.4.33 (*)
- 5.5.16
- 5.6.0 (new since August!)
Our code is PHP 5.4+ compliant

Obtaining PHP: Combined

A preconfigured PHP is included in Wampserver / MAMP
- Install one of these for this course
- Follow these instructions afer installation
- Be sure to add the PHP binary to your system's PATH
  - Windows: Add C:\wamp\bin\php\version\ to PATH via Computer Settings
  - OS X: Paste this on the Terminal: echo 'export PATH=/Applications/MAMP/bin/php/phpversion/bin/:$PATH' >> ~/.bash_profile
Shipped with most Unix/Linux distributions

Obtaining PHP: Manual

PHP can be downloaded from http://php.net.
- Just extract the .zip onto your filesystem and you're good to go
- Windows users must download from http://windows.php.net/
- OS X users obtain prebuilt binaries using PHP Homebrew formulae or from Liip AG

Configuring PHP

PHP can be configured via a file named php.ini
We'll take a closer look at this file when it's needed
Note: the php.ini shipped with Wampserver/MAMP is configured mostly correctly

Running PHP (1)

From the shell
- Run php -a to get an interative shell at which you can type in PHP statements
  - cfr. the MySQL shell where you type in SQL statements (queries)
  - A ; ends a statement
  - Type quit or exit to leave the shell
```
bramus$ php -a
Interactive shell

php > echo 'hello';
hello
php > quit
bramus$
```

Running PHP (2)

From the shell (continued)
- Run php -r "one line of PHP code" to run a single line of PHP code
```
bramus$ php -r "echo 'hello' . PHP_EOL;"
hello
bramus$
```
- Run php [-f] file.php to “execute” a file that contains PHP code
  - You must wrap your PHP code between <?php and ?>
  - The closing ?> is optional.
```
<?php
	echo 'hello' . PHP_EOL;
?>
```
```
bramus$ php cli-example.php
hello
bramus$
```

Running PHP (3)

In a web context
- Give your file a .php extension and the PHP interpreter will interpret the file
  - The webserver must of course be configured to do so
- PHP 5.4+ ships with a built-in webserver which can be started from anywhere
```
php -S localhost:8080
```
  - All PHP files in that folder will be served

PHP Variables

Before we dive in

Strings are enclosed by ' or "

Use echo or print to output something onscreen.

bramus$ php -a
Interactive shell

php > echo 'hello';
hello
php > echo('hello');
hello
php > print 'hello';
hello
php > print('hello');
hello

The first example is the preferred syntax

Statements end in a ;
```
php > echo 'hello'
php > ;
hello
```

Name, Value & Type

Variables have a name and a value
- Variable names start with a $
```
php > $a = 3;
php > echo $a;
3
```
Variables are of a certain type
- Primitive types: boolean, integer, float (aka double), string
- Combined types: Array, Object
- Special types: resource, NULL
- Pseudo types: mixed, number, callback

Dynamic & Weak typing

PHP is dynamically typed
- When declaring a variable, you cannot specify the type. PHP will guess the data type when assigning a value
PHP is weakly typed
- PHP will adjust the type of a var when a new value is assigned
  - This phenomenon is known as implicit type conversion or coercion

php > $a = 3;
php > echo gettype($a);
integer
php > $a = 'Hello';
php > echo gettype($a);
string

Type casting

To enforce a variable being of a certain type, you must explicitly cast it to that type

php > $a = 3;
php > echo gettype($a);
integer
php > $a = (string) $a;
php > echo gettype($a);
string

A few pointers

PHP is case sensitive

$firstName and $firstname are not the same!

php > $firstName = 'Bramus';
php > echo $firstName;
Bramus
php > echo $firstname;

Notice: Undefined variable: firstname in php shell code on line 1

To concatenate strings, you must use a .

When using a +, PHP will think you're adding numbers (weak typing!)

php > $firstName = 'Bramus';
php > $lastName = 'Van Damme';
php > echo $firstName + ' ' + $lastName;
0
php > echo $firstName . ' ' . $lastName;
Bramus Van Damme

Interpolation

Also known as Variable Substitution

When enclosed between ", PHP will try to substitute any string that could resemble a variable

php > $firstName = 'Bramus';
php > echo "variable: $firstName\n";
variable: Bramus
php > echo "variable: \$firstName\n";
variable: $firstName
php > echo 'variable: $firstName\n';
variable: $firstName\n
php > echo 'variable: \$firstName\n';
variable: \$firstName\n
php > echo 'variable: ' . $firstName . '\n';
variable: Bramus\n
php > echo 'variable: ' . $firstName . "\n";
variable: Bramus
php > echo 'variable: ' . $firstName . PHP_EOL;
variable: Bramus

Course convention: always use ' to prevent interpolation
Course convention: always use PHP_EOL instead of "\n"

Arrays (1)

php > $arr = array();
php > $arr[] = 'se7en';
php > $arr[] = 123;
php > $arr[] = true;
php > echo $arr[1];
123

Declaration rule isn't mandatory but attests a good coding style
Mixing of types forms no problem
Automatic indexing
Index is numeric and sequential. We call this type of array a sequential array

Arrays (2)

It's possible to set the start index

php > $arr = array();
php > $arr[2] = 'se7en';
php > $arr[] = 123;
php > $arr[] = true;
php > echo $arr[3];
123

Arrays (3)

It's possible to set the indices/keys yourself

php > $arr = array();
php > $arr[2] = 'se7en';
php > $arr[8] = 123;
php > $arr[4] = true;
php > echo $arr[8];
123

Indices/keys can be strings too

php > $arr = array();
php > $arr['BE'] = 'Belgium';
php > $arr['NL'] = 'The Netherlands';
php > $arr['FR'] = 'France';
php > echo $arr['BE'];
Belgium

We call these associative arrays

Arrays (4)

It's possible to declare and initialize an array in one go

php > $arr1 = array('Brussels', 'Ghent', 'Antwerp');

php > $arr2 = array('NL' => 'The Netherlands', 'BE' => 'Belgium');

php > $arr2 = array(
php ( 'NL' => 'The Netherlands',
php ( 'BE' => 'Belgium'
php ( );

Since PHP 5.4 this is also possible

php > $arr1 = ['Brussels', 'Ghent', 'Antwerp'];

Code Comments

Same as in Java

// Single line comment

/* Multi
line
comment
*/

/**
 * Preferred way
 * to layout
 * multi-line
 * comments
 */

Selections, Iterations & Operators

Selections (1)

Same as in Java

<?php

	if ($condition) {
		// do something
	}

	if ($condition) {
		// do something
	} else {
		// do something else
	}

	switch ($var) {

		case $value1:
			// do something
			break;

		case $value2:
			// do something
			break;

		default:
			// do something

	}

Selections (2)

Example
```
<?php

	$a = 7;
	if ($a < 9) {
		echo '$a is less than 9';
	} else {
		echo '$a is greater than 9';
	}
```
- Course convention: always place curly brackets
- Course convention: place the curly brackets on the same line
- Course convention: indent one TAB inside curly brackets

Selections (3)

When possible, use the ternary operator

<?php

	$a = 7;
	echo (($a < 9) ? '$a is less than 9' : '$a is greater than 9');

Since PHP 5.3, the ternary operator has gotten smarter:
```
<?php

	echo $nickName ?: $firstName;
```
- If $nickName is truthy then it will be outputted. If not $firstName will.

Iterations (1)

Again, same as in Java

<?php

	while ($condition) {
		// do something
	}

	do {
		// do something
	} while ($condition);

	for ($x = 0; $x < 5; $x++) {
		// do something
	}

	foreach ($arr as $value) {
		// do something
	}

	foreach ($arr as $key => $value) {
		// do something
	}

Also possible to use break; and continue;

Iterations (2)

Example

php > for ($x = 1; $x <= 6; $x++) {
php { echo 'Hello 2ICT' . $x . PHP_EOL;
php { }
Hello 2ICT1
Hello 2ICT2
Hello 2ICT3
Hello 2ICT4
Hello 2ICT5
Hello 2ICT6

Example

php > $countries = array('BE' => 'Belgium', 'NL' => 'The Netherlands');
php > foreach ($countries as $key => $value) {
php { echo $key . ' = ' . $value . PHP_EOL;
php { }
BE = Belgium
NL = The Netherlands

Operators

Same as in Java
- Relational operators: ==, !=, <, >, <=, >=
- Logical operators: &&, ||, !, &, |
- Post/pre- in/de-crement: $var--, $var++, --$var, ++$var
- Math shorthands: +=, *=, …

Since PHP4 support for identical operators: check for both type and value to be equal

php > $a = 13; // integer
php > $b = 13.0; // double
php > echo ($a == $b) ? 'equal' : 'not equal';
equal
php > echo ($a === $b) ? 'equal' : 'not equal';
not equal

PHP Functions

Built-in Functions (1)

PHP has a lot of functions built-in
A few string-related functions
- addslashes/stripslashes — see 04.forms
- ltrim/rtrim/trim — strips leading/trailing/enclosing whitespace
- str_replace — replaces a part of a string with an other value
- strip_tags — strips html from a string
- strlen — returns the length of a string
- strtolower/strtoupper — convert a string to uppercase/lowercase
- substr — extract a part of a string
- ...

How to use: see http://php.net/nameofthefunction

Built-in Functions (2)

A few math-related functions
- ceil — round numerical values up
- floor — round numerical values down
- round — round numerical values mathematically
- rand/mt_rand — generate a random number
- sqrt — calculate the square root of a number
- ...

Built-in Functions (3)

A few array-related functions
- sizeof/count — get the size of an array
- sort — sort an array
- asort — sort an associative array
- explode — split a string on a given delimiter and get an array
- implode — opposite of explode
- array_push — push an element onto an array
- array_pop — get an element off the end of an array
- array_key_exists — check if a key in an associative array exists
- ...

Custom functions (1)

Same as in Java

<?php

	// Our chopStringEnd function
	function chopStringEnd($str, $len, $ending) {
		if (strlen($str) < $len) {
			return $str;
		} else {
			return substr($str, 0, $len - strlen($str)) . $ending;
		}
	}

	// Our variables
	$origStr = '/Users/bramus/Dropbox/Kaho/Lesactiviteiten/Webscripting1';
	$cutoffLength = 40;
	$endStr	= '...';

	// Go!
	echo chopStringEnd($origStr, $cutoffLength, $endStr);

Custom functions (2)

Possible to define default values for function arguments

<?php

	// Our chopStringEnd function
	function chopStringEnd($str, $len = 30, $ending = '---') {
		if (strlen($str) < $len) {
			return $str;
		} else {
			return substr($str, 0, $len - strlen($str)) . $ending;
		}
	}

	// Our variables
	$origStr = '/Users/bramus/Dropbox/Kaho/Lesactiviteiten/Webscripting1';
	$cutoffLength = 40;
	$endStr = '...';

	// Go!
	echo chopStringEnd($origStr, $cutoffLength, $endStr) . PHP_EOL;
	echo chopStringEnd($origStr, $cutoffLength) . PHP_EOL;
	echo chopStringEnd($origStr);

Custom functions (3)

Provide PHPDoc-style comments

<?php

	/**
	 * Chops a string at the given length with the given ending
	 *
	 * @param	string 	$str 	The initial String
	 * @param	int 	$len 	The length to chop off at
	 * @param	string 	$ending	The ending to add
	 *
	 * @return	string 	The circumcised up string
	 */
	function chopStringEnd($str, $len = 30, $ending = '---') {
		if (strlen($str) < $len) {
			return $str;
		} else {
			return substr($str, 0, $len - strlen($str)) . $ending;
		}
	}

	...

Scoping

Problem

This won't work

<?php

	$host = 'http://www.myhost.com/';

	function absUrl($relUrl) {
		return $host.$relUrl;
	}

	echo absUrl('files/uploads/me.jpg');

Result

Notice: Undefined variable: host in /Users/bramus/Dropbox/Kaho/Lesactiviteiten/.../assets/01/examples/scoping1.php on line 8
files/uploads/me.jpg

How we would've fixed this in 1995

The global keyword to the rescue

<?php

	$host = 'http://www.myhost.com/';

	function absUrl($relUrl) {
		global $host;
		return $host . $relUrl;
	}

	echo absUrl('files/uploads/me.jpg');

Don't ever do this; it's a bad programming style!

How we would've fixed this in 1998

Extra function argument

<?php

	$host = 'http://www.myhost.com/';

	function absUrl($relUrl, $host) {
		return $host . $relUrl;
	}

	echo absUrl('files/uploads/me.jpg', $host);

Extra function argument, revised

<?php

	function absUrl($relUrl, $host = 'http://www.myhost.com/') {
		return $host . $relUrl;
	}

	echo absUrl('files/uploads/me.jpg');

How to properly fix it (since 2000)

Use define(), a function that shipped with PHP4

<?php

	define('HOST', 'http://www.myhost.com/');

	function absUrl($relUrl) {
		return HOST . $relUrl;
	}

	echo absUrl('files/uploads/me.jpg');

Course convention: always use define() to define global constants, never use the global keyword

How we can fix this since 2009

Since PHP 5.3 it's possible to use the use keyword to inject a variable into a function

<?php

	$host = 'http://www.myhost.com/';

	$absUrl = function ($relUrl) use ($host) {
		return $host . $relUrl;
	};

	echo $absUrl('files/uploads/me.jpg');

This syntax is mostly used when working with callback functions. We'll stick to using define() for now.

Errors and debugging

Before we dive in

When developing, make sure errors are shown on screen

Put this at the very top of your code:

<?php

	error_reporting(E_ALL); // = Report all errors
	ini_set('display_errors', 'on'); // = Show the errors on screen

These settings can also be set in the php.ini file

Suppress errors with `@`

It's possible, but it's not recommended as the script will continue execution

<?php

	function divide($numerator, $denominator) {
		return $numerator / $denominator;
	}

	echo divide(1, 2) . PHP_EOL;	// 0.5
	echo divide(1, 0) . PHP_EOL;	// "Warning: Division by zero"
	echo @divide(1, 0) . PHP_EOL;	// (suppressed)
	echo divide(1, 2) . PHP_EOL;	// 0.5

Later on, we'll learn how to work with Exception

Debugging helper functions

This won't work

php > $arr = array('one', 'two', 'three');
php > echo $arr;
Array

Use print_r() and var_dump() instead to inspect variables

php > print_r($arr);
Array
(
    [0] => one
    [1] => two
    [2] => three
)
php > var_dump($arr);
array(3) {
  [0]=>
  string(3) "one"
  [1]=>
  string(3) "two"
  [2]=>
  string(5) "three"
}

Real debugging

Using print_r() and var_dump() is no real debugging
Real debugging is possible with
- Built-in IDE debugger
  (eg. Zend Studio/PHPStorm have one, Aptana had one)
- External debugger, linked to IDE
  (eg. XDebug + Aptana/PHPStorm/Netbeans)

Dates in PHP

Timestamps

Epoch time
- Numerical value: number of seconds since the epoch
  - epoch = Midnight January 1st, 1970 (GMT)
  - Not counting leap seconds
- Also known as Unix time or Posix time
- Dates expressed in Unix time are called timestamps
Allow one to precisely indicate a given point in time
- 0 = January 1 1970, 00:00:00 GMT
- 86400 = Januari 2 1970, 00:00:00 GMT
- 31536000 = Januari 1 1971, 00:00:00 GMT
- 440423100 = December 26 1983, 11:45:00 GMT
- 946684800 = Januari 1 2000, 00:00:00 GMT
- 1234567890 = February 13 2009, 23:31:30 GMT
- …

Dates and PHP

Timestampfunctions in PHP
- time() returns the number of seconds since the epoch
- mktime() allows you to build a timestamp for a given hour, minute, second, month, day and year
Converting between dates and timestamps
- strtotime(string $time, [int $now])
  - Convert a given date to a timestamp
  - $time is something like 2012-24-09 but can also be next friday
  - Second (optional) param used to calculate an offset
- date(string $format, [int $timestamp])
  - Convert a given timestamp to a date
  - If $timestamp is empty, the current one is used

Date Format

The $format param needs to be built manually

`format` character	Description	Example returned values
d	Day of the month, 2 digits with leading zeros	01 to 31
D	A textual representation of a day, three letters	Mon through Sun
l (lowercase 'L')	A full textual representation of the day of the week	Sunday through Saturday
w	Numeric representation of the day of the week	0 (for Sunday) through 6 (for Saturday)
F	A full textual representation of a month, such as January or March	January through December
m	Numeric representation of a month, with leading zeros	01 through 12
M	A short textual representation of a month, three letters	Jan through Dec
Y	A full numeric representation of a year, 4 digits	Examples: 1999 or 2003
y	A two digit representation of a year	Examples: 99 or 03
H	24-hour format of an hour with leading zeros	00 through 23
i	Minutes with leading zeros	00 to 59
s	Seconds, with leading zeros	00 through 59

Date Examples

Example 1

<?php
	echo date('l');
	echo date('l jS \of F Y h:i:s A');
	echo 'July 1, 2000 is on a ' . date('l', mktime(0, 0, 0, 7, 1, 2000));

Example 2

<?php
	// Assuming today is March 10th, 2001, 5:16:18 pm, and that we are in the
	// Mountain Standard Time (MST) Time Zone
	$today = mktime(17,16,18,3,10,2001);
	date_default_timezone_set('America/Phoenix');

	echo date('F j, Y, g:i a'); // March 10, 2001, 5:16 pm
	echo date('m.d.y'); // 03.10.01
	echo date('j, n, Y'); // 10, 3, 2001
	echo date('Ymd'); // 20010310
	echo date('h-i-s, j-m-y, it is'); // 05-16-18, 10-03-01, 1631 1618
	echo date('\i\t \i\s \t\h\e jS \d\a\y.'); // it is the 10th day.
	echo date('D M j G:i:s T Y'); // Sat Mar 10 17:16:18 MST 2001
	echo date('H:m:s \m \i\s\ \m\o\n\t\h'); // 17:03:18 m is month
	echo date('H:i:s'); // 17:16:18

Dates sidenote

Later on this course we'll see how to use PHP's DateTime and DateTimeZone classes.

CLI input/output

CLI Arguments

The CLI allows arguments being passed in

PHP automatically populates two vars: $argc and $argv

<?php
	echo 'Number of arguments ' . $argc . PHP_EOL;
	foreach ($argv as $key => $value) {
		echo 'Argument #' . $key . ' : ' . $value . PHP_EOL;
	}

bramus$ php cli-args1.php foo bar baz
Number of arguments 4
Argument #0 : args1.php
Argument #1 : foo
Argument #2 : bar
Argument #3 : baz

Beware: $argc and $argv only available in CLI mode!

Named CLI Arguments (1)

You can also use named arguments if you want, but it gets a bit tricky

Version 1

<?php
	$args = getopt('ab:c::');
	# nothing = don't accept any value (why? WHYYYY?)
	# trailing : = required
	# trailing :: = optional
	var_dump($args);

bramus$ php cli-args2.php -a -b 2 -c3
array(3) {
  ["a"]=>
  bool(false)
  ["b"]=>
  string(1) "2"
  ["c"]=>
  string(1) "3"
}

Named CLI Arguments (2)

Version 2

<?php
	$args = getopt('', array('a', 'b:', 'c::'));
	# nothing = don't accept any value (why? WHYYYY?)
	# trailing : = required
	# trailing :: = optional
	var_dump($args);

bramus$ php cli-args3.php --a --b "2" --c=3
array(3) {
  ["a"]=>
  bool(false)
  ["b"]=>
  string(1) "2"
  ["c"]=>
  string(1) "3"
}

Interactive scripts

Use readline() to ask for input whilst the script is runnning

<?php
	$name = readline('What is your name? ');
	$city = readline('Where do you live? ');
	echo 'Hello ' . $name . ' from ' . $city . PHP_EOL;

bramus$ php cli-interactive.php
What is your name? Bramus
Where do you live? Vinkt
Hello Bramus from Vinkt

STDIN/STDOUT/STDERR (1)

PHP (in CLI mode) automatically opens some io streams

STDIN = input

<?php
	while(!feof(STDIN)) {
		$line = trim(fgets(STDIN));
		if(strlen($line) > 0) {
			echo strrev($line).PHP_EOL;
		}
	}

bramus$ cat cli-stdin-input.txt
monkey
elephant
cow
giraffe

bramus$ cat cli-stdin-input.txt | php cli-stdin.php
yeknom
tnahpele
woc
effarig

STDIN/STDOUT/STDERR (2)

STDOUT/STDERR = output

bramus$ php -r "fwrite(STDOUT, 'hello world');"
hello world

bramus$ php -r "fwrite(STDERR, 'hello world');"
hello world

Difference between STDOUT and STDERR?

bramus$ php -r "fwrite(STDOUT, 'stdout world') . fwrite(STDERR, 'stderr world');" > /dev/null
stderr world

Interactive scripts, Revisited

Unfortunately readline() isn't available everywhere
- On Unix PHP needs to be compiled with it enabled
- On Windows it's not available at all

Fortunately we can knock up an alternative for that platform, using STDIN

function getInput($question = '') {
	if (!function_exists('readline')) {
		echo $question . ' ';
		return stream_get_line(STDIN, 1024, PHP_EOL);
	} else {
		return readline($question . ' ');
	}
}

$name = getInput('What is your name?');
$city = getInput('Where do you live?');
echo 'Hello ' . $name . ' from ' . $city . PHP_EOL;

More CLI goodness

Check a file syntax

Check a file for syntax errors with php -l faulty.php

<?php
	echo $foo;
	for ($x = 0; $x < 5; x++) {
		echo $x;
	}

PHP will tell you what went wrong and where

bramus$ php -l faulty.php

Parse error: parse error, expecting `')'' in faulty.php on line 4
Errors parsing faulty.php

Handy if you link this to a precommit hook in Git to prevent you from committing faulty code

Check your PHP config

Check your PHP config by running php -i

bramus$ php -i
phpinfo()
PHP Version => 5.4.24

System => Darwin brm.local 13.3.0 Darwin Kernel Version 13.3.0: Tue Jun  3 21:27:35 PDT 2014; root:xnu-2422.110.17~1/RELEASE_X86_64 x86_64
Build Date => Jan 19 2014 21:18:21
Configure Command =>  '/private/var/tmp/apache_mod_php/apache_mod_php-87.2~1/php/configure'  '--prefix=/usr' '--mandir=/usr/share/man' '--infodir=/usr/share/info'...

If you don't have access to the shell of the machine, upload a file with these contents to it and load it via the browser
```
<?php
	phpinfo();
```

Other command options

Know your PHP version by running php -v

bramus$ php -v
PHP 5.4.24 (cli) (built: Jan 19 2014 21:32:15)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2013 Zend Technologies

Convert a PHP file to a syntax highlighted HTML file with php -s file.php

Closing note: course conventions

Course conventions (1)

Code in English
Use the full PHP open tag <?php. The closing tag may be omitted
Develop with error_reporting() set to E_ALL and display_errors set to On
Develop without the XDebug extension (for now)
Correctly indent code
- Within if-else,do-while,for/foreach, switch,...
- Indent with a TAB, not a few spaces
Comment your code properly
- Think of the code checking your code afterwards
- Use PHPDoc-compliant comments

Course conventions (2)

Never use global but preferably use a constant/define
Use single quotes to delimit strings
Give variables and functions a clear name and use camelCasing
- e.g. $numArticles, $firstName, calculateDistance(), etc.
- Exception: counters in loops such as $x, $y
Curly braces always go on the same line as the keyword
Use identical operators when comparing variables/values with booleans or null
When necessary cast variables to prevent stupid errors
Never use $_REQUEST (see 04.forms)
When in doubt: check the domestic conventions or ask your lecturer

Questions?

Sources

PHP CLI, the other SAPI by Thijs Feryn

ikdoeict.be

Serverside Webscripting [JLW322]

01.php.intro

PHP Introduction

PHP

PHP Versions

Obtaining PHP: Combined

Obtaining PHP: Manual

Configuring PHP

Running PHP (1)

Running PHP (2)

Running PHP (3)

PHP Variables

Before we dive in

Name, Value & Type

Dynamic & Weak typing

Type casting

A few pointers

Interpolation

Arrays (1)

Arrays (2)

Arrays (3)

Arrays (4)

Code Comments

Code Comments

Selections, Iterations & Operators

Selections (1)

Selections (2)

Selections (3)

Iterations (1)

Iterations (2)

Operators

PHP Functions

Built-in Functions (1)

Built-in Functions (2)

Built-in Functions (3)

Custom functions (1)

Custom functions (2)

Custom functions (3)

Scoping

Problem

How we would've fixed this in 1995

How we would've fixed this in 1998

How to properly fix it (since 2000)

How we can fix this since 2009

Errors and debugging

Before we dive in

Suppress errors with @

Debugging helper functions

Real debugging

Dates in PHP

Timestamps

Dates and PHP

Date Format

Date Examples

Dates sidenote

CLI input/output

CLI Arguments

Named CLI Arguments (1)

Named CLI Arguments (2)

Interactive scripts

STDIN/STDOUT/STDERR (1)

STDIN/STDOUT/STDERR (2)

Interactive scripts, Revisited

More CLI goodness

Check a file syntax

Check your PHP config

Other command options

Closing note: course conventions

Course conventions (1)

Course conventions (2)

Questions?

Sources

Suppress errors with `@`