PHP in 2018

Code as Craft

Etsy, Brooklyn

Nov.13, 2018

http://talks.php.net/etsy18

Rasmus Lerdorf
@rasmus

1980s

1990s

1993

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

#define ishex(x) (((x) >= '0' && (x) <= '9') || ((x) >= 'a' && \
                   (x) <= 'f') || ((x) >= 'A' && (x) <= 'F'))

int htoi(char *s) {
	int     value;
	char    c;

	c = s[0];
	if(isupper(c)) c = tolower(c);
	value=(c >= '0' && c <= '9' ? c - '0' : c - 'a' + 10) * 16;

	c = s[1];
	if(isupper(c)) c = tolower(c);
	value += c >= '0' && c <= '9' ? c - '0' : c - 'a' + 10;

	return(value);
}

void main(int argc, char *argv[]) {
	char *params, *data, *dest, *s, *tmp;
	char *name, *age;

	puts("Content-type: text/html\r\n");
	puts("<HTML><HEAD><TITLE>Form Example</TITLE></HEAD>");
	puts("<BODY><H1>My Example Form</H1>");
	puts("<FORM action=\"form.cgi\" method=\"GET\">");
	puts("Name: <INPUT type=\"text\" name=\"name\">");
	puts("Age: <INPUT type=\"text\" name=\"age\">");
	puts("<BR><INPUT type=\"submit\">");
	puts("</FORM>");

	data = getenv("QUERY_STRING");
	if(data && *data) {
		params = data; dest = data;
    	while(*data) {
			if(*data=='+') *dest=' ';
			else if(*data == '%' && ishex(*(data+1))&&ishex(*(data+2))) {
				*dest = (char) htoi(data + 1);
				data+=2;
			} else *dest = *data;
			data++;
			dest++;
		}
		*dest = '\0';
		s = strtok(params,"&");
		do {
			tmp = strchr(s,'=');
			if(tmp) {
				*tmp = '\0';
				if(!strcmp(s,"name")) name = tmp+1;
				else if(!strcmp(s,"age")) age = tmp+1;
			}
		} while(s=strtok(NULL,"&"));

		printf("Hi %s, you are %s years old\n",name,age);
	}
	puts("</BODY></HTML>");
}

1993

use CGI qw(:standard);
print header;
print start_html('Form Example'),
    h1('My Example Form'),
    start_form,
    "Name: ", textfield('name'),
    p,
    "Age: ", textfield('age'),
    p,
    submit,
    end_form;
if(param()) {
    print "Hi ",em(param('name')),
        "You are ",em(param('age')),
        " years old";
}
print end_html;

1994-1995

<html><head><title>Form Example</title></head>
<body><h1>My Example Form</h1>
<form action="form.phtml" method="POST">
Name: <input type="text" name="name">
Age: <input type="text" name="age">
<br><input type="submit">
</form>
<?if($name):?>
Hi <?echo $name?>, you are <?echo $age?> years old
<?endif?>
</body></html>

Focus on the Ecosystem

LAMP wasn't an accident
Robustness, Performance and Security
♥ shared hosting ISPs

Scale

Scaling up is expected
Scaling down is surprisingly hard
Doing both is rocket science

PHP 7.2

Initial DCE and SCCP optimizations

Parameter Type Widening

class Orig {
  public function fn(array $arg) {  }
}
class Wider extends Orig {
  public function fn($arg) { }
}

In PHP 7.1 you would get:

Warning: Declaration of Wider::fn($arg) should be 
         compatible with Orig::fn(array $arg)

Allow trailing commas everywhere

// Arrays (already possible)
$array = [1, 2, 3,];

// Grouped namepaces
use Foo\Bar\{ Foo, Bar, Baz, };
 
// Function/method arguments (call)
fooCall($arg1, $arg2, $arg3,);

use Foo\Bar\{ Foo, Bar, Baz, };

class Foo implements
    // Interface implementations on a class
    FooInterface,
    BarInterface,
    BazInterface,
{
    // Trait implementations on a class
    use
        FooTrait,
        BarTrait,
        BazTrait,
    ;
 
    // Class member lists
    const
        A = 1010,
        B = 1021,
        C = 1032,
        D = 1043,
    ;

Object typehint

function fn(object $obj): object {
	return json_decode('{}');
}
fn("not an object");

Warning: Uncaught TypeError: Argument 1 passed to fn() must be an object,
         string given, called in php shell code on line 1 and defined in ...

Deprecate unquoted strings

echo HELLO;

Warning: Use of undefined constant HELLO - assumed 'HELLO' (this will throw
         an Error in a future version of PHP) in php shell code on line 1

extra headers array arg for mail() and mb_send_mail()

$to      = 'nobody@example.com';
$subject = 'the subject';
$message = 'hello';
$headers = ['From'     => 'webmaster@example.com',
            'Reply-To' => 'webmaster@example.com',
            'X-Mailer' => 'PHP/' . phpversion() ];

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

Argon2i added to password_hash()

$options = [
    'memory_cost' => 2048,
    'time_cost' => 10,
    'threads' => 2
];
echo password_hash("rasmuslerdorf", PASSWORD_ARGON2I, $options);

$argon2i$v=19$m=2048,t=10,p=2$akUuWkoxRDlMSi5TVGhYLg$j0D1Cl4aR8UMHOGGx5JtZ1BmCApr8RmOJA9qFWm5mz8

Add Sodium Crypto Library

// On Alice's computer:
$msg = 'This comes from Alice.';
$signed_msg = sodium_crypto_sign($msg, $secret_sign_key);

// On Bob's computer:
$original_msg = sodium_crypto_sign_open($signed_msg, $alice_sign_publickey);
if ($original_msg === false) {
    throw new Exception("Invalid signature");
} else {
    echo $original_msg; // Displays "This comes from Alice."
}

see: https://paragonie.com/book/pecl-libsodium

Things that may break your code

mcrypt extension has been removed
__autoload() deprecated, use spl_autoload_register()
create_function() deprecated, use anonymous functions
each() deprecated, use foreach()
read_exif_data() deprecated, use exif_read_data()

Full details are at:

https://github.com/php/php-src/blob/PHP-7.2/UPGRADING

And for extension authors:

https://github.com/php/php-src/blob/PHP-7.2/UPGRADING.INTERNALS

PHP 7.3

Flexible Heredoc

class foo {
    public $bar = <<<EOT
    bar
    EOT;
}

Continue in Switch

while ($foo) {
    switch ($bar) {
        case "baz":
            continue;
    }
}

Warning: "continue" targeting switch is equivalent to "break".
         Did you mean to use "continue 2"?

List References

$array = [1, 2];
list($a, &$b) = $array;
// or
[$a, &$b] = $array;

Trailing comma allowed in function calls

$newArray = array_merge(
    $arrayOne,
    $arrayTwo,
    ['foo', 'bar'],
);

# Parse error
function bar($a, $b,) { }

# Parse error
foo(,);

# Parse error
foo('function', 'bar',,);

# Also parse error
foo(, 'function', 'bar');

New Monotonic Timer function

php > print_r(hrtime());
Array
(
    [0] => 2320165    // seconds
    [1] => 979969517  // nanoseconds
)
php > print_r(hrtime(true));
2320183081647424

New fpm_get_status() function

print_r(fpm_get_status());
Array (
    [pool] => www
    [process-manager] => static
    [start-time] => 1536934549
    [start-since] => 26
    [accepted-conn] => 20039
    [listen-queue] => 0
    [max-listen-queue] => 0
    [listen-queue-len] => 0
    [idle-processes] => 0
    [active-processes] => 47
    [total-processes] => 47
    [max-active-processes] => 514
    [max-children-reached] => 0
    [slow-requests] => 0
    [procs] => Array (
            [0] => Array (
                    [pid] => 10819
                    [state] => Running
                    [start-time] => 1536934549
                    [start-since] => 26
                    [requests] => 2001
                    [request-duration] => 8108
                    [request-method] => GET
                    [request-uri] => /index.php
                    [query-string] => p=1
                    [request-length] => 0
                    [user] => -
                    [script] => /var/www/wordpress/index.php
                    [last-request-cpu] => 0
                    [last-request-memory] => 0
                )
            ...

is_countable()

if (is_array($foo) || $foo instanceof Countable) {
    // $foo is countable
}

if (is_countable($foo)) {
    // $foo is countable
}

array_key_first()/array_key_last()

$a = ['abc'=>'First', 'def'=>'Second', 'ghi'=>'Third'];
echo array_key_first($a);
// abc
echo array_key_last($a);
// ghi

More DCE and SCCP optimizations

Other changes

Upgraded from PCRE to PCRE2
getallheaders() now available in php-fpm
full case-mapping for mbstring
preg_quote() now also escapes '#'
new gmp functions: gmp_binomial, gmp_lcm, gmp_perfect_power, gmp_kronecker
new JsonException
default ftp transfer mode is now binary

Things that may break your code

PCRE2 differences (should be rare)
ODBCRouter and Birdstep support have been removed
Various deprecations - see UPGRADING

Full details are at:

https://github.com/php/php-src/blob/PHP-7.3/UPGRADING

And for extension authors:

https://github.com/php/php-src/blob/PHP-7.3/UPGRADING.INTERNALS

Version Support

Active Support	Regular releases and security fixes
Security Fixes	Only security fixes
End of Life	No longer supported

Saving the Planet?

Around 2 billion sites on the web
On 10 million physical machines
PHP drives at least 50%

Currently ~50% PHP 7 Adoption
which is about 2.5M physical servers

3000 KWH/year per server costs approx. US$400
Data center cooling doubles that
0.5kg CO2 per KWH

At 50% Adoption

US $2B savings
7.5B KWH Savings
3.75B kg less CO2

Let's double that to 100%!

$4B savings
15B KWH Savings
7.5B kg less CO2

Do your part

Upgrade to PHP 7!

Dead Code Elimination (DCE)

Escape Analysis

Sparse Conditional Constant Propagation

php -d opcache.optimization_level=-1 -d opcache.opt_debug_level=0x20000 script

function fn() {
    $a = 1;
    return 0;
}

PHP 7.1

fn: (lines=2, args=0, vars=1, tmps=0)
L0:   ASSIGN CV0($a) int(1)
L1:   RETURN int(0)

PHP 7.2/7.3

fn: (lines=1, args=0, vars=0, tmps=0)
L0:   RETURN int(0)

function foo(string $s1, string $s2, string $s3, string $s4) {
    $x = ($s1 . $s2) . ($s3 . $s4);
    $x = 0;
    return $x;
}

PHP 7.1                                   PHP 7.2/7.3
foo: (lines=10, args=4, vars=5, tmps=3)   foo: (lines=5, args=4, vars=4, tmps=0)
L0:   CV0($s1) = RECV 1                   L0:   CV0($s1) = RECV 1
L1:   CV1($s2) = RECV 2                   L1:   CV1($s2) = RECV 2
L2:   CV2($s3) = RECV 3                   L2:   CV2($s3) = RECV 3
L3:   CV3($s4) = RECV 4                   L3:   CV3($s4) = RECV 4
L4:   T6 = CONCAT CV0($s1) CV1($s2)       L4:   RETURN int(0)
L5:   T7 = CONCAT CV2($s3) CV3($s4)
L6:   T5 = CONCAT T6 T7
L7:   ASSIGN CV4($x) T5
L8:   ASSIGN CV4($x) int(0)
L9:   RETURN CV4($x)

Try to trick it

function foo($a) {
    $b = $a += 3;
    return $a;
}

PHP 7.2/7.3

foo: (lines=3, args=1, vars=1, tmps=1)
L0:   CV0($a) = RECV 1
L1:   ASSIGN_ADD CV0($a) int(3)
L2:   RETURN CV0($a)

But...

function foo(int $x, int $y) {
    $a = [$x];
    $a[1] = $y;
    $a = $y;
    return $a;
}

PHP 7.2                                    PHP 7.3
foo: (lines=7, args=2, vars=3, tmps=1)     foo: (lines=4, args=2, vars=3, tmps=0)
L0:   CV0($x) = RECV 1                     L0:     CV0($x) = RECV 1
L1:   CV1($y) = RECV 2                     L1:     CV1($y) = RECV 2
L2:   CV2($a) = INIT_ARRAY 1 CV0($x) NEXT  L2:     CV2($a) = QM_ASSIGN CV1($y)
L3:   ASSIGN_DIM CV2($a) int(1)            L3:     RETURN CV2($a)
L4:   OP_DATA CV1($y)
L5:   ASSIGN CV2($a) CV1($y)
L6:   RETURN CV2($a)

class A { }
function foo(int $x) {
    $a = new A;
    $a->foo = $x;
    return $x;
}

PHP 7.3

foo: (lines=2, args=1, vars=1, tmps=0)
L0:   CV0($x) = RECV 1
L1:   RETURN CV0($x)

class A {
    function __destruct() {}
}
function foo(int $x) {
    $a = new A;
    $a->foo = $x;
    return $x;
}

PHP 7.3

foo: (lines=7, args=1, vars=2, tmps=1)
L0:   CV0($x) = RECV 1
L1:   V2 = NEW 0 string("A")
L2:   DO_FCALL
L3:   CV1($a) = QM_ASSIGN V2
L4:   ASSIGN_OBJ CV1($a) string("foo")
L5:   OP_DATA CV0($x)
L6:   RETURN CV0($x)

function foo(int $x) {
    if ($x) {
        $a = [0,1];
    } else {
        $a = [0,2];
    }
    return $a[0];
}

PHP 7.3

foo: (lines=2, args=1, vars=1, tmps=0)
L0:   CV0($x) = RECV 1
L1:   RETURN int(0)

function foo() {
    $o = new stdClass();
    $o->foo = 0;
    $i = 1;
    $c = $i < 2;
    if ($c) {
        $k = 2 * $i;
        $o->foo = $i;
        echo $o->foo;
    }
    $o->foo += 2;
    $o->foo++;
    return $o->foo;
}

PHP 7.3

foo: (lines=2, args=0, vars=0, tmps=0)
L0:   ECHO int(1)
L1:   RETURN int(4)

Static Analysis

github.com/phan/phan

Install with composer

$ composer require --dev phan/phan

Create .phan/config.php

return [
    'target_php_version' => '7.2',
    'directory_list' => [ 'src/' ],
    "exclude_analysis_directory_list" => [ 'vendor/' ],
];

$ ./vendor/bin/phan

Checks

enhanced phpdoc type annotations
Everything is defined and accessible
Type safety
PHP version compatibility
No-ops
Unreachable code
Unused use statements
Redefinitions
Signature compatibility and final on inheritance
and many more

Enhanced PHPDoc type annotations

class C {
  /**
   * @param string|int $union
   * @param int[] $generic
   * @param array{mode:string,max:int} $shaped
   */
  static function fn($union, array $generic, $shaped) { }
}
C::fn("test", [1,2,3], ['mode'=>"test", 'max'=>10]);
C::fn(1, [1,2,3], ['mode'=>"test", 'max'=>10]);
C::fn("test", [1,2,3], ['max'=>10,'mode'=>"test"]);

C::fn([1], [1,2,3], ['mode'=>"test", 'max'=>10]);
// PhanTypeMismatchArgument Argument 1 (union) is array{0:1}
// but \C::fn() takes int|string

C::fn("test", [1,2,3], ['max'=>10]);
// PhanTypeMismatchArgument Argument 3 (shaped) is array{max:10}
// but \C::fn() takes array{mode:string,max:int}

User plugins

Writing Plugins for Phan

Included sample plugins

Demo Plugin
Preg Regex Checker
Printf Checker
Unreachable Code
DollarDollar
NonBool Branch
Numerical Comparison
Has PHPDoc
Duplicate Expression

Daemon mode

$ phan --daemonize-tcp-port default &
[1] 28610
Listening for Phan analysis requests at tcp://127.0.0.1:4846
Awaiting analysis requests for directory '/home/rasmus/phan_demo'

$ vi src/script.php

$ phan_client -l src/script.php
Phan error: TypeError: PhanTypeMismatchArgument: Argument 1 (union) is array{0:1} but \C::fn() takes int|string defined at src/script.php:8 in src/script.php on line 14
Phan error: TypeError: PhanTypeMismatchArgument: Argument 3 (shaped) is array{max:10} but \C::fn() takes array{mode:string,max:int} defined at src/script.php:8 in src/script.php on line 16

vim integration

phpspy

Low-overhead sampling profiler

https://github.com/adsr/phpspy

Sample frequency in nanoseconds (or Hz)

$ phpspy -s 200000000 -- php -r 'sleep(1);' 
0 sleep <internal>:-1
1 <main> <internal>:-1

0 sleep <internal>:-1
1 <main> <internal>:-1

0 sleep <internal>:-1
1 <main> <internal>:-1

0 sleep <internal>:-1
1 <main> <internal>:-1

0 sleep <internal>:-1
1 <main> <internal>:-1

process_vm_readv: No such process

Attach to a running process

$ sudo phpspy -r -p $(pgrep -n php-fpm)

0 wp_installing /var/www/wordpress/wp-includes/load.php:944
1 wp_load_alloptions /var/www/wordpress/wp-includes/option.php:189
2 get_option /var/www/wordpress/wp-includes/option.php:90
3 create_initial_taxonomies /var/www/wordpress/wp-includes/taxonomy.php:43
4 WP_Hook::apply_filters /var/www/wordpress/wp-includes/class-wp-hook.php:286
5 WP_Hook::do_action /var/www/wordpress/wp-includes/class-wp-hook.php:310
6 do_action /var/www/wordpress/wp-includes/plugin.php:453
7 <main> /var/www/wordpress/wp-settings.php:450
8 <main> /var/www/wordpress/wp-config.php:89
9 <main> /var/www/wordpress/wp-load.php:37
10 <main> /var/www/wordpress/wp-blog-header.php:13
11 <main> /var/www/wordpress/index.php:17
# 1537119612.459615 /index.php p=1 /var/www/wordpress/index.php -

0 mysqli_query <internal>:-1
1 wpdb::_do_query /var/www/wordpress/wp-includes/wp-db.php:1924
2 wpdb::query /var/www/wordpress/wp-includes/wp-db.php:1813
3 wpdb::get_results /var/www/wordpress/wp-includes/wp-db.php:2488
4 _prime_comment_caches /var/www/wordpress/wp-includes/comment.php:2871
5 WP_Comment_Query::get_comments /var/www/wordpress/wp-includes/class-wp-comment-query.php:427
6 WP_Comment_Query::query /var/www/wordpress/wp-includes/class-wp-comment-query.php:346
7 get_comments /var/www/wordpress/wp-includes/comment.php:226
8 WP_Widget_Recent_Comments::widget /var/www/wordpress/wp-includes/widgets/class-wp-widget-recent-comments.php:99
9 WP_Widget::display_callback /var/www/wordpress/wp-includes/class-wp-widget.php:372
10 dynamic_sidebar /var/www/wordpress/wp-includes/widgets.php:743
11 <main> /var/www/wordpress/wp-content/themes/twentyfifteen/sidebar.php:41
12 load_template /var/www/wordpress/wp-includes/template.php:688
13 locate_template /var/www/wordpress/wp-includes/template.php:647
14 get_sidebar /var/www/wordpress/wp-includes/general-template.php:110
15 <main> /var/www/wordpress/wp-content/themes/twentyfifteen/header.php:49
16 load_template /var/www/wordpress/wp-includes/template.php:688
17 locate_template /var/www/wordpress/wp-includes/template.php:647
18 get_header /var/www/wordpress/wp-includes/general-template.php:41
19 <main> /var/www/wordpress/wp-content/themes/twentyfifteen/single.php:10
20 <main> /var/www/wordpress/wp-includes/template-loader.php:74
21 <main> /var/www/wordpress/wp-blog-header.php:19
22 <main> /var/www/wordpress/index.php:17
# 1537119612.459615 /index.php p=1 /var/www/wordpress/index.php -

Memory usage on stack frames

$ sudo phpspy -m php src/phan.php

0 Phan\Analysis::parseNodeInContext /home/rasmus/phan/src/Phan/Analysis.php:176
1 Phan\Analysis::parseNodeInContext /home/rasmus/phan/src/Phan/Analysis.php:176
2 Phan\Analysis::parseNodeInContext /home/rasmus/phan/src/Phan/Analysis.php:176
3 Phan\Analysis::parseNodeInContext /home/rasmus/phan/src/Phan/Analysis.php:176
4 Phan\Analysis::parseFile /home/rasmus/phan/src/Phan/Analysis.php:63
5 Phan\Phan::analyzeFileList /home/rasmus/phan/src/Phan/Phan.php:94
6 <main> /home/rasmus/phan/src/phan.php:1
# mem 119159776 123721960

0 ast\parse_code <internal>:-1
1 Phan\AST\Parser::parseCode /home/rasmus/phan/src/Phan/AST/Parser.php:42
2 Phan\Analysis::parseFile /home/rasmus/phan/src/Phan/Analysis.php:63
3 Phan\Phan::analyzeFileList /home/rasmus/phan/src/Phan/Phan.php:94
4 <main> /home/rasmus/phan/src/phan.php:1
# mem 82471616 123721960

perf/callgrind output support soon, Adam?

Generate a flame graph

$ phpspy phan > /tmp/output
$ cat /tmp/output | stackcollapse-phpspy.pl | flamegraph.pl > flame.svg

PHP 7.4

Typed Properties

class User {
    public int $id;
    public string $name;
 
    public function __construct(int $id, string $name) {
        $this->id = $id;
        $this->name = $name;
    }
}

Without Opcache Preloading

class A {
    function __construct() {
        echo "A";
    }
}

spl_autoload_register('__load');
function __load($c) {
    echo "Autoloader called for $c\n";
    require "/home/rasmus/".strtolower($c).".php";
}

new A;

$ php script.php 
Autoloader called for A
A

With Opcache Preloading

function preload($filename) {
    if (!opcache_compile_file($filename)) {
        trigger_error("Preloading Failed", E_USER_ERROR);
    }
}

preload("/home/rasmus/a.php");

$ php -d opcache.preload=preload.php script.php 
A

Thank You

http://talks.php.net/etsy18

https://github.com/phan/phan

https://github.com/adsr/phpspy

https://github.com/php/php-src/blob/PHP-7.3/UPGRADING

https://bugs.php.net

Report Bugs

Useful bug reports, please!