25 Years of PHP

DevBreak

Château du Vivier

June 13, 2019

http://talks.php.net/devbreak

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>

C API for the Web

void Cos(void) {
    Stack *s;
    char temp[64];

    s = Pop();
    if(!s) {
        Error("Stack error in cos");
        return;
    }
    sprintf(temp,"%f",cos(s->douval));
    Push(temp,DNUMBER);
}

And you could then use it like this:

<html><head><title>Cos Example</title></head>
<body><h1>Cos Example</h1>
<?echo Cos($input)>
</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

Performance

mod_php
shared-nothing perfect sandbox model

Robustness

SQL LIMIT clause
Promote Prefork shared-nothing model

Security

max_execution_time
memory_limit
safe mode

What was he thinking?

Case insensitive function names?
Naming inconsistencies?
What's with the $ signs?
Globals?
register_globals?
magic_quotes?

OMGWTFBBQ?

array_search($needle, $haystack);
strstr($haystack, $needle);
in_array($needle, $haystack);
substr_count($haystack, $needle);
array_key_exists($needle, $haystack);
strchr($haystack, $needle);

Version Support

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

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;
    }
}

Arrow Functions

$cb = function ($x) use ($y) {
          return $x + $y;
      };

$cb = fn($x) => $x + $y;

__serialize/__unserialize

class Test {
    public $prop;
    public function __serialize() {
        return ['prop' => $this->prop];
    }
    public function __unserialize(array $data) {
        $this->prop = $data['prop'];
    }
}

Null Coalescing Assignment Operator

$this->config['value']   = $this->config['value'] ?? 'default_value';
$this->config['value'] ??= 'default_value';

Weak References

$std = new stdClass;
$wr = WeakReference::create($std);

Opcache Preloading

Loads userspace code at server startup as if it was part of core PHP
Trades some flexibility for performance
Inspired by the “Class Data Sharing” feature in Java's Hotspot VM

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

FFI - Foreign Function Interface

// create FFI object, loading libc and exporting function printf()
$ffi = FFI::cdef(
    "int printf(const char *format, ...);",
    "libc.so.6");
// call C printf()
$ffi->printf("Hello %s!\n", "world");

<?php
    $ffi = FFI::load("php_gifenc.h");

    $w = 240; $h = 180;
    $cols = $ffi->new("uint8_t[12]");
    /* 4 colours: 000000, FF0000, 00FF00, 0000FF */
    $cols[3] = 0xFF; $cols[7] = 0xFF; $cols[11] = 0xFF;

    $gif = $ffi->ge_new_gif("test.gif", $w, $h, $cols, 2, 0);

    for($i = 0; $i < 16; $i++) {
        for ($j = 0; $j < $w*$h; $j++) {
            $gif->frame[$j] = ($i*6 + $j) / 12 % 8;
        }
        echo "Add frame $i\n";
        $ffi->ge_add_frame($gif, 5);
    }
    $ffi->ge_close_gif($gif);

#define FFI_SCOPE "gifenc"
#define FFI_LIB "libgifenc.so"

typedef struct ge_GIF {
    uint16_t w, h;
    int depth;
    int fd;
    int offset;
    int nframes;
    uint8_t *frame, *back;
    uint32_t partial;
    uint8_t buffer[0xFF];
} ge_GIF;

ge_GIF *ge_new_gif(
    const char *fname, uint16_t width, uint16_t height,
    uint8_t *palette, int depth, int loop
);
void ge_add_frame(ge_GIF *gif, uint16_t delay);
void ge_close_gif(ge_GIF* gif);