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Create your own PHP extension, step by step

Create your own PHP extension, step by step

Workshop given at PHP NorthWest 2012 in Manchester with Derick Rethans and Anthony Ferrara

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Patrick Allaert

October 05, 2012
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  1. Create your own PHP extension, step by step Patrick Allaert,

    Derick Rethans PHPNW 2012 Manchester, United Kingdom
  2. Patrick Allaert • Founder of Libereco Technologies • Playing with

    PHP/Linux for +10 years • eZ Publish core developer • Author of the APM PHP extension • @patrick_allaert • patrickallaert@php.net • http://github.com/patrickallaert/ • http://patrickallaert.blogspot.com/
  3. Derick Rethans • Dutchman living in London • PHP Engineer/Evangelist

    for 10gen (the MongoDB people), where I also work on the MongoDB PHP driver. • Author of Xdebug • Author of the mcrypt, input_filter, dbus, translit and date/time extensions
  4. Workshop overview • Brief reminders about PHP architecture • Configure

    your environment • Grab the example extension • Do some exercises while seeing a bit of theory
  5. PHP architecture

  6. Configuring your environment • Debian-like: $ sudo apt-get install php5-dev

  7. Download the sample extension a) Using git: $ git clone

    git://github.com/patrickallaert/ PHP_Extension_Workshop.git b) Download archive at: https://github.com/patrickallaert/PHP_Extension_Wo rkshop/downloads
  8. Minimal C code (myext.c) #ifdef HAVE_CONFIG_H #include "config.h" #endif #include

    "php.h" #include "php_ini.h" #include "ext/standard/info.h" #include "php_myext.h" zend_module_entry myext_module_entry = { STANDARD_MODULE_HEADER, "myext", NULL, /* Function entries */ NULL, /* Module init */ NULL, /* Module shutdown */ NULL, /* Request init */ NULL, /* Request shutdown */ NULL, /* Module information */ "0.1", /* Replace with version number for your extension */ STANDARD_MODULE_PROPERTIES }; #ifdef COMPILE_DL_MYEXT ZEND_GET_MODULE(myext) #endif
  9. Compilation Prepare build environment: 1. $ phpize Configure the extension:

    2. $ ./configure Compile it: 3. $ make Install it (may require root): 4. $ make install
  10. Verify installation $ php -d extension=myext.so -m You should see

    “myext” as part of the loaded extensions.
  11. Minimal config.m4 dnl config.m4 for myext PHP_ARG_ENABLE(myext, whether to enable

    myext support, [ --enable-myext Enable myext support]) if test "$PHP_MYEXT" != "no"; then PHP_NEW_EXTENSION(myext, myext.c, $ext_shared) fi
  12. Exercise one: fibonacci (1/7) • F(n) = F(n-1) + F(n-2)

    with F(0) = 0 and F(1) = 1
  13. Exercise one: fibonacci (2/7) function fibo($n) { switch ($n) {

    case 0: case 1: return $n; } return fibo($n-2) + fibo($n-1); }
  14. Exercise one: fibonacci (3/7)

  15. Exercise one: fibonacci (4/7)

  16. Exercise one: fibonacci (5/7)

  17. Exercise one: fibonacci (6/7)

  18. Exercise one: fibonacci (7/7) Compile: $ make Install: $ make

    install Test: $ php -d extension=myext.so \ -r 'echo fibonacci(35), “\n”;' 9227465
  19. Exercise one: fibonacci solution The full changes required to implement

    the fibonacci function are available at: http://tinyurl.com/PHP-ext-fibonacci
  20. zend_parse_parameters • Handles the conversion of PHP userspace variables into

    C ones. • Generate errors in the case of missing parameters or if the type is wrong.
  21. zend_parse_parameters • Second parameter describes the type of the parameter(s)

    as a string composed of characters having all a special meaning. • To mark the start of optional parameter(s), a pipe (“|”) character is used. Type Cod e Variable type Boolean b zend_bool Long l long Double d double String s char *, int (length) Path p char *, int (length) Class name C zend_class_entry* Resource r zval* Array a zval* Object o zval* zval z zval* Zval pointer Z zval** Callback f zend_fcall_info, zend_fcall_info_cache
  22. zend_parse_parameters examples • sleep(), usleep(), func_get_arg(): zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &long)

    • bin2hex(), quotemeta(), ord(), ucfirst(): zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &str, &str_len) • str*pos(): zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "sz|l", &haystack, &haystack_len, &needle, &offset) • var_dump(): zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "+", &args, &argc) • file_put_contents() zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "pz/| lr!", &filename, &filename_len, &data, &flags, &zcontext)
  23. OpenGrok (1/2) • Your best friend to browse PHP's source

    code: http://lxr.php.net/
  24. OpenGrok (2/2)

  25. zval (=== _zval_struct) struct _zval_struct { /* Variable information */

    zvalue_value value; /* value */ zend_uint refcount__gc; zend_uchar type; /* active type */ zend_uchar is_ref__gc; }; typedef union _zvalue_value { long lval; /* long value */ double dval; /* double value */ struct { char *val; int len; } str; HashTable *ht; /* hash table value */ zend_object_value obj; } zvalue_value;
  26. Types • IS_NULL • IS_LONG • IS_DOUBLE • IS_BOOL •

    IS_ARRAY • IS_OBJECT • IS_STRING • IS_RESOURCE • IS_CONSTANT • IS_CONSTANT_ARRAY • IS_CALLABLE • http://lxr.php.net/xref/PHP_TRUNK/Zend/zend.h#IS_NULL
  27. Access macros Z_TYPE(zval) (zval).type Z_LVAL(zval) (zval).value.lval Z_BVAL(zval) ((zend_bool)(zval).value.lval) Z_DVAL(zval) (zval).value.dval

    Z_STRVAL(zval) (zval).value.str.val Z_STRLEN(zval) (zval).value.str.len Z_ARRVAL(zval) (zval).value.ht Z_OBJVAL(zval) (zval).value.obj Z_OBJ_HANDLE(zval) Z_OBJVAL(zval).handle Z_OBJ_HT(zval) Z_OBJVAL(zval).handlers Z_RESVAL(zval) (zval).value.lval Z_TYPE_P(zval_p) Z_TYPE(*zval_p) Z_LVAL_P(zval_p) Z_LVAL(*zval_p) Z_BVAL_P(zval_p) Z_BVAL(*zval_p) Z_DVAL_P(zval_p) Z_DVAL(*zval_p) Z_STRVAL_P(zval_p) Z_STRVAL(*zval_p) Z_STRLEN_P(zval_p) Z_STRLEN(*zval_p) Z_ARRVAL_P(zval_p) Z_ARRVAL(*zval_p) Z_RESVAL_P(zval_p) Z_RESVAL(*zval_p) Z_OBJVAL_P(zval_p) Z_OBJVAL(*zval_p) Z_OBJ_HANDLE_P(zval_p) Z_OBJ_HANDLE(*zval_p) Z_OBJ_HT_P(zval_p) Z_OBJ_HT(*zval_p) http://lxr.php.net/xref/PHP_TRUNK/Zend/zend_operators.h#Z_LVAL
  28. Exercise two: my_dump($val) (1/2) • Create a very simple my_dump($val)

    function: • my_dump(null); // null value! • my_dump(42); // Long: 42 • my_dump(123.456); // Double: 123.456 • my_dump(true); // Boolean: true • my_dump(“hello”); // String: hello
  29. Exercise two: my_dump($val) (2/2) • Hints: • Define a pointer

    to a zval: zval *val; • Use “z” with zend_parse_parameters() • Switch/case based on the type of val (Z_TYPE_P(uservar)) • Use php_printf() to print, except for strings from zval, since they may contain NULL characters: PHPWRITE(const char *, size_t);
  30. Exercise two: solution PHP_FUNCTION(my_dump) { zval *val; if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC,

    "z", val) == FAILURE) { return; } switch (Z_TYPE_P(val)) { case IS_NULL: php_printf("NULL"); break; case IS_BOOL: php_printf("Boolean: %s", Z_LVAL_P(val) ? "true" : "false"); break; case IS_LONG: php_printf("Long: %ld", Z_LVAL_P(val)); break; case IS_DOUBLE: php_printf("Double: %f", Z_DVAL_P(val)); break; case IS_STRING: php_printf("String: "); PHPWRITE(Z_STRVAL_P(val), Z_STRLEN_P(val)); break; default: php_printf("Not supported"); } }
  31. PHP life cycles • 4 functions (2 initializations, 2 shutdowns

    ones) let you do stuff at specific moments of the PHP life cycles: • PHP_MINIT_FUNCTION • PHP_MSHUTDOWN_FUNCTION • PHP_RINIT_FUNCTION • PHP_RSHUTDOWN_FUNCTION
  32. PHP life cycles - CLI • Credits: Extending and Embedding

    PHP by Sara Golemon (2006 June 9th)
  33. PHP life cycles – Web server (prefork) • Credits: Extending

    and Embedding PHP by Sara Golemon (2006 June 9th)
  34. PHP life cycles - Web server (multi thread) • Credits:

    Extending and Embedding PHP by Sara Golemon (2006 June 9th)
  35. Exercise three: MyClass (1/10) • Steps: • Create a class

    named “MyClass” • Create a class constant • Add some properties with various visibilities/modifiers • Add some methods
  36. Exercise three: MyClass (2/10)

  37. Exercise three: MyClass (3/10) • http://tinyurl.com/PHP-ext-MyClass-1

  38. Exercise three: MyClass (4/10) • Declaring a class constant can

    be made from a C type: • zend_declare_class_constant_null(); • zend_declare_class_constant_long(); • zend_declare_class_constant_bool(); • zend_declare_class_constant_double(); • zend_declare_class_constant_stringl(); • zend_declare_class_constant_string(); • Or from a zval: • zend_declare_class_constant();
  39. Exercise three: MyClass (5/10) • http://tinyurl.com/PHP-ext-MyClass-2

  40. Exercise three: MyClass (6/10) • Creating class properties can be

    made from a C type: • zend_declare_property_long(); • zend_declare_property_bool(); • zend_declare_property_double(); • zend_declare_property_stringl(); • zend_declare_property_string(); • Or from a zval: • zend_declare_property(); • Visibility: • ZEND_ACC_PUBLIC, ZEND_ACC_PROTECTED, ZEND_ACC_PRIVATE • Modifiers: • ZEND_ACC_STATIC, ZEND_ACC_ABSTRACT, ZEND_ACC_FINAL
  41. Exercise three: MyClass (7/10) • http://tinyurl.com/PHP-ext-MyClass-3

  42. Exercise three: MyClass (8/10)

  43. Exercise three: MyClass (9/10)

  44. Exercise three: MyClass (10/10) • http://tinyurl.com/PHP-ext-MyClass-4

  45. Questions?

  46. Thanks • Don't forget to rate this workshop on https://joind.in/7070