Wednesday, March 20, 2013

An Efficient Way Of Developing PHP Extension

Many people think developing PHP extension is really hard and too complex for them, so they rarely consider developing PHP extensions by themselves.

Here we want to show you an efficient, easier way of developing PHP extension that might make you reconsider about it. :-)

Creating Extension Skeleton

To make a basic extension works, you need 3 files to build your extension.
  • config.m4
  • your_ext.c
  • your_ext.h
Yes, only three files you need to create. But to write the C header files and the .c file, there are still many things to understand and to be configured well.

With GenPHP you don't need to write these files by yourself. By using GenPHP, you can simply run a single command to generate these files through a simple template engine.

To get GenPHP works, first you need to install it:
$ curl -O
$ chmod +x genphp
$ mv genphp /usr/bin/
Then, to generate something you need to install the GenPHP flavours:
    $ git clone ~/.genphp/flavors
Now run genphp list, you should see the flavour list:
    $ genphp list
    Available flavors:
        extension   /Users/c9s/.genphp/flavors
OK, now we've got the extension flavor, to use it, simply type:
    $ mkdir app
    $ cd app
    $ genphp new extension app
    Loading flavor extension...
    Running main generator...
        render        config.m4
        render        php_app.h
        render        php_app.c
        copy          .gitignore
See? it's really easy.
The "app" above is your extension name, you may just replace the "app" with anything you want.
To build the basic extension, you can type the commands to build the extension as usual:
    $ phpize
    $ ./configure
    $ make
    $ make install
The extension flavor creates a basic extension for you, which contains a simple PHP function, see below:
        RETURN_STRING("Hello World", 1);
Now you can simply start here with ease!


To test your extension code, there is already a tool called "", which is shipped from PHP distribution.
If you ever used it, you should know it's really hard to do the tests and use gdb to debug.

The Old Way

To debug your php extension, you need setup these configuration by yourself:

You need to create your own .gdbinit with the content below:

file /Users/c9s/.phpbrew/php/php-5.4.12/bin/php set args -d 'output_handler=' -d 'open_basedir=' -d 'safe_mode=0' -d 'disable_functions=' -d 'output_buffering=Off' -d 'error_reporting=32767' -d 'display_errors=1' -d 'display_startup_errors=1' -d 'log_errors=0' -d 'html_errors=0' -d 'track_errors=1' -d 'report_memleaks=1' -d 'report_zend_debug=0' -d 'docref_root=' -d 'docref_ext=.html' -d 'error_prepend_string=' -d 'error_append_string=' -d 'auto_prepend_file=' -d 'auto_append_file=' -d 'magic_quotes_runtime=0' -d 'ignore_repeated_errors=0' -d 'precision=14' -d 'memory_limit=128M' -d 'extension_dir=/Users/c9s/src/work/php/fileutil/modules/' -d 'session.auto_start=0' -d 'zlib.output_compression=Off' -d 'mbstring.func_overload=0' -d '' -n {your PHP script}

Now you should understand the hard place.

2. The phpt does not show the expected result and actual result very clearly, please see the actual output below:
PHP         : /Users/c9s/.phpbrew/php/php-5.4.12/bin/php
PHP_SAPI    : cli
PHP_VERSION : 5.4.12
PHP_OS      : Darwin - Darwin c9smba.local 12.3.0 Darwin Kernel Version 12.3.0: Sun Jan  6 22:37:10 PST 2013; root:xnu-2050.22.13~1/RELEASE_X86_64 x86_64
INI actual  : /Users/c9s/.phpbrew/build/php-5.4.12/ext/tidy/tmp-php.ini
More .INIs  :
CWD         : /Users/c9s/.phpbrew/build/php-5.4.12/ext/tidy
Extra dirs  :
VALGRIND    : Not used
TIME START 2013-03-20 15:54:16
PASS Check for tidy presence [tests/001.phpt]
PASS tidy_parse_string() [tests/002.phpt]
PASS tidy_clean_repair() [tests/003.phpt]
FAIL tidy_diagnose() [tests/004.phpt]
PASS tidy_parse_file() [tests/005.phpt]
FAIL Verbose tidy_get_error_buffer() [tests/006.phpt]
PASS Verbose  tidy_getopt() [tests/007.phpt]
FAIL Accessing the error buffer via $obj->error_buf... [tests/008.phpt]
PASS tidy_doc object overloading [tests/009.phpt]
FAIL Accessing root, body, html, and head nodes.. [tests/010.phpt]
PASS Accessing attributes of a node [tests/011.phpt]
FAIL Accessing children nodes [tests/012.phpt]
PASS Parsing a file using constructor [tests/013.phpt]
PASS Passing configuration options through tidy_parse_string(). [tests/014.phpt]
PASS Passing configuration options through tidy_parse_file(). [tests/015.phpt]
PASS Passing configuration file through tidy_parse_file() (may fail with buggy libtidy) [tests/016.phpt]
PASS The Tidy Output Buffer Filter [tests/017.phpt]
PASS binary safety [tests/018.phpt]
PASS tidy_repair_*() and invalid parameters [tests/019.phpt]
PASS OO API [tests/020.phpt]
PASS tidy_get_opt_doc() [tests/021.phpt]
PASS tidy_repair_*() and invalid parameters [tests/022.phpt]
PASS tidy and tidyNode OO [tests/023.phpt]
SKIP libtidy handling of 'new-blocklevel-tags' [tests/024.phpt] reason: old libtidy
PASS tidyNode tests [tests/025.phpt]
PASS tidy.clean_output test [tests/026.phpt]
PASS Bug: tidy segfaults with markup=false [tests/027.phpt]
PASS tidyNode::getParent() [tests/028.phpt]
PASS tidy_get_body() crash [tests/029.phpt]
PASS getConfig() method - basic test for getConfig() [tests/030.phpt]
PASS tidy_config_count() function - basic test for tidy_config_count() [tests/031.phpt]
PASS tidy_error_count() function - basic test for tidy_error_count() [tests/032.phpt]
PASS tidy_warning_count() function - basic test for tidy_warning_count() [tests/033.phpt]
PASS tidy_access_count() function - basic test for tidy_access_count() [tests/034.phpt]
PASS tidyNode::__construct() [tests/035.phpt]
PASS Tidy::diagnose() NULL pointer dereference [tests/bug54682.phpt]
PASS Bug #50558 - Broken object model when extending tidy [tests/bug_50558.phpt]
PASS Ensure tidy_get_status() returns correct status [tests/tidy_error.phpt]
PASS Notice triggered by invalid configuration options [tests/tidy_error1.phpt]
TIME END 2013-03-20 15:54:19

Exts skipped    :    0
Exts tested     :   49

Number of tests :   39                38
Tests skipped   :    1 (  2.6%) --------
Tests warned    :    0 (  0.0%) (  0.0%)
Tests failed    :    5 ( 12.8%) ( 13.2%)
Expected fail   :    0 (  0.0%) (  0.0%)
Tests passed    :   33 ( 84.6%) ( 86.8%)
Time taken      :    3 seconds

tidy_diagnose() [tests/004.phpt]
Verbose tidy_get_error_buffer() [tests/006.phpt]
Accessing the error buffer via $obj->error_buf... [tests/008.phpt]
Accessing root, body, html, and head nodes.. [tests/010.phpt]
Accessing children nodes [tests/012.phpt]

You may have found a problem in PHP.
This report can be automatically sent to the PHP QA team at and
This gives us a better understanding of PHP's behavior.
If you don't want to send the report immediately you can choose
option "s" to save it.  You can then email it to later.
Do you want to send this report now? [Yns]:

As you seen, it only shows "FAIL" and "PASS" and it's asking you whether to send the test report.. it's really excruciating..

3. If you have both pure PHP implementation and the C extension implementation, it's hard to switch and test them.


We developed ExtUnit to improve the extension unit test, you can even write your extension in PHPUnit, and with ExtUnit, you can easily run the tests with your pure PHP implementation or with your extension implementation by two simple commands.
Install ExtUnit:
    $ pear channel-discover
    $ pear install -f -a corneltek/ExtUnit
To let ExtUnit work, you need to define the extunit.xml config file:
<?xml version="1.0" encoding="UTF-8"?>
    <!-- local extensions for php to load -->
Then you can simply type the command to phpunit tests:
    $ extunit --phpunit
Or use gdb to debug the test cases:
    $ extunit --gdb --phpunit
Or simply run a php script with gdb:
    $ extunit --gdb example.php
ExtUnit runs "make" before you run the tests, so you can simply run single command to test, which improves the extension development iteration.
Now you might want to test your pure PHP implementation, just type the phpunit as usual:
    $ phpunit

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