PHP tips/tricks/HOWTOs

HOWTO: Install PHP

OS-specific instructions follow; see below for general information about switches and environment variables.

OS X 10.5 Leopard

Install, via port, libxml2, libxslt, libiconv, gd2 (+no_x11), freetype, sqlite3.

Download from:

<http://uk.php.net/get/php-5.3.0.tar.gz/from/a/mirror>

Configure with:

$ export PHP_ROOT=/usr/local/php-5.x.y

$ ./configure --prefix=$PHP_ROOT \
  --enable-fastcgi --with-xsl=/Ports --with-libxml-dir=/Ports \
  --with-gd=/Ports --with-jpeg-dir=/Ports --with-pdo-sqlite=/Ports \
  --without-sqlite --without-sqlite3 --with-freetype-dir=/Ports \
  --with-ttf=/Ports --enable-calendar --with-zlib=/Ports --with-iconv \
  --with-openssl --enable-discard-path --enable-bcmath --with-curl

$ make

$ make install

$ cp php.ini-recommended $PHP_ROOT/lib/php.ini

$ jed $PHP_ROOT/lib/php.ini # set extension_dir to $PHP_ROOT/php-config --extension-dir

OS-specific notes (see below for general notes):

  1. This doesn't install the MySQL library, because it's a pain. If you want MySQL, then add:

     --with-mysql=$MYSQL --with-pdo-mysql=$MYSQL
    

    Where $MYSQL is where the MySQL client libraries and header files are installed. (e.g. $HOME/local or /usr--you can't install MySQL into separate "binary" and "shared" directories.) These are installed as part of the MySQL server distribution, but if you only want to install the client libraries, download the source and configure with --without-server. Do not install the library itself and header files into separate directories (i.e. do not use --exec-prefix)--the PHP configure script can't deal with these being in separate directories.

  2. If compiling with some versions of OS X (10.5.0, 10.5.4, 10.5.5 and 10.5.6 seem to be affected, at least), replace /usr/include/iconv.h with MacPorts' version before configuring, to prevent iconv link errors.

Ubuntu 10.04

Install the likely module suspects:

libjpeg62-dev libxslt1-dev libcurl4-openssl-dev libssl-dev
libsqlite3-dev libgd2-noxpm libpng12-dev libfreetype6-dev

libmysqlclient16-dev # optional?

Download from:

<http://php.net/downloads.php>

Configure with:

$ export PHP_ROOT=/usr/local/php-5.x.y

# For PHP 5.3.0
$ ./configure --prefix=$PHP_ROOT --with-xsl=/usr \
  --with-libxml-dir=/usr --with-gd --with-pdo-sqlite=/usr \
  --without-sqlite3 --without-sqlite --with-freetype-dir=/usr \
  --enable-calendar --with-zlib --with-iconv --with-openssl \
  --with-jpeg-dir=/usr/lib --with-png-dir=/usr/lib --enable-bcmath \
  --disable-xmlreader --disable-xmlreader --enable-mbstring \
  --without-pear --with-config-file-scan-dir=/usr/local/etc/php.d
  --with-mysql --with-pdo-mysql # these two optional?

# For PHP 5.2.x
$ ./configure --prefix=$PHP_ROOT \
  --enable-fastcgi --with-xsl=/usr --with-libxml-dir=/usr \
  --with-gd --with-pdo-sqlite=/usr --without-sqlite \
  --with-freetype-dir=/usr --with-ttf=/usr --enable-calendar \
  --with-zlib --with-iconv --with-openssl --enable-discard-path \
  --with-jpeg-dir=/usr/lib --with-png-dir=/usr/lib --with-mysql \
  --with-pdo-mysql --enable-bcmath --with-curl

$ make

$ make install

# For PHP 5.3.0
$ cp php.ini-development $PHP_ROOT/lib/php.ini
# or
$ cp php.ini-production $PHP_ROOT/lib/php.ini

# For PHP 5.2.x
$ cp php.ini-recommended $PHP_ROOT/lib/php.ini

# set extension_dir to $PHP_ROOT/bin/php-config --extension-dir
$ jed $PHP_ROOT/lib/php.ini 

OS-specific notes (see below for general notes):

  1. Note that for some reason the --with-jpeg-dir and --with--dir directory parameters specify the location of their respective libraries, not the root. (I don't know why either of these is necessary; for some reason the bundled GD doesn't come with JPEG and PNG libraries.)

SunOS (not recently tested)

Install libxml2, libxslt, gd, libjpeg, libpng, zlib (configure zlib with --shared, otherwise you'll get link errors), then:

$ lconfigure --with-apxs2=$LOCAL/bin/apxs \
  --with-xsl=$LOCAL --with-libxml-dir=$LOCAL --with-gd=$LOCAL \
  --with-jpeg-dir=$LOCAL --with-png-dir=$LOCAL --with-zlib-dir=$LOCAL \
  --enable-debug --with-mysql=/usr/local/mysql --enable-calendar

(Might also need to ln -s $HOME/local/include to $LOCAL/include--one of the dependencies couldn't find the include files from the architecture-independent directory.)

Windows/win32 (not recently tested)

  1. Get Apache running first.

  2. Download the "ZIP package".

  3. Add something like the following to httpd.conf:

    LoadModule php5module "C:/server/php-5.2.4/php5apache22.dll" PHPIniDir "c:/server/php-5.2.4"

  4. (Probably:) Copy php.ini-recommended to php.ini, and tweak as required. (If enabling modules, be sure to set extension_dir!)

  5. Add your PHP directory to PATH, so that various supporting DLLs (e.g. libmysql.dll, libeay32.dll) can be loaded automatically. (How to modify the PATH.)

  6. (optional) Install the Zend debugger

    i. Download site. (The "cygwin_nt-i386" version works fine with the regular Windows binaries.)

    i. Put the ZendDebugger.dll from the 52x_comp (thread-safe) directory into your PHP extensions directory. (Probably C:\server\php-5.2.4\ext.)

    i. Modify php.ini, as described in the README.txt.

    i. Restart Apache. A phpinfo() call should mention the debugger.

    i. (After all this, couldn't get breakpoints working.)

  7. (optional) Install the Xdebug debugger

    i. Download site.

    i. Put the php_xdebug-2.0.0-5.2.2.dll into the PHP extensions directory. (Probably C:\server\php-5.2.4\ext.)

    i. Add the following to php.ini:

    zend_extension_ts=c:/server/php-5.2.4/ext/php_xdebug-2.0.0-5.2.2.dll
    xdebug.remote_enable = On
    xdebug.remote_host=10.171.99.124
    

    i. Restart Apache. A phpinfo() call should mention the debugger.

    i. More info

General Installation Notes

  1. $PHP_ROOT specifies the root of your PHP installation and will probably be something like

    $ export PHP_ROOT=$HOME/local-linux/php-5.2.6
    

    or

    $ export PHP_ROOT=/usr/local/php-5.3.0    
    

    After PHP is installed with make install, $PHP_ROOT/bin/php will be your PHP binary.

  2. You may want to remove --without-pear if you need PEAR.

  3. You can also drop the --without-sqlite to use the bundled sqlite3. (In this case you also don't need to install sqlite3 via port.)

  4. The directory specified by --prefix determines where PHP is installed. The php and php-cgi binaries can be safely moved to other locations, however a few scripts have this location hardcoded, and won't work if the binaries are moved (phpize, pear).

  5. --enable-discard-path supposedly eliminates a security problem.

  6. --with-curl provides curl support. This is potentially unnecessary. (Zend_Http_Client does not use it.)

  7. --enable-pear and --disable-xml are incompatible: pear requires xml.

  8. Zend Framework requirements.

    • Zend_OpenId requires --enable-bcmath.
    • ZendRestClient_Result requires --enable-simplexml.
  9. --enable-mbstring is needed for mb_encoding_convert. Is this really necessary? It seems to make the PHP binary a whole lot bigger!

HOWTO: Install Generic PECL Extension

(See below for instructions for specific extensions.)

Configure, build and install:

$ $PHP_ROOT/bin/phpize
$ ./configure --with-php-config=$PHP_ROOT/bin/php-config
$ make
$ mkdir -p $($PHP_ROOT/bin/php-config --extension-dir)
$ cp modules/*.so $($PHP_ROOT/bin/php-config --extension-dir)

Or, in one line:

$ $PHP_ROOT/bin/phpize && \
  ./configure --with-php-config=$PHP_ROOT/bin/php-config && \
  make && \
  mkdir -p $($PHP_ROOT/bin/php-config --extension-dir) && \
  cp modules/*.so $($PHP_ROOT/bin/php-config --extension-dir)

Modify php.ini files as appropriate, adding the line

extension=new_module.so

You do not need to specify the full pathname. At a minimum, you'll probably want to modify:

$ $EDITOR $PHP_ROOT/lib/php.ini

Some common modules:

HOWTO: Install Xdebug

Download from:

<http://www.xdebug.org/download.php>

Configure, compile and install as above.

When editing php.ini and add the line:

zend_extension=/full/path/xdebug.so

(Xdebug itself can actually be installed anywhere on the filesystem.)

HOWTO: Install memcached

Download and install libmemcached (not the same as the libmemcache-dev Debian package!):

<http://tangent.org/552/libmemcached.html>

Download:

<http://pecl.php.net/package/memcached/>

Configure, make and install as above.

HOWTO: Run your own version of PHP on Dreamhost (not recently tested)

Install libxml2, libxslt, then:

$ lconfigure --enable-fastcgi --with-xsl=$LOCAL \
  --with-libxml-dir=$LOCAL --with-gd --with-ttf=/usr \
  --with-freetype-dir=/usr --enable-calendar

(Uses their gd, ttf, freetype, etc.)

To install:

$ make install

Stripping the binary will save a lot of memory (optional):

$ strip `which php`

Note that this doesn't install the full command-line version (cli). To get that you need to

$ make install-cli

however the command-line version has the same filename--this installs a new "php" binary over the top of your old one. (? I think this changed around 5.2.3.)

To get Dreamhost's Apache to run your php under FastCGI, you need these lines in your .htaccess:

# Remove the default action for *.php files.

RemoveHandler php

# For some reason the following really does need to be called
# dispatch.fcgi.  The contents of dispatch.fcgi:
#
#   #!/usr/bin/env bash
#
#   exec ./php
#
# DOCUMENT_ROOT/cgi is symlinked to $LOCAL/bin.  Dreamhost's config
# seems to have already configured fastcgi-script for *.fcgi.

Action php-fastcgi /cgi/dispatch.fcgi
AddType php-fastcgi html
AddType php-fastcgi php

HOWTO: Handle standard input and output

http://php.net/wrappers.php

TIP: Predefined variables

http://php.net/reserved.variables

TIP: Object oriented programing/inheritance

http://php.net/extends

TIP: String concatenation/string operators

Use "." for concatenation; see the PHP manual for more.

HOWTO: Break out of a loop

Use "break".

TIP: Documentation of control structures

http://php.net/manual/en/language.control-structures.php

Includes the alternative syntax.

TIP: Regular expression example

if (!preg_match("/^foo/", "some string")) {
    # ...
}

GOTCHA: ODBC

This doesn't work in PHP:

$sth = odbc_prepare($dbh, $sql);

foreach (...) {
    $res = odbc_execute($sth, $arg);
    ...
}

(The prepared statement gets mashed somewhere--move the odbc_prepare() into the loop...)

GOTCHA: MDB2's SQLite supports SQLite2, not SQLite3!

True! You need to use PDO.

HOWTO: Set the include path from the command line

i.e. the equivalent of PERL5LIB, PYTHONPATH, RUBYLIB, etc.:

$ php -d include_path=$PHPLIB

HOWTO: Create a static constructor

This doesn't seem to be possible in PHP; the best way is to do something like:

Foo::$bar = "hullo, world"!;

class Foo {

  public static $bar;

}

HOWTO: Static (class) variables

class Foo {

  static $bar = null;

  function quux() {
    return self::$bar;
  }

}

HOWTO: Retrieve multiple values/process checkboxes, and multiple selects

Give the variable a name that ends in "[]". If there are multiple keys with the same value, and the keys end in "[]", PHP creates an array of values for that value. i.e. if the HTML looks like

<select multiple name="beer[]">
  <option value="warthog">Warthog</option>
  <option value="guinness">Guinness</option>
  <option value="stuttgarter">Stuttgarter</option>
</select>

and the user selects multiple beers, then

gettype($_REQUEST["beer"]) == "array"

See:

http://www.php.net/variables.external

HOWTO: "apply" the PHP way

Use call_user_func_array():

call_user_func_array("foo", array(1, 2, 3));

Note that this can also be used to call a method:

call_user_func_array(array($obj, $method), array(1, 2, 3));

HOWTO: Create MySQL-compatible date string format

date("Y-m-d H:i:s")

HOWTO: Convert XHTML entities to XML

If you need to convert e.g. &rsquo; to &#8217; do something like:

$table = array(
  '&Aacute;' => '&#193;',
  '&aacute;' => '&#225;',
  ...
);

$s = strtr($s, $table);

The Wikipedia source contains an entity conversion table.

TIP: Error control operator (@)

@ as a prefix suppresses any warning or error that might otherwise be emitted.

Note that this works with both method calls and assignments:

$res = @$doc->loadXML($string);
$foo = @$GET_["foo"];

(Other error handling functions.)

HOWTO: Convert a UTF-8/Unicode string to XML/HTML entities

Use [mb_encode_numericentity](http://php.net/manual/en/function.mb-encode-numericentity.php). The exact arguments seem somewhat hard to come by; this is my current best effort:

$map = array(
    0x0000, 0x001f, 0, 0xffff,
    0x0026, 0x0026, 0, 0xffff, // &
    0x003c, 0x003c, 0, 0xffff, // <
    0x003e, 0x003e, 0, 0xffff, // >
    0x007f, 0xffff, 0, 0xffff
);

mb_encode_numericentity($s, $map, 'utf-8');

GOTCHA: error_log() quotes backlashes

echo("\\hello\\") -> \hello\

error_log("\\hello\\") -> \\hello\\

WART:

odbc_execute($sth, $a);

If any of the element of $a begin and end with a single quote, the bit in between is interpreted as a filename, the contents of which are inserted.

WART:

Very strange arguments in php.ini:

; Define the probability that the 'garbage collection' process is started
; on every session initialization.
; The probability is calculated by using gc_probability/gc_divisor,
; e.g. 1/100 means there is a 1% chance that the GC process starts
; on each request.

session.gc_probability = 1
session.gc_divisor     = 1000

WART:

Include is a "special language construct", which means that these two things are not equivalent:

if ($condition)
  include $this;
else
  include $that;

and

 if ($condition) {
   include $this;
 } else {
   include $that;
 }

WART:

array_filter() and array_map() take their arguments in opposite order:

array array_filter ( array input [, callback callback] )
array array_map ( callback callback, array arr1 [, array ...] )

WART:

imageepsbbox returns an array of four values giving the bottom left and top right coordinates of a given string.

imagettfbbox returns an array of eight values, giving the coordinates of all four corners of a given string.

WART:

parse_str() parses--guess what?--a query string. (Also, the inverse is http_build_query().)

More unfortunately-named pairs:

WART:

The insanity of:

isset($foo)
empty($foo)
is_null($foo)
$foo

(Could possibly add array_key_exists() and defined() to this list too.)

Note also that empty(trim($foo)) doesn't work--the argument to empty() needs to be a variable, not an expression.

See also:

http://php.net/types.comparisons

WART:

include() is relative to the original file, not the included file.

See:

http://bugs.php.net/bug.php?id=9673

You can include() relative to the included file with:

include(dirname(__FILENAME__) . "/../$filename");

HOWTO: Interpolate complex array/object references

Like this:

echo "This works: {$obj->values[3]->name}";

See:

http://php.net/manual/en/language.types.string.php#language.types.string.parsing.complex

FAQ: How to call parent constructor

parent::__construct(...);

More info.

FAQ: How to use a custom statement class with PDO?

Comment describing how to extend PDOStatement (not tested).

FAQ: Why does addition/subtraction not work! (Operator precedence)

The operators "+", "-" and "." have the same precedence. This means that e.g.

error_log("elapsed time = " . $t1 - $t0)

doesn't do what you expect--it evaluates as

error_log(("elapsed time = " . $t1) - $t0)

(This is the same as Perl.)

(The full operator precedence table. Note the Perl-like low precedence "and", "xor", "or".)

GOTCHA: parse_ini_file() returns unexpected results

"true", "on", "yes", "1" are converted to "1" (the number 1, as a string).

"false", "off", "no" are converted to "" (the empty string).

"0" is not converted, and is returned as "0" (the number 0, as a string).

Because of this behaviour, and the way values are compared, when checking for a boolean value via parse_ini_file() (i.e. whether some setting is true or false), you should simply use if ($value) { ... } instead of trying to be clever with if ($value == true) { ... }, etc.

(PHP type comparison tables.)

GOTCHA: Array iterators pass by value, not reference

$data = array(array(), array());

print_r($data);

foreach ($data as $d) {
    $d[0] = "qqq";
}

print_r($data);

GOTCHA: Arithmetic comparison: 0.0 !== 0

0.0 == 0, but 0.0 !== 0. For some reason this isn't listed in the type comparison table.

HOWTO: Pretty-print an array

print_r(), var_export() and the like output a line per key => value pair. If you want a few key => value pairs per line, try something like the following ($table is the original array):

  $a = array();

  foreach ($table as $k => $v) {
    $a[] = sprintf("%11s => %9s,", "'{$k}'", "'{$v}'");
  }

  for ($i = 0; $i < count($a); $i++) {
    echo $a[$i], " ";
    if (($i + 1) % 5 === 0) {
      echo "\n";
    }
  }

(Quick hack, doesn't handle ' in either the key or value, for example.)

HOWTO: Extend PDO and use __call() within functions

This doesn't work, and is a bug, at least as of PHP 5.2.5.

It can be fixed by applying a patch and re-compiling.

ERROR: Install fails with libgcrypt error

This happens if you're building with XSL (--with-xsl) and libgcrypt isn't available. You need to install both libgcrypt and its dependency libgpg-error:

(Or add --without-xsl to your ./configure line.)

ERROR: "Unable to load dynamic library XXX"

(Followed by "The specified module could not be found", and where XXX actually exists.)

PHP seems to produce this error fairly indiscriminately if the module can't be loaded for any reason at all, not just in the case where the apparently missing module doesn't exist on the filesystem. For example, it can happen if you neglect to include a dependency of the named module, such as if you load php_pdo_oci.dll without loading php_pdo.dll.

It can also happen if an external dependency can't be found (database DLLs?) or the wrong version is being found (Apache DLLs? Windows DLLs?). (The PATH is searched for DLLs, but DLLs can come from other places as well, such as Apache's bin directory.)

If you're having trouble with php_mysql.dll, make sure that libmySQL.dll can be found.

If you're having trouble with php_pdo_oci.dll, make sure the Oracle client libraries can be found.

If you're having trouble with php_openssl.dll, make sure libeay32.dll can be found, and that the wrong version (Apache's?) isn't being found.

FAQ: What's the syntax for PDO DSNs?

Username and password are specified as follows:

$dbh = new PDO($dsn, $username, $password);

HOWTO: eval() a string as if it were a PHP file

i.e. a function like include_string($string) to parallel include($filename).

eval($string) evaluates $string as if it were PHP code. If you want to eval a string that looks like a PHP file (i.e. a string that contains <?php and ?>), do:

function include_string($string) {
  eval('?>' . $string . '<?php ');
}  

(Astonishing that this works. What is the parser/interpreter doing there?!)

This is documented, somewhat misleadingly, on the eval manpage.

ERROR: "MDB2 Error: unknown error"

This less than helpful message may be emitted if a pragma command fails. (You do get slightly more helpful error messages if there's an error in your SQL proper.) For example, this error will be emitted if you set the charset to a character set that doesn't exist. To diagnose the problem, it might help to do a var_dump() on the database handle or statement handle--sometimes useful information is embedded there.

HOWTO: Upload large files

Despite appearances, the largest file you can upload is affected by several php.ini settings:

It's possible that since the uploaded file needs to be encoded, which increases their size, these limits need to be larger than you think.

TIP: Information about the FastCGI version of PHP

See sapi/cgi/README.FastCGI in the source.

HOWTO: Serialize a DOMNode or DOMElement to a string

i.e. the equivalent of toString() or asString() in other implementations.

Use the saveXML() method on the associated document:

echo $doc->saveXML($node);

Or, if you don't have the owner document handy:

echo $node->ownerDocument->saveXML($node);

FAQ: Where's the inverse of strftime?

As far as I can tell, there isn't one. strtotime, date_parse or--if you're using WordPress--mysql2date might do in some circumstances.

HOWTO: Access raw POST data

Use php://input:

$data = file_get_contents("php://input");

The POSTed data is URL-encoded, so you may need to decode it first:

$data = urldecode(file_get_contents("php://input"));

HOWTO: Use Zend_Mail with Google Mail's SMTP server

$config = array(
  'auth' => 'login',                                                                  
  'username' => "XXXX@gmail.com",
  'password' => "XXXX",
  'ssl' => 'ssl', // not 'tls'
  'port' => 465                                                                       
);                                                                                  

$transport = new Zend_Mail_Transport_Smtp('smtp.gmail.com', $config);

$mail = new Zend_Mail();
$mail->setBodyText('This is the text of the mail.');                                                
$mail->setFrom('sender@test.com', 'Some Sender');                                                   
$mail->addTo('mjs@beebo.org', 'Some Recipient');                                                    
$mail->setSubject('TestSubject');                                                                   
$mail->send($transport);                                                                            

See configuring other mail clients.

HOWTO: Convert an object to an array

Convert an object (i.e. $user->name) to an array (i.e. $user["name"]):

$arr = (array) $obj;

If you have nested objects you'll need to convert it manually:

function object_to_array($obj) {

    if (!is_object($obj) && !is_array($obj)) {
        return $obj;
    }
    else {
        $a = array();
        foreach ($obj as $k => $v) {
            $a[$k] = object_to_array($v);
        }
        return $a;
    }

}

(Might be able to use json_encode/json_decode as well.)

HOWTO: Log reliably

file_put_contents("/tmp/log", var_export($foo, true), FILE_APPEND | LOCK_EX);

HOWTO: Dump stack reliably

$a = array();
foreach (debug_backtrace() as $s) {
  $a[] = array(
     "file" => $s["file"],
     "link" => $s["line"]
   );
}
rawlog($a);

FAQ: How can I prevent content from being cached?

It's up to the browser whether it obeys this, but you might have have success with:

header("Pragma: no-cache");
header("Cache-Control: private, no-cache, no-cache=\"Set-Cookie\", proxy-revalidate");

(From Google Analytics headers, I think.)

FAQ: Why use array_key_exists to check if a key exists?

i.e. why not use isset()? The reason is that isset() can return true if the thing you're checking isn't an array at all, but a string:

$foo = "asdf";
$v = isset($foo['qq']); // $v is true!

This is because the string 'qq' is cast to the number 0, and $foo[0] is the first letter of the string $foo.

TIP: Quick code to convert SQL with bound parameters to a straight string

$sql = "SELECT * FROM entry WHERE email = ?";
$args = array("michael@example.com");
foreach ($args as $a) {
    $sql = preg_replace("/\?/", is_numeric($a) ? $a : "\"" . $a . "\"", $sql, 1);
}

// $sql = "SELECT * FROM entry WHERE email = 'michael@example.com'";

(If you're doing this to figure out what SQL code is being executed against the database it may be faster to turn on MySQL query logging.)

FAQ: What's the deal with PHP's time functions?

Some things to know:

ERROR: "make test" fails with "Unable to load dynamic library"

Run with:

$ TEST_PHP_ARGS=-n make test

FAQ: What's going on with my static properties?

There's only ever one instance of class-static variables (or static properties)--even if the class is extended. (The derived classes do not get their own copies of the variable--it's shared with the parent and all other classes that are derived from the same base.

That is, if you have

class Base {
    public static $data;
}

class Derived extends Base {
}

then Base::$data and Derived::$data refer to the same variable. (Within both methods, self::$data similarly refers to the same thing.)

FAQ: How to run individual/selected PHP tests?

To test the /usr/local/php-5.3.0/bin/php binary using the phpt files in ext/xsl/tests,

$ TEST_PHP_EXECUTABLE=/usr/local/php-5.3.0/bin/php sapi/cli/php run-tests.php ext/xsl/tests

(Can replace the directory with individual files as well.)

FAQ: How to compile from svn checkout?

See http://www.php.net/svn.php.

Note if you're building on a virtual machine, you may wish to do the checkout on the virtual machine, rather than on the host. This is because the buildconf script seems to run svn under some circumstances, and if the version of svn on the virtual machine is older than the version which checkout out the source, it will fail.

FAQ: How to debug with gdb?

If you have a broken test that you want to debug with gdb, you'll probably still have the *.php file in a tests directory. (If the test fails, run-tests.php keeps the generated parts.) In that case, you can debug with gdb via something like:

$ gdb --args sapi/cli/php ext/xsl/tests/*method1.php

HOWTO: Install pear

[Edit: I don't recommend doing this anymore. pear causes a lot of confusion and problems when installed with PHP, or separately. (In fact it doesn't seem to be possible to install it separately, the INSTALL file notwithstanding.)]

There's a few problems with the bundled pear: it gets confused, and it also wants to install iself once for every PHP binary installed. It seems to be slightly better to install pear separately (although there's problems with this approach as well...).

  1. Download go-pear.php from http://pear.php.net/go-pear.
  2. Start the installer with php go-pear.php.
  3. Change the "Installation prefix" to /usr/local.
  4. Don't let it edit php.ini.

HOWTO: Install PHPUnit

  1. Download from http://pear.phpunit.de/get/.
  2. Once extracted, copy the PHPUnit directory somewhere like /usr/local/lib/php.
  3. Rename phpunit.php to phpunit, and then amend it so that it uses set_include_path() to add /usr/local/lib/php to the include_path.
  4. Copy phpunit to /usr/local/bin/phpunit.
  5. Enjoy!

FAQ: Xdebug doesn't "break"

If Xdebug seems to be working fine (e.g. it's listed in phpinfo()), and your client (e.g. NetBeans) isn't complaining that it couldn't connect then the problem could be that it's being loaded as an extension instead of a zend_extension. (Note that if you load it "twice", first as an extension and once as an zend_extension, the first will take precedence, and you won't be given any warning that anything went wrong. More info.)

HOWTO: Troubleshoot Xdebug problems

Check whether the xdebug extension appears in phpinfo() output

Check that it's being loaded via zend_extension

Comment out this line, and see that it isn't loaded, to make sure it's not being loaded by an extension line somewhere else.

Check that you can connect to the client from the server

You should be able to telnet mel.beebo.org 9000 and have something accept your connection. (There doesn't seem to be any "ping" command or similar that is guaranteed to generate a response, unfortunately.)

Check that the server is responding as expected

It's probably easiest and most reliable to use the command-line debugclient that comes with Xdebug for this. (Compilation instructions; it's a standalone executable; you don't need to install it with make install.)

When you run it, it will start listening on port 9000. Configure Xdebug with something like:

xdebug.remote_enable = 1
xdebug.remote_host = mel.beebo.org

(Other settings.)

Load a URL like http://beebo.local/?XDEBUG_SESSION_START=netbeans-xdebug and Xdebug should attempt to connect to the debugclient--you'll see a message.

In the client, enter

status -i qqqq

and you should receive a response from the server. (The -i qqqq is merely to identify the session; the value shouldn't be important.)

If you next enter

step_into -i qqqq

you should receive a response from Xdebug indicating that it has stopped, the filename and line number, etc. (If it doesn't stop, see the above FAQ!)