Removed PHP functions and their replacements #

Part 4, chapter 6. An extension written for PHP 5 may call functions that no longer exist. The result is Call to undefined function, a fatal error, when the line runs. This chapter lists the functions old extensions use most, the PHP version that removed them, and a replacement. Every function in the first table was checked to be missing in PHP 8.0.

Find them #

grep -rnE '\b(each|create_function|split|spliti|ereg|eregi|ereg_replace|eregi_replace|mysql_[a-z_]+|money_format|get_magic_quotes_gpc|get_magic_quotes_runtime|set_magic_quotes_runtime|fgetss|call_user_method|session_register|mcrypt_[a-z_]+|is_real|hebrevc|convert_cyr_string)\s*\(' --include='*.php' extension/myoldext/

A hit inside a comment or inside a string is harmless; a hit preceded by -> or :: is a method of the same name, not the PHP function.

The table #

each() #

The old idiom walks an array one entry at a time:

// before
while ( list( $key, $value ) = each( $array ) )
{
    echo "$key=$value\n";
}

// after
foreach ( $array as $key => $value )
{
    echo "$key=$value\n";
}

Where the loop really depends on the array's internal pointer (it continues where an earlier loop stopped), keep the pointer and replace only the call. That was the fix in the birthday extension during the PHP 8.0 review:

<?php
function myOldExtNextPair( array &$array )
{
    $key = key( $array );
    if ( $key === null )
    {
        return false;
    }
    $value = current( $array );
    next( $array );
    return array( $key, $value );
}

create_function() #

create_function() built a function from a string with eval(), which is also why it was removed. Replace the string with a real anonymous function:

// before
usort( $nodes, create_function( '$a,$b', 'return strcmp( $a->attribute( "name" ), $b->attribute( "name" ) );' ) );

// after
usort( $nodes, function( $a, $b ) {
    return strcmp( $a->attribute( 'name' ), $b->attribute( 'name' ) );
} );

ereg() and split() #

POSIX regular expressions became PCRE ones. Add delimiters, and escape the delimiter if it appears in the pattern:

split() with a plain separator was the fix in enhancedezbinaryfile during the PHP 8.0 review.

mysql_*() #

An extension that talks to the database through mysql_query() was already wrong in its own time: it worked only on MySQL and only on the kernel's connection by chance. Exponential 6 supports several database engines, and the replacement is the kernel's database layer, which uses the site's connection:

<?php
$db = eZDB::instance();
$id = (int)$http->postVariable( 'ItemID' );
$name = $db->escapeString( $http->postVariable( 'Name' ) );

$rows = $db->arrayQuery( "SELECT id, name FROM myoldext_item WHERE id = $id" );
$db->query( "UPDATE myoldext_item SET name = '$name' WHERE id = $id" );

Integers are cast with (int), strings go through escapeString(). For anything more than a few queries, use eZPersistentObject instead (Persistent objects and your own tables). The whole topic is in Database code for PHP 8 and every engine.

Magic quotes #

Old code often wrapped every input in a check like this:

// before
$value = get_magic_quotes_gpc() ? stripslashes( $_POST['value'] ) : $_POST['value'];

// after
$value = $http->postVariable( 'value' );

Magic quotes were removed in PHP 5.4, so the stripslashes() branch has not run for over a decade. Read input through eZHTTPTool ($http = eZHTTPTool::instance();), which the kernel's modules already do.

mcrypt #

mcrypt was removed from PHP in 7.2. Data encrypted with it can be decrypted with OpenSSL only for some of its ciphers and modes, and only with care. Plan this change separately: write a one-time script that decrypts with the old method on a PHP 7.1 installation and re-encrypts with sodium_crypto_secretbox() or openssl_encrypt(). The sources of this project do not contain such a migration, so test it on a copy of the data.

When a library is the problem #

Sometimes the removed function is inside a third-party library the extension ships (an old PDF writer, an old mail library). Do not patch the library line by line. Look for a newer release of the same library, or for a maintained replacement, and upgrade it as a whole, with its license. Write down in the extension's changelog which version you moved to and why.

Related pages #

• Previous: PHP 8.1 to 8.5 deprecations
• Next: Old-style constructors and static calls
• PHP 8.0 support
• Removed extensions and SAPIs in the PHP manual
• Free documentation: this page is free to copy, translate and improve under the GNU FDL 1.3.