utf8_decode() functions in PHP are used for encoding and decoding strings between ISO-8859-1 (Latin-1) encoding and UTF-8 encoding.
While PHP’s standard library does include
utf8_decode functions, they are limited to converting between ISO-8859-1 (Latin-1) and UTF-8 encodings. It is important to note that these functions cannot be relied upon to detect and convert other character encodings, such as Windows-1252, UTF-16, and UTF-32, to UTF-8. Attempting to use these functions with arbitrary text can introduce bugs that may not produce any warnings or errors, but can result in unexpected and undesired outcomes.
Examples of common bugs that can occur include:
- The Euro sign (
€, character sequence
\xE2\x82\xAC), when passed to
utf8_encode function as
utf8_encode("€") results in a a garbled (also called as “Mojibake”) text output of
- The German Eszett character (
ß, character sequence
\xDF), when passed through
utf8_encode("ß") results in
utf8_decode functions have been deprecated in PHP 8.2 due to their misleading function names, lack of error messages and warnings, and their inability to support character encodings other than ISO-8859-1.
As a result, using these functions in PHP 8.2 will emit a deprecation notice. It is recommended to use alternative functions or libraries that provide better support for handling different character encodings. These functions will be removed entirely in PHP 9.0, so it is important to migrate to alternative solutions as soon as possible to avoid compatibility issues in future versions of PHP.
// Function utf8_encode() is deprecated in ... on line ...
// Function uft8_decode() is deprecated in ... on line ...
Replacement for the deprecated functions
Instead, the PHP documentation recommends using the multibyte string functions that are part of the mbstring extension for handling multibyte encodings, including UTF-8. For example, the
mb_convert_encoding() function can be used to convert strings between different character encodings, including to and from UTF-8.
Here is an example of how to use
mb_convert_encoding() to encode a string to UTF-8:
$string = "Some string with non-ASCII characters: é, ö, ü";
$utf8_string = mb_convert_encoding($string, 'UTF-8');
And here is an example of how to use
mb_convert_encoding() to decode an UTF-8 string:
$utf8_string = "Some UTF-8 encoded string: é, ö, ü";
$string = mb_convert_encoding($utf8_string, 'ISO-8859-1', 'UTF-8');