mb_detect_encoding in PHP — Detect Character Encoding

Basic Detection Example

Detect the encoding of a string with Russian text:

<?php
$string = "??????, ???!"; // Russian text
$encoding = mb_detect_encoding($string, "UTF-8, ISO-8859-1, Windows-1251");

echo "Detected encoding: " . ($encoding ?: "Unknown");
?>

Output: Detected encoding: UTF-8

Checking Against Specific Encodings

<?php
$text = "Hello World";  // Text with accented characters
$encodings = ["UTF-8", "ISO-8859-1", "Windows-1252"];
$detected = mb_detect_encoding($text, $encodings, true); // Strict mode

echo $detected ? "Encoding: $detected" : "Encoding not detected";
?>

Possible Output: Encoding: UTF-8

Detect and Convert to UTF-8

<?php
// Simulate reading content that might be in a different encoding
$string = file_get_contents("legacy_data.txt");

// Detect the current encoding
$encoding = mb_detect_encoding($string, ["UTF-8", "ISO-8859-1", "Windows-1252"]);

if ($encoding && $encoding !== "UTF-8") {
    // Convert to UTF-8
    $string = mb_convert_encoding($string, "UTF-8", $encoding);
    echo "Converted from $encoding to UTF-8.";
} else {
    echo "String is already UTF-8 or encoding detection failed.";
}

// Now $string is (hopefully) in UTF-8
echo "Processed string: " . $string;
?>

Fallback Strategies

1. Force conversion with "auto" detection:

$string = mb_convert_encoding($string, "UTF-8", "auto");

2. Use iconv() with IGNORE option to handle invalid characters:

$detected = mb_detect_encoding($string, mb_list_encodings(), true);
if ($detected) {
    $string = iconv($detected, "UTF-8//IGNORE", $string);
}

3. Check if string is valid UTF-8 before processing:

if (!mb_check_encoding($string, 'UTF-8')) {
    // Not UTF-8, try to detect and convert
    $string = mb_convert_encoding($string, 'UTF-8', 'auto');
}