PHP & JSON: Serialization, Deserialization & REST Integration

JSON (JavaScript Object Notation) is the universal lingua franca of the modern internet. When a PHP backend communicates with a React frontend, a Flutter mobile app, or third-party web services (like Google Maps, Stripe, or Weather APIs), data is exchanged as JSON. PHP provides two native, lightning-fast C-level functions: json_encode() (converting PHP data to JSON) and json_decode() (parsing JSON into PHP arrays/objects).

1. Converting PHP Arrays to JSON: json_encode()

<?php
    $student = [
        "id"        => 1001,
        "name"      => "Vikram Aditya",
        "course"    => "BCA",
        "skills"    => ["PHP 8", "MySQL", "JavaScript"],
        "graduated" => false
    ];

    // Standard JSON output
    $jsonOutput = json_encode($student);
    echo $jsonOutput . "<br><br>";

    // Pretty Printed JSON for human readability
    $prettyJson = json_encode($student, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE);
    echo "<pre>" . htmlspecialchars($prettyJson) . "</pre>";
?>

2. Parsing JSON into PHP: json_decode()

When reading JSON payloads from API endpoints or frontend AJAX requests:

<?php
    $jsonString = '{"brand":"Veewom","course":"PHP 8 Masterclass","duration_weeks":12}';

    // 1. Decode into a PHP Associative Array (2nd param = true)
    $arr = json_decode($jsonString, true);
    echo "Course Name (Array): " . $arr["course"] . "<br>";

    // 2. Decode into a PHP Object (2nd param omitted or false)
    $obj = json_decode($jsonString);
    echo "Course Name (Object): " . $obj->course . "<br>";
?>

Robust Error Handling with json_last_error()

Malformed JSON strings (e.g. missing quotes or trailing commas) will fail to decode. Always check for errors in production APIs:

<?php
    $badJson = '{"name": "Vikram", "marks": 90, }'; // Invalid trailing comma!

    $data = json_decode($badJson, true);

    if (json_last_error() !== JSON_ERROR_NONE) {
        echo "JSON Parse Error: " . json_last_error_msg();
    }
?>

BCA / CS University Exam Corner

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