PHP JSON Exercises : Display JSON decode errors

PHP JSON: Exercise-4 with Solution

Write a PHP function to display JSON decode errors.

Sample Solution:

PHP Code:

<?php
// Define a function to handle JSON error messages
function json_error_message($json_str)
{
    // Create an array to hold the JSON string
    $json[] = $json_str;
    
    // Output the JSON string
    echo $json;
    
    // Iterate through the array of JSON strings
    foreach ($json as $string)
    {
        // Output the decoding attempt
        echo 'Decoding: ' . $string."\n";
        
        // Attempt to decode the JSON string
        json_decode($string);
        
        // Check for JSON decoding errors and output corresponding messages
        switch (json_last_error())
        {
            case JSON_ERROR_NONE:
                echo ' - No errors'."\n";
                break;
            case JSON_ERROR_DEPTH:
                echo ' - Maximum stack depth exceeded'."\n";
                break;
            case JSON_ERROR_STATE_MISMATCH:
                echo ' - Underflow or the modes mismatch'."\n";
                break;
            case JSON_ERROR_CTRL_CHAR:
                echo ' - Unexpected control character found'."\n";
                break;
            case JSON_ERROR_SYNTAX:
                echo ' - Syntax error, malformed JSON'."\n";
                break;
            case JSON_ERROR_UTF8:
                echo ' - Malformed UTF-8 characters, possibly incorrectly encoded'."\n";
                break;
            default:
                echo ' - Unknown error'."\n";
                break;
        }
    }
}

// Call the function with a sample JSON string
json_error_message('{"color1": "Red Color"}');
?>

Output:

PHP Notice:  Array to string conversion in /home/students/98837c40-6
86c-11e7-a315-21e19fc8c51e.php on line 5                            
ArrayDecoding: {"color1": "Red Color"}                              
 - No errors

Explanation:

In the exercise above,

• function json_error_message($json_str): Defines a function called "json_error_message()" that takes a JSON string as input.
• $json[] = $json_str;: Creates an array containing the provided JSON string.
• echo $json;: Outputs the JSON string.
• foreach ($json as $string) { ... }: Iterates through each JSON string in the array.
• echo 'Decoding: ' . $string."\n";: Outputs a message indicating the JSON decoding attempt.
• json_decode($string);: Attempts to decode the JSON string.
• switch (json_last_error()) { ... }: Checks for JSON decoding errors and outputs corresponding messages based on the error code.

Flowchart :

PHP Code Editor:

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