July 28, 2025 in Php
how to write concurrent data in json file in php
<?php
$file = 'data.json';
$fp = fopen($file, 'c+'); // Open for reading and writing, create if not exists
if (flock($fp, LOCK_EX)) { // Acquire an exclusive lock
$current_data = [];
if (filesize($file) > 0) {
$json_content = fread($fp, filesize($file));
$current_data = json_decode($json_content, true);
if ($current_data === null) {
// Handle JSON decoding error
error_log("Error decoding JSON from $file. Resetting data.");
$current_data = [];
}
}
// Simulate adding new data
$new_entry = [
'id' => uniqid(),
'message' => 'Hello from process ' . getmypid(),
'timestamp' => date('Y-m-d H:i:s')
];
$current_data[] = $new_entry;
ftruncate($fp, 0); // Truncate the file
rewind($fp); // Rewind file pointer
$json_output = json_encode($current_data, JSON_PRETTY_PRINT);
fwrite($fp, $json_output);
flock($fp, LOCK_UN); // Release the lock
fclose($fp);
echo "Data written successfully by process " . getmypid() . "\n";
} else {
echo "Could not acquire lock for $file by process " . getmypid() . "\n";
}
?> $file = 'activitydata.json';
$fp = fopen($file, 'c+');
if (flock($fp, LOCK_EX)) {
$arrayData = [];
if (filesize($file) > 0) {
$currentData = fread($fp, filesize($file));
$arrayData = json_decode($currentData, true); // true for associative array
if ($arrayData === null) {
// Handle JSON decoding error
error_log("Error decoding JSON from $file. Resetting data.");
$arrayData = [];
}
}
$arrayData[] = $success;
ftruncate($fp, 0); // Truncate the file
rewind($fp); // Rewind file pointer
$jsonData = json_encode($arrayData, JSON_PRETTY_PRINT); // JSON_PRETTY_PRINT for readability
fwrite($fp, $jsonData);
flock($fp, LOCK_UN); // Release the lock
fclose($fp);
}
