Using PHP file_put_contents() to Write Data to Files and URLs

In PHP development, the built‑in file_put_contents() function can write a string or other data to a specified file or URL.

The function creates a new file if it does not exist and returns the number of bytes written or false on failure.

Basic syntax:

file_put_contents(string $filename, mixed $data, int $flags = 0, resource $context = ?): int|false

Parameters: $filename – target file name or URL; $data – data to write; $flags – optional write mode; $context – optional stream context.

Example 1 shows writing a string to a local file, creating the file if necessary and checking the result.

$data = "Hello, world!";
$file = "test.txt";
$result = file_put_contents($file, $data);
if ($result !== false) {
    echo "Data successfully written to file";
} else {
    echo "Failed to write file";
}

Example 2 demonstrates writing the same string to a remote URL, assuming the URL has write permissions.

$data = "Hello, world!";
$url = "https://example.com/test.php";
$result = file_put_contents($url, $data);
if ($result !== false) {
    echo "Data successfully written to URL";
} else {
    echo "Failed to write URL";
}

The function is useful for logging, file caching, and remote API calls due to its simplicity and flexibility.