PHP Reading Files

How it works

fopen returns a resource or false, and read operations have their own failure/end-of-file results. A loop can process one line at a time while try/finally closes the handle if processing fails. Keep encoding and maximum sizes explicit for untrusted imports. A line-based reader also needs a policy for a maliciously long single line, not just a large number of ordinary lines.

Run it locally

Run this complete source locally with PHP 8.2 or newer. Save it using the filename shown and run the command below. PHP is not currently available in Bhylu’s browser playground. Apache and MySQL are not needed for an ordinary CLI example.

php -l file-read.php
php file-read.php

Download this source as a local PHP lab file. Keep lab files separate from the Bhylu project and production data.

Example

<?php
declare(strict_types=1);

$file = tempnam(sys_get_temp_dir(), "bhylu-read-");
if ($file === false) throw new RuntimeException("Cannot create fixture");
file_put_contents($file, "Spade\nDrill\n");
$handle = fopen($file, "rb");
if ($handle === false) { unlink($file); throw new RuntimeException("Cannot open fixture"); }
try {
    while (($line = fgets($handle, 256)) !== false) echo trim($line), "\n";
    if (!feof($handle)) throw new RuntimeException("Read failure");
} finally { fclose($handle); unlink($file); }

Expected result

Spade
Drill

The handle is owned by this block and closed even if an exception is raised. fgets has a bounded read size, so a longer physical line could arrive in several pieces; a real parser must detect and reject or assemble that condition according to its contract. The fixture’s lines are deliberately short and use a known UTF-8-compatible ASCII subset.