Reading and writing files

file_get_contents

Function file_get_contents reads a whole file into a string.

Build the path from __DIR__ so the script works from any working directory. Use it for small text files and templates.

$path = __DIR__ . "/data.txt"; $text = file_get_contents($path); echo $text;

file_put_contents with LOCK_EX

Function file_put_contents writes a string in one call. Add flag LOCK_EX to lock the file during writing.

The function returns the number of bytes written or false on failure.

$path = __DIR__ . "/data.txt"; file_put_contents($path, "Hello files\n", LOCK_EX); echo file_get_contents($path);

Check with is_file

Always check existence before reading user supplied paths.

Function is_file returns true only for regular files. Function file_exists also matches directories, so pick the check that fits the task.

$path = __DIR__ . "/data.txt"; var_dump(is_file($path)); var_dump(file_exists($path));

Anchor paths with __DIR__

Constant __DIR__ holds the directory of the current file. Join it with a file name to get an absolute path.

Absolute paths keep includes and reads stable after moves and deploys.

$path = __DIR__ . "/data.txt"; echo __DIR__; echo dirname($path);

Next: Errors: read, reproduce, fix

Article author: Arthur Isaev