PHP File Handling Tutorial: Practical Techniques for Reading and Writing Files

Introduction

File handling is one of the most common tasks in web development. PHP provides a variety of built-in functions that make it easy to read and write files. This article introduces several commonly used PHP file operation methods and demonstrates their implementation with practical examples.

Reading File Content

There are multiple ways to read a file in PHP. Below are two of the most commonly used methods.

Using file_get_contents()

The file_get_contents() function is one of the simplest and most direct ways to read a file. It reads the entire file into a single string.

$fileContent = file_get_contents('path/to/file.txt');
echo $fileContent;

The code above reads the entire contents of file.txt and outputs it to the browser.

Using fopen() and fgets()

If you need to read a file line by line or process large files, you can open it with fopen() and read each line with fgets(). Here’s an example:

$filePath = 'path/to/file.txt';
$handle = fopen($filePath, 'r');
if ($handle) {
    while (($line = fgets($handle)) !== false) {
        echo $line;
    }
    fclose($handle);
}

This approach is ideal for handling large files or performing operations while reading data incrementally.

Writing File Content

Writing to files is a frequent task in PHP, such as for logging or saving configuration data. Below are two efficient methods for writing files.

Using file_put_contents()

The file_put_contents() function provides a simple way to write strings to a file. It takes the file path and the data to be written as parameters and returns the number of bytes written.

$filePath = 'path/to/file.txt';
$fileContent = 'Hello, world!';
$result = file_put_contents($filePath, $fileContent);
if ($result !== false) {
    echo 'Write successful';
} else {
    echo 'Write failed';
}

This method is perfect for simple write operations, such as saving small files or logs.

Using fopen() and fwrite()

For more control over file writing — for instance, writing data in parts — you can use fopen() and fwrite() together. Example:

$filePath = 'path/to/file.txt';
$handle = fopen($filePath, 'w');
if ($handle) {
    $data = 'Hello, world!';
    fwrite($handle, $data);
    fclose($handle);
    echo 'Write successful';
}

This method is suitable for dynamically writing data, such as generating files or saving logs in real time.

Important Considerations for File Operations

When performing file operations in PHP, pay attention to the following points:

• Permission issues: Ensure the PHP script has sufficient read and write permissions for the target file or directory; otherwise, the operation will fail.
• Path issues: Use absolute paths or correct relative paths to avoid errors caused by incorrect file locations.
• Error handling: Always handle possible failures using conditional checks or exceptions to keep your program robust.

Conclusion

This tutorial introduced PHP’s most common file handling techniques, including file_get_contents(), file_put_contents(), fopen(), fread(), and fwrite(). By mastering these operations, you can efficiently manage file-related tasks in your web development projects.