File Read/Write

Introduction

File handling is an essential part of programming that allows applications to create, read, update, and delete files. File Read/Write operations help developers store data permanently and manage information efficiently.

In PHP, file handling functions make it easy to work with text files, logs, reports, configuration files, and user-generated content.

Objectives

By the end of this training, you will be able to:

• Understand file handling concepts
• Create and open files in PHP
• Read data from files
• Write and append data to files
• Close files properly
• Check file existence and permissions
• Handle file operations safely
• Build simple file management applications

What is File Read/Write

File Read/Write refers to the process of accessing file content for reading information or storing data into files.

File Reading

Used to retrieve data stored inside a file.

File Writing

Used to create new content or update existing file content.

Importance of File Handling

File handling is important because it helps developers:

• Store data permanently
• Generate reports and logs
• Save user information
• Manage application settings
• Process uploaded files
• Build data-driven applications

Common PHP File Functions

fopen()

Used to open a file.

<?php
$file = fopen("data.txt", "r");
?>

fclose()

Used to close a file after use.

<?php
fclose($file);
?>

fread()

Reads data from a file.

<?php
$file = fopen("data.txt", "r");
echo fread($file, filesize("data.txt"));
fclose($file);
?>

fwrite()

Writes data into a file.

<?php
$file = fopen("data.txt", "w");
fwrite($file, "Welcome to PHP File Handling");
fclose($file);
?>

File Modes in PHP

Read Mode

r

Opens a file for reading only.

Write Mode

w

Opens a file for writing and clears existing content.

Append Mode

a

Adds new content at the end of the file.

Read and Write Mode

r+

Allows both reading and writing.

Reading Files Line by Line

<?php
$file = fopen("data.txt", "r");

while(!feof($file)) {
    echo fgets($file);
}

fclose($file);
?>

Appending Data to a File

<?php
$file = fopen("data.txt", "a");
fwrite($file, "\nNew Record Added");
fclose($file);
?>

Checking if a File Exists

<?php
if(file_exists("data.txt")) {
    echo "File Exists";
} else {
    echo "File Not Found";
}
?>

Creating a New File

<?php
$file = fopen("newfile.txt", "w");
fclose($file);
?>

Deleting a File

<?php
unlink("oldfile.txt");
?>

File Handling Best Practices

• Always close files after use
• Check if files exist before reading
• Use proper file permissions
• Validate user input for file operations
• Avoid overwriting important files
• Handle errors properly

Advantages of File Read/Write

• Permanent data storage
• Easy report generation
• Improved application management
• Efficient log handling
• Better data organization

Real World Applications

File handling is used in:

• Student management systems
• Attendance systems
• Website logs
• Report generation tools
• Content management systems
• Backup systems

Practical Exercise

Create a PHP application that:

• Creates a text file
• Stores student records
• Reads and displays stored data
• Appends new records
• Deletes unwanted files

Final Presentation

In your final presentation, explain:

• What File Read/Write means
• Importance of file handling
• Common PHP file functions
• File modes and their uses
• Reading and writing operations
• Real-world applications of file handling