• +91-9142290450

  • Hajipur, Bihar, 844101

☰
❮
❯

PHP File Handling

← Previous Next →

Files are a vital part of every website. Whether you’re saving user feedback, uploading photos, or generating reports, file handling allows your PHP application to store, read, and update information efficiently.

PHP provides built-in functions to create, read, write, and delete files easily. Understanding file handling is essential for building interactive applications where data needs to persist even after the user leaves the page.

Why File Handling Matters

When Vrinda builds a feedback system, she might want to save user comments to a file instead of a database. Similarly, Ananya could generate daily logs for her website’s visitors. File handling makes these tasks simple and effective.

With PHP file functions, you can:

  • Store data in text or CSV files

  • Read or display content from existing files

  • Append new data without overwriting old content

  • Delete or rename files when needed

Understanding PHP File Functions

PHP provides several key functions for file handling:

Function Purpose
fopen() Opens a file
fclose() Closes an open file
fread() Reads data from a file
fwrite() Writes data into a file
file_exists() Checks if a file exists
unlink() Deletes a file

Let’s go through these step-by-step.

Opening a File

To work with a file, you first need to open it using the fopen() function.

<?php
$file = fopen("example.txt", "r"); // open file in read mode
?>

The fopen() function requires two parameters:

  1. File name

  2. Mode (how you want to open it)

File Modes in PHP

Mode Description
r Read-only; starts at the beginning of the file
w Write-only; erases existing content or creates a new file
a Write-only; appends data to the end of the file
x Creates a new file for writing; returns an error if file exists
r+ Read and write; starts at the beginning of the file
w+ Read and write; overwrites existing content
a+ Read and write; appends data if the file exists

For example, Riya wants to open a file in write mode to save her notes:

<?php
$file = fopen("notes.txt", "w");
fwrite($file, "Riya is learning PHP File Handling.");
fclose($file);
?>

This code creates a new file notes.txt if it doesn’t exist and writes the sentence into it.

Reading from a File

Let’s say Ananya created a file named message.txt containing a welcome message. She can read it using fopen() and fread().

<?php
$file = fopen("message.txt", "r");
$content = fread($file, filesize("message.txt")); // read full file
fclose($file);
echo $content;
?>

Here, filesize() tells PHP how many bytes to read. This way, the whole content is read and displayed.

Writing to a File

You can write data using the fwrite() function.

<?php
$file = fopen("data.txt", "w");
fwrite($file, "This file is created by Ananya.\n");
fclose($file);
echo "Data written successfully!";
?>

This will overwrite the file if it already exists. If you want to append data instead of overwriting, open it in append mode (a).

<?php
$file = fopen("data.txt", "a");
fwrite($file, "Vrinda added another line.\n");
fclose($file);
?>

Now, the new line will be added at the end of the file without deleting the old content.

Checking if a File Exists

Before opening or deleting a file, it’s good practice to check if it exists using file_exists().

<?php
if (file_exists("data.txt")) {
    echo "File exists!";
} else {
    echo "File not found!";
}
?>

If Riya runs this code and data.txt exists, she’ll get the message “File exists!”.

Deleting a File

To delete a file, use the unlink() function.

<?php
if (file_exists("old_data.txt")) {
    unlink("old_data.txt");
    echo "File deleted successfully.";
} else {
    echo "File does not exist.";
}
?>

This is useful when cleaning up temporary or outdated files.

Reading File Line by Line

Sometimes, you don’t need the entire file at once. You can read it line by line using fgets().

<?php
$file = fopen("notes.txt", "r");
while (!feof($file)) { // loop until end of file
    echo fgets($file) . "<br>";
}
fclose($file);
?>

If Vrinda wrote multiple lines in her notes file, this will display each line separately on a webpage.

Example: Writing User Feedback to a File

Here’s a practical example. Suppose Ananya creates a simple feedback form.

feedback.html

<form action="save_feedback.php" method="post">
    Name: <input type="text" name="name"><br>
    Feedback: <textarea name="feedback"></textarea><br>
    <input type="submit" value="Submit">
</form>

save_feedback.php

<?php
$name = $_POST['name'];
$feedback = $_POST['feedback'];

$file = fopen("feedback.txt", "a"); // open file in append mode
fwrite($file, "Name: $name\nFeedback: $feedback\n\n");
fclose($file);

echo "Thank you, $name! Your feedback has been saved.";
?>

Whenever a user submits feedback, the data is added to feedback.txt.
Each new entry is written on a new line without overwriting the old ones.

File Handling with Error Checking

It’s good practice to check for errors when opening files.

<?php
$file = @fopen("missing.txt", "r") or die("Unable to open file!");
?>

The @ suppresses warnings, and die() displays a custom message if the file can’t be opened.

If the file doesn’t exist, the script will stop and show “Unable to open file!”

Security Tips for File Handling

  1. Validate user input: Never trust filenames from user input. Always sanitize them.

  2. Use proper permissions: Make sure your files are not publicly writable.

  3. Avoid including user-uploaded files directly: This prevents malicious code execution.

  4. Keep sensitive files outside the web root: Store configuration or log files in secure directories.

Real-Life Example: Logging User Activity

If Riya wants to log whenever a user visits her site:

<?php
date_default_timezone_set("Asia/Kolkata");
$log = "User visited on " . date("Y-m-d H:i:s") . "\n";
$file = fopen("visits.log", "a");
fwrite($file, $log);
fclose($file);
?>

Each time someone visits, this code adds a new timestamp to visits.log.
Later, she can analyze this file to see daily or weekly traffic.

Summary of the Tutorial

PHP file handling allows you to work with files easily — whether you’re reading, writing, or deleting them.
You learned how to:

  • Open and close files with fopen() and fclose()

  • Write and append data with fwrite()

  • Read file content using fread() and fgets()

  • Check for existence and delete files with file_exists() and unlink()

These functions are the building blocks of many features such as logs, uploads, reports, and configuration systems.

Practice Questions

  1. Create a file named example.txt and write the text “Hello, Vrinda!” into it.

  2. Open an existing file notes.txt and read its full content using fread().

  3. Append the line “Riya added a note.” to notes.txt without overwriting existing content.

  4. Check if a file named data.txt exists before trying to open it.

  5. Delete a file named old_feedback.txt if it exists.

  6. Read a file line by line using fgets() and display each line in a separate HTML paragraph.

  7. Create a simple HTML form to submit feedback and save it to a text file named feedback.txt.

  8. Log the current date and time into a file named visits.log each time a user accesses the page.

  9. Use mktime() or date() to include the current timestamp in a file when writing new content.

  10. Handle file open errors gracefully using @fopen() and die() to display a custom message if the file cannot be opened.

← Previous Next →

PHP

online coding class codepractice

PHP Basics

PHP Data

Control Flow

PHP Functions

PHP Arrays

PHP Forms

PHP Advanced

Cookies & Sessions

Filters & JSON

PHP Exceptions

PHP OOP

MySQL with PHP

PHP and XML

AJAX with PHP

codepractice logo
Login
Go Back Top