File Handling in PHP with Example

What is file in PHP?

• In PHP, a "file" typically refers to a digital document or a resource that is stored on a computer's file system.
• Files in PHP can come in various formats, such as text files, binary files, and more.

What is file handling in PHP?

PHP Open File - fopen()

• You can open a file with the fopen() function.
• It takes two arguments: the filename and the mode in which you want to open the file (read, write, append, etc.).

1$file = fopen("example.txt", "r"); 

• example.txt is the name of the file we want to open.
• "r" indicates that we are opening the file in read-only mode.

PHP Close File - fclose()

1fclose($file); // Closes the file

PHP Read File - fread()

• Reading a file is a common task, and PHP makes it straightforward with fread().
• This function allows you to read the content of a file.

1$file = fopen("example.txt", "r");
2$data = fread($file, filesize("example.txt"));
3fclose($file);

• filesize("example.txt") calculates the size of the "example.txt" file in bytes, which is then used as the number of bytes to read.

PHP Write File - fwrite()

• Writing to a file is useful when you want to store data or configuration changes.
• Here's how you can write content to a file using fwrite():

1$file = fopen("example.txt", "w"); // Open in write mode
2$content = "file handling in php";
3fwrite($file, $content);
4fclose($file);

PHP Delete File - unlink()

• Deleting a file is as simple as it gets.
• The unlink() function removes a file from the server or local directory.

1unlink("example.txt"); // Deletes example.txt

Creating a Directory in PHP

• To create a directory in PHP, you can use the mkdir() function.
• Accepts a list as an argument and creates the list in the current working directory.

1mkdir("new_directory"); 

PHP Open File

1<?php
2// Open a file in read-only mode
3$file = fopen("example.txt", "r");
4
5if ($file) {
6    echo "File opened successfully.";
7    fclose($file); // Close the file when you're done
8} else {
9    echo "Failed to open the file.";
10}
11?>
12

PHP Close File

1<?php
2$file = fopen("example.txt", "r"); // Open a file in read-only mode
3
4if ($file) {
5    // Do some operations with the file
6
7    // Close the file when you're done
8    fclose($file);
9    echo "File closed successfully.";
10} else {
11    echo "Failed to open the file.";
12}
13?>

PHP Read File

1<?php
2$file = fopen("example.txt", "r"); // Open in read-only mode
3
4if ($file) {
5    // Read the entire file
6    $content = fread($file, filesize("example.txt"));
7    fclose($file); // Close the file
8
9    // Display the file content
10    echo $content;
11} else {
12    echo "Failed to open the file.";
13}
14?>

PHP Delete file

1<?php
2$fileToDelete = "example.txt";
3
4if (unlink($fileToDelete)) {
5    echo "File '$fileToDelete' has been deleted.";
6} else {
7    echo "Failed to delete '$fileToDelete'.";
8}
9?>
10

PHP Write file

1<?php
2$file = fopen("example.txt", "w"); // Open in write mode
3
4if ($file) {
5    // Content to write to the file
6    $content = "This is some text to be written to the file.";
7
8    // Write content to the file
9    fwrite($file, $content);
10
11    // Close the file when you're done
12    fclose($file);
13    echo "Content has been written to the file.";
14} else {
15    echo "Failed to open the file.";
16}
17?>
18

What is File Inclusion in PHP?

• File Inclusion is a powerful feature in PHP that allows you to include the contents of one PHP file within another.
• Think of it as building blocks; you can create modular code and reuse common elements, saving time and effort.

Including Files in PHP

Difference between Include and Require

Include Statement:

• The include statement is used to include a file in your PHP script.
• If the included file is not found or there's an error, PHP will generate a warning but continue executing the script.
• In other words, if the included file is missing or has an issue, it won't stop your entire script from running. It's more lenient.
• It's commonly used for including files that are not crucial for the script's functionality, such as optional components or templates.

Require Statement:

• The require statement is also used to include a file in your PHP script.
• However, if the included file is not found or there's an error, PHP will generate a fatal error, and the script execution will stop immediately.
• In essence, if the required file is missing or problematic, it will halt the entire script. It's more strict and ensures that essential files are present and functioning.
• It's typically used for including files that are critical for the script's functionality, such as configuration files or important libraries.

• include generating a warning for errors and continuing script execution.
• require generates a fatal error for errors and stops script execution.

Handling File Uploads

Uploading Files

• To allow users to upload files to your web application, create an HTML form with an input field of type "file."
• PHP can then handle the uploaded files using the $_FILES superglobal.

1<form action="upload.php" method="post" enctype="multipart/form-data">
2    <input type="file" name="fileToUpload">
3    <input type="submit" value="Upload File">
4</form>

Enabling File Downloads

1$file = "example.pdf";
2header("Content-Disposition: attachment; filename=" . basename($file));
3readfile($file);

Getting Information about Files

File Information Functions

• file_exists(): Checks if a file exists.
• is_file(): Determines if a path is a regular file.
• filemtime(): Retrieves the last modification time of a file.

1$filename = "example.txt";
2if (file_exists($filename)) {
3    echo "File $filename exists.";
4}

Conclusion