Learn how to create a secure and efficient file upload system using PHP with step-by-step examples and best practices.
Uploading files to a server is a common feature in modern web applications. Whether you're building a contact form, a content management system, or a custom file sharing platform, PHP offers straightforward tools to help you handle file uploads securely and efficiently.
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Start by creating a simple HTML form that allows users to choose and upload a file.
<!DOCTYPE html>
<html>
<head>
<title>File Upload</title>
</head>
<body>
<h2>Upload a File</h2>
<form action="upload.php" method="post" enctype="multipart/form-data">
<label for="file">Select a file:</label><br>
<input type="file" name="file" id="file"><br><br>
<input type="submit" name="submit" value="Upload">
</form>
</body>
</html>
Now let’s write the PHP script that processes the uploaded file.
<?php
// upload.php
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
$targetDirectory = "uploads/";
$targetFile = $targetDirectory . basename($_FILES["file"]["name"]);
$uploadOk = 1;
$fileType = strtolower(pathinfo($targetFile, PATHINFO_EXTENSION));
// Check if file already exists
if (file_exists($targetFile)) {
echo "Sorry, file already exists.<br>";
$uploadOk = 0;
}
// Limit file size (e.g., 2MB)
if ($_FILES["file"]["size"] > 2000000) {
echo "Sorry, your file is too large.<br>";
$uploadOk = 0;
}
// Allow only specific file types
$allowedTypes = ["jpg", "png", "pdf", "docx"];
if (!in_array($fileType, $allowedTypes)) {
echo "Sorry, only JPG, PNG, PDF & DOCX files are allowed.<br>";
$uploadOk = 0;
}
// Upload file if everything is ok
if ($uploadOk == 1) {
if (move_uploaded_file($_FILES["file"]["tmp_name"], $targetFile)) {
echo "The file " . htmlspecialchars(basename($_FILES["file"]["name"])) . " has been uploaded.";
} else {
echo "Sorry, there was an error uploading your file.";
}
}
}
?>
Make sure to create a folder named uploads in your project directory and give it the correct permissions so PHP can write to it. On most systems, 755 or 775 permissions will work.
Creating a file upload system with PHP is simple but requires attention to security and validation. With the right checks in place, you can safely allow users to upload files to your server as part of a broader application.
Happy coding!
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