PDF upload & download system inaruhusu:

Users kupakia PDF files kwenye server.

Users kupakua files zilizopakiwa.

Management ya documents (reports, forms, manuals).

Usalama muhimu:

Validate file type (PDF pekee).

Validate file size.

Store files securely na rename ili kuepuka overwrite.

⚙️ 2. HTML Form ya PDF Upload
<h2>Upload PDF</h2>
<form action="upload_pdf.php" method="POST" enctype="multipart/form-data">
<input type="file" name="pdf_file" accept="application/pdf" required><br><br>
<button type="submit" name="submit">Upload PDF</button>
</form>


accept="application/pdf" inasaidia browser filter.

enctype="multipart/form-data" lazima iwe.

🧩 3. PHP Script ya PDF Upload (upload_pdf.php)
<?php
if(isset($_POST['submit'])){
$target_dir = "uploads/pdfs/";

if(!is_dir($target_dir)){
mkdir($target_dir, 0755, true);
}

$original_name = basename($_FILES['pdf_file']['name']);
$file_type = strtolower(pathinfo($original_name, PATHINFO_EXTENSION));
$file_size = $_FILES['pdf_file']['size'];
$target_file = $target_dir . time() . "_" . $original_name;

// Validate type
if($file_type !== 'pdf'){
die("❌ Error: Only PDF files are allowed.");
}

// Validate size (10MB max)
if($file_size > 10 * 1024 * 1024){
die("❌ Error: File too large. Max 10MB allowed.");
}

// Move file
if(move_uploaded_file($_FILES['pdf_file']['tmp_name'], $target_file)){
echo "✅ PDF uploaded successfully: <a href='$target_file' target='_blank'>View PDF</a>";
} else {
echo "❌ Error uploading PDF.";
}
}
?>


💡 Maelezo:

time() . "_" . $original_name inazalisha unique filenames.

Validation inazuia files zisizo halali au kubwa kupakiwa.

📥 4. Download Function
<?php
// download.php?file=filename.pdf
if(isset($_GET['file'])){
$file = basename($_GET['file']);
$filepath = "uploads/pdfs/" . $file;

if(file_exists($filepath)){
header('Content-Description: File Transfer');
header('Content-Type: application/pdf');
header('Content-Disposition: attachment; filename="'.basename($filepath).'"');
header('Expires: 0');
header('Cache-Control: must-revalidate');
header('Pragma: public');
header('Content-Length: ' . filesize($filepath));
readfile($filepath);
exit;
} else {
die("❌ File not found.");
}
}
?>


Use basename() kuzuia directory traversal attacks.

Proper headers kuhakikisha browser inapakua file.

🔑 5. Vidokezo vya Usalama

Validate file type & size – prevent malicious files.

Rename files – avoid overwriting & predictable filenames.

Store outside web root optionally – extra security.

Limit folder permissions – usually 0755.

Use authentication – only authorized users can upload or download.

✅ 6. Hitimisho

PDF upload & download system ni muhimu kwa document management.

Combine na authentication & CSRF protection kwa secure workflow.

Best practices: validate type & size, unique filenames, secure folder, restrict access.

🔗 Tembelea:

👉 https://www.faulink.com/

Kwa mafunzo zaidi ya PHP, file handling, na secure web applications.