PHP File uploads

PHP  provides file uploading in-built functionality, there are you can upload both text & binary files. It provides full control over on during file uploading i.e:

• who is allowed to upload file.

• what is to be done with the file once it has been uploaded.

PHP file uploading standard

1. PHP is capable of receiving file uploads from any RFC-1867 compliant browser.

2. PHP also supports PUT-method file uploads as used by Netscape Composer and W3C's Amaya clients.

Runtime configuration

Predefined constants

• UPLOAD_ERR_OK – Value: 0; There is no error, the file uploaded with success.

• UPLOAD_ERR_INI_SIZE – Value: 1; The uploaded file exceeds the upload_max_filesize directive in php.ini.

• UPLOAD_ERR_FORM_SIZE – Value: 2; The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.

• UPLOAD_ERR_PARTIAL – Value: 3; The uploaded file was only partially uploaded.

• UPLOAD_ERR_NO_FILE – Value: 4; No file was uploaded.

• UPLOAD_ERR_NO_TMP_DIR – Value: 6; Missing a temporary folder. Introduced in PHP 5.0.3.

• UPLOAD_ERR_CANT_WRITE – Value: 7; Failed to write file to disk. Introduced in PHP 5.1.0.

• UPLOAD_ERR_EXTENSION – Value: 8; A PHP extension stopped the file upload. PHP does not provide a way to ascertain which extension caused the file upload to stop; examining the list of loaded extensions with phpinfo() may help. Introduced in PHP 5.2.0.

How to upload a file in few step

Step-1 : create a html form named 'form.php'.

<form action="upload.php" method="post" enctype="multipart/form-data">

<input type="file" name="file" />
<input type="submit" name="upload" value="upload" />

</form>

Step-2 : create a file name 'upload.php'.

<?php

$upload_dir = '/var/www/html/upload';
$upload_file = $upload_dir .basename( $_FILES['file']['name'] );

if( move_uploaded_file( $_FILES['file']['tmp_name'], $upload_file ) )
{
   echo "File successfully uploaded.";
}
else
{
   echo "File did not uploaded!";
}

?>

Output : if  move_uploaded_file() function successfully run, it will display success message otherwise display error message as per given code.

How to catch success and error message during file upload

<?php

print_r($_FILES);

?>

It will display data in array form:

Array
(
    [file] => Array
        (
            [name] => Sample_image.png
            [type] => image/png
            [tmp_name] => /opt/lampp/temp/phpSO1SSy
            [error] => 0
            [size] => 159202
        )
)

in this array [error] key data return either 0 or 1.

• 0 - means file successfully uploaded.

• 1 – means file did not uploaded.

You can get all error exception messages related to file uploading via file uploading predefined constants, these are given above here:

How to upload multiple files at once

Step-1 : create a html form named 'form.php'.

<form action="upload.php" method="post" enctype="multipart/form-data">

<input type="file" name="file[]" />
<input type="file" name="file[]" />
<input type="file" name="file[]" />
<input type="file" name="file[]" />
<input type="submit" name="upload" value="upload" />

</form>

Step-2 : create a file name 'upload.php'.

<?php

foreach ($_FILES["file"]["error"] as $key => $error) {
    if ($error == UPLOAD_ERR_OK) {
        $tmp_name = $_FILES["file"]["tmp_name"][$key];

        $upload_dir = '/var/www/html/upload/';
        $name = basename($_FILES["file"]["name"][$key]);
        move_uploaded_file( $tmp_name, $upload_dir"/".$name );
    }
}

?>