В каком массиве содержатся данные о загруженном пользователем файле

<?php
$uploaddir = ‘/var/www/uploads/’;
$uploadfile = $uploaddir . basename($_FILES[‘userfile’][‘name’]);

echo 

‘<pre>’;
if (move_uploaded_file($_FILES[‘userfile’][‘tmp_name’], $uploadfile)) {
    echo «Файл корректен и был успешно загружен.n»;
} else {
    echo «Возможная атака с помощью файловой загрузки!n»;
}

echo 

‘Некоторая отладочная информация:’;
print_r($_FILES);

print 

«</pre>»;?>

PHP поддерживает возможность передачи массива из HTML
в том числе и с файлами.

<?php
foreach ($_FILES[«pictures»][«error»] as $key => $error) {
    if ($error == UPLOAD_ERR_OK) {
        $tmp_name = $_FILES[«pictures»][«tmp_name»][$key];
        // basename() может спасти от атак на файловую систему;
        // может понадобиться дополнительная проверка/очистка имени файла
        $name = basename($_FILES[«pictures»][«name»][$key]);
        move_uploaded_file($tmp_name, «data/$name»);
    }
}
?>

I think the way an array of attachments works is kind of cumbersome. Usually the PHP guys are right on the money, but this is just counter-intuitive. It should have been more like:

Array
(
    [0] => Array
        (
            [name] => facepalm.jpg
            [type] => image/jpeg
            [tmp_name] => /tmp/phpn3FmFr
            [error] => 0
            [size] => 15476
        )

    [1] => Array
        (
            [name] =>
            [type] =>
            [tmp_name] =>
            [error] => 4
            [size] =>
        )
)

and not this
Array
(
    [name] => Array
        (
            [0] => facepalm.jpg
            [1] =>
        )

    [type] => Array
        (
            [0] => image/jpeg
            [1] =>
        )

    [tmp_name] => Array
        (
            [0] => /tmp/phpn3FmFr
            [1] =>
        )

    [error] => Array
        (
            [0] => 0
            [1] => 4
        )

    [size] => Array
        (
            [0] => 15476
            [1] => 0
        )
)

Anyways, here is a fuller example than the sparce one in the documentation above:

<?php
foreach ($_FILES[«attachment»][«error»] as $key => $error)
{
       $tmp_name = $_FILES[«attachment»][«tmp_name»][$key];
       if (!$tmp_name) continue;$name = basename($_FILES[«attachment»][«name»][$key]);

    if (

$error == UPLOAD_ERR_OK)
    {
        if ( move_uploaded_file($tmp_name, «/tmp/».$name) )
            $uploaded_array[] .= «Uploaded file ‘».$name.»‘.<br/>n»;
        else
            $errormsg .= «Could not move uploaded file ‘».$tmp_name.»‘ to ‘».$name.»‘<br/>n»;
    }
    else $errormsg .= «Upload error. [«.$error.»] on file ‘».$name.»‘<br/>n»;
}
?>

Do not use Coreywelch or Daevid’s way, because their methods can handle only within two-dimensional structure. $_FILES can consist of any hierarchy, such as 3d or 4d structure.

The following example form breaks their codes:

<form action=»» method=»post» enctype=»multipart/form-data»>
    <input type=»file» name=»files[x][y][z]»>
    <input type=»submit»>
</form>

As the solution, you should use PSR-7 based zendframework/zend-diactoros.

GitHub:

https://github.com/zendframework/zend-diactoros

Example:

<?phpuse PsrHttpMessageUploadedFileInterface;
use ZendDiactorosServerRequestFactory;$request = ServerRequestFactory::fromGlobals();

if (

$request->getMethod() !== ‘POST’) {
    http_response_code(405);
    exit(‘Use POST method.’);
}$uploaded_files = $request->getUploadedFiles();

if (
    !isset(

$uploaded_files[‘files’][‘x’][‘y’][‘z’]) ||
    !$uploaded_files[‘files’][‘x’][‘y’][‘z’] instanceof UploadedFileInterface
) {
    http_response_code(400);
    exit(‘Invalid request body.’);
}$file = $uploaded_files[‘files’][‘x’][‘y’][‘z’];

if (

$file->getError() !== UPLOAD_ERR_OK) {
    http_response_code(400);
    exit(‘File uploading failed.’);
}$file->moveTo(‘/path/to/new/file’);?>

The documentation doesn’t have any details about how the HTML array feature formats the $_FILES array.

Example $_FILES array:

For single file —

Array
(
    [document] => Array
        (
            [name] => sample-file.doc
            [type] => application/msword
            [tmp_name] => /tmp/path/phpVGCDAJ
            [error] => 0
            [size] => 0
        )
)

Multi-files with HTML array feature —

Array
(
    [documents] => Array
        (
            [name] => Array
                (
                    [0] => sample-file.doc
                    [1] => sample-file.doc
                )

            [type] => Array
                (
                    [0] => application/msword
                    [1] => application/msword
                )

            [tmp_name] => Array
                (
                    [0] => /tmp/path/phpVGCDAJ
                    [1] => /tmp/path/phpVGCDAJ
                )

            [error] => Array
                (
                    [0] => 0
                    [1] => 0
                )

            [size] => Array
                (
                    [0] => 0
                    [1] => 0
                )

        )

)

The problem occurs when you have a form that uses both single file and HTML array feature. The array isn’t normalized and tends to make coding for it really sloppy. I have included a nice method to normalize the $_FILES array.

<?phpfunction normalize_files_array($files = []) {$normalized_array = [];

        foreach(

$files as $index => $file) {

            if (!

is_array($file[‘name’])) {
                $normalized_array[$index][] = $file;
                continue;
            }

            foreach(

$file[‘name’] as $idx => $name) {
                $normalized_array[$index][$idx] = [
                    ‘name’ => $name,
                    ‘type’ => $file[‘type’][$idx],
                    ‘tmp_name’ => $file[‘tmp_name’][$idx],
                    ‘error’ => $file[‘error’][$idx],
                    ‘size’ => $file[‘size’][$idx]
                ];
            }

        }

        return

$normalized_array;

    }

?>

The following is the output from the above method.

Array
(
    [document] => Array
        (
            [0] => Array
                (
                [name] => sample-file.doc
                    [type] => application/msword
                    [tmp_name] => /tmp/path/phpVGCDAJ
                    [error] => 0
                    [size] => 0
                )

        )

    [documents] => Array
        (
            [0] => Array
                (
                    [name] => sample-file.doc
                    [type] => application/msword
                    [tmp_name] => /tmp/path/phpVGCDAJ
                    [error] => 0
                    [size] => 0
                )

            [1] => Array
                (
                    [name] => sample-file.doc
                    [type] => application/msword
                    [tmp_name] => /tmp/path/phpVGCDAJ
                    [error] => 0
                    [size] => 0
                )

        )

)

For clarity; the reason you would NOT want to replace the example script with
$uploaddir = ‘./’;
is because if you have no coded file constraints a nerd could upload a php script with the same name of one of your scripts in the scripts directory.

Given the right settings and permissions php-cgi is capable of replacing even php files.

Imagine if it replaced the upload post processor file itself. The next «upload» could lead to some easy exploits.

Even when replacements are not possible; uploading an .htaccess file could cause some problems, especially if it is sent after the nerd throws in a devious script to use htaccess to redirect to his upload.

There are probably more ways of exploiting it. Don’t let the nerds get you.

More sensible to use a fresh directory for uploads with some form of unique naming algorithm; maybe even a cron job for sanitizing the directory so older files do not linger for too long.

Also note that since MAX_FILE_SIZE hidden field is supplied by the browser doing the submitting, it is easily overridden from the clients’ side.  You should always perform your own examination and error checking of the file after it reaches you, instead of relying on information submitted by the client.  This includes checks for file size (always check the length of the actual data versus the reported file size) as well as file type (the MIME type submitted by the browser can be inaccurate at best, and intentionally set to an incorrect value at worst).

mpyw is right, PSR-7 is awesome but a little overkill for simple projects (in my opinion).

Here’s an example of function that returns the file upload metadata in a (PSR-7 *like*) normalized tree. This function deals with whatever dimension of upload metadata.

I kept the code extremely simple, it doesn’t validate anything in $_FILES, etc… AND MOST IMPORTANTLY, it calls array_walk_recursive in an *undefined behaviour* way!!!

You can test it against the examples of the PSR-7 spec ( https://www.php-fig.org/psr/psr-7/#16-uploaded-files ) and try to add your own checks that will detect the error in the last example ^^

<?php
function getNormalizedFiles()
{
  $normalized = array();

  if ( isset(

$_FILES) ) {
   
    foreach ( $_FILES as $field => $metadata ) {
     
      $normalized[$field] = array(); foreach ( $metadata as $meta => $data ) { if ( is_array($data) ) {
         
          array_walk_recursive($data, function (&$v,$k) use ($meta) { $v = array( $meta => $v ); });
         
          $normalized[$field] = array_replace_recursive($normalized[$field], $data);
       
        } else {
          $normalized[$field][$meta] = $data;
        }
      }
    }
  }
  return $normalized;
}
?>

I have found it useful to re-order the multidimensional $_FILES array into a more intuitive format, as proposed by many other developers already.

Unfortunately, most of the proposed functions are not able to re-order the $_FILES array when it has more than 1 additional dimension.

Therefore, I would like to contribute the function below, which is capable of meeting the aforementioned requirement:

<?php
    function get_fixed_files() {
        $function = function($files, $fixed_files = array(), $path = array()) use (&$function) {
            foreach ($files as $key => $value) {
                $temp = $path;
                $temp[] = $key;
           
                if (is_array($value)) {
                    $fixed_files = $function($value, $fixed_files, $temp);
                } else {
                    $next = array_splice($temp, 1, 1);
                    $temp = array_merge($temp, $next);
                   
                    $new = &$fixed_files;
                   
                    foreach ($temp as $key) {
                        $new = &$new[$key];
                    }
                   
                    $new = $value;
                }
            }
           
            return $fixed_files;
        };
       
        return $function($_FILES);
    }
?>

Side note: the unnamed function within the function is used to avoid confusion regarding the arguments necessary for the recursion within the function, for example when viewing the function in an IDE.

$_FILES will be empty if a user attempts to upload a file greater than post_max_size in your php.ini

post_max_size should be >= upload_max_filesize in your php.ini.

Note that the MAX_FILE_SIZE hidden field is only used by the PHP script which receives the request, as an instruction to reject files larger than the given bound. This field has no significance for the browser, it does not provide a client-side check of the file-size, and it has nothing to do with web standards or browser features.

«If no file is selected for upload in your form, PHP will return $_FILES[‘userfile’][‘size’] as 0, and $_FILES[‘userfile’][‘tmp_name’] as none.»

Note that the situation above is the same when a file exceeding the MAX_FILE_SIZE hidden field is being uploaded. In this case $_FILES[‘userfile’][‘size’] is also set to 0, and $_FILES[‘userfile’][‘tmp_name’] is also empty. The difference would only be the error code.
Simply checking for these two conditions and assuming no file upload has been attempted is incorrect.

Instead, check if $_FILES[‘userfile’][‘name’] is set or not. If it is, a file upload has at least been attempted (a failed attempt or not). If it is not set, no attempt has been made.

Some suggestions here:

1. It is always better to check for your error status. If MAX_FILE_SIZE is active and the uploaded file crossed the limit, it will set the error. So, only when error is zero (0), move the file.

2. If possible, never allow your script to upload in the path where file can be downloaded. Point your upload path to outside of public_html area or prevent direct browsing (using .htaccess restrictions). Think, if someone uploads malicious code, specially php codes, they will be executed on the server.

3. Do not use the file name sent by the client. Regenerate a new name for newly uploaded file. This prevents overwriting your old files.

4. Regularly track the disk space consumed, if you are running out of storage.

Here’s a complete example of the $_FILES array with nested and non-nested names. Let’s say we have this html form:

<form action=»test.php» method=»post»>

    <input type=»file» name=»single» id=»single»>

    <input type=»file» name=»nested[]»          id=»nested_one»>
    <input type=»file» name=»nested[root]»      id=»nested_root»>        
    <input type=»file» name=»nested[][]»        id=»nested_two»>
    <input type=»file» name=»nested[][parent]»  id=»nested_parent»>
    <input type=»file» name=»nested[][][]»      id=»nested_three»>
    <input type=»file» name=»nested[][][child]» id=»nested_child»>

    <input type=»submit» value=»Submit»>

</form>

In the test.php file:

<?php

    print_r

($_FILES);
    exit;?>

If we upload a text file with the same name as the input id for each input and click submit, test.php will output this:

<?phpArray
(

    [

single] => Array
        (
            [name] => single.txt
            [type] => text/plain
            [tmp_name] => /tmp/phpApO28i
            [error] => 0
            [size] => 3441
        )

    [

nested] => Array
        (
            [name] => Array
                (
                    [0] => nested_one.txt
                    [root] => nested_root.txt
                    [1] => Array
                        (
                            [0] => nested_two.txt
                        )

                    [

2] => Array
                        (
                            [parent] => nested_parent.txt
                        )

                    [

3] => Array
                        (
                            [0] => Array
                                (
                                    [0] => nested_three.txt
                                )

                        )

                    [

4] => Array
                        (
                            [0] => Array
                                (
                                    [child] => nested_child.txt
                                )

                        )

                )

)

)

?>