PHP file txt upload content validation

Question

I wrote a PHP script to upload a .txt file and it works partially:

<?php
    $allowedExts = array("txt");
    $temp = explode(".", $_FILES["file"]["name"]);
    $extension = end($temp);
    $dest = "/etc/squid/squid.conf";
    if ((($_FILES["file"]["type"] == "text/plain")
    && ($_FILES["file"]["size"] < 170000)
    && in_array($extension, $allowedExts)))
    {
        if ($_FILES["file"]["error"] > 0)
        {
            echo "Return Code: " . $_FILES["file"]["error"] . "<br>";
        }
        else
        {
            echo "<div style='text-align: center'>";
            echo "Upload File Success!!<br><br>";
            echo "FIle : " . $_FILES["file"]["name"] . "<br>";
            echo "Type : " . $_FILES["file"]["type"] . "<br>";
            echo "Size : " . ($_FILES["file"]["size"] / 1024) . " kB<br>";
            
            echo "</div>";

            move_uploaded_file($_FILES["file"]["tmp_name"],
            "/var/www/squid_proxy/upload/" . $_FILES["file"]["name"]);
            copy("/var/www/squid_proxy/upload/" . $_FILES["file"]["name"],
                $dest);
        }
    }
    else
    {
        echo "<div style='text-align: center'>";
        echo "Error, File upload only .txt";
        echo "</div>";
    }
?>

Both file type and MIME validation work well, but I want a validation of the file's content. The file is stuctured with headers. See this example:

#ADVANCED

#WIZARD

Before the file upload to server, it must be checked that the file contains #ADVANCED in the first line and #WIZARD in the third line. If the headers are missing or the file is empty, an error message should be shown.

How can I validate the content of the uploaded file?

Eisa Adil · Accepted Answer · 2013-12-23 18:48:07Z

2

Here $line[0] is Line 1 and $line[2] is line 3. file() reads entire file into an array.

$lines = file($myFile); //file lines into an array

if (strip($lines[0]) == '#ADVANCED' && strip($lines[2]) == '#WIZARD'){
//success
}

EDIT (as suggested by @barmar)

Added strip() to the variable $lines[0] and $lines[2] to trim the /n char.

edited Dec 23, 2013 at 18:48

answered Dec 23, 2013 at 18:32

Eisa Adil

1,74311 silver badges16 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Barmar Over a year ago

You need the flag FILE_IGNORE_NEW_LINES, or call strip($lines[0]) and strip($lines[2]).

Eisa Adil Over a year ago

@Barmar Is this necessary? If yes, then why?

Barmar Over a year ago

By default, each string will end with newline, e.g. "#ADVANCED\n". This won't be equal to the string without newline.

u_mulder · Accepted Answer · 2013-12-23 18:33:24Z

0

Use file function. It will return array of lines of you txt-file.

$lines = file($filename);
// Then you can check if 
if ($lines[0] == '#ADVANCED' && $lines[2] == '#WIZARD') {
    // do some stuff
}

answered Dec 23, 2013 at 18:33

u_mulder

54.8k5 gold badges54 silver badges72 bronze badges

Collectives™ on Stack Overflow

PHP file txt upload content validation

2 Answers 2

3 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related