Base64使用PHP解码文本区域内的多行

Question

I have a simple script where the user clicks a button and the code will execute a shell command that cuts base64 encrypted data from a csv and places it inside of a textarea. Then, I simply assign that value to a variable and echo the decoded result. However, my result is nothing. If I echo $encoded_data I do see the encoded strings.

My data is laid out like this within the textarea:

ZGF2aWRAZW1haWwuY29t
ZGF2aWRAZW1haWwuY29t
ZGF2aWRAZW1haWwuY29t
ZGF2aWRAZW1haWwuY29t
...

There are hundreds of lines of encoded strings.

If I pass a string, the decoder works. But, with the text inside of the textarea it returns nothing at all. I'm assuming the amount of strings passed causes a memory issue. I also noticed that if i try to pass multiple strings I get weird characters likely because of the line breaks. How can I avoid this as well?

<form name="decode" action="" method="post" enctype="multipart/form-data">
<textarea id="decode_field" name="decode_field" rows="10" cols="50" autofocus><?
if (isset($_POST['decode_btn'])) {

       // Cut base64 data from csv file. Selected data is in col 2 of    each row.
       $encoded_data = shell_exec("cut -d, -f2 test.csv");

       // Display data to user.
       echo base64_decode($encoded_data);

}
?></textarea>
<input type="submit" name="decode_btn" value="Get Decoded Data" />
</form>

output should be the base64 strings decoded to regular strings line by line.

Answer 1

You want to use exec instead, which will allow you to get an array of lines of the output from your cut.

   $data = array();
   exec("cut -d, -f2 test.csv", $data);
   foreach($data as $line) {
       echo base64_decode($line);
   }