PHP Passing a variable containing huge text data on form submit

Question

Ok, I got a PHP page wherein it reads a.txt file (large server log) and stores it in a variable $logcontents. I then need to pass that variable to another php page where it will process the $logcontents contents accordingly. I am using a form inside the main php page to submit that variable to the other php page, the code is:

<input type="hidden" name="hiddenlogcontents" value="<?php echo $logcontents ?>">

My problem is $logcontents when passed to the other php page, it contains only 1 character which is {. I'm thinking php can't pass a variable that contains a large amount of data? The first page is able to echo $logcontents in the page, it is only when forwarding this variable to another php page that it displays empty or one character. Any ideas? I tried researching but I'm lost of keywords to use for this issue.

Answer 1

I thought someone would pick up the slack here, but apparently nobody is...

<input type="hidden" name="hiddenlogcontents" value="<?php echo $logcontents ?>">

Since you say the first and only character that gets transmitted is "{", I'll make a lucky guess that the log data consists of JSON strings and looks something like this:

{"foo":"bar"...

Well, let's interpolate that data into your HTML to see the result of your code snippet:

<input type="hidden" name="hiddenlogcontents" value="{"foo":"bar"...">

Can you see it here in the SO code highlighter? The value of the value attribute is "{". The rest that follows is incorrectly formatted garbage. You're just creating the attribute value="{" as far as the HTML parser is concerned.

If you want to embed quotes in HTML attributes, those need to be HTML encoded:

<input type="hidden" name="hiddenlogcontents" value="<?php echo htmlspecialchars($logcontents, ENT_QUOTES); ?>">

Please read The Great Escapism (Or: What You Need To Know To Work With Text Within Text).

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Secondarily I'd question how wise it is to transfer huge data blobs this way, forcing the client to download and upload the data repeatedly. But that's another topic...

Answer 2

I'm not sure if is that your issue but encode your $logcontents for url like that :

<?php echo urlencode($logcontents); ?>

If your text are too long you could short it with encode_base64 :

<?php echo base64_encode($logcontents); ?>

And use decode_base64 where your retrieve your data :

<?php echo base64_decode($logcontents); ?>

Hope that could help you ;)

Answer 3

You may close the echo. Try GET to see if the correct value is sent by the URL. If yes, check your echo command.