PHP text going missing, possible regex issue? [duplicate]

Question

I'm attempting to create an automatic installer for a system I have created, but the ONLY issue is the generation of a php file, in which variables simply do not show up.

Here's my code to create the file

<?php
$content = " <?php
    $sqlHost = '".$host."';
    $sqlUser = '".$user."';
    $sqlPass = '".$pass."';
    $sqlDatabase = '".$db."';
    $sqlTables = array('donate_categories', 'donate_items', 'donate_claim', 'donate_admin');

    $connection = new PDO('mysql:host='.$sqlHost.';dbname='.$sqlDatabase.';charset-utf8', $sqlUser, $sqlPass);
    $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
?>";

$fp = fopen("connection.php", "wb");
fwrite($fp, $content);
$fclose($fp);
?>

as you can see there's php code wrapped in a string there; However the output is a little strange...

<?php
     = 'localhost';
     = 'root';
     = '';
     = 'test';
     = array('donate_categories', 'donate_items', 'donate_claim', 'donate_admin');

     = new PDO('mysql:host='..';dbname='..';charset-utf8', , );
    (PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
?>

None of the variables are there, and I've looked up possible issues with this, but I haven't found any.

Try error_reporting(E_ALL);. Double quotes interpolate variables. — mario
– mario, Commented Dec 19, 2014 at 23:16
The problem itself can be easily fixed by escaping the $ symbols (or switching the double quotes to single quotes), but why would you want to do this? What exactly is the point of using PHP code generate more PHP code? — NullUserException
– NullUserException, Commented Dec 19, 2014 at 23:20
This seems like a good use case for a heredoc rather than this confusing concatenation. php.net/manual/en/… The $connection would still need \$ escaping though. — Michael Berkowski
– Michael Berkowski, Commented Dec 19, 2014 at 23:20
Just a thought: it would probably be cleaner to generate a ini or yaml file. — fejese
– fejese, Commented Dec 19, 2014 at 23:21
@Dagon It's not a duplicate. That question is for displaying PHP on a web page. This question is about writing it to a file. The solutions are different. The problem he has here is actually with quoting. — Barmar
– Barmar, Commented Dec 20, 2014 at 0:33

Jhecht · Accepted Answer · 2014-12-19 23:18:30Z

4

I can't test this right now, but since you've wrapped the text in double quotes, your server is parsing the variables $sqlHost, $sqlUser, ... etc as variables and looking up their values in the string. Try escaping the values like so, and let me know if it works as you intend it to.

<?php
$content = " <?php
    \$sqlHost = '".$host."';
    \$sqlUser = '".$user."';
    \$sqlPass = '".$pass."';
    \$sqlDatabase = '".$db."';
    \$sqlTables = array('donate_categories', 'donate_items', 'donate_claim', 'donate_admin');

    \$connection = new PDO('mysql:host='.\$sqlHost.';dbname='.\$sqlDatabase.';charset-utf8', \$sqlUser, \$sqlPass);
   \$connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
?>";

$fp = fopen("connection.php", "wb");
fwrite($fp, $content);
$fclose($fp);
?>

answered Dec 19, 2014 at 23:18

Jhecht

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6 Comments

Hobbyist Over a year ago

Thanks, it works; Could you provide a link to more information on the different between using 'string' and "string".. I had no idea that "string" would parse variables, does 'string' not?

NullUserException Over a year ago

The manual is your friend: php.net/manual/en/language.types.string.php

Michael Berkowski Over a year ago

@Christian.tucker That is explained in the strings doc I linked up in the main comment thread

Jhecht Over a year ago

Null User beat me to it, that link should have all the information you need. And to answer your question, no, strings encapsulated in single quotes such as '$string' would not parse variables, but "$string" would. I believe (been awhile since I thumbed through the INI specs) there's an option you can turn on/off, but it could be totally deprecated by now.

C3roe Over a year ago

@Christian.tucker: You are writing an installer script for a system you created … without even knowing such absolute basics? Wow … installing your system might turn out “interesting” for whoever uses it.

|

Maximiliano Hornes · Accepted Answer · 2014-12-19 23:22:22Z

0

Use single quotes, because it is trying to replace the variables into the string.

<?php
$content = ' <?php
    $sqlHost = "'.$host.'";
    $sqlUser = "'.$user.'";
    $sqlPass = "'.$pass.'";
    $sqlDatabase = "'.$db.'";
    $sqlTables = array("donate_categories", "donate_items", "donate_claim", "donate_admin");

    $connection = new PDO("mysql:host=".$sqlHost.";dbname=".$sqlDatabase.";charset-utf8", $sqlUser, $sqlPass);
    $connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
?>';

$fp = fopen('connection.php', 'wb');
fwrite($fp, $content);
$fclose($fp);
?>

http://php.net/manual/es/language.types.string.php

Regards.

answered Dec 19, 2014 at 23:22

Maximiliano Hornes

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