Form Processing Question

arunspig

Got a problem. I've created an online enrollment application, that collects data from multiple forms before writing to a .txt file. On each form, I'm using the following script to dynamically create hidden input fields as the user travels through the application:

<?php

// ---------------------

// Do while there is an element in $HTTP_POST_VARS...

while (list($name, $value) = each($HTTP_POST_VARS))

/ ...get the name and value of the element and use it to construct a hidden input field.

Then go back to the beginning of the loop and do the same thing with the next element. /

{
echo "<input type=\"hidden\" value=\"$value\" name=\"$name\">\n";
}

The problem comes when the data needs to be deposited into a txt file. When I list all possible data types, and try to $_POST[firstName], the variables that were filled out are fine but all others error out. There are over 300 different variables being collected, some required others not.

Is there anyway to dynamically look at what variables are available in the $HTTP_POST_VARS trick i used above, and only list those?

Or should I use some sort of If...else trick to see if that variable is present, and if so echo the value?

Any help would be greatly appreciated. Thx

sarahk

I'd be inclined to...

<?php
function writeStuff( $varName)
// this checks that the variable exists and writes it.
{
  if isset($_POST[ $varName])
  {
    // do all the writing stuff
  }
}

//main processing stuff

writeStuff("firstName");
writeStuff("lastName");
writeStuff("dob");
writeStuff("course");

// and so on through all the vars in the order you want
?>

arunspig

I've implemented the following code, to see if it can pull one of the variables passed to it.

<?php

function writeStuff( $firstName)
// this checks that the variable exists and writes it.
{
if isset($_POST[ $firstName])
{
// do all the writing stuff
echo '$firstName';
}
}

//main processing stuff

writeStuff("firstName");

// and so on through all the vars in the order you want

I'm certain that varName is being passed through my form, except each time I change "firstName" to another value, I keep getting the following error:

Parse error: parse error, unexpected T_ISSET, expecting '(' in etc..(name of file & line)

Now I'm getting confused. Any suggestions?

sarahk

there's something funny in php, sure it's htere for a reason but ...

<?php
//you can do this
   echo "$firstName";
//and this
echo $firstName;  

//but not this
echo '$firstName'; 
?>

Now in the function - it's a generic variable handler so the variable caught should have a generic kind of name - like my $varName. No problem changing it to $firstName except that you'll be using it for alot of other stuff too.

I'm assuming that it's this line which is causing the problem:
if isset($_POST[ $firstName])

Maybe it needs to be
if isset($_POST[ "$firstName"])

have a play around and if it doesn't work identify the exact line which falls over.

good luck

MrAlaska

A couple parens in your if() statement will get rid of your error, but if you are passing $firstName to the function it would imply that you already checked the _POST array and extracted $firstName which would make the if() condition redundant.

function writeStuff( $firstName)
// this checks that the variable exists and writes it.
{
if (isset($_POST[ $firstName]))
{
// do all the writing stuff
echo '$firstName';
}
}

sarahk

Thanks for your post Mr Alaska (do they still have that catalogue?)

Yes, I missed the extra () - been working in another language last few weeks, won't tell you how hard it's been to use my ; the other way around 🙂

Anyway, what should be passed to the function is not $firstName but "firstName" - ie the name of the posted variable which needs to be checked.

The idea is to modularise as much as possible and not have to have all the isset()'s in the main program. Why repeat when you can have a function to do it for you. Much more readable.

Anyway, Arunspig, hope you can make sense of our posts.

arunspig

Thanks guys! Your help has been awesome. Unfortunately, you're talking to someone pretty green w/ PHP. I've combined both your posts and now passing the error mode. But now, I have a new question. The writeStuff function is working, and will print out the varNames that are present and that's great. How or where do I implement the function to not only print out the varName but also the value of that varName? I've tried implementing a $_POST into the mix, with many errors. What do you guys think?

Code Example:
<?php

function writeStuff($varName)
// this checks that the variable exists and writes it.
{
if (isset($POST[$varName]))
{
// do all the writing stuff
//echo "$varName";
echo "$varName = $Post[$varName]\n";
}
}

//main processing stuff

writeStuff('firstName');
writeStuff('lastName');
writeStuff('addr1');

// and so on through all the vars in the order you want

MrAlaska

A catalog? We always used Sears. I think there is still a 1969 edition in the cabin outhouse. I haven't been home if a few years, but from what I hear not much has changed 😃

For code flow, readability, and ease of maintainance I am a firm believer of extracting all the expected variable at the top of each page, with the help of server independant functions of course.

Not to confuse anybody or anything, but if you want this example perform without any unexpected behavior, to keep it portable I am using this line as the return:

return get_magic_quotes_gpc() ? stripslashes($var) : $var;

But it also means I need to explicitly validate the data. The way I have it posted will give you possibly safer (if magic quotes are turned on), if unexpected behavior sometimes if magic quotes take you by surprise.

<?php
$firstName = get_post_var('firstName');
$lastName= get_post_var('lastName');
// and so on....

// in an included function file, something like...
function get_post_var ($var) {
	if (isset($GLOBALS['_POST'][$var])) {
		$var=$GLOBALS['_POST'][$var];
	} elseif (isset($GLOBALS['HTTP_POST_VARS'][$var])) {
		$var=$GLOBALS['HTTP_POST_VARS'][$var];
	}  else $var="";
	return $var;
}

?>

[EDIT] Ooops, the naming conventions didn't make much sense when I first posted it. I need to be more careful with my C&P. All better now lol[/EDIT]

sarahk

Mr Alaska wasn't quite Sears, it was a lonely hearts catalogue featuring hunky alaskan men 😉

anyway... putting our ideas together

<?php
// in an included function file, something like...
function get_post_var ($var) 
{
    if (isset($GLOBALS['_POST'][$var])) {
        $var=$GLOBALS['_POST'][$var];
    } elseif (isset($GLOBALS['HTTP_POST_VARS'][$var])) {
        $var=$GLOBALS['HTTP_POST_VARS'][$var];
    }  else $var="";
    return $var;
}
function writeStuff( $varName) 
// this checks that the variable exists and writes it. 
{ 
  $varVal = get_post_var( $varName);
  if (!empty($varVal)
  { 
  // do all the writing stuff 
   $writeme=fopen("myFile.txt","a");
   $textString = $varName . " - " . $varVal;
   fputs($writeme, $textString ); 
   fclose($writeme); 
  } 
} 
$firstName = writeStuff('firstName');
$lastName= writeStuff('lastName');
// and so on....
?>

although looking at this I might open the text file once and pass $writeme into writeStuff, or even make it global so writeStuff can get to it easily. There is bound to be an overhead associated with opening and closing it.

the "a" means the text is appended to the file, which is necessary for this example. If you open it once and leave open then use "w"