Using variable from one function in another

Looking for help on using a variable created in a function, in another func

[adambruzon]

Hi Guys,

So, I am playing with functions on my latest project and I have got a problem.

I create a function which makes a call to the MySQL database, which then sets variables for the results, then my second function uses one of those variables, however, I get an error saying "Undefined variable".

If I echo the variables in the index.php I get a result, the only problem is trying to use $AID in the second function.

Please help...

functions.php

function UserDetails() {
 global $USERID, $USER, $AID;
 $USER = $_SESSION[SESSIONUSER];
 $getUserDetails = mysql_query("SELECT * FROM `users` WHERE `username` = '$USER'");
 while ($userArray = mysql_fetch_assoc($getUserDetails)) {
  $USERID = $userArray['id'];
  $AID = $userArray['address_id'];
 }
}

function MainAddressDetails() {
 global $POSTCODE, $noAddressFound;
 if ([b]$AID[/b] > 0) {
  $getAddressDetails = mysql_query("SELECT * FROM `address` WHERE `id` = '$AID'");
  $numberOfAddresses = mysql_num_rows($getAddressDetails);
  if ($numberOfAddresses > 0) {
   while ($addressArray = mysql_fetch_assoc($getAddressDetails)) {
    $POSTCODE = $addressArray['postcode'];
   }
  } else {
   $noAddressFound = "Uh-Oh!";
  }
 }
}

index.php

<?php
UserDetails();
MainAddressDetails();

echo "<p>User: " . $USER . "</p>";
echo "<p>Postcode: " . $POSTCODE . "</p>";
?>

[rocknbil]

Welcome aboard adambruzon,

<?php
include($_SERVER['DOCUMENT_ROOT']."/functions.php");
UserDetails();
MainAddressDetails();
echo "<p>User: " . $USER . "</p>";
echo "<p>Postcode: " . $POSTCODE . "</p>";
?>

Is that what you mean?

[Matthew1980]

Hi there adam_bruzon,

Or if you want to set the var in the second function as a global, then the parser will search the entire scope of your project until a var is found that matches.

This will work equally as well as rocknbils example.

Cheers,
MRb

[adambruzon]

Hi rocknbil,
Thank you for the welcome.
I forgot to add that bit in the example but the functions.php is included. Thank you for you response...

Hi Matthew1980,
That was the ticket, as soon as I specified the variables as global in the function that i wanted to use it in, it worked!

Thank you both - I was getting really frustrated with this one...

So final code blocks are as follows:

functions.php

function UserDetails() { 
global $USERID, $USER, $AID; 
$USER = $_SESSION[SESSIONUSER]; 
$getUserDetails = mysql_query("SELECT * FROM `users` WHERE `username` = '$USER'"); 
while ($userArray = mysql_fetch_assoc($getUserDetails)) { 
$USERID = $userArray['id']; 
$AID = $userArray['address_id']; 
} 
}

function MainAddressDetails() { 
global $POSTCODE, $noAddressFound, $AID; 
if ($AID > 0) { 
$getAddressDetails = mysql_query("SELECT * FROM `address` WHERE `id` = '$AID'"); 
$numberOfAddresses = mysql_num_rows($getAddressDetails); 
if ($numberOfAddresses > 0) { 
while ($addressArray = mysql_fetch_assoc($getAddressDetails)) { 
$POSTCODE = $addressArray['postcode']; 
} 
} else { 
$noAddressFound = "Uh-Oh!"; 
} 
} 
}

index.php

<?php
include 'functions.php';

UserDetails(); 
MainAddressDetails(); 

echo "<p>User: " . $USER . "</p>"; 
echo "<p>Postcode: " . $POSTCODE . "</p>"; 
?>

[Matthew1980]

Hi there adambruzon,

Glad your sorted out, but as Rocknbill points out, it is always good to define a root path beit in a constant or using a superglobal (like his example).

To get base dir (make sure that you are in the root of your site) do something like:-

define('ROOTPATH', dirname(__FILE__). "/"); //current dir..

this gives you the root path in a constant that you can refer to throughout the scope of your script, I always find it handy anyway,

Cheers,
MRb

[adambruzon]

Thanks for that, I can see why this is good practice.

Which do you think is faster:

1. Using the superglobal in all includes or...

2. Using the superglobal once, to include my header.php, then defining the ROOTPATH for the rest?

Thanks

[rocknbil]

Which do you think is faster:

Speedwise, I don't think it matters.

But in terms of good practice, you should create a class, or at the very least, return the values from functions rather than using program globals. You want a function to be a stand-alone bit of code you don't have to futz about with once written; a black box, you pass input to it (or no input) and it returns a value. Then you can reuse it and set the program variables to what you need them to be, at any time.

Have a look at this experiment for an example. May contain errors, typed on the fly, but examine the logic.

functions.php

function UserDetails($user) { 
 // initialize 
 $userid=$aid=null; 
 if (! $user) { die("no user passed to user details"); } 
 // Actually, the above should be changed to validate the $user value too . . .  
 $getUserDetails = mysql_query("SELECT * FROM `users` WHERE `username` = '$user'"); 
 // only one record - use IF, not WHILE 
 if ($userArray = mysql_fetch_assoc($getUserDetails)) { 
 $userid = $userArray['id']; 
 $aid = $userArray['address_id']; 
 } 
 return Array($userid,$aid); 
} 
// 
function MainAddressDetails($aid) { 
 $postcode=$noAddressFound=null; 
 if (is_numeric($aid) and ($aid >0)) { 
 // so . . .no need for > 0 block now . . . and 
 // NO NEED TO COUNT. :-) for a single record, fieldname is more 
 // efficient than * Again, use if for one record. 
 $getAddressDetails = mysql_query("SELECT postcode FROM `address` WHERE `id` = '$aid'"); 
 if ($addressArray = mysql_fetch_assoc($getAddressDetails)) { 
  $postcode = $addressArray['postcode']; 
 } 
 else { $noAddressFound = "Uh-Oh!"; } 
 } 
 else { die("No aid passed to address details"); } 
 return Array($postcode,$noAddressFound); 
} 

OK? Now look what we can do. :-)

index.php

<?php 
include($_SERVER['DOCUMENT_ROOT']."/functions.php"); 
// See above, validate this too, not just check if set 
if (isset($_SESSION[SESSIONUSER])) { 
 list($USERID,$AID) = UserDetails($_SESSION[SESSIONUSER]); 
 // since $aid is initialized as null, in UserDetails, we don't need to 
 // check if isset - simple if is all that's required 
 if ($AID) { 
 list($POSTCODE,$MAILERROR) = MainAddressDetails($AID); 
 if ($MAILERROR) { echo $MAILERROR; } 
 else { 
 echo "<p>User: $USER </p>"; 
 echo "<p>Postcode: $POSTCODE </p>"; 
 } 
 } 
 else { die("Session user OK, no AID"); } 
} 
else { die("No session user has been set"); } 
// 
// OK let's look up another user! 
// Of course, validate this input - for example only 
// 
if (isset($_GET['other_user'])) { 
 // Note we can use any variables in this scope. 
 list($newuserid,$newaid) = UserDetails($_GET['other_user']); 
 if ($newaid) { 
 list($newcode,$newerr) = MainAddressDetails($newaid); 
 if ($newerr) { echo $newerr; } 
 else { 
 echo "<p>New User: $newuserid </p>"; 
 echo "<p>New Postcode: $newcode </p>"; 
 } 
 } 
 else { die("New user input OK, no AID"); } 
} 
?>  

Just something to get your thinking turned toward better use of functions, next up you can learn classes, an even better extension of these concepts.

[Matthew1980]

Hi all,

Well with regards to speed - I suppose it must be down to uS, but personally, when referencing include() files, I always set a constant (just like I did in the above post) and then refer to it throughout my script.

But WRT Rocknbills last post, I couldn't agree more :), where you find yourself in this position, or need to retype a process, pop it in a function, this makes for better coding & it will open more doors for you in the long run, especially when you transfer to writing classes - doing this method has done exactly that for me, I'm now hooked on classes! (Doesn't mean they always work though ;))

[EDIT:]Good point there Readie, I suppose it's down to preference, and if you are coding the software with memory optimization top of your design spec of course ;)

Cheers,
MRb

[edited by: Matthew1980 at 9:12 pm (utc) on Jun 18, 2010]

[Readie]

There's no need to define a constant to get the root path:

include $_SERVER['DOCUMENT_ROOT'] . '/path/to/file.php';

Will go from the root directory. A constant just consumes additional memory.

[adambruzon]

rocknbil - Classes are definitely next on my list of things to learn. Thank you for that code there, I will look at it more carefully and examine the logic to really understand it. :)

Matthew1980 - I have just got hooked on functions, saving so much coding time and file sizes on repeated code. I am sure that I will have as much fun with classes, but all in good time... Thank you. :)

Readie - Thank you for your input, I will stick to the superglobal method rather than defining a constant. :)