Nested includes/requires not working correctly

dannysehr

I'm having a strange problem with requires that I've searched over multiple discussion boards and haven't seen anything that addresses it. The problem. in short, is that I have 4 scripts in the following directories:

/SendEmail.php
/common/constants/DatabaseConstants.php
/common/lib/DatabaseLibrary.php
/common/lib/EmailLibrary.php

All of the files are rooted off the web server document root. The SendEmail.php file has a require_once() including the EmailLibrary file and calling the sendEmail() function in that library. The sendEmail() function require_once()'s the DatabaseConstants and DatabaseLibrary files and calls the constructInsert() function on DatabaseLibrary. Inside that function it again require_once()'s the DatabaseConstants file.

In this scenario, I have a problem where constants defined in the DatabaseConstants file are not recognized in EmailLibrary or DatabaseLibrary functions if I use require_once(). If I switch to using require() the functions read in the file but, in this case, I get an error because the same file is included twice.

I'm trying to make this code highly modular and not rely on certain constants being included in calling code (i.e. rely on constants being included in the code that calls the constructInsert() function. The way I understand the way that these functions should work is that if you require the same code more than once in one call chain that require_once() avoids include conflicts, but I'm getting this kind of strange erratic behavior when requiring files in functions that call other functions.

Any ideas? I'm very stumped.

tsinka

Hi,

just to understand ... you require_once files inside a function. The variables defined in the constant definition file would be available in that function ony.

Try to change your code to the following scheme (example):

constants.php:

<?PHP
$var1="value1";
$var2="value2";
?>

sendmail.php:

<PHP
require_once("constants.php");
require_once("maillibrary.php");

function sendmail(....) {
    global $var1,$var2;

mailfunc($var1,$var2.....);

/*
    or:
    mailfunc($GLOBALS["var1"],$GLOBALS["var2"]);
*/
}
?>

In the maillibrary.php file you would have to do the same with globally defined variables. I'd suggest to include files outside of functions if you need the constants in more than one function.

Thomas

dannysehr

Thomas,

Thanks for your reply. Been on holiday here, thus the delay in responding. I believe that your understanding is correct. I did consider doing what you suggested by declaring variables global or using defined constants, but since I have some "constants" that are arrays using those methods is problematic. I found another approach that seems to resolve the issue once I figured out the real problem that I was having.

The real problem was that using require_once for files that contain functions works fine since it appears that the function declarations are somehow globally valid throughout the entire execution chain. For scripts that contain variables, though, they have to be physically included in each function call in order for the variables to be locally defined in each function. Using require_once does not accomplish this since it will not physically include the code more than once.

So, the solution I came to was to use require_once() for all includes of scripts containing functions and simple require() for all includes of scripts containing only variable declarations. Since I keep functions and "constant" variables divided into separate files this approach is working.

This may not be the most technically correct way to proceed, but the limitations (unless I'm missing something) of doing global definitions of constants compels me to try a different approach. I would certainly like to hear any suggestions on other approaches that might resolve this issue taking into consideration that I need to have non-scalars as "constants".