[RESOLVED] Very Strange Class Visibility Problem

[rebelo]

I have spent a couple hours wasting my time on this now and I am just completely stumped. I sure hope someone can explain this one. Even the freenode/#php guys have exhausted their efforts on this one...

I am developing a web application, the nature of which is irrelevant. The basic structure is as follows:

The application has a dozen or so documents. As an example, let's use comments.php.

Each of these documents starts off with a require_once() call which requires the include/init.php initialization script. The init.php file defines some site-wide variables, starts an http session and includes a few more libraries. In particular, init.php has 3 require_once() calls for the the following files:

/usr/lib/php/adodb/adodb.inc.php
include/codegallery.inc.php
include/functions.php

After including these files and setting variables, init.php finishes up and hands control back to the calling script (in this example, comments.php). So far, so good.

I promise I'm getting to the point, I just want to give all the information I can think of which might help you help me. 😉

So, now that the initalization routines are complete, the primary script then does its thing. It does any processing requires depending on arguments which were passed to the script and then it generates an html page. Of important note, two files are included as part of the html layout. header.php and footer.php. After header.php, the page content is printed, followed by the inclusion of footer.php and it's all over.

Here's where it gets really bizarre.

The file called codegallery.inc.php is my own library which defines four classes, the names of which are of no relevance. The problem I am having is that these classes are available throughout the entire processing of the script except in header.php's part. I have done a lot of testing by echoing the class_exists() result for the classes and basically they work everywhere except inside header.php. When I make a reference to the classes from within that file, it gives a fatal error saying they are undefined.

Note that in the primary script (after header.php's inclusion) the classes ARE still defined and accessible. So as soon as codegallery.inc.php gets included, everything is great. Right up until header.php inclusion, everything is still great. And AFTER header.php, still great. I just cannot see them inside that file.

Does anyone have any clue whatsoever as to why I cannot access the classes inside that one file? Is there some limit to the depth of file inclusion which I am reaching which prevents files from access values set in files too many levels up?

Basically this is the hierarchy of the included files as the script goes:

• comments.php
  |
  +-+ init.php
  | +--+ codegallery.inc.php
  | |
  | +--+ functions.php
  |
  +--+ adodb.inc.php
  |
  +--+ header.php
  |
• + footer.php

[planetsim]

Can you display header.php and any file you think maybe relevant, Im not going to make any wild assumptions.

[Shrike]

Like planetsim says, without code examples it's hard to say. But here is a wild guess: are you trying to instantiate a class or refer to an instance of a class defined in one of the includes?

[rebelo]

@: Well, yes. As I said, the classes are defined in the codegallery.inc.php include which is included by init.php (which is the first thing included by all of the site files).

@Both: here's the code for header.php

As you can see, there's little to explain why it wouldn't be working. I have done echo tests to see if the classes exist at the very top of this file and they return false, however from the calling script they echo true both on the line immediately before and immediately after the include() directive which calls this file.

It's on the reference to the HTML class toward the bottom that the fatal error occurs:

Fatal error: Undefined class name 'html' in /home/justin/public_html/codegallery/include/header.php on line 47

Again, the HTML class IS defined before and after this file is included.

Here's something extra to add to the confusion:

I have since noticed that variables defined in init.php are not being passed to header.php either. The echo $site; command in the <title> tag does not return anything, though, once again, in the calling script these variables ARE defined before and after.

<html>

<head>

<link rel="stylesheet" href="<?php echo $site; ?>include/stylesheet.css" type="text/css">

<title>PHP Codegallery Beta - Code Sharing Repository<?php echo $site; ?></title>

<script language=\"javascript\">
function verify()
{
	msg = "Are you sure you want to remove this record?";
	return confirm(msg);
}
function verify_redirect(url)
{
	msg = "Are you sure you want to remove this record?";
	if (confirm(msg)) {
		location.href=url
	}
}
</script>


</head>

<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">

<table width="800" height="100%" cellspacing="1" cellpadding="4" bgcolor="#000000" align="center">

<tr>
	<td class="pageheader" height="60">
	PHP Codegallery Beta
	</td>
</tr>
<tr>
	<td class="titlemenu" height="16">
	Site Menu: (
	<a href="<?php echo $site; ?>">Front Page</a> |
	<a href="<?php echo $site;?>browse.php">Browse Code</a> |
	<a href="<?php echo $site;?>search.php">Search</a>
	)
	</td>
</tr>
<tr>
	<td height="16" class="menubar" valign="top">
	User Menu: ( <?php echo HTML::showUserMenu(); ?> )
	</td>
</tr>
<tr>
	<td valign="top" bgcolor="#FFFFFF">
	<!-- End Header Document -->

[Shrike]

Could you also show the code which includes header.php? You might also want to try running HTML::showUserMenu() outside of header.php just to be sure it does work.

I've recreated your file structure and am not having any problems:

// test.php
<?php
require_once( 'inc.php' );
require_once( 'header.php' );
?>
// inc.php
<?php
require_once( 'class.php' );
?>
// header.php
<?php
echo Foo::bar();
?>
// class.php
<?php
class Foo
{
  function bar()
  {
    return "here";
  }
}
?>

[rebelo]

@: Yes, it's a very bizarre thing...check this out. I took the top level file (in this case index.php) and put the following code around the header.php include:

<?php echo HTML::drawUserMenu(); ?>
<?php include("{$site}include/header.php"); ?>
<?php echo HTML::drawUserMenu(); ?>

The output is, as I expected:

1. Draws a user menu.
2. Gives an error for undefined class HTML in header.php line 47.
3. Draws another user menu.

header.php:47

    User Menu: ( <?php echo HTML::drawUserMenu(); ?> )

[rebelo]

Just to do some more elimination, I did the following.

I backed up header.php to another location and replaced it with a header.php containing a single line of code:

header.php

<?php echo HTML::drawUserMenu(); ?>

Again, on the calling page, I used the following code:

<?php echo HTML::drawUserMenu(); ?>
<?php include("{$site}include/header.php"); ?>
<?php echo HTML::drawUserMenu(); ?>

Even with this setup, the page output is:

1. User Menu
2. Undefined class name 'html' in <path to header.php> on line 1
3. User Menu

[rebelo]

Stop the presses. I have solved the problem and the problem was this:

In the init.php file, I define two path variables which I use throughout the script to refer to the location of the script directory:

$site = 'http://mysite.com/folder/';
$path = '/home/www/folder/';

In the main file, when I was sourcing header.php for inclusion, I was using:

include("{$site}include/header.php");

I must shamefully admit that I didn't even think about the fact that I was drawing the file by URI and not system path. Part of my hunting for clues took me to the php.net/include page where I read the following paragraph and had an epiphany:

If "URL fopen wrappers" are enabled in PHP (which they are in the default configuration), you can specify the file to be included using a URL (via HTTP or other supported wrapper - see Appendix M for a list of protocols) instead of a local pathname. If the target server interprets the target file as PHP code, variables may be passed to the included file using a URL request string as used with HTTP GET. This is not strictly speaking the same thing as including the file and having it inherit the parent file's variable scope; the script is actually being run on the remote server and the result is then being included into the local script.

So, what this boils down to is that header.php did not have access to my classes or variables or anything because it was actually being returned from the webserver already processed.

So, kids, make sure you include with absolute paths!

Thread resolved and hopefully this can help someone one day.