Wesley Alan Wright: Notes, Lessons, and Projects

client asked

Best to use absolute path, so there is no ambiguity

Best to use alias of your script’s folder. In general, any users alias is formed using the convention

    /users/x/y/xyzzzzz

where x is the first letter of the use’rs NetID, y is the second letter of the user’s NetID, and xyzzzzz is the user’s netid.

here’s an example. No issues for me running this in my home directory

#!/usr/local/bin/php
<?
passthru("/users/w/a/waw/mysqltest.pl");
$dog=exec("/usr/bin/date");
print "dog=$dog";
?>

except he meant to run it via http://www.uvm.edu/

I sugegsted he try cgi.uvm.edu — no SAFE mode there

Student asked about 

Long reply:

‘"virtual directory value relative from the root" of my website. ‘ may have several interpretations, and may have different values and meanings depending upon the context and the server environment.

For example, you could use the PHP Magic Constant

    __FILE__

as in

    $virtual_directory_value = dirname( __FILE__ );

Which, in the case say of this script

    http://www.uvm.edu/~waw/archives/dog.php

has the value of

    /…/uvm.edu/fs/rack1e/u/staff/waw/public_html/archives

Which isn’t so much the "virtual directory value relative from the root" as it is the absolute path of the directory containing the script. And, on www.uvm.edu, at least, a value that may change, since sometimes CIT Technical Resources groups shifts users from one physical disk (rack1e above) to another without warning — so beware if you ever hard-code this value in a script as opposed to obtaining it from the Magic Constant.

We have the following other $HTTP_SERVER_VARS

    [SCRIPT_FILENAME] => /users/w/a/waw/public_html/archives/dog.php

    [SCRIPT_URI] => http://www.uvm.edu/~waw/archives/dog.php

    [SCRIPT_URL] => /~waw/archives/dog.php

    [REQUEST_URI] => /~waw/archives/dog.php

    [SCRIPT_NAME] => /~waw/archives/dog.php

$HTTP_SERVER_VARS[SCRIPT_FILENAME] is a preferred alternative to Magic Constant __FILE__, as it returns a fixed alias for the absolute path name of the script. In general, any users alias is formed using the convention

    /users/x/y/xyzzzzz

where x is the first letter of the use’rs NetID, y is the second letter of the user’s NetID, and xyzzzzz is the user’s netid. But again, such conventions are only needed if and when you have to hard-code such a value in a script (usually when you are using some package like older versions of phpBB or wordpress or mediawiki that cat figure it out themselves).

I expect SCRIPT_FILENAME is what you think you are looking for. Then

$spaw_dir = '/spaw/';

$spaw_root = $HTTP_SERVER_VARS['DOCUMENT_ROOT'].$spaw_dir;

Becomes

$spaw_dir = '/spaw/';

$spaw_root = dirname($HTTP_SERVER_VARS['SCRIPT_FILENAME ']).$spaw_dir;

But now let’s put that in the context of the uvmsnow site. If your spaw code lives here

    /users/u/v/uvmsnow/public_html/spaw

and the code you want to have USE spaw is here

    /users/u/v/uvmsnow/public_html/admin

Then the code in, say, admin/demo.php that reads

    $spaw_dir = '/spaw/';

    $spaw_root = dirname($HTTP_SERVER_VARS['SCRIPT_FILENAME ']).$spaw_dir;

    include $spaw_root.'spaw_control.class.php';

tries to include "/users/u/v/uvmsnow/public_html/admin/spaw/"

But that ain’t right — unless you put a copy of /spaw/ in admin. But then ,if you want to use spew from code in another folder, you have to do the same thing. Messy.

So, you could do something funky like this

    $spaw_dir = '/spaw/';
    $spaw_root = $HTTP_SERVER_VARS['SCRIPT_FILENAME'];
    $i=0;
    while (!file_exists($spaw_root.$spaw_dir) && $i < 10) {
        $i++;
        $spaw_root =dirname($spaw_root);
    }
    $spaw_root.=$spaw_dir;
    include $spaw_root.'spaw_control.class.php';

The $i helps to keep the loop in check in case of typos, missing folders, etc.

Colleauge had troubles amking wiki go. I found solutions (bad version of LocalSettings.php).