Re: Full versus relative URLs

On Wed, Feb 18, 2009 at 12:05:21PM -0500, PJ wrote: > Stuart wrote: > > 2009/2/18 PJ <af.gourmet@videotron.ca>: > > > >> Stuart wrote: > >> > >>>>> <?php include dirname(__FILE__)."/../header.php"; ?> > >>>>> <snip> > > > > > What confused me here is that often, in examples, there are all sorts of > references to files and there seems to be no standard as to how to refer > to them in non-scripts such as these e-mails. So, I thought that > dirname(_FILE_) was a general reference to a directory name and a > file... :-( > I don't want to defend myself here, but I cannot be expected to know all > functions and look up anything that might resemble a function... > I still do not understand, and that is the keyword here, I am trying to > understand things - what does /../header.php mean. I know the 2 dots > mean a higher directory in Unix... but I understood that ../ would mean > the root directory - so what is the / before the ../header.php mean? > When including scripts or pages, i find that if I am referencing to the > current directory, just the filename or /filename works. If the > reference is up a level, ../ works > > e.g. to reference root/images/ from root/authors = ../images/file.ext > from root = /images/file.ext or images/file.ext > > I haven't needed to go to a deeper level yet. Let's break it down: dirname(__FILE__) . "/../header.php"; __FILE__ is a constant that represents the filename of whatever file it's in. This filename includes the directory to the file. dirname() parses out just the directory for the filename passed as a parameter. The "." is, of course, the "concatenate" parameter for PHP. So we're going to add on whatever comes after the directory for the file. "/../header.php" This one is a little trickier. We want a file called header.php, but it's in a directory just above where you are. In Unix/Linux (and therefore most internet servers), "../header.php" represents a file called header.php in the directory just above where you are. Now, you'll notice that what's quoted is "/../header.php", not "../header.php". There's a leading slash there. Why? That's because we're going to append it to a directory which has no leading slash. So if dirname(__FILE__) yields "/var/www/includes", and you just add "../header.php" to it, you'd get: /var/www/includes../header.php, not the file you want. The file you want is: /var/www/includes/../header.php. And in this case, header.php actually resides in /var/www (one directory up from /var/www/includes). Paul -- Paul M. Foster