Beginner PHP Tutorial - 61 - $_SERVER Variables: Script Name Video Lecture | PHP for Absolute Beginners: From Novice to PHP Master - Web Development

hi this is Alex from PHP academy' de org
and this is a video tutorial for the new
Boston now in this video tutorial and
the video tutorials that are going to
come after this and in the short server
series are talking about a predefined
variable in PHP called dollar underscore
server now you may have seen this before
if you've dealt with PHP before server
is a predefined set of environmental
information and it allows you to let's
just go back to up it allows you to
access certain information about the
page the user requests that have been
sent for example so in this video we're
going to be looking at the file name and
how it can be useful to us now how do we
go about doing this so I've already
shown you the the variable name which is
dollar underscore server so it's much
like things like dollar underscore post
and does underscore session so if you're
learning PHP for the first time you're
probably starting to see some kind of
resemblance to with all these so what do
we do if we want to echo out or display
to the user the current file name
of the PHP script that we're on now you
wouldn't necessarily in everyday
applications want to do this because you
know the user can already see the file
name and we're working within the next
stop PHP at the moment we've got this
error because we haven't specified
anything but yeah we can already see the
script name so why would we want to do
this
well it's useful for us when with doing
things like submitting forms for example
you specify your the the key inside of
here so I'm going to say script
underscore name now what this is going
to do is it's going to take the script
name and it's going to apply it into a
variable so I'm going to say script name
you can just echo it out straight away
like this but I'm going to put it into a
variable so it's just a bit easier to
see what we're doing so we've got the
script name here and we're using the
predefined server variable and this is
the environmental information that we're
we're putting through
so we've got script underscore name in
capital letters now we're echoing this
script name so let's test this and see
what we get okay so we've got forward
slash series forward slash server
forward slash index now you can see this
corresponds somewhat to my URL in the
sense that we're not including the
domain name at the moment I'm working
locally on my computer but we we don't
include the we're not including the
domain name so why is this useful now
let's say we wanted to submit a form but
we didn't know the far the name that the
the name of the file that the user was
actually currently on for example let's
create another file and we'll put a form
in and we'll have the action of this
well we'll leave the action out that's
the point
so method equals post and in here we'll
just create a submit button equals
submit name equals submit and value
equals submit now I've given this a name
so you can keep track of when this
button has actually been pressed so
let's save this as header Inc dot PHP
now what I'm going to do with this is
I'm going to include it in the top of my
script so you should have already had a
look at the include function already so
heading PHP now what this is going to do
is it's going to include this inside of
our script so let's just check that out
and see what happens
okay so now we've included this button
here now what happens if we want to I
mean at the moment I've left action
blank what happens if we have another
page so I'm going to create another PHP
page here another page dot PHP what
happens if we had another page and we
were including this file as well so
header Inc dot PHP now what I want to do
is I want to have let's just get rid of
this for now
I want to submit this this form but I
won the action to be updated depending
on what page I'm on because if I was to
say have this button here but I had
let's say if is set dollar underscore
post submit echo we could say anything
really process one this process might be
say registering the user if that makes
sense let's just copy and paste this
over to the other page but we can now
call this process to so on index.php
we're dealing with process one and on
here we're dealing with process two
however we've got the same form so what
happens if we want to say submit it to
and this information the button come
back to index.php or on this one the
button to come back to index another
page dot PHP so in here I could type
index dot PHP so we've solved half of
our problem so let's refresh the page
and I click Submit and it comes up with
process one but now if we access the
other page you can see that when I click
Submit we go back to index dot PHP
however what I want to do is stay on
another page dot PHP but process this
here so how are we going to go about
this well the answer is simple we've
already looked at this we've already
looked at this script file name or
script name so what we can do is we can
specify a full filename so we could say
a script name equals and and this could
be relative obviously to server and in
here we could type let's say um
script name now what's happened here is
we have we've created a something that's
going to be dynamically updated
depending on what page they're on so
this header include is included on index
and another page but when we run index
this will be different and we're on
another page this will be different
again so let's change this action here
and update it dynamically so we can set
PHP tags to to put this in here and we
can just echo out scripts name so now
what's going to happen is whatever page
we're on let's just view the source you
can see that form action equals another
page dot PHP there with the long live
filenames that were with directories
that we're currently in
however when wait on index.php you can
see that it's automatically changed
again
so obviously this isn't going to work at
the mic well it will because the way
everything's set up so let's go over to
another page and we click submit and
we've done that so we've used the same
form to process but on two different
pages now how will this be useful in a
real life application now let's say this
submit button had a form field which was
username and password and you wanted to
log your users in but keep them on the
same page as they are you could use a
form to log your user in everything
could work out so you find and then what
you could do is using this variable that
we've we've set here you could redirect
them back to the page that they
submitted the user login from so most
websites you have the username and
password at the top of the page and you
will return to the page that you are
currently reviewing before you logged on
so that's a really useful way of using
that server predefined environmental
variable