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WCTL
Server-side Scripting
More
WCTL
Introduction
Visitor Counter
Troubleshooting
Resources
Next Section
Introduction
In the
previous section, you learned
the difference between different variable types and experimented
with user and author variables. In this section
we will expand your use of WCTL by making a more useful, yet still
very simple script - a visitor counter.
You will
see how it is often easier to use WCTL to create your own customized
features, rather than working with external scripting languages,
such as Perl or other scripting languages.
A
Visitor Counter
It is
simplicity itself to add a visitor counter to your Web Crossing
conference using WCTL.
In your
Control Panel, edit the site banner (shown at the top of all pages,
by default) and add the following line to your current banner:
%% set site.VisitorCount site.VisitorCount + 1 %%
This simple
example uses the WCTL set command to increment (add 1 to)
a site variable called VisitorCount. Let's examine
the syntax in more detail to see how it works:
- site.VisitorCount
is a site variable. As we learned in the previous
section, this means that VisitorCount is a global
variable, stored in the Web Crossing database and available
for use anywhere. If site.VisitorCount doesn't already
exist, the above WCTL will create the variable upon execution
and store a null value in it.
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Note:
Unlike some programming languages like C, WCTL is not a
"typed" language. Basically all variables are considered
to be character strings, which may be evaluated as numbers
as needed. In this example, the initial value of site.VisitorCount
is a null or empty string. When used as a number, the initial
value is zero.
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- The
set command is used to store a value into a variable.
We have already seen values and variables, but
let's just go over what they are one more time so we are clear
on it. A variable is just the name of a place-holder
that you can use to store things in, like names or numbers.
An example of a variable is user.userName. A value
is the actual contents held in a variable. An example of the
value of a variable is the character string Doug. The
set command can be used to store a value into a variable
for later use.
- The
format of the set command looks like:
%% set variable value %%
The
value is stored in variable. In our example variable
is site.VisitorCount and value is the WCTL
expression site.VisitorCount + 1.
If the value of site.VisitorCount is 0, then the
value of site.VisitorCount + 1 is 1. If the value
of site.VisitorCount is 1, then the value of site.VisitorCount
+ 1 is 2. This expression increments the value
of site.VisitorCount .
- The
incremented value is stored in the variable site.VisitorCount,
which is saved automatically in the Web Crossing database and
can be used later on.
Now that
this is saved as part of your Web Crossing site banner, every
time a conference page is opened that line of WCTL is silently
executed. You won't see anything happen, because all you did was
increment the value of site.VisitorCount. You have
not actually used the value in a displayed page anywhere
yet. However, the value will now be incremented by any user who
opens any location in your conference which uses the default site
banner.
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Note:
In this example, the site banner is used to increment the
visitor counter. If you have separate banners set in your
sub-folders, then the WCTL will not be executed at those
locations because the local banner overrides the site banner.
You can include the same WCTL in your local folder banner
if you want to increment site.VisitorCount there as well.
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To see
the current visitor count, you now need to use the WCTL expression
%% site.VisitorCount %% somewhere, just like you used
%% user.userName %% in previous sections.
You can
do this in the site banner, in your top level header, your user
greeting, in a folder or any place you like.
For now,
just go back and edit the site banner again and add the line
You are visitor %% site.VisitorCount %%
Now if
you look at any page that displays the site banner you will see
the current visitor count.
That
is all there is to it! With just two lines of WCTL you created
a site Visitor Counter and displayed it in your site banner.
There
are additional commands for formatting the count number (such
as adding commas automatically), but this is the general idea.
Next Section
In the
next section we will look at
WCTL conditional logic, which will give you even more control
over the actions taken by your conference in controlling what
users can see and do.
Troubleshooting
I tried
the example above, but when I look at the header all I see is
the WCTL itself, with all the double-percent marks. What am I
doing wrong?
- Make
sure you have turned on WCTL evaluation in the Control
Panels > General Settings:
Resources
Web
Crossing FAQ:
Sysop
docs:
WCTL
Concept Reference Page
Web
Crossing Tech Support Forum
Developer
Center
WebX
Harbor
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