CGI Program: form-maker
Description
A general purpose script that dynmically creates an HTML form using a
template file. It reads variables from the URL, and inserts those
variables in the form when it is displayed. It will also replace text
strings in the form template. This means we can have a variety of
similar forms that are based on a single template.
Examples
The script is normally invoked with a URL using method=get. For an
example, see
-
http://www.columbia.edu/httpd/cgi/form-maker-example.html
This example uses the template in
-
http://www.columbia.edu/httpd/cgi/form-maker-template.html
The form-maker script can also be invoked using method=post. In this
case you would use hidden variables to pass the necessary information,
instead of embedding that information in the URL. For an example, see
-
http://www.columbia.edu/httpd/cgi/form-maker-post.html
Variables
When invoked with method=GET, variables appear at the end of the URL
in the format
?variable1=value1&variable2=value2&variable3=value3
The variables can appear in any order. One of those variables must be
"template", which specifies the URL of the template file, for example
- template=/http/cgi/form-maker-template.html
The template file name must end in "template.html", for security
reasons. If the file name ends in "cu-template.html" the form
will be restricted to users in the columbia.edu domain.
The variables in the URL are added to the template before the
</form> tag, so they override any variables that
are included in the template. That means you can include default
values in the template. They will be present in the dynamic form if
they are not overriden in the URL.
The "template" variable is required by form-maker, all other variables
will be specific to your application. For example, you could include
the "file_dest" variable if your template uses the generic-inbox
script.
- file_dest=~ark7/inbox
In addition to hidden variables, you can also replace text strings in
the template. Our example illustrates this using the "bkname"
variable. The template includes the text "$bkname" in the place(s)
where this text replacement is to occur. We pass this information to
the form-maker script by including it in the URL
- bkname=Moby+Dick
In the resulting form you will see the text "Moby Dick" instead of
$bkname. This text replacement can occur wherever you like: in the
descriptive text, part of a header, an input field, a select option,
etc. Notice that the space character has been replaced with "+" so it
can be included in the URL that invokes form-maker. Other special
characters can also be included using the % prefix notation, which is
defined in the HTTP specification. For example you can use %7F to
represent tilde (~) because the numeric value of ASCII tilde is hex
7F.
Pager Variable
The pager variable can be used in forms that require links to the
"next" and "previous" pages. This variable can be set to a comma
separated list of four values: current page number, first page, last
page, and next template. The next template can be omitted if it is
the same as the current template. For example
- pager=2,1,10
- pager=2,1,10,bk-template.html
When the pager variable is set, form-maker will replace template
variables called pagination_current, pagination_previous,
pagination_next, and template_url. The "next" and "previous" links
will call form-maker again with the correct pager values for the next
and previous pages.
