Write CGI Scripts

The script must generate a legal HTTP reply, taking into account that VOV already provides the first line which is always

HTTP/1.0 200 OK

Typically, the script must begin by printing to stdout the following data:

Content-Type:  text/html
Content-Length: the length of the HTML page
<<-- Will not work without this empty line!!
The content of the HTML page

This task is greatly simplified by:

• writing the CGI script as a Tcl script;
• taking advantage of the procedures defined in VOVDIR/tcl/vtcl/vovhtmlgen.tcl.

#!/bin/csh -f
# The rest is -*- Tcl -*- \
exec vovsh -f $0 $*

# Try this by means of the URL /cgi/ciaobello.cgi

VOVHTML_START 
HTML {
    HEAD { TITLE "Ciao bello example" } 
    BODY {
        OUT "CIAO BELLO"
    }
} 
VOVHTML_FINISH

You can use the vtk library to get information from the trace. Here is a simple example, that also shows a way to generate tables.

#!/bin/csh -f
# The rest is -*- Tcl  -*- \
exec vovsh -f $0 $*

# This script responds to a URL of type: /cgi/getnode.cgi?nodeid
set id [shift]

VOVHTML_START 
HTML {
    HEAD { TITLE "Get Node $id" } 
    BODY {
        H1 { OUT "Node $id" }
        set nodeInfo [vtk_node_get $id]
        TABLE {
            foreach field { status barrier timestamp type } {
            TR {
                TH { OUT $field }
                    TD { OUT [shift nodeInfo] }
                }
            }
        }
        OUT "CIAO BELLO"
    }
} 
VOVHTML_FINISH