Client requests containing a .info suffix should return to the
client HTML text containing documentation of both the server usage and
the dataset named in the query. DODS provides a usage filter
that can be used for this purpose. The DODS_Dispatch class
invokes this filter.
The DODS-provided usage filter accepts two arguments, the data
file name requested and the name of the CGI script (the dispatch CGI)
in use:
usage filename CGI-name
The usage filter looks in the dataset directory for a file
called filename.html, and in the directory specified in
the CGI-name argument for a file called
CGI-name.html. These two files must contain HTML, but
without the
<html>, <head> or <body>
tags.
For example, suppose a dispatch CGI using the DODS_Dispatch
class receives a URL like this:
http://dods/cgi-bin/nph-nc/data.info
In this case, the usage filter looks for two files:
cgi-bin/nph-nc.html and data.html (the htdocs directory is
assumed in the second case). The contents of these two files are
concatenated with an HTML representation of the DAS and
DDS for the data.nc file, and the whole thing is
returned to the client. If the HTML files are not found, the returned
document contains only the DAS and DDS.