Dependency perl code

Web Interface

The web interface is a visual aid for the DPC. It displays the object levels, the commands used to create objects. And provided the web server can see the files, it provides information of the status of file, such as which parent files are newer than an object file. This information also makes it very useful for spotting typing errors in the dependency file, which are very easy to introduce. The reason it is only a visual aid, because it's unlikely that the user wants anyone with access on the internet being able to alter their files.

The reason for putting the DPC under a cgi-bin directory, is so the web interface will work. The cgi file is dependencies.cgi, so the URL for viewing the web interface usually ends cgi-bin/update/dependencies.cgi.

There are three types of page available on the web interface, which are described below.

The main page: the levels

The main page lists all the object types in the levels they've been placed in. If there's a typing error in the dependency file, it will typically show up here - through a parent type that wasn't expected or a file being in an unexpected level. From this page the user can click on any of the file types, to provide more information on the file type.

File types

Provides information on the file type, namely

• which file types does this type depend on
• if any file types are created at the same time as this file
• which file types depend on this file type
• instructions for making this file. It will also display the contents of scripts if a script in the command directory is used.
• list the files of this type. Clicking on one of these files will provide information about a specific file. Although this will not be possible if the web server cannot see these files.

A specific file

Provides the same information as for the file type page, but with its explicity parent, sibling and child files listed. In addition it will also carry out tests on the parent and child files, such as if the parent is newer or if a file is empty. None of this is possible if the web server cannot see the files.