NetAlive Sources

Overview

Many NetAlive applications give meaningful results when applied to diverse sources. However, NetAlive requires a source agent for accessing each source. This document describes how to find a suitable agent if one exists and describes how to make one if not.

Finding an Existing Agent

NetAlive's agents are external to the program itself. The advantage of this is that anybody can create agents and share them through Web self-publishing. The disadvantage is that it can be tricky to find a specific agent. Here are different places where agents may be stored:

As part of the NetAlive system NetAlive includes agents that can monitor common sites.
Hard disk. Any user can create agents and store them on their hard disk.
On a content-provider's site A site operator can create a NetAlive agent for their site. The operator can put a hyperlink to these agents on their Website or can index them in Web search engines.
On a third party's site A third party can create an agent for any site and post the agent on their own Web site. The third party can put hyperlinks to these agents on pages on their site or can index them in Web search engines.

Creating a New Agent

NetAlive uses source agents to access and pre-process each source. The job of a source agent is to analyze a Web page, separate the information from the formatting, and divide the information into concepts. Since computers lack the judgment required for this task, a human imparts their judgment to the agent during creation. This can be done in several ways:

Creating an agent by configuring a general-purpose agent. NetAlive has some general purpose agents which can be applied to any Web site. In this method, the user selects a general-purpose agent and then fills out a form with certain parameters. The resulting agent can be used directly or self-published to a Web site for others to use.
Creating a new agent using programming. If there is no suitable general purpose agent, a new agent will have to be programmed.

Using a General-Purpose Agent

[Diagram showing how to select and customize a general-purpse agent.] The figure illustrates the procedure for creating an agent.

NetAlive has a page with instructions on how a human can analyze a Web page. After selecting an agent using human judgment, a hyperlink causes the agent to be displayed in a separate window on the computer's screen.
Drag the selected agent with the mouse. It can be dropped directly into an application or into a palette.
Most general-purpose agents need to be configured. This may be as easy as typing a URL or there may be other parameters.
The computer's memory now contains an edited application or agent. The user can run it or save it for later use. To self-publish to the Internet, save the application to a Web server.

Click here for instructions on how to add a new source to a palette.

Programming An Agent

Refer to the "programmers only" section of this Web site for full instructions on programming an agent.

Source agents are generally Perl programs. The program's input is HTML data and its output is a series of application-dependent records. A record includes:

headline (text)
call to action (URL) -- URL to load in a Web browser when the user clicks on the headline
name of the source (e. g. "NetAlive home page") (text)
graphic (URL) -- a picture in lieu or in addition to a textual headline
advertisement (URL) -- a picture representing an advertisement by the content supplier
price (number) A numeric field for sorting.