Overview of Active Messenger

1.4Overview of Active Messenger

The primary design goal for the Active Messenger is to forward incoming text messages to the available portable and stationary devices like text and voice pagers, cellular phones etc. If necessary, the agent can send messages to several devices in turn, monitoring the reactions of the user and the success of the delivery.

------------- Mapping personal = canard timely = canard, skytel important = canard, skytel, fax veryimportant = canard, skytel, sms, iridium ultraimportant = canard, sms, phone, cellphone, iridium -------------- home phone = 568-5031, not 22-9 fax = 396-8499 (no cover), not 23-8 computer = dialup ------------- Mapping personal = canard timely = canard, skytel important = canard, skytel, fax veryimportant = canard, skytel, sms, iridium ultraimportant = canard, sms, phone, cellphone, iridium -------------- home phone = 568-5031, not 22-9 fax = 396-8499 (no cover), not 23-8 computer = dialup -------------- office phone = 553-5386, anytime fax = 495-5244, M-F 10-23 computer = magama, klingklong -------------- Devices canard = johndoe@canard.media.mit.edu skytel = 4963278@skytel.com sms = 16178183421@omnipoint.net iridium = 881536082914@iridium.com cellphone = 818-5346 -------------- office phone = 553-5386, anytime fax = 495-5244, M-F 10-23 computer = magama, klingklong -------------- Devices canard = johndoe@canard.media.mit.edu skytel = 4963278@skytel.com sms = 16178183421@omnipoint.net iridium = 881536082914@iridium.com

Figure 7: Sample user preference file

This file is the only information the agent needs from the user.

Figure 8: Sample status monitor page

All incoming messages are stored in a separate directory by a program that is called by the user’s Procmail. When Active Messenger starts up, it first loads the user preference file and then the stored email messages. After that, Active Messenger goes into an infinite loop, where the following modules are called sequentially:

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  Load messages (chapter 2.6.1). If new messages have arrived, load them into the message list and schedule the initial event, e.g., where and when to send them.
  
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  Find user location (chapter 2.6.2). Where may the user be?
  
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  Check message read status (chapter 2.6.3). Go through all messages: What is the likelihood that the message is read? Checking the mail spool file, Canard, SkyTel™, and other resources.
  
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  Check status of paging systems (chapter 2.6.4). Did the Canard or SkyTel™ handsets come back in range? Is it necessary to resend older messages?
  
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  Send messages (chapter 2.6.6). Go through all messages: If a scheduled event is due, send the message to the specified device.
  
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  Schedule next events (chapter 2.6.5). After sending a message, schedule the next event.
  
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  Write web file (chapter 2.6.7). Store the current status in a file that is accessible on the web.
  
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  If user preference file has changed, reload user preferences. Like that, changes can be made to the behavior of the agent without necessarily restarting the program. By editing the user preference file, the user can change most of the internal variables.
  

The following chapter describes the system: first, the background and basic concept of Active Messenger (chapter 2.1), then the current implementation. For that purpose, the devices and communication channels are described that the agent can interact with (chapter 2.3). What follows is a description of the architecture of Active Messenger: the program structure (chapter 2.4), the data structure (chapter 2.5), the main modules (chapter 2.6), and finally the user interface (chapter 2.7).