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Interface-Queuer Communicatoins

@everyfooting Author: ensley // Editor: ensley // Texinfo: ensley @| @| 3 December 1994

Overview

All interfaces use a common technique so adding additional interfaces later is easy and has no effect on queuer or other module.

They communicate via a named pipe (FIFO) called /tmp/FIFO. Each time an interface recieves a search request, it sends the following ASCII data packet to the FIFO in this order:

• Type of search
• Number of maximum hits
• Search string
• Unique ID
• Verbosity value
• Niceness value

Let's look at the data packet in more detail.

• Type of Search - Integer The current search types are:
  • 2 - EXACT
  • 3 - SUBCASE
  • 4 - SUBSTRING
  • 5 - REGEXP

  These are defined in ~server/src/include/search-types.h. This file should be included in all interfaces and queuer source. All types will be referred in the source code as EXACT, SUBCASE, SUBSTRING, and REGEXP.

• Number of maximum hits - Integer Range 0-1000 Default: 100

• Search String - String (null terminating)

• Unique ID - String (null terminating) Holds the interface's process ID and the search number. It has the form "pid.number"

• Verbosity Value - Integer Range: 0-1 0=no verbosity 1=yes verbosity Default: 0

• Niceness Value - Integer Range: 0-35765 0=not nice 35765=most nice Default: 0

The data should be sent down the pipe in one statement to avoid munging the data with another interface. The queuer will continually read from the FIFO and queue the requests accordingly.

It might be wise to have functions that write and read from the named pipe that can be shared by all interfaces and the queuer to make maintenance more efficient.

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