Chimera Protocol Configuration

Chimera can be configured to use other programs to retrieve data. For example, an external protocol program can be used to retrieve USENET news data for chimera. The file that describes the protocol configuration is called the protocol file. Each protocol is described by a line in the protocol file. Blank lines or lines beginning with '#' are ignored.

Each protocol entry is made up of the following white space (excluding carriage returns and line feeds) delimited fields:

protocol program

Protocol

The protocol is the protocol part of the URL: protocol://hostname/

Program

The name of the program for chimera to start to handle the external protocol. This must be the full pathname.

Example Protocol File

# # protocol_name program name # nntp /home/john/bin/nntp mailto /home/john/bin/mailto

Design of External Protocol Programs

External protocol programs should read a request from chimera on stdin and output the result on stdout. An example request: GET /something HTTP/1.0 User-Agent: Chimera/1.65 Accept: */* URI: news:comp.infosystems.announce X-protocol: news X-hostname: X-port: 0 X-filename: comp.infosystems.announce The response might be: HTTP/1.0 999 Ooops Content-type: text/plain Content-length: 42 You specified a bogus newsgroup. Go away. In general, stick to the HTTP protocol specification and you will be OK. If it breaks and you are doing a standard HTTP thing then send email to bug-chimera@cs.unlv.edu.

You can also use the 'Pragma' field to provide hints about how to handle the document. Currently, 'nocache' and 'nothing' is supported. For example,

Pragma: nocache If 'nocache' is present then chimera will not cache the document which is useful for constantly changing information. If 'nothing' is present then chimera treats the returned document as a null document and nothing happens.

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john@cs.unlv.edu