Hi Alex,
Here is the content transcoding example. I have tried to keep it simple and yet
functional. Please let me know if its too simple - I tried to simplify things
since I work with this kind of functionality all the time, so I wasn't sure
whether it would be difficult/easy for other people to grasp the idea quicky.
Example 4: User-Agent-based content transcoding. The request is parsed for
User-Agent and subscriber info. This info is used to authenticate the user and
forward the request if authenticated. The response data is passed through
transcoders based on their content types and finally directed to the client.
Http := import "http://ietf.org/opes/rules/p/HTTP";;
Services := import "http://ietf.org/opes/rules/p/Services";;
userAgentInfo := request.getUserAgent();
subscriberInfo := request.getSubscriberAccountInfo();
if( defined subscriberInfo )
{
/* Check if the user is a valid subscriber */
{
userAccountingService :=
Services.findOne("opes://isp.net/UserValidatorNAccounting");
Services.applyOne(userAccountingService,
request.header);
}
otherwise
{
/* Use backup service provider in case of failures */
userAccountingService :=
Services.findOne("opes://ispbackup.net/BackupUserValidatorNBilling");
Services.applyOne(userAccountingService,
request.header);
}
otherwise
{
/* Deny access in case the accounting server is
inaccessible */
request.denyAccess();
}
if( !request.isAuthorized() )
{
/* respond to the client with an error message since
user is not authorized*/
response.header.setStatus(401, "Unauthorized User");
response.setBody("<html>You are not an authorized
user</html>");
sendResponse();
}
else
{
/* The user is an authorized user and has access to
transcoding services */
/* forward the request to the content server and wait
till response received */
forwardRequest();
contentType := Http.response.getContentType();
if(contentType begins_with "image/")
{
transcoderService :=
Services.findOne("opes://ispservices.net/Transcoder");
service.setUserDevice( userAgentInfo );
Services.applyOne(transcoderService,
response.body);
//track user service record via the accounting
service
Services.applyOne(userAccountingService,
"Service name = "+transcoderService, subscriberInfo);
}
else if (contentType equals
"application/x-shockwave-flash")
{
flashTranscoderService :=
Services.findOne("opes://ispservices.net/Flash2PNG");
service.setUserDevice( userAgentInfo );
Services.applyOne(flashTranscoderService,
response.body);
//track user service record via the accounting
service
Services.applyOne(userAccountingService,
"Service name = "+flashTranscoderService, subscriberInfo);
}
/* forward the response (possibly modified) to client */
sendResponse();
}
}
Suggestion 2:
*************
Since string is a primitive type, can we add a binary operator , '+' or
'append' for string, such that operations such as :
"sampl" + "e" would equal "sample" ? Or is this already covered ?
Thanks,
Anwar
-----Original Message-----
From: Alex Rousskov [mailto:rousskov(_at_)measurement-factory(_dot_)com]
Sent: Sunday, September 21, 2003 4:52 PM
To: Anwar M. Haneef
Cc: ietf-openproxy(_at_)imc(_dot_)org
Subject: Re: Decision on Rules Language
On Sat, 20 Sep 2003, Anwar M. Haneef wrote:
Example 4: User-Agent-based content transcoding - This might be a
more complicated example. In case you are interested, I can write
this up. Being a telecom industry person, this would be more
relevant for my applications.
I would be interested to see this implemented. IMO, at least one
complicated example would be good for both us writing the spec and
folks considering supporting it.
Thanks,
Alex.
P.S. I will work your other examples in, thank you for posting them!