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Re: B2B proposal

  • From: "Lewis, Keith" < >
  • To: jsr359-experts < >
  • Subject: Re: B2B proposal
  • Date: Fri, 31 May 2013 14:48:35 +0100
  • List-id: <jsr359-experts.sipservlet-spec.java.net>

I attach a new version of the transaction proposal.
It addresses some issues I noticed with the previous version.
There are some changes to the method names and a reduction in the number of methods which may address some of the comments from the last meeting.

Here are the main changes
  1. For reliable provisional responses I now use the term "unacknowledged" rather than pending in the method names and description.
  2. I realised that there can be more than one invite transaction within a dialogue which has unacknowledged provisional responses. This means that when retrieving a provisional response we need to use a combination of the invite request, the session and the rseq. This could have been achieved by adding the invite as a parameter to a method on the session. It seemed more natural to put the method on the request and pass the session and rseq as parameters. Since the method only applies to invite requests I am proposing that we create a new interface - SipInviteRequest -  which extends SipServletRequest.
  3. The section on linking has been updated to reflect the fact the we need to store a reference to the invite as well as the rseq when linking provisional responses.
  4. I moved the method for accessing final responses to the new interface and renamed it from getPendingInviteResponse to getFinalResponse.
  5. I combined the two getPendingRequest methods on SipSession into one method which returns a map and simplified the definition of pending. I added a UAMode parameter to select just incoming or outgoing requests - this seemed more useful than mixing both in the same map and reflects which is done in the B2buaHelper.getPendingMessages method.
  6. I added a new method SipSession.getActiveInvites which returns a map of SipInviteRequests.
  7. I split the createInviteResponseForDerivedSession method into 2 separate methods - createDerivedSession and SipInviteRequest.createResponse - this addresses the concern with the complex name. It also allows additional responses to be sent on a derived session thus allowing some useful B2B behaviour missing from the existing B2BuaHelper.
Keith

On Tue, May 14, 2013 at 5:11 PM, Lewis, Keith < " target="_blank"> > wrote:
Binod,

Thanks for the feedback.

Some comments inline below.

Keith


On Fri, May 10, 2013 at 8:58 AM, Binod < " target="_blank"> > wrote:
Hi Keith,

Here are some comments on this document.

- In general, we should try to keep the methods as generic as possible.
  We do not need to save developer writing one extra line of code for
  "a particular case" at the cost of introducing a "special purpose" method.

- SipFactory.createContinuationRequest :
  I would instead have a createRequest(originalrequest, from, to, Set<String> excludeList)

- For the pendingxxx methods, there is conflict between pending state and
  Implicit transaction state defined in JSR 289. While it may be difficult to
  now change the behavior of implicit transaction state, we should not try to
  ignore that completely.

The aim in providing these methods is to reduce the need for applications to store messages. In defining the meaning of "pending" we are saying when the container can stop holding a reference to the message. We are not defining when the transaction is complete. I think the fact that we have now removed references to transactions from the names of the methods will help avoid confusion.
 

- There is no alternative to current b2buahelper.getPendingMessages method.
This is deliberate. Developers who are happy with this method can continue to use the B2BuaHelper. The fact that this method is cumbersome to use was the main motivating factor for us suggesting a new API. 

- How about defining the pending messages as a readonly collection? And retrieve
  that collection from session? For example, we can define a interface
  called Session.PendingMessageCollection that extend the java collection.   
  By default, this interface can act as the collection of uncommitted messages.
  The additional usecases like getting pending invites and getting reliable provisional
  responses etc can be added as extra methods to this interface.

- If an invite gets a reliable provisional response and involves prack, does the
  invite remain pending until ack for invite 2xx, right?
Yes

- Why do we need createInviteResponseForDerivedSession? The name sounds quite odd to
  me. Application can always do getPendingInvite() and then create a response, right?

Previously I named it the same as the equivalent method on the B2BuaHelper - createResponseToOriginalRequest -  but it was suggested that it should have a new name. This is my attempt. The method is special in that it creates a new (derived) session for a forked response so the name is meant to indicate this.

- SipServletRequest.getRequestId -> SipServletRequest.getId()

- I would try not to use sip method names directly in the api. So, instead of getPendingInvite,
  may be PendingMessageCollection.getRequest(String methodName) might be better?
 
Chapter 17 of RFC3261 distinguishes INVITE transactions and explains the special processing they receive. Since the method returns the initial request of an INVITE transaction it seems OK to name the method getPendingInvite(). We have the method getPendingRequest(String requestId) which can be used more generally for both INVITE and non-INVITE requests.

thanks,
Binod.

 

On Wednesday 08 May 2013 09:03 PM, Lewis, Keith wrote:
Here is an updated version of the B2B and transaction API.
Most of the changes are those suggested by the group.

Keith Lewis


On Fri, Mar 22, 2013 at 6:03 PM, Lewis, Keith < " target="_blank"> > wrote:
Hi all,

Here is the thrupoint proposal for B2B changes.

Keith

 
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--------------------
Note: The information contained in this message may be privileged and confidential 
and protected from disclosure. If the reader of this message is not the intended 
recipient, or an employee or agent responsible for delivering this message to the 
intended recipient, you are hereby notified that any dissemination, distribution or 
copying of this communication is strictly prohibited. If you have received this 
communication in error, please notify us immediately by replying to the message and 
deleting it from your computer. Thank you. Thrupoint, Inc.
nXaR2cC3

Attachment: PendingTransactionandB2BSupportmethods-v3.pdf
Description: Adobe PDF document



Re: B2B proposal

Lewis, Keith 05/08/2013

Re: B2B proposal

Binod 05/10/2013

Re: B2B proposal

Lewis, Keith 05/14/2013

Re: B2B proposal

Binod 05/29/2013

Pending Messages Design. [Re: B2B proposal]

Binod 05/31/2013

Re: B2B proposal

Lewis, Keith 05/31/2013
 
 
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