IVOA Web>SampRfcV13 (2012-03-07, MatthewGraham)

SAMP v1.3 Proposed Recommendation: Request For Comments

This page contains public discussion of the SAMP v1.3 Proposed Recommendation. The RFC was announced on 12 December 2011 and will run until 29 January 2012 (period extended in consideration of the Christmas break).

Version under review: PR-SAMP-1.3-20111128
RFC Review Period: 12 December 2011 - 29 January 2012
TCG Review Period: 30 January 2012 - 27 February 2012

Change Summary

The main change between the previous version 1.2 and this version 1.3 is the addition of a new section (Section 5) defining the new SAMP Web Profile. Some other more minor changes and clarifications have been made elsewhere in the document as listed in Appendix B.

This document has been developed within the public subversion repository Volute, in directory projects/samp/doc. The exact changes between the 1.2 REC and 1.3 PR LaTeX source files can be seen on this diff page.

Implementations and Validators

There are two interoperating implementations of the entire SAMP standard, including the new Web Profile:

SAMPy (Python): From version 1.2.1 includes a Web Profile hub implementation. This currently has one small incompatibility in the registration call (left over from a previous draft of the standard) which will be fixed in the next release.
JSAMP (Java): From version 1.3-1 includes a Web Profile hub implementation and (mainly for testing) a Web Profile client.

A Web Profile client implementation library (working, though not beautiful) in JavaScript (which, unlike Python and desktop Java, is one of the languages it makes sense to write Web Profile clients in) is available at http://www.star.bristol.ac.uk/~mbt/websamp/, along with a few examples of web pages that use it.

These all work with no known problems, except that the Web Profile doesn't work from all browsers (Firefox, IE, Chrome, Safari all OK, Opera not working, others not tried). This is down to variable implementation of relevant standards in browsers, and not unexpected.

JSAMP contains a hub validation suite which tests pretty much all of SAMP and runs without error against both SAMPy and JSAMP hubs. There is not however a comprehensive validation suite that runs from a web page, which might be a good idea for testing the Web Profile.

-- MarkTaylor - 08 Dec 2011

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IVOA Community Comments during RFC period (12 Dec 2011 - 29 Jan 2012)

(please add comments here)

Comments by Hugo Buddelmeijer

Hugo (currently waiting for wiki password) has commented on the apps-samp list that the web profile does not facilitate use of a tablet for SAMP control, since connections from non-local hosts are blocked by the web profile hub. Followups on the mailing list or here - the discussion will at least be summarised here.

Following a short discussion, to address this issue, the following text has been added (rev 1626) to section 5.4.2.1:

There may be circumstances under which it is appropriate to relax this local host restriction, for instance to enable collaboration with a known external host not capable of Standard Profile communication, such as a mobile device operated by the hub user. However, it is RECOMMENDED that Web Profile implementations at least restrict access to the local host in their default configuration, and if access is permitted to external hosts it is only by explicit user request, and to a named host or list of hosts. Opening the well-known Web Profile hub server port to the internet at large would invite denial of service and perhaps phishing attacks in which the user is exposed to unwanted SAMP registration requests.

plus a couple of adjustments to the existing text noting that the previous recommendation admits of relaxation. Thanks to Hugo for this input, the change should make it easier to use the Web Profile in situations other than the strict browser-hub configuration originally envisaged. -- MarkTaylor - 30 Jan 2012

TCG Comments during the RFC period (12 Dec 2011 - 29 Jan 2012)

(TCG members are encouraged to consider the document during the RFC stage so that any problems can be addressed before the TCG Review stage when the chair or vice chair of each WG will be required to review it).