#809 Haystack 4 Proposal - Op defs

Brian Frank Mon 27 Apr

As we continue to port the Haystack 3 docs over to Haystack 4, I believe we should evaluate how the new def model might apply to the HTTP API operations.  Ops are a great use case where having a first class definition for each operation makes a lot of sense.  

So I'm proposing to create a new feature namespace called "op", and mapping all the standard ops to defs:

op:formats  // deprecate in favor of op:filetypes
op:ops  // will return op defs themselves
op:pointWrite, op:invokeAction
op.hisRead, op:hisWrite
op:watchSub, op:watchUnsub, op:watchPoll

Also, we need to introduce some new ops to query the def namespace, so I propose the following new ops:

op:libs  // list the library modules in project namespace
op:defs  // list all the defs in the project namespace

Another related topic is the issue of using GET to invoke ops with side effects.  This has the potential to allow CSRF attacks when using cookies for authorization.  So I'd like to standardize how this works.  I propose a new tag noSideEffects which will be applied to the "safe ops" such as about, read, nav.  Only these ops will be permitted to use HTTP GET.  All other ops will be required to use POST.

Stephen Frank Wed 29 Apr

No objections.

Steve Eynon Thu 30 Apr

Sounds good.

Will the op namespace be locked down for only the default ops - or would servers / data providers be able to add their own Ops to it?

Cory Mosiman Fri 1 May

I like the concept of enabling GET requests for certain ops and POST for others.

No objections!

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