Thanks for your thoughts Nick. Do you happen to have a sample with the
"router action" ? Does it replace "triggers" by invoking other actions
directly, after understanding what kind of event it is ? Or the router
fires other events, based on the properties of the incoming event ?

On Tue, Jun 20, 2017 at 6:06 PM Nick Mitchell <[email protected]> wrote:

> hi dragos,
>
> an approach we took, in this regard, was the "router action" pattern.
> facebook (similarly for slack) is configured to communicate with the router
> action, which will discriminate challenge invocations from normal event
> flow invocations.
>
> in the case of facebook (and slack, more recently, can be configured to
> operate in this way), you (not facebook) can choose the challenge
> parameter. so, this can be bound to the router action in advance.
>
> a nice thing about this is that it allows some flexibility: re-establishing
> the challenge parameter can be done without tearing down any openwhisk
> assets. also, the router pattern allows for a router that fans out events,
> e.g. further discriminating based on some property of the incoming event
> (actually more truly as a router)
>
> the pattern also can be generalized to the case where the event source
> chooses the challenge. the challenge parameter can then be self-bound
> (dynamically) as a package parameter (to the package in which the router
> action sits). then, even flows can easily validate the event-flow challenge
> parameter (because the pre-established parameter is a package binding, it
> is readily accessible by the router action)
>
> nick
>
> On Tue, Jun 20, 2017 at 8:45 PM, Dragos Dascalita Haut <
> [email protected]> wrote:
>
> > Is there a pattern for registering feeds with providers that require a
> > verification action to be invoked, in order to validate the webhook ?
> >
> >
> > I'm trying to add a new feed provider for FB to the OW catalog [1]. Some
> > providers may enforce a verification step before accepting the webhook;
> it
> > could be as simple as the provider sending a verification token that it
> > expects to be sent back by that webhook. See an example at [2].
> >
> >
> > In OW triggers and rules are separate concerns, a design I personally
> > like. The issue is that when the providers want to verify something,
> > there's no "default verification rule" associated with a trigger.
> >
> >
> > The pattern I'm currently trying to implement is:
> >
> >   1.  When the CREATE event for the feed is called, register the new
> > trigger
> >   2.  Create a "verification" rule for this trigger to invoke an action
> > that satisfies the provider requirements
> >   3.  Invoke the provider API for registering a new webhook
> >   4.  Wait for the provider to verify the webhook, and then delete the
> > rule created at step 2.
> >
> >
> > Do you have any thoughts regarding this approach ?
> >
> >
> > Thanks,
> >
> > dragos
> >
> > [1] - https://github.com/apache/incubator-openwhisk-catalog
> > [2] -
> https://developers.facebook.com/docs/graph-api/webhooks#callback-url
> >
>

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