Allow only one subscription per affordance #356
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| @@ -1213,6 +1213,16 @@ <h4>Internal slots for ConsumedThing</h4> | |||
| <td>`null`</td> | |||
| <td>The <a>Thing Description</a> of the {{ConsumedThing}}.</td> | |||
| </tr> | |||
| <tr> | |||
| <td><dfn>[[\activeSubscriptions]]</dfn></td> | |||
| <td>`{}`</td> | |||
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It was a good idea to have an internal slot as a set, as it is usable with all policies (replace existing, reject if existing, add, ...).
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| @@ -1739,8 +1764,16 @@ <h3>The <dfn>subscribeEvent()</dfn> method</h3> | |||
| Takes as arguments |eventName:string|, |listener:WoTListener| and | |||
| optionally |onerror:ErrorListener| and |options:InteractionOptions|. | |||
| It returns a {{Promise}} to signal success or failure. | |||
| <p class="ednote"> | |||
| This algorithm allow for only one active {{Subscription}} per <a>Event</a>. If a new | |||
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Should we repeat this every time, or just say once for the whole API?
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Good point. I think another good place to state this is in the Subscription section but I don't know if we want to keep this simple to possibly change it in the future.
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We can also omit the ednote, since the algorithm is clear enough.
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typo?: this algorithm allowS ...
fix 358
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Cleaned up commit history and added a fix for #358. |
| <tr> | ||
| <td><dfn>[[\activeObservations]]</dfn></td> | ||
| <td>`{}`</td> | ||
| <td>A {{Set}} containing the names of active {{Subscription}}'s for an <a>Property</a></td> |
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I guess it should read
a set of active Observations but then internal linking is no longer working.... maybe we can refer to it by id
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| @@ -1677,8 +1687,16 @@ <h3>The <dfn>observeProperty()</dfn> method</h3> | |||
| Takes as arguments |propertyName:string|, |listener:InteractionListener| and | |||
| optionally |onerror:ErrorListener| and |options:InteractionOptions|. | |||
| It returns a {{Promise}} that resolves on success and rejects on failure. | |||
| <p class="ednote"> | |||
| This algorithm allow for only one active {{Subscription}} per <a>Property</a>. If a new | |||
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typo?: this algorithm allowS ...
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Scripting Call 2021-12-13 |
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@danielpeintner it should be ready to go :) |
This PR adds an additional step to
observePropertyandsubscribeEventalgorithms of theConsumeThing. It forces the runtime implementation to check whether the affordance has already an active Subscription, and if it is the case the runtime must throw aNotAllowedError. This should make clear to implementers that it is not possible to subscribe multime times to the same affordance, but I also added an editor note to make it cristal clear.The PR is currently in draft mode cause I wanted to use Set as type of the list of active Subscriptions/Observations but ECMA specification is not included among our
xrefand it conflicts withweb-platform.Note: It covers the points raised in #346.
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