13:05:44 RRSAgent has joined #wot-td 13:05:44 logging to http://www.w3.org/2015/09/02-wot-td-irc 13:05:53 present+ DanhLePhuoc 13:05:56 rrsagent, set logs public 13:06:15 meeting: Thing description task force 13:06:21 Ari_Keranen has joined #wot-td 13:06:21 chair: Sebastian 13:06:57 scribenick: dsr 13:07:25 agenda: https://lists.w3.org/Archives/Public/public-wot-ig/2015Sep/0000.html 13:09:47 Sebastian summarises the agenda for today’s call 13:12:10 He shows us his idea for how to deal with an LED Lamp 13:13:28 The metadata includes the datamodel, the name of the lamp, and communications metadata 13:13:55 cabo has joined #wot-td 13:14:16 The action to turn the light on could also be modelled as a property. 13:14:41 He presents his idea for a JSON-LD representation 13:17:10 Sebastian has added metadata to allow a server to indicate which protocols it prefers 13:19:23 He switches the screen to show some ideas for how the data model could be bound to CoAO 13:19:31 s/CoAO/CoAP/ 13:21:07 Some question about how frequently given properties need to be sent 13:21:34 Question: will Sebastian make his ideas available on github? 13:21:43 Sebastian responds yes. 13:23:01 Dave asks what HATEOAS means? 13:23:32 XXX: it means metadata that allows ??? 13:23:51 s/XXX/MichaelKoster/ 13:23:54 yingying has joined #wot-td 13:25:16 So it means the communications metadata that end points need to select the protocols, data formats, encodings etc. 13:25:19 right 13:26:17 present+ yingying 13:26:25 Michael: the metdata should be optional, i.e. you don’t need it in all cases 13:27:02 You can cache it and its use may depend on the power of the client, etc. 13:28:05 taki1 has joined #wot-td 13:29:07 Sebastian talks further about metadata details 13:30:26 Dave here a simpler example: 13:30:30 A data model for your example could look something like: 13:30:30 { 13:30:32 “name” : “MyLED”, 13:30:33 “properties”: { 13:30:35 on: { 13:30:36 “type” : “boolean”, 13:30:38 “writeable”: true 13:30:39 }, 13:30:41 “colorTemp”: { 13:30:42 “type” : “uint16”, 13:30:44 “writeable” : true 13:30:45 }, 13:30:47 “red”: “uint8”, 13:30:49 “green”: “uint8”, 13:30:50 “blue”: “uint8” 13:30:51 } 13:30:53 } 13:30:54 see https://lists.w3.org/Archives/Public/public-wot-ig/2015Aug/0063.html 13:32:50 schuki has joined #wot-td 13:37:42 Sebastian: in last week’s AP task force call Michael asked us to look at HATEOAS approach. 13:38:35 Dave still doesn’t know what HATEOAS is and it would be great to have some more details 13:39:15 Johannes: we are working on the plug-fest plans and need to define the metadata involved 13:41:22 Johannes committed to set out a template for people to fill in and would send out last week 13:43:15 Johannes will email a pointer ... 13:44:39 Sebastian_ has joined #wot-td 13:45:03 with interactions at https://github.com/w3c/wot/blob/master/plugfest/interactions.md 13:45:18 and protocol bindings at https://github.com/w3c/wot/blob/master/plugfest/binding_coap.md 13:45:24 for CoAP 13:46:08 Johannes presents the plug-fest draft info as per the above links 13:48:16 He describes a means for scripts to monitor or cancel long running actions 13:49:19 He then describes informal bindings to CoAP 13:50:16 This is our idea for the plug-fest for you to comment on 13:50:34 It would be good to have more people contributing to this 13:52:09 Dave volunteers to add some info on bindings to Web Sockets and to HTTP 13:52:43 This includes the question for how a server can push messages back asynchronously 13:53:17 Johannes: newer versions of HTTP include a basic pub-sub model which could be useful 13:53:35 taki has joined #wot-td 13:54:41 Sebastian goes back to present his tutorial which he will post later 13:57:10 Topic: Sebastian’s question about “observe” 13:57:44 Sebastian wonders if it makes sense to be able to indicate that a property can be observed? 13:58:20 Carsten: we have something like that in the CoAP LINK format, but it isn’t so useful 13:58:46 If you are a client you can always use a GET with the observe option, so this is part of the protocol 13:59:23 You might have a property that is changing and if so you can just ask for it. 13:59:44 You have two different dimensions and it may be worth exploring that space some more 14:00:16 Danh: in our work we use a pub-sub approach to properties 14:02:12 Dave: I believe it depends on the details of the context and we need to study the use cases before we can have a meaningful discussion 14:03:42 There is risk of mixing up perspectives at the application and transport layer and unless we clarify this, we risk constraining which protocols can be used for the web of things 14:04:01 (Dave: That is the transfer layer, not the transport layer...) 14:07:28 Carsten: the layers may need to be leaky, we will need to explore use cases to get a better feel 14:11:32 Dave and Danh talk through the need for metadata at the transfer layer 14:13:27 Sebastian: so we need to collect use cases to explore the question in more details 14:14:08 Dave: I have an idea for a progressive elaboration of use cases in mind, but it will take time to work through 14:14:59 Johannes: it seems reasonable to have metadata that indicates whether a given property is static or frequently changes 14:15:58 Sebastian: so what is the resolution here? 14:16:35 Dave: defer a decision, but allow people to experiment, let’s learn to walk before we learn to run 14:17:04 Danh: JSON-LD allows you to add properties and clients can ignore the ones that they don’t know 14:17:16 That’s the way RDF works 14:19:14 Sebastian: so we will make Johannes’s static/frequently changing attribute as an optional piece of metadata 14:19:21 s/make/treat/ 14:21:03 Sebastian: ideas for naming this attribute? 14:21:44 Dave: how about “changes” with a value that is never, rarely, frequently? The details don’t matter as this is just experimental at this stage 14:22:00 Danh: how about “frequency” with a float for time interval or Hz 14:22:33 Carsten: for HTTP, you get a value that indicates how long a response is valid for 14:23:01 This is used for caching 14:24:10 We discuss the idea of giving an expiry time 14:25:43 Carsten: it could be hours, seconds or milliseconds 14:26:23 There is no infinity in JSON 14:26:45 Dave: we could add infinity via the default context 14:28:33 Sebastian will add a proposal for this 14:30:15 RRSAgent, draft minutes 14:30:15 I have made the request to generate http://www.w3.org/2015/09/02-wot-td-minutes.html jhund 14:30:27 RRSAgent, make minutes public 14:30:27 I'm logging. I don't understand 'make minutes public', jhund. Try /msg RRSAgent help 14:30:46 present: Dave, Sebastian, Ari, Arne, Carsten, Danh, Hans, Johannes, KH, Takuki, Yingying 14:30:55 rrsagent, make minutes 14:30:55 I have made the request to generate http://www.w3.org/2015/09/02-wot-td-minutes.html dsr 15:33:21 cabo has joined #wot-td 19:00:30 cabo has joined #wot-td 23:46:57 cabo has joined #wot-td