REST APIs for the Internet of Things

REST APIs for the Internet of Things
REST APIs for the Internet Of Things Michael J Koster Open Source Internet Of Things Meetup 19 March 2014
Resource oriented API •  Resource == web resource (URI) •  Resources change state in response to what is being sensed •  Actuator changes state in response to web resource update •  Abstract data sources and sinks •  REST API has 2 important characterisJcs for IoT use case…
RepresentaJonal State Transfer •  Resource interacJon through exchange of representaJon of resource state •  E.g. a representaJon of the state of a temperature sensor might be “63.6” •  Convenient for applicaJon soTware to use read/write semanJcs to interact with resources •  Stateful resource representaJons => Stateless applicaJon soTware
Based on Hypermedia •  Use of web links to locate resources of interest •  IoT needs machine-‐readable links that enable applicaJon soTware to discover things of interest •  Subset of web linking, semanJc web using relaJon/aribute •  Links encode metadata about the resource, e.g. type=‘temperature’, ct=‘applicaJon/json’
Web Linking for IoT •  Links are managed in 2 ways •  Object encapsulaJon: self-‐describing objects have links associated with endpoint, e.g. ./ well-‐known/core •  Resource Directory: Directories and Catalogs of links, stored at well-‐known locaJons, that point to resources and to other catalogs
Web Linking for IoT •  Links can be registered with a Resource Directory when sensors are brought online •  A crawler can discover links at ./well-‐known/core locaJons and populate catalogs •  ApplicaJon soTware can discover resources by aribute, e.g. query using type=‘temperature’, units=‘celsius’, locaJon=‘outdoor’ etc. •  System returns a set of links matching the query aributes
CoAP •  Part of IPV6 for Constrained Resource Environments (CoRE) •  IoT oriented REST API mapped to an eﬃcient binary protocol •  End devices can have both client and server roles, can also communicate directly •  Resource representaJon e.g. ‘applicaJon/ json’, is negoJated as in hp protocol
CoAP •  Observe opJon for long-‐term event stream response to GET, asynchronous updates •  Web linking using IETF standard core-‐link-‐ format (RFC 6690) •  Resource discovery using ./well-‐known/core or external Resource Directory
HTTP/REST •  HTTP and REST is useful for most web applicaJons, services, and gateways •  Uses web callbacks, websockets, HTTP PUT for asynchronous updates •  Links in JSON, Link-‐format, Hypercat, linked data •  Well deﬁned CoAP-‐to-‐HTTP proxy paerns, standard middleware
Hybrid system •  It’s possible to use REST for resource discovery and other stateful interacJons, and messaging e.g. MQTT for asynchronous updates •  Various methods to bind message endpoints to REST resources •  ApplicaJon soTware can easily use both REST API and event handler interfaces like onUpdate •  IoT Toolkit uses observers to bind
Standards and SoTware •  CoAP hps://datatracker.iel.org/doc/draT-‐iel-‐core-‐coap/ •  CoRE link-‐format hp://tools.iel.org/html/rfc6690 •  CoRE Observe hps://datatracker.iel.org/doc/draT-‐iel-‐core-‐observe/ •  CoRE Resource Directory hps://tools.iel.org/html/draT-‐iel-‐core-‐resource-‐directory-‐00 •  Hypercat hp://wiki.1248.io/doku.php?id=hypercat
IoT Toolkit Interoperability Demo smartobjectservice.com Node-‐RED Node-‐RED
MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Connects REST Resource to MQTT Topic Publish and Subscribe
MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Publisher Publishes REST Resource updates to the broker
MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Subscriber Makes last published data available at the REST endpoint
MQTT Observer MQTT Broker REST Endpoint ObservableProperty mqObserver PUT GET Publish from data producer Publish From REST API Publish to Other Subscribers SUB Publish to REST API Pub+Sub Repeats data updates in both direcJons
MQTT Bridge to mulJple REST endpoints MQTT Broker REST Endpoint ObservableProperty mqObserver PUT GET Publish from data producer Publish to Other Subscribers REST Endpoint ObservableProperty mqObserver PUT GET

REST APIs for the Internet of Things

Check these out next

REST APIs for the Internet of Things

Recommended

More Related Content

Slideshows for you(20)

Viewers also liked(18)

Similar to REST APIs for the Internet of Things(20)

Recently uploaded(20)

REST APIs for the Internet of Things