By adding another connectivity type - HTTP - to Ditto’s connectivity, it is now (to be released in the next Ditto milestone 1.0.0-M2) possible to publish twin events, messages, live commands and events to existing HTTP servers/endpoints.

That is especially useful for invoking existing APIs (which are most of the time HTTP based) whenever e.g. a digital twin was modified.

One example on how to benefit from this new feature is to invoke a custom IFTTT (if-this-than-that) webhook via a HTTP POST request which then may trigger other IFTTT follow-up-actions (e.g. send a chat message to a Slack room).

For IFTTT “webhooks” the address would be POST https://maker.ifttt.com/trigger/<your-event-name>/with/key/<your-key> and the expected JSON body:

{
  "value1": "...",
  "value2": "...",
  "value3": "..."
}

In combination with payload mapping, the value1 to value3 fields requested by the IFTTT API can be extracted from the Ditto Protocol and could contain the changed value.

In combination with filters for targets you can even specify to only publish e.g. twin events, where the temperature of a twin exceeded a certain threshold:

{
  "address": "POST:/trigger/<your-event-name>/with/key/<your-key>",
  "topics": [
    "_/_/things/twin/events?filter=gt(features/temperature/properties/value,25)"
  ],
  ...
}

Get creative on which HTTP APIs to trigger based on twin events. E.g. invoke a “function-as-a-service” API or invoke the Twitter API and let your digital twin tweet whenever it detects, that it is getting too warm in your office.

Ditto

–
The Eclipse Ditto team