Support broadcast in FDC3 Action

[symphony-jean-michael]

Enhancement Request

Use Case:

Today, in Symphony, the user can send a chat message using the FDC3 StartChat intent. ℹ️ The format of the message can be found here : https://fdc3.finos.org/docs/context/ref/Message.

A great FDC3 feature is the ability to attach entities to the message. This is defined in the FDC3 action.

Example: The user can send an FDC3 message containing a button. When the user clicks on the button, it will trigger the FDC3 action attached to the button. This is the entity defined in FDC3.action. See example in the standard: https://fdc3.finos.org/docs/context/ref/Action#example

This works perfectly. But today, some of our customers would also like to broadcast a context instead of raising an intent. But the current FDC3 action format doesn't allow this for now.

In the FDC3 specification, you can read :

The action may be completed by calling fdc3.raiseIntent() with the specified Intent and Context, or, if only a context is specified, by calling fdc3.raiseIntentForContext()

(From https://fdc3.finos.org/docs/context/ref/Action)

Workflow Description

So, we would like to suggest an update of the FDC3 action to support the broadcast.

We propose to modify the current table of FDC3 Action properties. Our modifications are shown in bold.

Property	Type	Required	Example Value
type	string	Yes	'fdc3.action'
action	string	No	'broadcast' or 'raiseIntent'
title	string	Yes	'Click to view Chart'
intent	string	No	'ViewChart'
context	string	Yes	See Below
channel	object	No	myChannel
channel.id	string	Yes	'Channel 1'
app	object	No	'myApp'
app.appId	string	Yes	'app1'
app.instanceId	string	No	'instance1'

The action field indicates the type of action:

• raiseIntent : If no action or raiseIntent is specified, then the current default behaviour would be used with fdc3.rainseIntent / fdc3.raiseIntentForContext
• broadcast : If broadcast action is specified, it will call fdc3.getOrCreateChannel('Channel 1')to retrieve the channel, then broadcast the context to that channel with channel.broadcast(context). If no, channel has been specified, it will try to broadcast to the current channel (fdc3.getCurrentChannel())

Workflow Examples

Here is the Action example updated :

const action = {
    type: 'fdc3.action',
    title: 'Click to view Chart',
    action: 'broadcast',      <========= NEW
    channel: {      <========= NEW
      id : 'Channel 1'
    },
    context {
        type: 'fdc3.chart',
        instruments: [
            {
                type: 'fdc3.instrument',
                id: {
                    ticker: 'EURUSD'
                }
            }
        ],
        range: {
            type: 'fdc3.dateRange',
            starttime: '2020-09-01T08:00:00.000Z',
            endtime: '2020-10-31T08:00:00.000Z'
        },
        style: 'candle'
    },
    app {
        appId: 'MyChartViewingApp',
        instanceId: 'instance1'
    }
}

What do you think ? Thank you

[kriswest]

Seems a reasonable addition. As neither of the new properties, action or channel, are required I think this is non-breaking.

However:

• app and channel seem to be mutually exclusive, but you provide both in your example...
  • It's hard to do so via a non-breaking change but a better design for the context might have been to have nested properties under the action so raise intent has optional intent and app properties, while broadcast has a channel property. We could only do that now via a breaking change or adding new properties and deprecating old ones, hence, I suggest we just handle it via documentation (e.g. "the channel property is ignored unless the action is broadcast", etc.)
• The channel element only has one property, might it be simpler to have just a channelId property?

[symphony-jean-michael]

Hi @kriswest

Thank you for your comments.

app and channel seem to be mutually exclusive, but you provide both in your example... It's hard to do so via a non-breaking change but a better design for the context might have been to have nested properties under the action so raise intent has optional intent and app properties, while broadcast has a channel property. We could only do that now via a breaking change or adding new properties and deprecating old ones, hence, I suggest we just handle it via documentation (e.g. "the channel property is ignored unless the action is broadcast", etc.)

I totally agree with your remarks 👍

The channel element only has one property, might it be simpler to have just a channelId property?

I suggested using an object because I noticed that a channel can have other properties such as type and displayMetadata. In my case, I only need the ID when broadcasting, but maybe this information will be useful in another case. 🤔 getOrCreateChannel needs only the channel id, so I guess we can leave the other parameters optional.

[kriswest]

@symphony-jean-michael the additional properties of a channel are not used by the API (which only ever takes the channelId as an argument). The additional values are only provided for display purposes.

The one exception is a private channel, which can't be retrieved by id, you have to raise an intent and receive that back. While the additional type property could indicate that its a private channel that you already have to have a refernece to to use, you could also just figure that out using the id if private channels end up involved in your use case - you would have had to receive the channel via a previous interaction where you raised an intent so that should be easy to recognise. Hence, I'd suggest dropping the additional channel params.

[kriswest]

P.S. we're about to try and close the FDC3 2.2 scope - this is not a big change but would need to go onto a PR and the change be agreed this Thursday. Otherwise, it can be agreed and merged post 2.2 and you can start using before it comes out in a later standard version.

[symphony-jean-michael]

P.S. we're about to try and close the FDC3 2.2 scope - this is not a big change but would need to go onto a PR and the change be agreed this Thursday. Otherwise, it can be agreed and merged post 2.2 and you can start using before it comes out in a later standard version.

Thanks @kriswest for the explanation. I will create the PR this afternoon.

[symphony-jean-michael]

Hi @kriswest I've juste created the PR https://github.com/finos/FDC3/pull/1368 Could you please have review it ?

Thank you