DesktopAgent
An FDC3 Desktop Agent is a desktop component (or aggregate of components) that serves as an orchestrator for applications in its domain.
A Desktop Agent can be connected to one or more App Directories and will use directories for application identity and discovery. Typically, a Desktop Agent will contain the proprietary logic of a given platform, handling functionality like explicit application interop workflows where security, consistency, and implementation requirements are proprietary.
It is expected that the DesktopAgent interface is made availabe via the window.fdc3 global object, and that the fdc3Ready event fires when it is ready to be used.
interface DesktopAgent {
// apps
open(app: TargetApp, context?: Context): Promise<void>;
// context
broadcast(context: Context): void;
addContextListener(contextType: string | null, handler: ContextHandler): Listener;
/**
* @deprecated 'Use `addContextListener(null, handler)` instead of `addContextListener(handler)`
*/
addContextListener(handler: ContextHandler): Listener;
// intents
findIntent(intent: string, context?: Context): Promise<AppIntent>;
findIntentsByContext(context: Context): Promise<Array<AppIntent>>;
raiseIntent(intent: string, context: Context, app?: TargetApp): Promise<IntentResolution>;
raiseIntentForContext(context: Context, app?: TargetApp): Promise<IntentResolution>;
addIntentListener(intent: string, handler: ContextHandler): Listener;
// channels
getOrCreateChannel(channelId: string): Promise<Channel>;
getSystemChannels(): Promise<Array<Channel>>;
joinChannel(channelId: string) : Promise<void>;
getCurrentChannel() : Promise<Channel | null>;
leaveCurrentChannel() : Promise<void>;
//implementation info
getInfo(): ImplementationMetadata;
}
Methods
addContextListener
addContextListener(contextType: string | null, handler: ContextHandler): Listener;
/**
* @deprecated 'Use `addContextListener(null, handler)` instead of `addContextListener(handler)`
*/
addContextListener(handler: ContextHandler): Listener;
Adds a listener for incoming context broadcast from the Desktop Agent on the current System Channel. If the consumer is only interested in a context of a particular type, they can use the relevant overload that allows the type to be specified.
Examples
// any context
const listener = fdc3.addContextListener(null, context => { ... });
// listener for a specific type
const contactListener = fdc3.addContextListener('fdc3.contact', contact => { ... });
See also
addIntentListener
addIntentListener(intent: string, handler: ContextHandler): Listener;
Adds a listener for incoming Intents from the Agent.
Examples
const listener = fdc3.addIntentListener('StartChat', context => {
// start chat has been requested by another application
});
See also
broadcast
broadcast(context: Context): void;
Publishes context to other apps on the desktop. Calling broadcast at the DesktopAgent scope will push the context to whatever Channel the app is joined to. If the app is not currently joined to a channel, calling fdc3.broadcast will have no effect. Apps can still directly broadcast and listen to context on any channel via the methods on the Channel class.
DesktopAgent implementations should ensure that context messages broadcast to a channel by an application joined to it should not be delivered back to that same application.
Example
const instrument = {
type: 'fdc3.instrument',
id: {
ticker: 'AAPL'
}
};
fdc3.broadcast(instrument);
See also
findIntent
findIntent(intent: string, context?: Context): Promise<AppIntent>;
Find out more information about a particular intent by passing its name, and optionally its context.
findIntent is effectively granting programmatic access to the Desktop Agent's resolver. It returns a promise resolving to the intent, its metadata and metadata about the apps that are registered to handle it. This can be used to raise the intent against a specific app.
If the resolution fails, the promise will return an Error with a string from the ResolveError enumeration.
Examples
// I know 'StartChat' exists as a concept, and want to know more about it ...
const appIntent = await fdc3.findIntent("StartChat");
// returns a single AppIntent:
// {
// intent: { name: "StartChat", displayName: "Chat" },
// apps: [{ name: "Skype" }, { name: "Symphony" }, { name: "Slack" }]
// }
// raise the intent against a particular app
await fdc3.raiseIntent(appIntent.intent.name, context, appIntent.apps[0].name);
See also
findIntentsByContext
findIntentsByContext(context: Context): Promise<Array<AppIntent>>;
Find all the available intents for a particular context. findIntentsByContext is effectively granting programmatic access to the Desktop Agent's resolver. A promise resolving to all the intents, their metadata and metadata about the apps that registered as handlers is returned, based on the context types the intents have registered.
If the resolution fails, the promise will return an Error with a string from the ResolveError enumeration.
Example
// I have a context object, and I want to know what I can do with it, hence, I look for intents...
const appIntents = await fdc3.findIntentsByContext(context);
// returns, for example:
// [{
// intent: { name: "StartCall", displayName: "Call" },
// apps: [{ name: "Skype" }]
// },
// {
// intent: { name: "StartChat", displayName: "Chat" },
// apps: [{ name: "Skype" }, { name: "Symphony" }, { name: "Slack" }]
// }];
// select a particular intent to raise
const startChat = appIntents[1];
// target a particular app
const selectedApp = startChat.apps[0];
// raise the intent, passing the given context, targeting the app
await fdc3.raiseIntent(startChat.intent.name, context, selectedApp.name);
See also
getCurrentChannel
getCurrentChannel() : Promise<Channel | null>;
Returns the Channel object for the current channel membership. Returns null if the app is not joined to a channel.
Examples
// get the current channel membership
let current = await fdc3.getCurrentChannel();
See also
getInfo
getInfo(): ImplementationMetadata;
Retrieves information about the FDC3 Desktop Agent implementation, such as the implemented version of the FDC3 specification and the name of the implementation provider.
Returns an ImplementationMetadata object. This metadata object can be used to vary the behavior of an application based on the version supported by the Desktop Agent and for logging purposes.
Example
import {compareVersionNumbers, versionIsAtLeast} from '@finos/fdc3';
if (fdc3.getInfo && versionIsAtLeast(fdc3.getInfo(), "1.2")) {
await fdc3.raiseIntentForContext(context);
} else {
await fdc3.raiseIntent("ViewChart", context);
}
See also
getOrCreateChannel
getOrCreateChannel(channelId: string): Promise<Channel>;
Returns a Channel object for the specified channel, creating it (as an App channel) - if it does not exist.
Error with a string from the ChannelError enumeration if channel could not be created or access was denied.
Example
try {
const myChannel = await fdc3.getOrCreateChannel("myChannel");
const myChannel.addContextListener(null, context => {});
}
catch (err){
//app could not register the channel
}
See also
getSystemChannels
getSystemChannels() : Promise<Array<Channel>>;
Retrieves a list of the System channels available for the app to join. This should include the 'global' channel.
Example
const systemChannels = await fdc3.getSystemChannels();
const redChannel = systemChannels.find(c => c.id === 'red');
See also
joinChannel
joinChannel(channelId: string) : Promise<void>;
Joins the app to the specified channel.
If an app is joined to a channel, all fdc3.broadcast calls will go to the channel, and all listeners assigned via fdc3.addContextListener will listen on the channel.
An app can only be joined to one channel at a time.
Rejects with error if the channel is unavailable or the join request is denied.
Error with a string from the ChannelError enumeration.
Examples
// get all system channels
const channels = await fdc3.getSystemChannels();
// create UI to pick from the system channels
// join the channel on selection
fdc3.joinChannel(selectedChannel.id);
See also
leaveCurrentChannel
leaveCurrentChannel() : Promise<void>;
Removes the app from any channel membership. Context broadcast and listening through the top-level fdc3.broadcast and fdc3.addContextListener will be in a no-op when the app is not on a channel.
Examples
//desktop-agent scope context listener
const fdc3Listener = fdc3.addContextListener(null, context => {});
await fdc3.leaveCurrentChannel();
//the fdc3Listener will now cease recieving context
//listening on a specific channel though, will continue to work
redChannel.addContextListener(null, channelListener);
open
open(app: TargetApp, context?: Context): Promise<void>;
Launches an app with target information, which can be either be a string like a name, or an AppMetadata object.
The open method differs in use from raiseIntent. Generally, it should be used when the target application is known but there is no specific intent. For example, if an application is querying the App Directory, open would be used to an app returned in the search results.
Note, if both the intent and target app name are known, it is recommended to instead use raiseIntent with the app argument.
If a Context object is passed in, this object will be provided to the opened application via a contextListener.
The Context argument is functionally equivalent to opening the target app with no context and broadcasting the context directly to it.
If opening errors, it returns an Error with a string from the OpenError enumeration.
Example
// no context
await fdc3.open('myApp');
// no context, with AppMetadata object as target
await fdc3.open({
name: 'myApp',
title: 'The title for the application myApp.',
description: '...'
});
// with context
await fdc3.open('myApp', context);
See also
raiseIntent
raiseIntent(intent: string, context: Context, app?: TargetApp): Promise<IntentResolution>;
Raises a specific intent against a target app.
The desktop agent will resolve the correct app to target based on the provided intent name and context data.
If multiple matching apps are found, the user may be presented with an app picker. Alternatively, the specific app to target can also be provided (if known).
Returns an IntentResolution object with a handle to the app that responded to the intent.
If a target app for the intent cannot be found with the criteria provided, an Error with a string from the ResolveError enumeration is returned.
Example
// find apps to resolve an intent to start a chat with a given contact
const appIntent = await fdc3.findIntent("StartChat", context);
// use the name of one of the associated apps returned by findIntent as the specific intent target
await fdc3.raiseIntent("StartChat", context, appIntent.apps[0].name);
// or use the metadata of the app to fully describe the target app for the intent
await fdc3.raiseIntent("StartChat", context, appIntent.apps[0]);
See also
raiseIntentForContext
raiseIntentForContext(context: Context, app?: TargetApp): Promise<IntentResolution>;
Finds and raises an intent against a target app based purely on context data.
The desktop agent will resolve the correct app to target based on the provided context.
This is similar to calling findIntentsByContext, and then raising an intent against one of the returned apps, except in this case
the desktop agent has the opportunity to provide the user with a richer selection interface where they can choose the intent and target app.
Returns an IntentResolution object with a handle to the app that responded to the selected intent.
If a target app for the intent cannot be found with the criteria provided, an Error with a string from the ResolveError enumeration is returned.
Example
const intentResolution = await fdc3.raiseIntentForContext(context);