Improve app message types

app/src/bridge/components/chromecast/Media.ts

@@ -4,8 +4,8 @@ import castv2 from "castv2";
 
 import Session from "./Session";
 
-import { Message } from "../../types";
-import { sendMessage } from "../../lib/messaging"
+import { Message } from "../../messaging";
+import { sendMessage } from "../../lib/nativeMessaging"
 
 
 const NS_MEDIA = "urn:x-cast:com.google.cast.media";

app/src/bridge/components/chromecast/Session.ts

@@ -2,8 +2,8 @@
 
 import { Channel, Client } from "castv2";
 
-import { Message } from "../../types";
-import { sendMessage } from "../../lib/messaging";
+import { Message } from "../../messaging";
+import { sendMessage } from "../../lib/nativeMessaging";
 
 
 export const NS_CONNECTION = "urn:x-cast:com.google.cast.tp.connection";

app/src/bridge/components/discovery.ts

@@ -4,7 +4,7 @@ import mdns from "mdns";
 
 import StatusListener from "./chromecast/StatusListener";
 import { ReceiverStatus } from "../types";
-import { sendMessage } from "../lib/messaging";
+import { sendMessage } from "../lib/nativeMessaging";
 
 
 interface CastTxtRecord {
@@ -44,7 +44,7 @@ function onBrowserServiceUp (service: mdns.Service) {
     });
 }
 
-function onBrowserServiceDown (service: mdns.Service) {
+function onBrowserServiceDown (_service: mdns.Service) {
     // TODO: Fix service down detection
 }
 
@@ -109,7 +109,7 @@ export function startDiscovery (options: InitializeOptions) {
         statusListeners.set(id, listener);
     }
 
-    function onStatusBrowserServiceDown (service: mdns.Service) {
+    function onStatusBrowserServiceDown (_service: mdns.Service) {
         // TODO: Fix service down detection
     }
 }

app/src/bridge/components/mediaServer.ts

@@ -8,7 +8,7 @@ import stream from "stream";
 
 import mime from "mime-types";
 
-import { sendMessage } from "../lib/messaging";
+import { sendMessage } from "../lib/nativeMessaging";
 import { convertSrtToVtt } from "../lib/subtitles";
 
 

app/src/bridge/components/receiverSelector.ts

@@ -3,7 +3,7 @@
 import child_process from "child_process";
 import path from "path";
 
-import { sendMessage } from "../lib/messaging";
+import { sendMessage } from "../lib/nativeMessaging";
 
 
 function fatal (message: string) {

app/src/bridge/index.ts

@@ -1,7 +1,7 @@
 "use strict";
 
-import { decodeTransform, encodeTransform } from "./lib/messaging";
-import { Message } from "./types";
+import { decodeTransform, encodeTransform } from "./lib/nativeMessaging";
+import { Message } from "./messaging";
 
 import { handleSessionMessage, handleMediaMessage, stopReceiverApp }
         from "./components/chromecast";

app/src/bridge/lib/nativeMessaging.ts

@@ -1,7 +1,7 @@
 "use strict";
 
 import { DecodeTransform, EncodeTransform } from "../../transforms";
-import { Message } from "../types";
+import { Message } from "../messaging";
 
 
 export const decodeTransform = new DecodeTransform();

app/src/bridge/messaging.ts

@@ -0,0 +1,172 @@
+"use strict";
+
+import { Receiver
+       , ReceiverSelectionCast
+       , ReceiverSelectionStop
+       , ReceiverStatus } from "./types";
+
+
+type MessageDefinitions = {
+      "shim:serviceUp": { id: Receiver["id"] }
+    , "shim:serviceDown": { id: Receiver["id"] }
+  
+    , "shim:launchApp": { receiver: Receiver }
+  
+      // Session messages
+    , "shim:session/stopped": {}
+    , "shim:session/connected": {
+          sessionId: string
+        , namespaces: Array<{ name: string }>
+        , displayName: string
+        , statusText: string
+      }
+    , "shim:session/updateStatus": { volume: any /* Volume */ }
+    , "shim:session/impl_addMessageListener": {
+          namespace: string
+        , data: string
+      }
+    , "shim:session/impl_sendMessage": {
+          messageId: string
+        , error: boolean
+      }
+    , "shim:session/impl_setReceiverMuted": {
+          volumeId: string
+        , error: boolean
+      }
+    , "shim:session/impl_setReceiverVolumeLevel": {
+          volumeId: string
+        , error: boolean
+      }
+    , "shim:session/impl_stop": {
+          stopId: string
+        , error: boolean
+      }
+  
+      // Bridge session messages
+    , "bridge:session/initialize": {
+          address: string
+        , port: number
+        , appId: string
+        , sessionId: string
+        , _id: string
+      }
+    , "bridge:session/close": {}
+    , "bridge:session/impl_leave": {
+          id: string
+        , _id: string
+      }
+    , "bridge:session/impl_sendMessage": {
+          namespace: string
+        , message: any
+        , messageId: string
+        , _id: string
+      }
+    , "bridge:session/impl_setReceiverMuted": {
+          muted: boolean
+        , volumeId: string
+        , _id: string
+      }
+    , "bridge:session/impl_setReceiverVolumeLevel": {
+          newLevel: number
+        , volumeId: string
+        , _id: string
+      }
+    , "bridge:session/impl_stop": {
+          stopId: string;
+          _id: string;
+      }
+    , "bridge:session/impl_addMessageListener": {
+          namespace: string;
+          _id: string;
+      }
+  
+      // Media messages
+    , "shim:media/update": {
+          currentTime: number
+        , _lastCurrentTime: number
+        , customData: any
+        , playbackRate: number
+        , playerState: string
+        , repeatMode: string
+        , _volumeLevel: number
+        , _volumeMuted: boolean
+        , media: unknown // MediaInfo
+        , mediaSessionId: number
+      }
+    , "shim:media/sendMediaMessageResponse": {
+          messageId: string
+        , error: boolean
+      }
+  
+      // Bridge media messages
+    , "bridge:media/initialize": {
+          sessionId: string
+        , mediaSessionId: number
+        , _internalSessionId: string
+        , _id: string
+      }
+    , "bridge:media/sendMediaMessage": {
+          message: any
+        , messageId: string
+        , _id: string
+      }
+  
+      // Bridge messages
+    , "main:receiverSelector/selected": ReceiverSelectionCast
+    , "main:receiverSelector/error": string
+    , "main:receiverSelector/close": {}
+    , "main:receiverSelector/stop": ReceiverSelectionStop
+  
+    , "bridge:getInfo": string
+    , "bridge:initialize": { shouldWatchStatus: boolean }
+  
+    , "bridge:receiverSelector/open": any
+    , "bridge:receiverSelector/close": {}
+  
+    , "bridge:stopReceiverApp": { receiver: Receiver }
+  
+    , "bridge:mediaServer/start": {
+          filePath: string
+        , port: number
+      }
+    , "bridge:mediaServer/stop": {}
+    , "mediaCast:mediaServer/started": {
+          mediaPath: string
+        , subtitlePaths: string[]
+        , localAddress: string
+      }
+    , "mediaCast:mediaServer/stopped": {}
+    , "mediaCast:mediaServer/error": {}
+  
+    , "main:serviceUp": Receiver
+    , "main:serviceDown": { id: string }
+  
+    , "main:receiverStatus": {
+          id: string
+        , status: ReceiverStatus
+      }
+}
+
+
+interface MessageBase<K extends keyof MessageDefinitions> {
+    subject: K;
+    data: MessageDefinitions[K];
+}
+
+type Messages = {
+    [K in keyof MessageDefinitions]: MessageBase<K>;
+}
+
+/**
+ * For better call semantics, make message data key optional if
+ * specified as blank or with all-optional keys.
+ */
+type NarrowedMessage<L extends MessageBase<keyof MessageDefinitions>> =
+    L extends any
+        ? {} extends L["data"]
+            ? Omit<L, "data"> & Partial<L>
+            : L
+        : never;
+
+        
+export type Message = NarrowedMessage<Messages[keyof Messages]>;

app/src/bridge/types.ts

@@ -84,211 +84,3 @@ export interface Receiver {
     port: number;
     status?: ReceiverStatus;
 }
-
-
-export type Messages = [
-    {
-        subject: "shim:serviceUp"
-      , data: { id: Receiver["id"] }
-    }
-  , {
-        subject: "shim:serviceDown"
-      , data: { id: Receiver["id"] }
-    }
-  , {
-        subject: "shim:launchApp"
-      , data: { receiver: Receiver }
-    }
-
-    // Session messages
-  , {
-        subject: "shim:session/stopped"
-    }
-  , {
-        subject: "shim:session/connected"
-      , data: {
-            sessionId: string;
-            namespaces: Array<{ name: string }>;
-            displayName: string;
-            statusText: string;
-        }
-    }
-  , {
-        subject: "shim:session/updateStatus"
-      , data: any
-    }
-  , {
-        subject: "shim:session/impl_addMessageListener"
-      , data: { namespace: string, data: string }
-    }
-  , {
-        subject: "shim:session/impl_sendMessage"
-      , data: { messageId: string, error: boolean }
-    }
-  , {
-        subject: "shim:session/impl_setReceiverMuted"
-      , data: { volumeId: string, error: boolean }
-    }
-  , {
-        subject: "shim:session/impl_setReceiverVolumeLevel"
-      , data: { volumeId: string, error: boolean }
-    }
-  , {
-        subject: "shim:session/impl_stop"
-      , data: { stopId: string, error: boolean }
-    }
-
-    // Bridge session messages
-  , {
-        subject: "bridge:session/initialize"
-      , data: {
-            address: string
-          , port: number
-          , appId: string
-          , sessionId: string
-        }
-      , _id: string;
-    }
-  , {
-        subject: "bridge:session/close"
-      , _id: string;
-    }
-  , {
-        subject: "bridge:session/impl_leave"
-      , data: { id: string }
-      , _id: string
-    }
-  , {
-        subject: "bridge:session/impl_sendMessage"
-      , data: { namespace: string, message: any, messageId: string }
-      , _id: string
-    }
-  , {
-        subject: "bridge:session/impl_setReceiverMuted"
-      , data: { muted: boolean, volumeId: string }
-      , _id: string
-    }
-  , {
-        subject: "bridge:session/impl_setReceiverVolumeLevel"
-      , data: { newLevel: number, volumeId: string }
-      , _id: string
-    }
-  , {
-        subject: "bridge:session/impl_stop"
-      , data: { stopId: string }
-      , _id: string
-    }
-  , {
-        subject: "bridge:session/impl_addMessageListener"
-      , data: { namespace: string }
-      , _id: string
-    }
-
-    // Media messages
-  , {
-        subject: "shim:media/update"
-      , data: {
-            currentTime: number
-          , _lastCurrentTime: number
-          , customData: any
-          , playbackRate: number
-          , playerState: string
-          , repeatMode: string
-          , _volumeLevel: number
-          , _volumeMuted: boolean
-          , media: any
-          , mediaSessionId: number
-        }
-    }
-  , {
-        subject: "shim:media/sendMediaMessageResponse"
-      , data: { messageId: string, error: boolean }
-    }
-
-    // Bridge media messages
-  , {
-        subject: "bridge:media/initialize"
-      , data: {
-            sessionId: string
-          , mediaSessionId: number
-          , _internalSessionId: string
-        }
-      , _id: string;
-    }
-  , {
-        subject: "bridge:media/sendMediaMessage"
-      , data: { message: any, messageId: string }
-      , _id: string;
-    }
-
-    // Bridge messages
-  , {
-        subject: "main:receiverSelector/selected"
-      , data: ReceiverSelectionCast
-    }
-  , {
-        subject: "main:receiverSelector/error"
-      , data: string
-    }
-  , {
-        subject: "main:receiverSelector/close"
-    }
-  , {
-        subject: "main:receiverSelector/stop"
-      , data: ReceiverSelectionStop
-    }
-  , {
-        subject: "bridge:getInfo"
-    }
-  , {
-        subject: "bridge:initialize"
-      , data: { shouldWatchStatus: boolean }
-    }
-  , {
-        subject: "bridge:receiverSelector/open"
-      , data: any }
-  , {
-        subject: "bridge:receiverSelector/close"
-    }
-  , {
-        subject: "bridge:stopReceiverApp"
-      , data: { receiver: Receiver }
-    }
-  , {
-        subject: "bridge:mediaServer/start"
-      , data: { filePath: string, port: number }
-    }
-    , {
-        subject: "bridge:mediaServer/stop"
-    }
-
-  , {
-        subject: "mediaCast:mediaServer/started"
-      , data: {
-            mediaPath: string
-          , subtitlePaths: string[]
-          , localAddress: string
-        }
-    }
-  , {
-        subject: "mediaCast:mediaServer/stopped"
-    }
-  , {
-        subject: "mediaCast:mediaServer/error"
-    }
-
-  , {
-        subject: "main:serviceUp"
-      , data: Receiver
-    }
-  , {
-        subject: "main:serviceDown"
-      , data: { id: string }
-    }
-  , {
-        subject: "main:receiverStatus"
-      , data: { id: string, status: ReceiverStatus }
-    }
-];
-
-export type Message = Messages[number];

app/src/transforms.ts

@@ -1,7 +1,7 @@
 "use strict";
 
 import { Transform } from "stream";
-import { Message } from "./bridge/types";
+import { Message } from "./bridge/messaging";
 
 
 type ResponseHandlerFunction = (message: Message) => Promise<any>;