Merge branch 'master' of github.com:browngraphicslab/Dash-Web into no_db

1 files changed, 46 insertions, 0 deletions

diff --git a/src/server/session/agents/process_message_router.ts b/src/server/session/agents/process_message_router.ts
new file mode 100644
index 000000000..d359e97c3
--- /dev/null
+++ b/src/server/session/agents/process_message_router.ts
@@ -0,0 +1,46 @@
+import { MessageHandler, PromisifiedIPCManager } from "./promisified_ipc_manager";
+
+export default abstract class ProcessMessageRouter {
+
+    protected static IPCManager: PromisifiedIPCManager;
+    private onMessage: { [name: string]: MessageHandler[] | undefined } = {};
+
+    /**
+     * Add a listener at this message. When the monitor process
+     * receives a message, it will invoke all registered functions.
+     */
+    public on = (name: string, handler: MessageHandler, exclusive = false) => {
+        const handlers = this.onMessage[name];
+        if (exclusive || !handlers) {
+            this.onMessage[name] = [handler];
+        } else {
+            handlers.push(handler);
+        }
+    }
+
+    /**
+     * Unregister a given listener at this message.
+     */
+    public off = (name: string, handler: MessageHandler) => {
+        const handlers = this.onMessage[name];
+        if (handlers) {
+            const index = handlers.indexOf(handler);
+            if (index > -1) {
+                handlers.splice(index, 1);
+            }
+        }
+    }
+
+    /**
+     * Unregister all listeners at this message.
+     */
+    public clearMessageListeners = (...names: string[]) => names.map(name => this.onMessage[name] = undefined);
+
+    protected route: MessageHandler = async ({ name, args }) => {
+        const handlers = this.onMessage[name];
+        if (handlers) {
+            await Promise.all(handlers.map(handler => handler(args)));
+        }
+    }
+
+}
\ No newline at end of file