Add a delta streaming endpoint

api/app.js

@@ -64,6 +64,8 @@ server.register(plugins, (err) => {
   server.auth.strategy('api-consumer', 'basic', { validateFunc: validate });
   server.auth.default('api-consumer');
 
+  DatabaseConnectionFactory.setup()
+
   server.start((startErr) => {
     if (startErr) { throw startErr; }
     console.log('Server running at:', server.info.uri);

api/routes/delta.js

@@ -0,0 +1,37 @@
+const DeltaStreamQueue = require(`${__base}/core/delta-stream-queue`);
+
+module.exports = (server) => {
+  server.route({
+    method: 'GET',
+    path: '/delta/streaming',
+    config: {
+      description: 'Returns deltas since timestamp then streams deltas',
+      notes: 'Returns deltas since timestamp then streams deltas',
+      tags: ['threads'],
+      validate: {
+        params: {
+        },
+      },
+      response: {
+        schema: null,
+      },
+    },
+    handler: (request, reply) => {
+      const outputStream = require('stream').Readable();
+      outputStream._read = () => { return };
+      const pushMsg = (msg = "\n") => outputStream.push(msg)
+
+      request.getAccountDatabase()
+      .then((db) => {
+        return db.Transaction.findAll().then((transactions = []) => {
+          transactions.map(JSON.stringify).forEach(pushMsg);
+          DeltaStreamQueue.subscribe(db.accountId, pushMsg)
+        })
+      }).then(() => {
+        const keepAlive = setInterval(pushMsg, 1000);
+        request.on("disconnect", () => { clearTimeout(keepAlive) })
+        return reply(outputStream)
+      })
+    },
+  });
+};

core/delta-stream-queue.js

@@ -14,15 +14,16 @@ class DeltaStreamQueue {
     return `delta-${accountId}`
   }
 
-  hasSubscribers(accountId) {
-    return this.client.existsAsync(this.key(accountId))
+  notify(accountId, data) {
+    this.client.publish(this.key(accountId), JSON.stringify(data))
   }
 
-  notify(accountId, data) {
-    return this.hasSubscribers(accountId).then((hasSubscribers) => {
-      if (!hasSubscribers) return Promise.resolve()
-      return this.client.rpushAsync(this.key(accountId), JSON.stringify(data))
+  subscribe(accountId, callback) {
+    this.client.on("message", (channel, message) => {
+      if (channel !== this.key(accountId)) { return }
+      callback(message)
     })
+    this.client.subscribe(this.key(accountId))
   }
 }