Poll on subscribe; test message

web/src/app/Api.js

@@ -0,0 +1,24 @@
+import {topicUrlJsonPoll, fetchLinesIterator, topicUrl} from "./utils";
+
+class Api {
+    static async poll(baseUrl, topic) {
+        const url = topicUrlJsonPoll(baseUrl, topic);
+        const messages = [];
+        console.log(`[Api] Polling ${url}`);
+        for await (let line of fetchLinesIterator(url)) {
+            messages.push(JSON.parse(line));
+        }
+        return messages.sort((a, b) => { return a.time < b.time ? 1 : -1; }); // Newest first
+    }
+
+    static async publish(baseUrl, topic, message) {
+        const url = topicUrl(baseUrl, topic);
+        console.log(`[Api] Publishing message to ${url}`);
+        await fetch(url, {
+            method: 'PUT',
+            body: message
+        });
+    }
+}
+
+export default Api;