From b1f6a44a6a29c38c25f80503852fabdc399e9361 Mon Sep 17 00:00:00 2001
From: Starbeamrainbowlabs <sbrl@starbeamrainbowlabs.com>
Date: Fri, 25 Feb 2022 03:22:58 +0000
Subject: [PATCH] SystemQueryClient: Add generator for fetching tables via SSE

---
 src/static/js/SystemQueryClient.mjs | 22 ++++++++++++++++++++++
 src/static/js/misc/events.mjs       | 22 ++++++++++++++++++++++
 2 files changed, 44 insertions(+)
 create mode 100644 src/static/js/misc/events.mjs

diff --git a/src/static/js/SystemQueryClient.mjs b/src/static/js/SystemQueryClient.mjs
index acbe651..03720cd 100644
--- a/src/static/js/SystemQueryClient.mjs
+++ b/src/static/js/SystemQueryClient.mjs
@@ -1,5 +1,7 @@
 "use strict";
 
+import { once } from './misc/events.mjs';
+
 class SystemQueryClient {
 	constructor() {
 		
@@ -9,6 +11,26 @@ class SystemQueryClient {
 		return this.fetch_json(`/api/status`);
 	}
 	
+	async *table(table_name) {
+		const abort = new AbortController();
+		const source = new EventSource(`/api/table/${table_name}`);
+		
+		source.addEventListener(`end`, () => {
+			source.close();
+			abort.abort();
+		}, { once: true });
+		
+		let count = 0;
+		while(source.readyState !== EventSource.CLOSED) {
+			let item = await once(source, "table", abort.signal);
+			if(item.type === "abort") break;
+			
+			yield JSON.parse(item.data);
+			count++;
+		}
+		console.log(`FETCH TABLE ${table_name}: ${count} items returned`);
+	}
+	
 	async fetch_json(path) {
 		let response = await fetch(path, {
 			headers: {
diff --git a/src/static/js/misc/events.mjs b/src/static/js/misc/events.mjs
new file mode 100644
index 0000000..d596de5
--- /dev/null
+++ b/src/static/js/misc/events.mjs
@@ -0,0 +1,22 @@
+"use strict";
+
+function once(event_emitter, event_name, abort_signal = null) {
+	return new Promise((resolve, reject) => {
+		let options = {
+			once: true
+		};
+		if(abort_signal !== null) options.signal = abort_signal;
+		
+		let resolve_handler = function() {
+			event_emitter.removeEventListener("error", reject);
+			abort_signal.removeEventListener("abort", resolve_handler);
+			resolve(...arguments);
+		};
+		
+		abort_signal.addEventListener("abort", resolve_handler);
+		event_emitter.addEventListener("error", reject, options);
+		event_emitter.addEventListener(event_name, resolve_handler, options);
+	});
+}
+
+export { once };