ssb: Now add back the about cache, and load times are getting good.

apps/ssb.json

@@ -1,5 +1,5 @@
 {
 	"type": "tildefriends-app",
 	"emoji": "🦀",
-	"previous": "&NajVQD/6DKISEDlnyAVYh3NPO/vxMN7ksNZy3FwI378=.sha256"
+	"previous": "&VQsPosjAfr008a6UMb8vKmKxE/WS4DRKEspJL8Lewjw=.sha256"
 }

apps/ssb/tf-app.js

@@ -152,7 +152,32 @@ class TfElement extends LitElement {
 
 	async fetch_about(following, users) {
 		let ids = Object.keys(following).sort();
-		console.log('loading about for', ids.length, 'accounts');
+		const k_cache_version = 2;
+		let cache = await tfrpc.rpc.databaseGet('about');
+		let original_cache = cache;
+		cache = cache ? JSON.parse(cache) : {};
+		if (cache.version !== k_cache_version) {
+			cache = {
+				version: k_cache_version,
+				about: {},
+			};
+		}
+
+		for (let id of Object.keys(cache.about)) {
+			if (ids.indexOf(id) == -1) {
+				delete cache.about[id];
+			} else {
+				users[id] = Object.assign(
+					users[id] || {},
+					cache.about[id]
+				);
+			}
+		}
+
+		let ids_out_of_date = ids.filter(x => cache.about[x]?.seq === undefined || (users[x]?.seq && users[x]?.seq > cache.about[x].seq));
+
+		console.log('loading about for', ids.length, 'accounts', ids_out_of_date.length, 'out of date');
+		if (ids_out_of_date.length) {
 			try {
 				let rows = await tfrpc.rpc.query(
 					`
@@ -172,7 +197,7 @@ class TfElement extends LitElement {
 						WHERE rank = 1
 						GROUP BY all_abouts.author
 					`,
-				[JSON.stringify(ids)]
+					[JSON.stringify(ids_out_of_date)]
 				);
 				users = users || {};
 				for (let row of rows) {
@@ -180,11 +205,30 @@ class TfElement extends LitElement {
 						users[row.author] || {},
 						JSON.parse(row.about)
 					);
+					cache.about[row.author] = Object.assign(
+						{seq: users[row.author].seq},
+						JSON.parse(row.about)
+					);
 				}
-			console.log('updated users');
 			} catch (e) {
 				console.log(e);
 			}
+		}
+
+		for (let id of ids_out_of_date) {
+			if (!cache.about[id]?.seq) {
+				cache.about[id] = {seq: users[id]?.seq ?? 0};
+			}
+		};
+
+		let new_cache = JSON.stringify(cache);
+		if (new_cache != original_cache) {
+			let start_time = new Date();
+			tfrpc.rpc.databaseSet('about', new_cache).then(function() {
+				console.log('saving about took', (new Date() - start_time) / 1000);
+			});
+		}
+
 		return Object.assign({}, users);
 	}
 
@@ -365,7 +409,7 @@ class TfElement extends LitElement {
 		for (let row of info) {
 			users[row.author] = Object.assign(
 				{
-					seq: row.max_seq,
+					seq: row.max_sequence,
 					ts: row.max_ts,
 				},
 				users[row.author]