Added expanded followers data to the db

We're running into some performance issues when fetching large followers lists.
Ultimately we need to move away from using MySQL as a key value store - but for
now we can store the expanded list which should help with performance.

src/dispatchers.ts

@@ -64,6 +64,7 @@ export async function handleFollow(
     ctx.data.globaldb.set([sender.id.href], senderJson);
     await addToList(ctx.data.db, ['inbox'], follow.id.href);
     await addToList(ctx.data.db, ['followers'], sender.id.href);
+    await addToList(ctx.data.db, ['followers', 'expanded'], senderJson);
 
     const acceptId = ctx.getObjectUri(Accept, { id: uuidv4() });
     const accept = new Accept({
@@ -218,13 +219,24 @@ export async function inboxErrorHandler(
 
 async function lookupPerson(ctx: RequestContext<ContextData>, url: string) {
     try {
+        console.log('Looking up person locally', url);
         const local = await ctx.data.globaldb.get([url]);
         return await Person.fromJsonLd(local);
     } catch (err) {
-        const remote = await lookupObject(url);
-        if (remote instanceof Person) {
-            await ctx.data.globaldb.set([url], await remote.toJsonLd());
-            return remote;
+        console.log('Error looking up person locally', url);
+        console.log(err);
+        console.log('Looking up person remotely', url);
+        const documentLoader = await ctx.getDocumentLoader({handle: 'index'});
+        try {
+            const remote = await lookupObject(url, {documentLoader});
+            if (remote instanceof Person) {
+                await ctx.data.globaldb.set([url], await remote.toJsonLd());
+                return remote;
+            }
+        } catch (err) {
+            console.log('Error looking up person remotely', url);
+            console.log(err)
+            return null;
         }
     }
     return null;
@@ -235,18 +247,15 @@ export async function followersDispatcher(
     handle: string,
 ) {
     console.log('Followers Dispatcher');
-    const results = (await ctx.data.db.get<string[]>(['followers'])) || [];
-    console.log(results);
     let items: Person[] = [];
-    for (const result of results) {
-        try {
-            const thing = await lookupPerson(ctx, result);
-            if (thing instanceof Person) {
-                items.push(thing);
-            }
-        } catch (err) {
-            console.log(err);
-        }
+    const fullResults = await ctx.data.db.get<any[]>(['followers', 'expanded']);
+    if (fullResults) {
+        items = await Promise.all(fullResults.map(result => Person.fromJsonLd(result)));
+    } else {
+        const results = (await ctx.data.db.get<string[]>(['followers'])) || [];
+        const things = (await Promise.all(results.map((result) => lookupPerson(ctx, result)))).filter(thing => thing instanceof Person);
+        items = things.filter(thing => thing !== null);
+        await ctx.data.db.set(['followers', 'expanded'], await Promise.all(items.map(person => person.toJsonLd())));
     }
     return {
         items,