Add wakaValueText GQL field to items

Again, I think I'm getting a bit ahead of myself :p Mostly I wanted to see if this architecture would work out!

src/server/loaders.js

@@ -1,4 +1,5 @@
 import DataLoader from "dataloader";
+import fetch from "node-fetch";
 import { normalizeRow } from "./util";
 
 const buildClosetListLoader = (db) =>
@@ -600,6 +601,29 @@ const buildItemTradesLoader = (db, loaders) =>
     { cacheKeyFn: ({ itemId, isOwned }) => `${itemId}-${isOwned}` }
   );
 
+const buildItemWakaValueLoader = () =>
+  new DataLoader(async (itemIds) => {
+    // This loader calls our /api/allWakaValues endpoint, to take advantage of
+    // the CDN caching. This helps us respond a bit faster than Google Sheets
+    // API would, and avoid putting pressure on our Google Sheets API quotas.
+    // (Some kind of internal memcache or process-level cache would be a more
+    // idiomatic solution in a monolith server environment!)
+    const url =
+      process.env.NODE_ENV === "production"
+        ? "https://impress-2020.openneo.net/api/allWakaValues"
+        : "http://localhost:3000/api/allWakaValues";
+    const res = await fetch(url);
+    if (!res.ok) {
+      throw new Error(
+        `Error loading /api/allWakaValues: ${res.status} ${res.statusText}`
+      );
+    }
+
+    const allWakaValues = await res.json();
+
+    return itemIds.map((itemId) => allWakaValues[itemId]);
+  });
+
 const buildPetTypeLoader = (db, loaders) =>
   new DataLoader(async (petTypeIds) => {
     const qs = petTypeIds.map((_) => "?").join(",");
@@ -1213,6 +1237,7 @@ function buildLoaders(db) {
   );
   loaders.itemAllOccupiedZonesLoader = buildItemAllOccupiedZonesLoader(db);
   loaders.itemTradesLoader = buildItemTradesLoader(db, loaders);
+  loaders.itemWakaValueLoader = buildItemWakaValueLoader();
   loaders.petTypeLoader = buildPetTypeLoader(db, loaders);
   loaders.petTypeBySpeciesAndColorLoader = buildPetTypeBySpeciesAndColorLoader(
     db,

src/server/types/Item.js

@@ -25,6 +25,11 @@ const typeDefs = gql`
     # item was added so long ago that we don't have this field!
     createdAt: String
 
+    # This item's capsule trade value as text, according to wakaguide.com, as a
+    # human-readable string. Will be null if the value is not known, or if
+    # there's an error connecting to the data source.
+    wakaValueText: String
+
     currentUserOwnsThis: Boolean! @cacheControl(scope: PRIVATE)
     currentUserWantsThis: Boolean! @cacheControl(scope: PRIVATE)
 
@@ -249,6 +254,16 @@ const resolvers = {
       const item = await itemLoader.load(id);
       return item.createdAt && item.createdAt.toISOString();
     },
+    wakaValueText: async ({ id }, _, { itemWakaValueLoader }) => {
+      try {
+        const wakaValue = await itemWakaValueLoader.load(id);
+        return wakaValue.value;
+      } catch (e) {
+        console.error(`Error loading wakaValueText for item ${id}, skipping:`);
+        console.error(e);
+        return null;
+      }
+    },
 
     currentUserOwnsThis: async (
       { id },