refactor: items logic in KV (#284)

* refactor: items in db

* work

* fix

* tweaks

* tweaks

* tweak

routes/api/vote.ts

@@ -1,7 +1,7 @@
 // Copyright 2023 the Deno authors. All rights reserved. MIT license.
 import type { HandlerContext, Handlers, PageProps } from "$fresh/server.ts";
 import type { State } from "@/routes/_middleware.ts";
-import { createVote, deleteVote, getItemById } from "@/utils/db.ts";
+import { createVote, deleteVote, getItem } from "@/utils/db.ts";
 import { getUserBySessionId } from "@/utils/db.ts";
 
 async function sharedHandler(
@@ -19,7 +19,7 @@ async function sharedHandler(
   }
 
   const [item, user] = await Promise.all([
-    getItemById(itemId),
+    getItem(itemId),
     getUserBySessionId(ctx.state.sessionId),
   ]);
 

routes/index.tsx

@@ -8,13 +8,15 @@ import ItemSummary from "@/components/ItemSummary.tsx";
 import PageSelector from "@/components/PageSelector.tsx";
 import {
   compareScore,
-  getAllItemsInTimeAgo,
+  getAllItems,
   getAreVotedBySessionId,
+  getItemsSince,
   getManyUsers,
   incrementAnalyticsMetricPerDay,
   type Item,
   type User,
 } from "@/utils/db.ts";
+import { DAY, WEEK } from "std/datetime/constants.ts";
 
 interface HomePageData extends State {
   itemsUsers: User[];
@@ -24,17 +26,24 @@ interface HomePageData extends State {
 }
 
 function calcTimeAgoFilter(url: URL) {
-  return url.searchParams.get("time-ago") || "";
+  return url.searchParams.get("time-ago");
 }
 
 export const handler: Handlers<HomePageData, State> = {
   async GET(req, ctx) {
     await incrementAnalyticsMetricPerDay("visits_count", new Date());
 
     const url = new URL(req.url);
-    const timeAgo = calcTimeAgoFilter(url);
     const pageNum = calcPageNum(url);
-    const allItems = await getAllItemsInTimeAgo(timeAgo);
+    const timeAgo = calcTimeAgoFilter(url);
+    let allItems: Item[];
+    if (timeAgo === "week") {
+      allItems = await getItemsSince(WEEK);
+    } else if (timeAgo === "month") {
+      allItems = await getItemsSince(30 * DAY);
+    } else {
+      allItems = await getAllItems();
+    }
 
     const items = allItems
       .toSorted(compareScore)
@@ -80,7 +89,7 @@ export default function HomePage(props: PageProps<HomePageData>) {
           <PageSelector
             currentPage={calcPageNum(props.url)}
             lastPage={props.data.lastPage}
-            timeSelector={calcTimeAgoFilter(props.url)}
+            timeSelector={calcTimeAgoFilter(props.url) ?? undefined}
           />
         )}
       </div>

routes/item/[id].tsx

@@ -15,7 +15,7 @@ import {
   createComment,
   getAreVotedBySessionId,
   getCommentsByItem,
-  getItemById,
+  getItem,
   getManyUsers,
   getUserById,
   getUserBySessionId,
@@ -42,7 +42,7 @@ export const handler: Handlers<ItemPageData, State> = {
     const url = new URL(req.url);
     const pageNum = calcPageNum(url);
 
-    const item = await getItemById(id);
+    const item = await getItem(id);
     if (item === null) {
       return ctx.renderNotFound();
     }

routes/submit.tsx

@@ -3,7 +3,13 @@ import type { Handlers, PageProps } from "$fresh/server.ts";
 import Head from "@/components/Head.tsx";
 import { BUTTON_STYLES, INPUT_STYLES } from "@/utils/constants.ts";
 import type { State } from "@/routes/_middleware.ts";
-import { createItem, getUserBySessionId } from "@/utils/db.ts";
+import {
+  createItem,
+  getUserBySessionId,
+  incrementAnalyticsMetricPerDay,
+  type Item,
+  newItemProps,
+} from "@/utils/db.ts";
 import { redirect } from "@/utils/redirect.ts";
 import { redirectToLogin } from "@/utils/redirect.ts";
 
@@ -38,11 +44,14 @@ export const handler: Handlers<State, State> = {
 
     if (!user) return new Response(null, { status: 400 });
 
-    const item = await createItem({
+    const item: Item = {
       userId: user.id,
       title,
       url,
-    });
+      ...newItemProps(),
+    };
+    await createItem(item);
+    await incrementAnalyticsMetricPerDay("items_count", new Date());
 
     return redirect(`/item/${item!.id}`);
   },

routes/user/[username].tsx

@@ -8,7 +8,7 @@ import ItemSummary from "@/components/ItemSummary.tsx";
 import {
   compareScore,
   getAreVotedBySessionId,
-  getItemsByUserId,
+  getItemsByUser,
   getUserByLogin,
   type Item,
   type User,
@@ -30,7 +30,7 @@ export const handler: Handlers<UserData, State> = {
       return ctx.renderNotFound();
     }
 
-    const items = await getItemsByUserId(user.id);
+    const items = await getItemsByUser(user.id);
     items.sort(compareScore);
     const areVoted = await getAreVotedBySessionId(
       items,

tools/seed_submissions.ts

@@ -1,6 +1,12 @@
 // Copyright 2023 the Deno authors. All rights reserved. MIT license.
 // Description: Seeds the kv db with Hacker News stories
-import { createItem, createUser, type Item, kv } from "@/utils/db.ts";
+import {
+  createItem,
+  createUser,
+  incrementAnalyticsMetricPerDay,
+  type Item,
+  newItemProps,
+} from "@/utils/db.ts";
 
 // Reference: https://github.com/HackerNews/API
 const API_BASE_URL = `https://hacker-news.firebaseio.com/v0`;
@@ -54,18 +60,10 @@ async function fetchTopStories(limit = 10) {
   return stories;
 }
 
-async function createItemWithScore(item: Item) {
-  const res = await createItem(item);
-  return await kv.set(["items", res!.id], {
-    ...res,
-    score: item.score,
-    createdAt: item.createdAt,
-  });
-}
-
 async function seedSubmissions(stories: Story[]) {
   const items = stories.map(({ by: userId, title, url, score, time }) => {
     return {
+      ...newItemProps(),
       userId,
       title,
       url,
@@ -74,7 +72,14 @@ async function seedSubmissions(stories: Story[]) {
     } as Item;
   }).filter(({ url }) => url);
   for (const batch of batchify(items)) {
-    await Promise.all(batch.map((item) => createItemWithScore(item)));
+    await Promise.all(
+      batch.map((item) =>
+        Promise.all([
+          createItem(item),
+          incrementAnalyticsMetricPerDay("items_count", new Date()),
+        ])
+      ),
+    );
   }
   return items;
 }

utils/db.ts

@@ -1,5 +1,4 @@
 // Copyright 2023 the Deno authors. All rights reserved. MIT license.
-import { DAY, WEEK } from "std/datetime/constants.ts";
 
 const KV_PATH_KEY = "KV_PATH";
 let path = undefined;
@@ -31,75 +30,95 @@ async function getValues<T>(
 }
 
 // Item
-interface InitItem {
+export interface Item {
   userId: string;
   title: string;
   url: string;
-}
-
-export interface Item extends InitItem {
+  // The below properties can be automatically generated upon item creation
   id: string;
   createdAt: Date;
   score: number;
 }
 
-export async function createItem(initItem: InitItem) {
-  const item: Item = {
+export function newItemProps(): Omit<Item, "userId" | "title" | "url"> {
+  return {
     id: crypto.randomUUID(),
     score: 0,
     createdAt: new Date(),
-    ...initItem,
   };
+}
 
-  const itemKey = ["items", item.id];
-  const itemByTime = ["items_by_time", item.createdAt.getTime(), item.id];
+/**
+ * Creates a new item in KV. Throws if the item already exists in one of the indexes.
+ *
+ * @example New item creation
+ * ```ts
+ * import { newItemProps, createItem, incrementAnalyticsMetricPerDay } from "@/utils/db.ts";
+ *
+ * const item: Item = {
+ *   userId: "example-user-id",
+ *   title: "example-title",
+ *   url: "https://example.com"
+ *   ..newItemProps(),
+ * };
+ *
+ * await createItem(item);
+ * await incrementAnalyticsMetricPerDay("items_count", item.createdAt);
+ * ```
+ */
+export async function createItem(item: Item) {
+  const itemsKey = ["items", item.id];
+  const itemsByTimeKey = ["items_by_time", item.createdAt.getTime(), item.id];
   const itemsByUserKey = ["items_by_user", item.userId, item.id];
 
   const res = await kv.atomic()
-    .check({ key: itemKey, versionstamp: null })
-    .check({ key: itemByTime, versionstamp: null })
+    .check({ key: itemsKey, versionstamp: null })
+    .check({ key: itemsByTimeKey, versionstamp: null })
     .check({ key: itemsByUserKey, versionstamp: null })
-    .set(itemKey, item)
-    .set(itemByTime, item)
+    .set(itemsKey, item)
+    .set(itemsByTimeKey, item)
     .set(itemsByUserKey, item)
     .commit();
 
-  if (!res.ok) throw new Error(`Failed to set item: ${item}`);
-
-  await incrementAnalyticsMetricPerDay("items_count", new Date());
-
-  return item;
-}
-
-export async function getAllItemsInTimeAgo(timeAgo: string) {
-  switch (timeAgo) {
-    case "month":
-      return await getValues<Item>({
-        prefix: ["items_by_time"],
-        start: ["items_by_time", Date.now() - DAY * 30],
-      });
-    case "all":
-      return await getValues<Item>({
-        prefix: ["items_by_time"],
-      });
-    default:
-      return await getValues<Item>({
-        prefix: ["items_by_time"],
-        start: ["items_by_time", Date.now() - WEEK],
-      });
-  }
+  if (!res.ok) throw new Error(`Failed to create item: ${item}`);
 }
 
-export async function getItemById(id: string) {
+export async function getItem(id: string) {
   return await getValue<Item>(["items", id]);
 }
 
-export async function getItemByUser(userId: string, itemId: string) {
-  return await getValue<Item>(["items_by_user", userId, itemId]);
+export async function getItemsByUser(userId: string) {
+  return await getValues<Item>({ prefix: ["items_by_user", userId] });
 }
 
-export async function getItemsByUserId(userId: string) {
-  return await getValues<Item>({ prefix: ["items_by_user", userId] });
+export async function getAllItems() {
+  return await getValues<Item>({ prefix: ["items"] });
+}
+
+/**
+ * Gets all items since a given number of milliseconds ago from KV.
+ *
+ * @example Since a week ago
+ * ```ts
+ * import { WEEK } from "std/datetime/constants.ts";
+ * import { getItemsSince } from "@/utils/db.ts";
+ *
+ * const itemsSinceAllTime = await getItemsSince(WEEK);
+ * ```
+ *
+ * @example Since a month ago
+ * ```ts
+ * import { DAY } from "std/datetime/constants.ts";
+ * import { getItemsSince } from "@/utils/db.ts";
+ *
+ * const itemsSinceAllTime = await getItemsSince(DAY * 30);
+ * ```
+ */
+export async function getItemsSince(msAgo: number) {
+  return await getValues<Item>({
+    prefix: ["items_by_time"],
+    start: ["items_by_time", Date.now() - msAgo],
+  });
 }
 
 // Comment