Seems good?

server/src/lib/search/search.ts

@@ -9,10 +9,11 @@ import {
 	Playtypes,
 	SongDocument,
 	AnyChartDocument,
+	PrivateUserDocument,
 	integer,
 } from "tachi-common";
 import { EscapeStringRegexp } from "../../utils/misc";
-import { OMIT_PRIVATE_USER_RETURNS } from "../../utils/user";
+import { GetOnlineCutoff, OMIT_PRIVATE_USER_RETURNS } from "../../utils/user";
 import { CONF_INFO } from "../setup/config";
 
 const logger = CreateLogCtx(__filename);
@@ -125,18 +126,21 @@ export function SearchSessions(
  * aren't allowed spaces in their name. In short, $text is very
  * poor at actually matching usernames.
  */
-export function SearchUsersRegExp(search: string) {
+export function SearchUsersRegExp(search: string, matchOnline = false) {
 	const regexEsc = EscapeStringRegexp(search.toLowerCase());
 
-	return db.users.find(
-		{
-			usernameLowercase: { $regex: new RegExp(regexEsc, "u") },
-		},
-		{
-			limit: 25,
-			projection: OMIT_PRIVATE_USER_RETURNS,
-		}
-	);
+	const matchQuery: FilterQuery<PrivateUserDocument> = {
+		usernameLowercase: { $regex: new RegExp(regexEsc, "u") },
+	};
+
+	if (matchOnline) {
+		matchQuery.lastSeen = { $gt: GetOnlineCutoff() };
+	}
+
+	return db.users.find(matchQuery, {
+		limit: 25,
+		projection: OMIT_PRIVATE_USER_RETURNS,
+	});
 }
 
 /**

server/src/server/router/api/v1/users/router.test.ts

@@ -0,0 +1,77 @@
+import t from "tap";
+import db from "../../../../../external/mongo/db";
+import mockApi from "../../../../../test-utils/mock-api";
+import ResetDBState from "../../../../../test-utils/resets";
+import { PrivateUserDocument, PublicUserDocument } from "tachi-common";
+import { CloseAllConnections } from "../../../../../test-utils/close-connections";
+
+t.test("GET /api/v1/users", (t) => {
+	t.beforeEach(ResetDBState);
+
+	t.test("Should search users if search param is set.", async (t) => {
+		const res = await mockApi.get("/api/v1/users?search=zkldi");
+
+		t.equal(res.body.body.length, 1);
+		t.equal(res.body.body[0].username, "test_zkldi");
+
+		const res2 = await mockApi.get("/api/v1/users?search=nothing");
+
+		t.equal(res2.body.body.length, 0);
+
+		const res3 = await mockApi.get("/api/v1/users?search=ZklDI");
+
+		t.equal(res3.body.body.length, 1);
+		t.equal(res3.body.body[0].username, "test_zkldi");
+
+		t.end();
+	});
+
+	t.test("Should sanitise input for regex stuff.", async (t) => {
+		const res = await mockApi.get("/api/v1/users?search=.*");
+
+		t.equal(res.body.body.length, 0);
+
+		t.end();
+	});
+
+	t.test("Should restrict returns to only online users if online is set.", async (t) => {
+		const res = await mockApi.get("/api/v1/users?online=true");
+
+		t.equal(res.body.body.length, 0);
+
+		await db.users.insert({
+			usernameLowercase: "online_dude",
+			lastSeen: Date.now(),
+			id: 2,
+		} as PrivateUserDocument);
+
+		const res2 = await mockApi.get("/api/v1/users?online=true");
+
+		t.equal(res2.body.body.length, 1);
+		t.equal(res2.body.body[0].usernameLowercase, "online_dude");
+
+		t.end();
+	});
+
+	t.test("Should return users sorted by lastSeen if no arguments are passed.", async (t) => {
+		await db.users.insert({
+			usernameLowercase: "online_dude",
+			lastSeen: Date.now(),
+			id: 2,
+		} as PrivateUserDocument);
+
+		const res = await mockApi.get("/api/v1/users");
+
+		t.equal(res.body.body.length, 2);
+		t.strictSame(
+			res.body.body.map((e: PublicUserDocument) => e.usernameLowercase),
+			["online_dude", "test_zkldi"]
+		);
+
+		t.end();
+	});
+
+	t.end();
+});
+
+t.teardown(CloseAllConnections);

server/src/server/router/api/v1/users/router.ts

@@ -1,17 +1,49 @@
 import { Router } from "express";
 import db from "../../../../../external/mongo/db";
+import { SearchUsersRegExp } from "../../../../../lib/search/search";
+import { IsString } from "../../../../../utils/misc";
+import { GetOnlineCutoff, OMIT_PRIVATE_USER_RETURNS } from "../../../../../utils/user";
 import userIDRouter from "./_userID/router";
 
 const router: Router = Router({ mergeParams: true });
 
 /**
- * List Users.
- * @param online - Only return online users.
- * @param username - Return users similar to this username.
+ * Search users.
+ *
+ * @param online - Restrict returned users to those who are online.
+ * @param search - Search for users where their name contains this string. If not present, returns
+ * users sorted by last appearance.
+ *
  * @name GET /api/v1/users
  */
 router.get("/", async (req, res) => {
-	// i dont know yet.
+	const onlyOnline = !!req.query.online;
+
+	let users;
+
+	if (req.query.search) {
+		if (!IsString(req.query.search)) {
+			return res.status(400).json({
+				success: false,
+				description: `Search parameter was invalid.`,
+			});
+		}
+		users = await SearchUsersRegExp(req.query.search!, onlyOnline);
+	} else {
+		const query = onlyOnline ? { lastSeen: { $gt: GetOnlineCutoff() } } : {};
+
+		users = await db.users.find(query, {
+			sort: { lastSeen: -1 },
+			limit: 100,
+			projection: OMIT_PRIVATE_USER_RETURNS,
+		});
+	}
+
+	return res.status(200).json({
+		success: true,
+		description: `Returned ${users.length} users.`,
+		body: users,
+	});
 });
 
 router.use("/:userID", userIDRouter);

server/src/utils/user.ts

@@ -176,3 +176,13 @@ export async function GetUsersRanking(stats: UserGameStats) {
 		outOf: aggRes[0].outOf as integer,
 	};
 }
+
+const FIVE_MINUTES = 1000 * 60 * 5;
+
+/**
+ * Returns the cutoff point for "being online" in tachi. This means the user
+ * has made any page request in the past 5 minutes.
+ */
+export function GetOnlineCutoff() {
+	return Date.now() - FIVE_MINUTES;
+}