[WIP] Node backend for API service

.gitignore

@@ -5,7 +5,7 @@
 **/venv
 
 # build
-www/dist
+**/dist
 
 # cache
 **/__pycache

Procfile

@@ -0,0 +1 @@
+web: node dist/api_v2/app.js

api_v2/app.ts

@@ -0,0 +1,16 @@
+// import "module-alias/register";
+import * as express from "express";
+import * as cors from "cors";
+import * as routes from "./routes";
+import { logger } from "../shared/logger";
+
+const app = express();
+const port = process.env.PORT || 3000;
+
+// Add middleware
+app.use(cors());
+app.use(routes.courses);
+
+app.listen(port, () => {
+  logger.info(`Server running on port ${port}`);
+});

api_v2/libs/db.ts

@@ -0,0 +1,35 @@
+import { logger } from "../../shared/logger";
+import { DB_URI } from "../../shared/config";
+import { MongoClient, Db } from "mongodb";
+
+// The singleton MongoClient object
+let client: MongoClient;
+// The singleton DB object
+let db: Db;
+
+/** Connects to database. */
+export async function connectToDb() {
+  try {
+    if (!client) {
+      client = new MongoClient(DB_URI, {
+        useNewUrlParser: true,
+        useUnifiedTopology: true,
+      });
+    }
+    if (!client.isConnected()) {
+      await client.connect();
+    }
+  } catch (e) {
+    logger.error("Failed to connect to database");
+    logger.error(e);
+  }
+}
+
+/** Returns a database instance. */
+export async function getDbInstance() {
+  if (!db) {
+    await connectToDb();
+    db = client.db("db");
+  }
+  return db;
+}

api_v2/models/course.ts

@@ -0,0 +1,115 @@
+import { getDbInstance } from "../libs/db";
+
+type CourseSnippet = {
+  course_code: string;
+  course_title: string;
+  postgrad: boolean;
+};
+
+type CourseDetail = {
+  course_code: string;
+  au: number;
+  course_title: string;
+  constraint: {
+    prerequisite: string[];
+    na_to: string[];
+    na_to_all: string[];
+    mutex: string;
+  };
+  as_ue?: boolean;
+  as_pe?: boolean;
+  pass_fail: boolean;
+  semesters: string[];
+  description: string;
+  last_update: Date;
+  postgrad: boolean;
+};
+
+export async function getAllCourseSnippet(): Promise<Array<CourseSnippet>> {
+  // Connect to Db and get collection
+  const db = await getDbInstance();
+  const collection = db.collection("courses");
+
+  // Query database
+  const result: Array<CourseSnippet> = await collection
+    .aggregate<CourseSnippet>([
+      {
+        $project: {
+          _id: 0,
+          course_code: 1,
+          course_title: 1,
+          postgrad: 1,
+        },
+      },
+    ])
+    .toArray();
+
+  // Return result
+  return result;
+}
+
+export async function getCourseDetailByCourseCode(
+  courseCode: string
+): Promise<CourseDetail | null> {
+  // Connect to Db and get collection
+  const db = await getDbInstance();
+  const collection = db.collection("courses");
+
+  // Pre-process course code
+  courseCode = courseCode.toUpperCase();
+
+  // Query database
+  const result = await collection.findOne<CourseDetail | null>(
+    {
+      course_code: courseCode,
+    },
+    {
+      projection: {
+        _id: 0,
+      },
+    }
+  );
+
+  return result;
+}
+
+/**
+ * Returns an array of course snippets in which course titles match the regex.
+ * Currently, only supports title matching; TODO: add description matching in the future.
+ * @param query regex
+ */
+export async function getCourseSnippetByRegex(
+  query: string
+): Promise<Array<CourseSnippet>> {
+  if (!query || query.trim().length <= 1) {
+    return [];
+  }
+
+  // Connect to Db and get collection
+  const db = await getDbInstance();
+  const collection = db.collection("courses");
+
+  // Build regex
+  const keywords: string[] = query.trim().split(" ");
+  const regexPreBuild = keywords.map((val) => "(.*" + val + ".*)+").join("");
+  const regex = RegExp(regexPreBuild, "i");
+
+  // Search
+  const result = collection
+    .aggregate([
+      {
+        $match: { course_title: regex },
+      },
+      {
+        $project: {
+          _id: 0,
+          course_code: 1,
+          course_title: 1,
+          postgrad: 1,
+        },
+      },
+    ])
+    .toArray();
+
+  return result;
+}

api_v2/package.json

@@ -0,0 +1,17 @@
+{
+  "name": "api_v2",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "scripts": {
+    "start": "ts-node-dev app.ts"
+  },
+  "dependencies": {
+    "cors": "^2.8.5",
+    "express": "^4.17.1"
+  },
+  "devDependencies": {
+    "@types/cors": "^2.8.7",
+    "@types/express": "^4.17.8"
+  }
+}

api_v2/routes/courses/index.ts

@@ -0,0 +1,35 @@
+import { logger } from "../../../shared/logger";
+import { Router, Request, Response } from "express";
+import {
+  getCourseDetailByCourseCode,
+  getAllCourseSnippet,
+  getCourseSnippetByRegex,
+} from "../../models/course";
+
+/** Router instance. */
+const courses = Router();
+
+courses.get("/course/all", async (req: Request, res: Response) => {
+  logger.info("Getting course list.");
+  // await connectToDb();
+  logger.info("Connected to DB.");
+  // const course = new Course();
+  const courseList = await getAllCourseSnippet();
+  return res.json(courseList);
+});
+
+courses.get("/course/search", async (req: Request, res: Response) => {
+  const { query } = req.query;
+  logger.info(`Searching for ${query}`);
+  const searchResult = await getCourseSnippetByRegex(query as string);
+  return res.json(searchResult);
+});
+
+courses.get("/course/:course_code", async (req: Request, res: Response) => {
+  const courseCode = req.params.course_code.toUpperCase();
+  logger.info(`Getting course detail for ${courseCode}`);
+  const courseDetail = await getCourseDetailByCourseCode(courseCode);
+  return res.json(courseDetail);
+});
+
+export { courses };

api_v2/routes/index.ts

@@ -0,0 +1,3 @@
+import { courses } from "./courses";
+
+export { courses };

package.json

@@ -5,18 +5,28 @@
   "private": true,
   "license": "MIT",
   "scripts": {
-    "run:scraper": "ts-node scraper/scraper.ts"
+    "postinstall": "tsc",
+    "build": "tsc",
+    "run:scraper": "ts-node scraper/scraper.ts",
+    "api:run": "node dist/api_v2/app.js",
+    "api:debug": "ts-node-dev api_v2/app.ts"
+  },
+  "_moduleAliases": {
+    "@root": "./"
   },
   "engines": {
     "node": " >= 10.14.2"
   },
   "workspaces": [
     "shared",
     "www",
-    "scraper"
+    "scraper",
+    "api_v2"
   ],
   "dependencies": {
+    "module-alias": "^2.2.2",
     "ts-node": "^9.0.0",
+    "ts-node-dev": "^1.0.0",
     "typescript": "^4.0.3"
   }
 }

shared/logger/index.ts

@@ -0,0 +1,29 @@
+import * as winston from "winston";
+
+const logger = winston.createLogger({
+  level: "info",
+  format: winston.format.json(),
+  defaultMeta: { service: "user-service" },
+  transports: [
+    //
+    // - Write to all logs with level `info` and below to `combined.log`
+    // - Write all logs error (and below) to `error.log`.
+    //
+    new winston.transports.File({ filename: "error.log", level: "error" }),
+    new winston.transports.File({ filename: "combined.log" }),
+  ],
+});
+
+//
+// If we're not in production then log to the `console` with the format:
+// `${info.level}: ${info.message} JSON.stringify({ ...rest }) `
+//
+if (process.env.NODE_ENV !== "production") {
+  logger.add(
+    new winston.transports.Console({
+      format: winston.format.simple(),
+    })
+  );
+}
+
+export { logger };

shared/package.json

@@ -16,6 +16,7 @@
     "mongodb": "^3.6.0",
     "mongodb-memory-server": "^6.6.7",
     "ts-node-dev": "^1.0.0-pre.61",
-    "typescript": "^4.0.2"
+    "typescript": "^4.0.2",
+    "winston": "^3.3.3"
   }
 }

tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "exclude": ["functions", "**/*.test.ts"],
+  "exclude": ["functions", "scraper", "**/*.test.ts"],
   "compilerOptions": {
     "module": "commonjs",
     "noImplicitReturns": true,
@@ -9,8 +9,9 @@
     "strict": true,
     "target": "es2017",
     "baseUrl": "./",
+    "outDir": "dist",
     "paths": {
       "@root/*": ["./*"]
-    },
-  },
-}
+    }
+  }
+}