Refactored database connection system to use a shared pool per-request

lib/Class.js

@@ -3,8 +3,6 @@
 
 const crypto = require('crypto');
 
-const DatabaseConnectionPool = require('./DatabaseConnectionPool');
-
 const Subject = require('./Subject');
 const Test = require('./Test');
 
@@ -57,10 +55,14 @@ class Class {
 	 */
 	students;
 
+	#conn;
+
 	/**
 	 * @param {string} classID - The id of the class to fetch
 	 */
-	constructor(classId) {
+	constructor(conn, classId) {
+		this.#conn = conn;
+
 		const sql = `
 			select
 				classId as id,
@@ -95,9 +97,7 @@ class Class {
 		`;
 
 		return (async () => {
-			const conn = await new DatabaseConnectionPool();
-
-			const record = await conn.runQuery(sql, [
+			const record = await this.#conn.runQuery(sql, [
 				classId
 			]);
 
@@ -108,16 +108,14 @@ class Class {
 				this[k] = v;
 
 			const [ teacherRes, studentRes ] = await Promise.all([
-				conn.runQuery(teacherSQL, [
+				this.#conn.runQuery(teacherSQL, [
 					classId
 				]),
-				conn.runQuery(studentSQL, [
+				this.#conn.runQuery(studentSQL, [
 					classId
 				])
 			]);
 
-			conn.close();
-
 			this.teacherIds = teacherRes.map(record => record.id);
 			this.studentIds = studentRes.map(record => record.id);
 
@@ -140,7 +138,7 @@ class Class {
 	}
 
 	getSubject() {
-		return new (require('./Subject'))(this.subjectId);
+		return new (require('./Subject'))(this.#conn, this.subjectId);
 	}
 
 	getUsers(ids, type) {
@@ -153,7 +151,8 @@ class Class {
 			throw new Error('Invalid type');
 
 		const promises = ids.map(id => {
-			return new (require(`./${types[type]}`))(id);
+			const classFile = `./${types[type]}`;
+			return new (require(classFile))(this.#conn, id);
 		});
 
 		return Promise.all(promises);
@@ -190,11 +189,10 @@ class Class {
 
 		sql += `order by t.testDate  ${order};`;
 
-		const conn = await new DatabaseConnectionPool();
-		const tests = await conn.runQuery(sql, [ this.id ]);
+		const tests = await this.#conn.runQuery(sql, [ this.id ]);
 
 		const testObjects = tests.map(test => {
-			return new Test(test.testId);
+			return new Test(this.#conn, test.testId);
 		});
 
 		return await Promise.all(testObjects);
@@ -220,14 +218,12 @@ class Class {
 
 	}
 
-	static async createClass(accountId, name, subjectId) {
-		const s = await new Subject(subjectId);
-		const a = await new (require('./Account'))(accountId);
+	static async createClass(conn, accountId, name, subjectId) {
+		const s = await new Subject(conn, subjectId);
+		const a = await new (require('./Account'))(conn, accountId);
 
 		const id = crypto.randomUUID();
 
-		const conn = await new DatabaseConnectionPool();
-
 		let sql = `
 			insert into class(
 				classId,
@@ -256,7 +252,7 @@ class Class {
 			id
 		]);
 
-		return new Class(id);
+		return new Class(conn, id);
 	}
 }