Completed memcached server with add, set, get, replace support and tests (#20)

* Completed memcached server with add, set, get, replace support and tests

* added support for no reply, updated tests

* Fixed tests

* fixed tests

* updated tests

* segregated tests

* added error logging

* updated datetime usage and readme

* updated exptime and added at to store ms since epoch

* added debug logging

* added debug logging

Author: jainmohit2001

README.md

@@ -37,7 +37,7 @@ npm test
 To run tests for specific challenge, use the following command:
 
 ```bash
-# npm test tests/<challenge-number>
-npm test tests/2
-npm test tests/3
+# npm test tests/<challenge-number>/
+npm test tests/2/
+npm test tests/3/
 ```

jest.config.js

@@ -11,5 +11,5 @@ module.exports = {
   coverageDirectory: './coverage',
   collectCoverage: true,
   detectOpenHandles: true,
-  silent: false,
+  silent: false
 };

package-lock.json

@@ -20,6 +20,7 @@
     "dotenv": "^16.3.1",
     "express": "^4.18.2",
     "helmet": "^7.0.0",
+    "memcached": "^2.2.2",
     "redis": "^4.6.7",
     "ts-node": "^10.9.1",
     "winston": "^3.10.0"
@@ -30,6 +31,7 @@
     "@babel/preset-typescript": "^7.22.5",
     "@types/express": "^4.17.17",
     "@types/jest": "^29.5.3",
+    "@types/memcached": "^2.2.7",
     "@types/node": "^20.4.2",
     "@types/supertest": "^2.0.12",
     "@typescript-eslint/eslint-plugin": "^6.0.0",

package.json

@@ -0,0 +1,118 @@
+type SupportCommands = 'set' | 'get' | 'add' | 'replace';
+
+export interface IMemCommand {
+  /**
+   * The name of the support command.
+   *
+   * @type {SupportCommands}
+   */
+  name: SupportCommands;
+
+  /**
+   * The key corresponding to the command.
+   *
+   * @type {string}
+   */
+  key: string;
+
+  /**
+   * Flags for the command.
+   * This is used in set, add and replace command.
+   *
+   * @type {?number}
+   */
+  flags?: number;
+
+  /**
+   * The expiry time in seconds for the data.
+   * This is used in set, add and replace command.
+   *
+   * @type {?number}
+   */
+  expTime?: number;
+
+  /**
+   * Number of bytes for the data.
+   * This is used in set, add and replace command.
+   * @date 8/18/2023 - 9:14:01 PM
+   *
+   * @type {?number}
+   */
+  byteCount?: number;
+
+  /**
+   * If true then the server will not reply to the command.
+   *
+   * @type {?boolean}
+   */
+  noReply?: boolean;
+}
+
+export class MemCommand implements IMemCommand {
+  name;
+  key;
+  flags?;
+  expTime?;
+  byteCount?;
+  noReply?;
+
+  constructor(
+    commandName: SupportCommands,
+    key: string,
+    flags?: number,
+    expTime?: number,
+    byteCount?: number,
+    noReply: boolean = false
+  ) {
+    this.name = commandName;
+    this.key = key;
+    this.flags = flags;
+    this.expTime = expTime;
+    this.byteCount = byteCount;
+    this.noReply = noReply;
+  }
+}
+
+/**
+ * Function used to parse a valid command.
+ * The commands follow the following format:
+ *
+ * `<command name> <key> <flags> <expTime> <byte count> [noreply]`
+ *
+ * The trailing CRLF is already removed while reading the data from the socket.
+ *
+ * @export
+ * @param {string} input
+ * @returns {IMemCommand}
+ */
+export function parseMemCommand(input: string): IMemCommand {
+  // Split the command params with space
+  const params = input.split(' ');
+
+  const name = params[0] as SupportCommands;
+
+  const key = params[1];
+
+  let flags;
+  if (params[2]) {
+    flags = parseInt(params[2]);
+  }
+
+  let expTime;
+  if (params[3] && (name === 'set' || name === 'add' || name === 'replace')) {
+    try {
+      expTime = parseInt(params[3]);
+    } catch (e) {
+      expTime = undefined;
+    }
+  }
+
+  let byteCount;
+  if (params[4] && (name === 'set' || name === 'add' || name === 'replace')) {
+    byteCount = parseInt(params[4]);
+  }
+
+  const noreply = params[params.length - 1] === 'noreply';
+
+  return new MemCommand(name, key, flags, expTime, byteCount, noreply);
+}

src/17/command.ts

@@ -0,0 +1,23 @@
+import MemCachedServer from './memcached';
+
+let port = 11211;
+const host = '127.0.0.1';
+
+for (let i = 2; i < process.argv.length; i++) {
+  const arg = process.argv[i];
+  if (arg === '-p') {
+    try {
+      port = parseInt(process.argv[i + 1]);
+    } catch (e) {
+      console.error('Invalid port provided');
+      process.exit(1);
+    }
+  }
+}
+
+async function main() {
+  const server = new MemCachedServer(port, host);
+  server.startServer();
+}
+
+main();