Bringing local and remote repository in line with one another and adding Github Actions to publish package

src/middlewares/HealthCheckMiddleware.ts

@@ -0,0 +1,49 @@
+import { Request, Response, NextFunction, RequestHandler } from 'express';
+
+export enum HealthCheckStatus {
+    OK = 'ok',
+    ERROR = 'error'
+}
+
+export class HealthCheckMiddleware {
+    public static readonly HEALTH_CHECK_ENDPOINT = '/.well-known/health-check';
+
+    private static status: HealthCheckStatus;
+    
+    constructor(initialStatus: HealthCheckStatus = HealthCheckStatus.OK) {
+        HealthCheckMiddleware.status = initialStatus;
+    }
+
+    static setStatus(status: HealthCheckStatus) {
+        HealthCheckMiddleware.status = status;
+    }
+
+    middleware(req: Request, res: Response, next: NextFunction) {
+        if(req.path === HealthCheckMiddleware.HEALTH_CHECK_ENDPOINT) {
+            switch(HealthCheckMiddleware.status) {
+                case HealthCheckStatus.OK:
+                    return res.status(200).setHeader('Content-Type', 'application/health+json').json({ status: 'ok' });
+                    break;
+                case HealthCheckStatus.ERROR:
+                    return res.status(500).setHeader('Content-Type', 'application/health+json').json({ status: 'error' });
+                    break;
+            }
+        }
+
+        next();
+    }
+}
+
+/**
+ * Middleware function to create a health check endpoint.
+ * 
+ * This attempts to comply with the [Health Check Response Format for HTTP APIs](https://datatracker.ietf.org/doc/html/draft-inadarei-api-health-check-06) proposed standard.
+ * 
+ * @param initialStatus The initial status of the health check.
+ * @returns The middleware function.
+ */
+export function healthCheckMiddleware(initialStatus: HealthCheckStatus = HealthCheckStatus.OK) {
+    const instance = new HealthCheckMiddleware(initialStatus);
+
+    return instance.middleware.bind(instance);
+}