Introduce async local storage for request access, more view globals, and improved welcome view

src/http/RequestLocalStorage.ts

@@ -0,0 +1,32 @@
+import { AsyncLocalStorage } from 'async_hooks'
+import {Request} from './lifecycle/Request'
+import {Singleton} from '../di'
+import {ErrorWithContext} from '../util'
+
+export class InvalidOutOfRequestAccessError extends ErrorWithContext {
+    constructor() {
+        super(`Attempted to access request via local storage outside of async lifecycle!`)
+    }
+}
+
+@Singleton()
+export class RequestLocalStorage {
+    protected readonly store: AsyncLocalStorage<Request> = new AsyncLocalStorage<Request>()
+
+    get(): Request {
+        const req = this.store.getStore()
+        if ( !req ) {
+            throw new InvalidOutOfRequestAccessError()
+        }
+
+        return req
+    }
+
+    has(): boolean {
+        return Boolean(this.store.getStore())
+    }
+
+    run<T>(req: Request, closure: () => T): T {
+        return this.store.run(req, closure)
+    }
+}