Merge branch 'master' of https://github.com/browngraphicslab/Dash-Web into webcam_mohammad

1 files changed, 201 insertions, 0 deletions

diff --git a/src/server/RouteManager.ts b/src/server/RouteManager.ts
new file mode 100644
index 000000000..b07aef74d
--- /dev/null
+++ b/src/server/RouteManager.ts
@@ -0,0 +1,201 @@
+import RouteSubscriber from "./RouteSubscriber";
+import { DashUserModel } from "./authentication/models/user_model";
+import * as express from 'express';
+import { cyan, red, green } from 'colors';
+
+export enum Method {
+    GET,
+    POST
+}
+
+export interface CoreArguments {
+    req: express.Request;
+    res: express.Response;
+    isRelease: boolean;
+}
+
+export type AuthorizedCore = CoreArguments & { user: DashUserModel };
+export type SecureHandler = (core: AuthorizedCore) => any | Promise<any>;
+export type PublicHandler = (core: CoreArguments) => any | Promise<any>;
+export type ErrorHandler = (core: CoreArguments & { error: any }) => any | Promise<any>;
+
+export interface RouteInitializer {
+    method: Method;
+    subscription: string | RouteSubscriber | (string | RouteSubscriber)[];
+    secureHandler: SecureHandler;
+    publicHandler?: PublicHandler;
+    errorHandler?: ErrorHandler;
+}
+
+const registered = new Map<string, Set<Method>>();
+
+enum RegistrationError {
+    Malformed,
+    Duplicate
+}
+
+export default class RouteManager {
+    private server: express.Express;
+    private _isRelease: boolean;
+    private failedRegistrations: { route: string, reason: RegistrationError }[] = [];
+
+    public get isRelease() {
+        return this._isRelease;
+    }
+
+    constructor(server: express.Express, isRelease: boolean) {
+        this.server = server;
+        this._isRelease = isRelease;
+    }
+
+    logRegistrationOutcome = () => {
+        if (this.failedRegistrations.length) {
+            let duplicateCount = 0;
+            let malformedCount = 0;
+            this.failedRegistrations.forEach(({ reason, route }) => {
+                let error: string;
+                if (reason === RegistrationError.Duplicate) {
+                    error = `duplicate registration error: ${route} is already registered `;
+                    duplicateCount++;
+                } else {
+                    error = `malformed route error: ${route} is invalid`;
+                    malformedCount++;
+                }
+                console.log(red(error));
+            });
+            console.log();
+            if (duplicateCount) {
+                console.log('please remove all duplicate routes before continuing');
+            }
+            if (malformedCount) {
+                console.log(`please ensure all routes adhere to ^\/$|^\/[A-Za-z]+(\/\:[A-Za-z?_]+)*$`);
+            }
+            process.exit(1);
+        } else {
+            console.log(green("all server routes have been successfully registered:"));
+            Array.from(registered.keys()).sort().forEach(route => console.log(cyan(route)));
+            console.log();
+        }
+    }
+
+    /**
+     * 
+     * @param initializer 
+     */
+    addSupervisedRoute = (initializer: RouteInitializer): void => {
+        const { method, subscription, secureHandler: onValidation, publicHandler: onUnauthenticated, errorHandler: onError } = initializer;
+        const isRelease = this._isRelease;
+        const supervised = async (req: express.Request, res: express.Response) => {
+            let { user } = req;
+            const { originalUrl: target } = req;
+            if (process.env.DB === "MEM" && !user) {
+                user = { id: "guest", email: "", userDocumentId: "guestDocId" };
+            }
+            const core = { req, res, isRelease };
+            const tryExecute = async (toExecute: (args: any) => any | Promise<any>, args: any) => {
+                try {
+                    await toExecute(args);
+                } catch (e) {
+                    console.log(red(target), user && ("email" in user) ? "<user logged out>" : undefined);
+                    if (onError) {
+                        onError({ ...core, error: e });
+                    } else {
+                        _error(res, `The server encountered an internal error when serving ${target}.`, e);
+                    }
+                }
+            };
+            if (user) {
+                await tryExecute(onValidation, { ...core, user });
+            } else {
+                req.session!.target = target;
+                if (onUnauthenticated) {
+                    await tryExecute(onUnauthenticated, core);
+                    if (!res.headersSent) {
+                        res.redirect("/login");
+                    }
+                } else {
+                    res.redirect("/login");
+                }
+            }
+            setTimeout(() => {
+                if (!res.headersSent) {
+                    console.log(red(`Initiating fallback for ${target}. Please remove dangling promise from route handler`));
+                    const warning = `request to ${target} fell through - this is a fallback response`;
+                    res.send({ warning });
+                }
+            }, 1000);
+        };
+        const subscribe = (subscriber: RouteSubscriber | string) => {
+            let route: string;
+            if (typeof subscriber === "string") {
+                route = subscriber;
+            } else {
+                route = subscriber.build;
+            }
+            if (!/^\/$|^\/[A-Za-z]+(\/\:[A-Za-z?_]+)*$/g.test(route)) {
+                this.failedRegistrations.push({
+                    reason: RegistrationError.Malformed,
+                    route
+                });
+            } else {
+                const existing = registered.get(route);
+                if (existing) {
+                    if (existing.has(method)) {
+                        this.failedRegistrations.push({
+                            reason: RegistrationError.Duplicate,
+                            route
+                        });
+                        return;
+                    }
+                } else {
+                    const specific = new Set<Method>();
+                    specific.add(method);
+                    registered.set(route, specific);
+                }
+                switch (method) {
+                    case Method.GET:
+                        this.server.get(route, supervised);
+                        break;
+                    case Method.POST:
+                        this.server.post(route, supervised);
+                        break;
+                }
+            }
+        };
+        if (Array.isArray(subscription)) {
+            subscription.forEach(subscribe);
+        } else {
+            subscribe(subscription);
+        }
+    }
+
+}
+
+export const STATUS = {
+    OK: 200,
+    BAD_REQUEST: 400,
+    EXECUTION_ERROR: 500,
+    PERMISSION_DENIED: 403
+};
+
+export function _error(res: express.Response, message: string, error?: any) {
+    console.error(message);
+    res.statusMessage = message;
+    res.status(STATUS.EXECUTION_ERROR).send(error);
+}
+
+export function _success(res: express.Response, body: any) {
+    res.status(STATUS.OK).send(body);
+}
+
+export function _invalid(res: express.Response, message: string) {
+    res.statusMessage = message;
+    res.status(STATUS.BAD_REQUEST).send();
+}
+
+export function _permission_denied(res: express.Response, message?: string) {
+    if (message) {
+        res.statusMessage = message;
+    }
+    res.status(STATUS.PERMISSION_DENIED).send("Permission Denied!");
+}