1 files changed, 49 insertions, 3 deletions
diff --git a/src/server/database.ts b/src/server/database.ts
index db86b472d..b81fc03a4 100644
--- a/src/server/database.ts
+++ b/src/server/database.ts
@@ -5,19 +5,65 @@ import { Utils, emptyFunction } from '../Utils';
 import { DashUploadUtils } from './DashUploadUtils';
 import { Credentials } from 'google-auth-library';
 import { GoogleApiServerUtils } from './apis/google/GoogleApiServerUtils';
+import * as mongoose from 'mongoose';
 
 export namespace Database {
 
+    const schema = 'Dash';
+    const port = 27017;
+    export const url = `mongodb://localhost:${port}/${schema}`;
+
+    enum ConnectionStates {
+        disconnected = 0,
+        connected = 1,
+        connecting = 2,
+        disconnecting = 3,
+        uninitialized = 99,
+    }
+
+    export async function tryInitializeConnection() {
+        try {
+            const { connection } = mongoose;
+            process.on('SIGINT', () => {
+                connection.close(() => {
+                    console.log(`SIGINT closed mongoose connection at ${url}`);
+                    process.exit(0);
+                });
+            });
+            if (connection.readyState === ConnectionStates.disconnected) {
+                await new Promise<void>((resolve, reject) => {
+                    connection.on('error', reject);
+                    connection.on('disconnected', () => {
+                        console.log(`disconnecting mongoose connection at ${url}`);
+                    });
+                    connection.on('connected', () => {
+                        console.log(`mongoose established default connection at ${url}`);
+                        resolve();
+                    });
+                    mongoose.connect(url, { useNewUrlParser: true });
+                });
+            }
+        } catch (e) {
+            console.error(`Mongoose FAILED to establish default connection at ${url} with the following error:`);
+            console.error(e);
+            console.log('Since a valid database connection is required to use Dash, the server process will now exit.\nPlease try again later.');
+            process.exit(1);
+        }
+    }
+
     class Database {
         public static DocumentsCollection = 'documents';
         private MongoClient = mongodb.MongoClient;
-        private url = 'mongodb://localhost:27017/Dash';
         private currentWrites: { [id: string]: Promise<void> } = {};
         private db?: mongodb.Db;
         private onConnect: (() => void)[] = [];
 
         constructor() {
-            this.MongoClient.connect(this.url, (err, client) => {
+            this.MongoClient.connect(url, (_err, client) => {
+                if (!client) {
+                    console.error("\nPlease start MongoDB by running 'mongod' in a terminal before continuing...\n");
+                    process.exit(0);
+                }
                 this.db = client.db();
                 this.onConnect.forEach(fn => fn());
             });
@@ -256,7 +302,7 @@ export namespace Database {
 
             export type StoredCredentials = Credentials & { _id: string };
 
-            export const Fetch = async (userId: string, removeId = true) => {
+            export const Fetch = async (userId: string, removeId = true): Promise<Opt<StoredCredentials>> => {
                 return SanitizedSingletonQuery<StoredCredentials>({ userId }, GoogleAuthentication, removeId);
             };