database separation and preliminary functions

1 files changed, 27 insertions, 0 deletions

diff --git a/src/server/database.ts b/src/server/database.ts
index 25e1e67e0..4f93d1ee6 100644
--- a/src/server/database.ts
+++ b/src/server/database.ts
@@ -5,6 +5,7 @@ import { Utils, emptyFunction } from '../Utils';
 import { DashUploadUtils } from './DashUploadUtils';
 import { Credentials } from 'google-auth-library';
 import { GoogleApiServerUtils } from './apis/google/GoogleApiServerUtils';
+import mongoose, { ConnectionStates } from 'mongoose';
 
 export namespace Database {
 
@@ -12,6 +13,32 @@ export namespace Database {
     const port = 27017;
     export const url = `mongodb://localhost:${port}/${schema}`;
 
+    export async function tryInitializeConnection() {
+        try {
+            const { connection } = mongoose;
+            process.on('SIGINT', () => {
+                connection.close(() => {
+                    console.log('Mongoose default connection disconnected through app termination');
+                    process.exit(0);
+                });
+            });
+            if (connection.readyState === ConnectionStates.disconnected) {
+                await new Promise<void>((resolve, reject) => {
+                    connection.on('error', reject);
+                    connection.on('connected', () => {
+                        console.log(`Mongoose established default connection at ${url}`);
+                        resolve();
+                    });
+                });
+            }
+        } 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;