add hacky database error handling to prevent the server from crashing due to trivial errors

src/auth.ts

@@ -83,7 +83,7 @@ export function decodeToken(encoded: string): Promise<User> {
                 }
 
                 const user = await query("SELECT * FROM users WHERE id = $1", [decoded.id]);
-                if (user.rowCount < 1) {
+                if (!user || user.rowCount < 1) {
                     reject("user does not exist (could not find in database by id)");
                     return;
                 }

src/database/index.ts

@@ -1,5 +1,25 @@
-import { Pool } from "pg";
+import { Pool, QueryResult } from "pg";
 
 const pool = new Pool();
 
-export const query = pool.query.bind(pool);
+// hacky wrapper function that returns null on database errors.
+// this is done because express doesn't automatically call next()
+// when an async function throws, so this prevents the server
+// from crashing due to trivial database errors that can be handled.
+// we could use a try catch block for each query, but that will
+// quickly get cumbersome.
+export const query = function(text: string, params: any[] = [], rejectOnError = false): Promise<QueryResult | null> {
+    return new Promise((resolve, reject) => {
+        pool.query(text, params)
+            .then((data) => {
+                resolve(data);
+            })
+            .catch((error) => {
+                if (rejectOnError) {
+                    reject(error);
+                } else {
+                    resolve(null);
+                }
+            });
+    });
+};

src/errors.ts

@@ -20,4 +20,5 @@ export const gatewayErrors = {
     PAYLOAD_TOO_LARGE: { code: 4007, message: "Payload too large" },
     TOO_MANY_SESSIONS: { code: 4008, message: "Too many sessions" },
     NOT_AUTHENTICATED: { code: 4009, message: "Not authenticated" },
+    GOT_NO_DATABASE_DATA: { code: 4010, message: "Unexpectedly got no data from database" },
 };

src/gateway/index.ts

@@ -223,6 +223,10 @@ export default function(server: Server) {
                     // TODO: each user should have their own list of channels that they join
                     const channels = await query("SELECT id, name, owner_id FROM channels ORDER BY id ASC");
 
+                    if (!channels) {
+                        return closeWithError(ws, gatewayErrors.GOT_NO_DATABASE_DATA);
+                    }
+
                     clientSubscribe(ws, "*");
                     channels.rows.forEach(c => {
                         clientSubscribe(ws, `channel:${c.id}`);

src/routes/api/v1/channels.ts

@@ -26,7 +26,7 @@ router.post(
 
         const { name } = req.body;
         const result = await query("INSERT INTO channels(name, owner_id) VALUES ($1, $2) RETURNING id, name, owner_id", [name, req.user.id]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(500).json({
                 ...errors.GOT_NO_DATABASE_DATA
             });
@@ -60,7 +60,7 @@ router.put(
         const id = parseInt(req.params.id); // TODO: ??
 
         const permissionCheckResult = await query("SELECT owner_id FROM channels WHERE id = $1", [id]);
-        if (permissionCheckResult.rowCount < 1) {
+        if (!permissionCheckResult || permissionCheckResult.rowCount < 1) {
             return res.status(404).json({
                 ...errors.NOT_FOUND
             });
@@ -72,7 +72,7 @@ router.put(
         }
 
         const result = await query("UPDATE channels SET name = $1 WHERE id = $2", [name, id]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(500).json({
                 ...errors.GOT_NO_DATABASE_DATA
             });
@@ -106,7 +106,7 @@ router.delete(
         const id = parseInt(req.params.id); // TODO: ??
 
         const permissionCheckResult = await query("SELECT owner_id FROM channels WHERE id = $1", [id]);
-        if (permissionCheckResult.rowCount < 1) {
+        if (!permissionCheckResult || permissionCheckResult.rowCount < 1) {
             return res.status(404).json({
                 ...errors.NOT_FOUND
             });
@@ -118,7 +118,7 @@ router.delete(
         }
 
         const result = await query("DELETE FROM channels WHERE id = $1", [id]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(500).json({
                 ...errors.GOT_NO_DATABASE_DATA
             });
@@ -148,7 +148,7 @@ router.get(
 
         const { id } = req.params;
         const result = await query("SELECT id, name, owner_id FROM channels WHERE id = $1", [id]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(404).json({
                 ...errors.NOT_FOUND
             });
@@ -164,7 +164,7 @@ router.get(
     async (req, res) => {
         const result = await query("SELECT id, name, owner_id FROM channels");
 
-        return res.status(200).send(result.rows);
+        return res.status(200).send(result ? result.rows : []);
     }
 );
 
@@ -185,7 +185,7 @@ router.post(
         const createdAt = Date.now().toString();
 
         const result = await query("INSERT INTO messages(content, channel_id, author_id, created_at) VALUES ($1, $2, $3, $4) RETURNING id", [content, channelId, authorId, createdAt]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(500).json({
                 ...errors.GOT_NO_DATABASE_DATA
             });
@@ -226,10 +226,10 @@ router.get(
 
         if (before) {
             const result = await query(getMessagesByChannelPage, [before, channelId]);
-            finalRows = result.rows;
+            finalRows = result ? result.rows : [];
         } else {
             const result = await query(getMessagesByChannelFirstPage, [channelId]);
-            finalRows = result.rows;
+            finalRows = result ? result.rows : [];
         }
 
         return res.status(200).send(finalRows);

src/routes/api/v1/messages.ts

@@ -22,7 +22,7 @@ router.delete(
         const id = parseInt(req.params.id); // TODO: ??
 
         const permissionCheckResult = await query("SELECT author_id, channel_id FROM messages WHERE id = $1", [id]);
-        if (permissionCheckResult.rowCount < 1) {
+        if (!permissionCheckResult || permissionCheckResult.rowCount < 1) {
             return res.status(404).json({
                 ...errors.NOT_FOUND
             });
@@ -34,7 +34,7 @@ router.delete(
         }
 
         const result = await query("DELETE FROM messages WHERE id = $1", [id]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(500).json({
                 ...errors.GOT_NO_DATABASE_DATA
             });
@@ -67,7 +67,7 @@ router.put(
         const id = parseInt(req.params.id); // TODO: ??
 
         const permissionCheckResult = await query(getMessageById, [id]);
-        if (permissionCheckResult.rowCount < 1) {
+        if (!permissionCheckResult || permissionCheckResult.rowCount < 1) {
             return res.status(404).json({
                 ...errors.NOT_FOUND
             });
@@ -79,7 +79,7 @@ router.put(
         }
 
         const result = await query("UPDATE messages SET content = $1 WHERE id = $2", [content, id]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(500).json({
                 ...errors.GOT_NO_DATABASE_DATA
             });
@@ -111,7 +111,7 @@ router.get(
 
         const { id } = req.params;
         const result = await query(getMessageById, [id]);
-        if (result.rowCount < 1) {
+        if (!result || result.rowCount < 1) {
             return res.status(404).json({
                 ...errors.NOT_FOUND
             });

src/routes/api/v1/users.ts

@@ -26,7 +26,7 @@ router.post(
         const { username, password } = req.body;
 
         const existingUser = await query("SELECT * FROM users WHERE username = $1", [username]);
-        if (existingUser.rowCount > 0) {
+        if (existingUser && existingUser.rowCount > 0) {
             return res.status(400).json({
                 ...errors.INVALID_DATA,
                 errors: [ { location: "body", msg: "Username already exists", param: "username" } ]
@@ -35,7 +35,7 @@ router.post(
 
         const hashedPassword = await hash(password, 10);
         const insertedUser = await query("INSERT INTO users(username, password, is_superuser) VALUES ($1, $2, $3) RETURNING id, username, is_superuser", [username, hashedPassword, false]);
-        if (insertedUser.rowCount < 1) {
+        if (!insertedUser || insertedUser.rowCount < 1) {
             return res.status(500).json({
                 ...errors.GOT_NO_DATABASE_DATA
             });
@@ -58,7 +58,7 @@ router.post(
         const { username, password } = req.body;
 
         const existingUser = await query("SELECT * FROM users WHERE username = $1", [username]);
-        if (existingUser.rowCount < 1) {
+        if (!existingUser || existingUser.rowCount < 1) {
             return res.status(400).json({ ...errors.BAD_LOGIN_CREDENTIALS });
         }
 
@@ -95,7 +95,7 @@ router.post(
 
         if (superuserKey && superuserKey.length >= 1 && key === superuserKey && req.user) {
             const updateUserResult = await query("UPDATE users SET is_superuser = true WHERE id = $1", [req.user.id]);
-            if (updateUserResult.rowCount < 1) {
+            if (!updateUserResult || updateUserResult.rowCount < 1) {
                 return res.status(500).json({
                     ...errors.GOT_NO_DATABASE_DATA
                 });