From 8b4d0a96a47d25ba579a064958ad3adef5688cca Mon Sep 17 00:00:00 2001
From: ianwoodard <17186604+IanWoodard@users.noreply.github.com>
Date: Sun, 14 Apr 2024 09:36:19 -0700
Subject: [PATCH] Adding helmet and middleware

---
 package.json   |  1 +
 src/example.ts |  3 +--
 src/index.ts   | 32 +++++++++++++++++++++++++++++---
 yarn.lock      |  5 +++++
 4 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/package.json b/package.json
index b49857f..3329720 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
     "dotenv-expand": "^10.0.0",
     "ethereum-multicall": "^2.15.0",
     "express": "^4.18.2",
+    "helmet": "^7.1.0",
     "ts-node": "^10.9.2",
     "viem": "2.7.15",
     "winston": "3.8.2",
diff --git a/src/example.ts b/src/example.ts
index d211301..a7cbc1e 100644
--- a/src/example.ts
+++ b/src/example.ts
@@ -26,12 +26,11 @@ if (
   console.log("Configuring Sentry for Liquidator");
   Sentry.init({
     dsn: `https://${process.env.SENTRY_DSN0}@${process.env.SENTRY_DSN1}.ingest.sentry.io/${process.env.SENTRY_DSN2}`,
-    sampleRate: 0.1,
-    tracesSampleRate: 1,
     enabled:
       process.env.SENTRY_DSN0 !== undefined &&
       process.env.SENTRY_DSN1 !== undefined &&
       process.env.SENTRY_DSN2 !== undefined,
+    tracesSampleRate: 0.1,
     release: process.env.GIT_COMMIT_SHA || undefined,
     initialScope: { tags: { "chain_name": chain.name } },
   });
diff --git a/src/index.ts b/src/index.ts
index c7dcbf9..2cc9fcd 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,7 +1,8 @@
 import { fork } from "child_process";
-import express from "express";
+import express, { NextFunction, Request, Response } from "express";
 import * as Sentry from "@sentry/node";
 import { arbitrum, base, mainnet, optimism } from "viem/chains";
+import helmet from "helmet";
 
 const port = process.env.PORT || 8080;
 const app = express();
@@ -15,16 +16,26 @@ if (
   console.log("Configuring Sentry");
   Sentry.init({
     dsn: `https://${process.env.SENTRY_DSN0}@${process.env.SENTRY_DSN1}.ingest.sentry.io/${process.env.SENTRY_DSN2}`,
-    sampleRate: 0.1,
-    tracesSampleRate: 1,
     enabled:
       process.env.SENTRY_DSN0 !== undefined &&
       process.env.SENTRY_DSN1 !== undefined &&
       process.env.SENTRY_DSN2 !== undefined,
+    integrations: [
+      new Sentry.Integrations.Http({ tracing: true }),
+      new Sentry.Integrations.Express({ app }),
+    ],
     release: process.env.GIT_COMMIT_SHA || undefined,
+    tracesSampleRate: 0.1,
   });
 }
 
+// Configure Middleware
+app.use(Sentry.Handlers.requestHandler());
+app.use(Sentry.Handlers.tracingHandler());
+app.use(helmet());
+app.disable("x-powered-by");
+app.set("trust proxy", true);
+
 const chains = [mainnet.id, optimism.id, arbitrum.id, base.id];
 
 chains.forEach((chain) => {
@@ -38,6 +49,21 @@ app.get("/liquidator_readiness_check", (req, res) => {
   res.send("OK");
 });
 
+// Used after all other routes to catch any unhandled errors
+app.use(Sentry.Handlers.errorHandler());
+// Catch 404 and send our own error message (instead of the default Express one)
+// eslint-disable-next-line @typescript-eslint/no-unused-vars
+app.use((_req: Request, res: Response, _next: NextFunction) => {
+  res.status(404).send("Not found");
+});
+// Catch all other errors and sennd our own error message (instead of the default Express one)
+app.use(
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  (_err: unknown, _req: Request, res: Response, _next: NextFunction) => {
+    res.status(500).send("Internal server error");
+  }
+);
+
 const server = app.listen(port, () => {
   // eslint-disable-next-line no-console
   console.log(`Server is running on port ${port}`);
diff --git a/yarn.lock b/yarn.lock
index a175d8a..ff92276 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -952,6 +952,11 @@ hash.js@1.1.7, hash.js@^1.0.0, hash.js@^1.0.3:
     inherits "^2.0.3"
     minimalistic-assert "^1.0.1"
 
+helmet@^7.1.0:
+  version "7.1.0"
+  resolved "https://registry.yarnpkg.com/helmet/-/helmet-7.1.0.tgz#287279e00f8a3763d5dccbaf1e5ee39b8c3784ca"
+  integrity sha512-g+HZqgfbpXdCkme/Cd/mZkV0aV3BZZZSugecH03kl38m/Kmdx8jKjBikpDj2cr+Iynv4KpYEviojNdTJActJAg==
+
 hmac-drbg@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/hmac-drbg/-/hmac-drbg-1.0.1.tgz#d2745701025a6c775a6c545793ed502fc0c649a1"