Stop the server from crashing

When upgrading the http-proxy-middleware library I accidentally caused the app to create a new proxy server on every request (whether for the proxy or not), rather than just on startup. This led to a memory leak, and the Node process crashing.

This change creates it once, and uses the express-async-handler to get around triggering the no-misused-promises linting rule.

Refs #1636, chimurai/http-proxy-middleware#108 (comment), https://github.com/chimurai/http-proxy-middleware/tree/v3.0.0?tab=readme-ov-file#express-server-example, https://typescript-eslint.io/rules/no-misused-promises/

package.json

@@ -21,6 +21,7 @@
     "datacite-ts": "^0.1.4",
     "doi-ts": "^0.1.9",
     "express": "^4.19.2",
+    "express-async-handler": "^1.2.0",
     "fetch-fp-ts": "^0.1.6",
     "fp-ts": "^2.16.6",
     "fp-ts-routing": "^0.6.0",

src/app.ts

@@ -1,5 +1,6 @@
 import slashes from 'connect-slashes'
 import express from 'express'
+import asyncHandler from 'express-async-handler'
 import type { Json } from 'fp-ts/Json'
 import * as R from 'fp-ts/Reader'
 import * as RTE from 'fp-ts/ReaderTaskEither'
@@ -222,39 +223,41 @@ export const app = (config: ConfigEnv) => {
         },
       }),
     )
-    .use((req, res, next) => {
-      createProxyMiddleware({
-        target: config.legacyPrereviewApi.url,
-        changeOrigin: true,
-        pathFilter: '/api/v2/',
-        on: {
-          proxyReq: (proxyReq, req) => {
-            const payload = {
-              url: `${proxyReq.protocol}//${proxyReq.host}${proxyReq.path}`,
-              method: proxyReq.method,
-              requestId: req.headers['fly-request-id'] ?? null,
-            }
+    .use(
+      asyncHandler(
+        createProxyMiddleware({
+          target: config.legacyPrereviewApi.url,
+          changeOrigin: true,
+          pathFilter: '/api/v2/',
+          on: {
+            proxyReq: (proxyReq, req) => {
+              const payload = {
+                url: `${proxyReq.protocol}//${proxyReq.host}${proxyReq.path}`,
+                method: proxyReq.method,
+                requestId: req.headers['fly-request-id'] ?? null,
+              }
 
-            L.debugP('Sending proxy HTTP request')(payload)(config)()
+              L.debugP('Sending proxy HTTP request')(payload)(config)()
 
-            proxyReq.once('response', response => {
-              L.debugP('Received proxy HTTP response')({
-                ...payload,
-                status: response.statusCode as Json,
-                headers: response.headers as Json,
-              })(config)()
-            })
+              proxyReq.once('response', response => {
+                L.debugP('Received proxy HTTP response')({
+                  ...payload,
+                  status: response.statusCode as Json,
+                  headers: response.headers as Json,
+                })(config)()
+              })
 
-            proxyReq.once('error', error => {
-              L.warnP('Did not receive a proxy HTTP response')({
-                ...payload,
-                error: error.message,
-              })(config)()
-            })
+              proxyReq.once('error', error => {
+                L.warnP('Did not receive a proxy HTTP response')({
+                  ...payload,
+                  error: error.message,
+                })(config)()
+              })
+            },
           },
-        },
-      })(req, res, next)?.catch(() => next())
-    })
+        }),
+      ),
+    )
     .use(slashes(false))
     .use(express.urlencoded({ extended: true }))
     .use((req, res, next) => {