ISSUE: #97 - Partial responses Azure Container Apps

CHANGELOG.md

@@ -21,6 +21,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Bugs
 
+- [#97](https://github.com/DFE-Digital/polis-whitelabel/issues/97) Only partial responses returned when deployed to Azure Container App
 - [#91](https://github.com/DFE-Digital/polis-whitelabel/issues/91) Allow no email transport to be configured without crash
 - [#87](https://github.com/DFE-Digital/polis-whitelabel/issues/85) Client report no longer hardcoded to pol.is domain
 - [#85](https://github.com/DFE-Digital/polis-whitelabel/issues/85) Fix local Docker Compose script

deploy/docker/reverse-proxy-config/default.conf.template

@@ -41,6 +41,12 @@ server {
     add_header X-Cache-Status $upstream_cache_status;
     proxy_buffering on;
 
+    # Envoy (used in Azure Container Apps) requires HTTP 1.1 and also does chunked transfer
+    # so we need to make sure that the connection header isn't set to default of 'close'
+    proxy_http_version 1.1;
+    proxy_set_header   "Connection" "";
+
+
     # A health check endpoint
     location = /health {
         return 204;

server/package.json

@@ -53,7 +53,7 @@
     "@types/connect-timeout": "^0.0.34",
     "@types/express": "^4.17.11",
     "@types/fb": "^0.0.28",
-    "@types/http-proxy": "^1.17.5",
+    "@types/http-proxy": "^1.17.14",
     "@types/lru-cache": "^5.1.0",
     "@types/node": "^14.14.39",
     "@types/nodemailer": "^6.4.1",

server/src/handlers.ts

@@ -6806,13 +6806,7 @@ let handle_GET_conditionalIndexFetcher = (function () {
 
 function handle_GET_localFile_dev_only(
   req: Request,
-  res: {
-    writeHead: (
-      arg0: number,
-      arg1?: { "Content-Type": string } | undefined
-    ) => void;
-    end: (arg0?: undefined, arg1?: string) => void;
-  }
+  res: Response
 ) {
   const filenameParts = String(req.path).split("/");
   filenameParts.shift();

server/src/helpers.ts

@@ -1,6 +1,8 @@
 "use strict";
 
 import akismetLib from "akismet";
+import http from 'http';
+import https from 'https';
 import async from "async";
 import badwords from "badwords/object";
 import crypto from "crypto";
@@ -5752,7 +5754,7 @@ function makeFileFetcher(
     }
     let url = "http://" + hostname + ":" + port + path;
     console.log("info", "fetch file from " + url);
-    let fsReq = request.get(url)
+    let fsReq = request.get(url, { forever: true })
 
     fsReq
       .on("error", function (err: any) {
@@ -6119,11 +6121,10 @@ function browserSupportsPushState(req: { headers?: { [x: string]: string } }) {
   return !/MSIE [23456789]/.test(req?.headers?.["user-agent"] || "");
 }
 
-// 'new' expression, whose target lacks a construct signature, implicitly has an 'any' type.ts(7009)
-// @ts-ignore
-let routingProxy = new httpProxy.createProxyServer();
 
-function proxy(req: Request, res: any) {
+let routingProxy = httpProxy.createProxyServer();
+
+function proxy(req: Request, res: Response) {
   let hostname = buildStaticHostname(req, res);
   if (!hostname) {
     let host = req?.headers?.host || "";
@@ -6148,7 +6149,13 @@ function proxy(req: Request, res: any) {
   let port = process.env.STATIC_FILES_PORT;
   // set the host header too, since S3 will look at that (or the routing proxy will patch up the request.. not sure which)
   if (req && req.headers && req.headers.host) req.headers.host = hostname;
+
+  const isHttps = port === '443'
+
   routingProxy.web(req, res, {
+    agent: isHttps 
+      ? new https.Agent({ keepAlive: true }) 
+      : new http.Agent({ keepAlive: true }),
     target: {
       host: hostname,
       port: port,