Allow the safe-chain to act as a regular http proxy too (besides the CONNECT tunneling implementation)

packages/safe-chain/src/registryProxy/plainHttpProxy.js

@@ -0,0 +1,58 @@
+import * as http from "http";
+import * as https from "https";
+
+export function handleHttpProxyRequest(req, res) {
+  const url = new URL(req.url);
+
+  let protocol;
+  if (url.protocol === "http:") {
+    protocol = http;
+  } else if (url.protocol === "https:") {
+    protocol = https;
+  } else {
+    res.writeHead(502);
+    res.end(`Bad Gateway: Unsupported protocol ${url.protocol}`);
+    return;
+  }
+
+  const proxyRequest = protocol
+    .request(
+      req.url,
+      { method: req.method, headers: req.headers },
+      (proxyRes) => {
+        res.writeHead(proxyRes.statusCode, proxyRes.headers);
+        proxyRes.pipe(res);
+
+        proxyRes.on("error", () => {
+          // Stream error while piping response
+          // Response headers already sent, can't send error status
+        });
+      }
+    )
+    .on("error", (err) => {
+      res.writeHead(502);
+      res.end(`Bad Gateway: ${err.message}`);
+    });
+
+  req.on("error", () => {
+    // Client request stream error
+    // Abort the proxy request
+    proxyRequest.destroy();
+  });
+
+  res.on("error", () => {
+    // Client response stream error (client disconnected)
+    // Clean up proxy streams
+    proxyRequest.destroy();
+  });
+
+  res.on("close", () => {
+    // Client disconnected
+    // Abort the proxy request to avoid unnecessary work
+    if (!res.writableEnded) {
+      proxyRequest.destroy();
+    }
+  });
+
+  req.pipe(proxyRequest);
+}

packages/safe-chain/src/registryProxy/registryProxy.js

@@ -1,6 +1,7 @@
 import * as http from "http";
 import { tunnelRequest } from "./tunnelRequestHandler.js";
 import { mitmConnect } from "./mitmRequestHandler.js";
+import { handleHttpProxyRequest } from "./plainHttpProxy.js";
 import { getCaCertPath } from "./certUtils.js";
 import { auditChanges } from "../scanning/audit/index.js";
 import { knownRegistries, parsePackageFromUrl } from "./parsePackageFromUrl.js";
@@ -54,13 +55,7 @@ export function mergeSafeChainProxyEnvironmentVariables(env) {
 }
 
 function createProxyServer() {
-  const server = http.createServer((_, res) => {
+  const server = http.createServer(handleHttpProxyRequest);
-    res.writeHead(400, "Bad Request");
-    res.write(
-      "Safe-chain proxy: Direct http not supported. Only CONNECT requests are allowed."
-    );
-    res.end();
-  });
 
   return server;
 }