Convert routes to Express

src/node/proxy.ts

@@ -0,0 +1,73 @@
+import { Request, Router } from "express"
+import proxyServer from "http-proxy"
+import { HttpCode } from "../common/http"
+import { ensureAuthenticated } from "./http"
+
+export const proxy = proxyServer.createProxyServer({})
+proxy.on("error", (error, _, res) => {
+  res.writeHead(HttpCode.ServerError)
+  res.end(error.message)
+})
+
+// Intercept the response to rewrite absolute redirects against the base path.
+proxy.on("proxyRes", (res, req) => {
+  if (res.headers.location && res.headers.location.startsWith("/") && (req as any).base) {
+    res.headers.location = (req as any).base + res.headers.location
+  }
+})
+
+export const router = Router()
+
+/**
+ * Return the port if the request should be proxied. Anything that ends in a
+ * proxy domain and has a *single* subdomain should be proxied. Anything else
+ * should return `undefined` and will be handled as normal.
+ *
+ * For example if `coder.com` is specified `8080.coder.com` will be proxied
+ * but `8080.test.coder.com` and `test.8080.coder.com` will not.
+ *
+ * Throw an error if proxying but the user isn't authenticated.
+ */
+const maybeProxy = (req: Request): string | undefined => {
+  // Split into parts.
+  const host = req.headers.host || ""
+  const idx = host.indexOf(":")
+  const domain = idx !== -1 ? host.substring(0, idx) : host
+  const parts = domain.split(".")
+
+  // There must be an exact match.
+  const port = parts.shift()
+  const proxyDomain = parts.join(".")
+  if (!port || !req.args["proxy-domain"].includes(proxyDomain)) {
+    return undefined
+  }
+
+  // Must be authenticated to use the proxy.
+  ensureAuthenticated(req)
+
+  return port
+}
+
+router.all("*", (req, res, next) => {
+  const port = maybeProxy(req)
+  if (!port) {
+    return next()
+  }
+
+  proxy.web(req, res, {
+    ignorePath: true,
+    target: `http://127.0.0.1:${port}${req.originalUrl}`,
+  })
+})
+
+router.ws("*", (socket, head, req, next) => {
+  const port = maybeProxy(req)
+  if (!port) {
+    return next()
+  }
+
+  proxy.ws(req, socket, head, {
+    ignorePath: true,
+    target: `http://127.0.0.1:${port}${req.originalUrl}`,
+  })
+})