index.ts

// noinspection ES6ConvertVarToLetConst

import assert from "assert";
import http, { OutgoingHttpHeaders } from "http";
import https from "https";
import { Transform, Writable } from "stream";
import { ReadableStream } from "stream/web";
import { URL } from "url";
import zlib from "zlib";
import {
  CorePluginSignatures,
  MiniflareCore,
  Request,
  Response,
  logResponse,
} from "@miniflare/core";
import { prefixError, randomHex } from "@miniflare/shared";
import { coupleWebSocket } from "@miniflare/web-sockets";
import { BodyInit, Headers } from "undici";
import { getAccessibleHosts } from "./helpers";
import { HTTPPlugin, RequestMeta } from "./plugin";

export * from "./helpers";
export * from "./plugin";

export const DEFAULT_PORT = 8787;

export type HTTPPluginSignatures = CorePluginSignatures & {
  HTTPPlugin: typeof HTTPPlugin;
};

const liveReloadScript = `<script defer type="application/javascript">
(function () {
  // Miniflare Live Reload
  var url = new URL("/cdn-cgi/mf/reload", location.origin);
  url.protocol = url.protocol.replace("http", "ws");
  function reload() { location.reload(); }
  function connect(reconnected) {
    var ws = new WebSocket(url);
    if (reconnected) ws.onopen = reload;
    ws.onclose = function(e) {
      e.code === 1012 ? reload() : e.code === 1000 || e.code === 1001 || setTimeout(connect, 1000, true);
    }
  }
  connect();
})();
</script>`;
const liveReloadScriptLength = Buffer.byteLength(liveReloadScript);

export async function convertNodeRequest(
  req: http.IncomingMessage,
  meta?: RequestMeta
): Promise<{ request: Request; url: URL }> {
  // @ts-expect-error encrypted is only defined in tls.TLSSocket
  const protocol = req.socket.encrypted ? "https" : "http";
  const origin = `${protocol}://${req.headers.host ?? "localhost"}`;
  const url = new URL(req.url ?? "", origin);

  let body: BodyInit | null = null;
  if (req.method !== "GET" && req.method !== "HEAD") {
    // Adapted from https://github.com/nodejs/undici/blob/ebea0f7084bb1efdb66c46409d1bfc87054b2870/lib/core/util.js#L269-L304
    // to create a byte stream instead of a regular one. This means we don't
    // create another "byte-TransformStream" later on to allow byob reads.
    let iterator: AsyncIterableIterator<any>;
    body = new ReadableStream({
      type: "bytes",
      start() {
        iterator = req[Symbol.asyncIterator]();
      },
      async pull(controller) {
        const { done, value } = await iterator.next();
        if (done) {
          queueMicrotask(() => controller.close());
        } else {
          const buffer = Buffer.isBuffer(value) ? value : Buffer.from(value);
          controller.enqueue(new Uint8Array(buffer));
        }
      },
      async cancel() {
        await iterator.return?.();
      },
    });
  }

  // Add additional Cloudflare specific headers:
  // https://support.cloudflare.com/hc/en-us/articles/200170986-How-does-Cloudflare-handle-HTTP-Request-headers-
  const proto = meta?.forwardedProto ?? "https";
  let ip = meta?.realIp ?? req.socket.remoteAddress ?? "";
  // Convert IPv6 loopback address to IPv4 address
  if (ip === "::1") ip = "127.0.0.1";
  // Remove IPv6 prefix for IPv4 addresses
  if (ip.startsWith("::ffff:")) ip = ip.substring("::ffff:".length);
  // We're a bit naughty here mutating the incoming request, but this ensures
  // the headers are included in the pretty-error page. If we used the new
  // converted Request instance's headers, we wouldn't have connection, keep-
  // alive, etc as we strip those. We need to take ownership of the request
  // anyway though, since we're consuming its body.
  req.headers["x-forwarded-proto"] ??= proto;
  req.headers["x-real-ip"] ??= ip;
  req.headers["cf-connecting-ip"] ??= ip;
  req.headers["cf-ipcountry"] ??= meta?.cf?.country ?? "US";
  req.headers["cf-ray"] ??= randomHex(16);
  req.headers["cf-visitor"] ??= `{"scheme":"${proto}"}`;
  req.headers["host"] = url.host;

  // Build Headers object from request
  const headers = new Headers();
  for (const [name, values] of Object.entries(req.headers)) {
    // These headers are unsupported in undici fetch requests, they're added
    // automatically
    if (
      name === "transfer-encoding" ||
      name === "connection" ||
      name === "keep-alive" ||
      name === "expect"
    ) {
      continue;
    }
    if (Array.isArray(values)) {
      for (const value of values) headers.append(name, value);
    } else if (values !== undefined) {
      headers.append(name, values);
    }
  }

  // Create Request with additional Cloudflare specific properties:
  // https://developers.cloudflare.com/workers/runtime-apis/request#incomingrequestcfproperties
  const request = new Request(url, {
    method: req.method,
    headers,
    body,
    cf: meta?.cf,
  });
  return { request, url };
}

export type RequestListener = (
  req: http.IncomingMessage,
  res?: http.ServerResponse
) => Promise<Response | undefined>;

export function createRequestListener<Plugins extends HTTPPluginSignatures>(
  mf: MiniflareCore<Plugins>
): RequestListener {
  return async (req, res) => {
    const { HTTPPlugin } = await mf.getPlugins();
    const start = process.hrtime();
    const { request, url } = await convertNodeRequest(
      req,
      await HTTPPlugin.getRequestMeta(req)
    );

    let response: Response | undefined;
    let waitUntil: Promise<unknown[]> | undefined;
    let status = 500;

    // Check if path matches /cdn-cgi/* ignoring trailing slash. These paths
    // can't be handled by workers and are used for utility interfaces.
    const pathname = url.pathname.replace(/\/$/, "");
    if (pathname.startsWith("/cdn-cgi/")) {
      // TODO (someday): consider adding other utility interfaces for KV, DO, etc
      //  (maybe add another Plugin field/method/decorator for contributes)
      if (pathname === "/cdn-cgi/mf/scheduled") {
        req.method = "SCHD";
        const time = url.searchParams.get("time");
        const cron = url.searchParams.get("cron");
        waitUntil = mf.dispatchScheduled(
          time ? parseInt(time) : undefined,
          cron ?? undefined
        );
        status = 200;
      } else {
        status = 404;
      }
      res?.writeHead(status, { "Content-Type": "text/plain; charset=UTF-8" });
      res?.end();
    } else {
      try {
        response = await mf.dispatchFetch(request);
        waitUntil = response.waitUntil();
        status = response.status;
        const headers: OutgoingHttpHeaders = {};
        // eslint-disable-next-line prefer-const
        for (let [key, value] of response.headers) {
          key = key.toLowerCase();
          if (key === "set-cookie") {
            // Multiple Set-Cookie headers should be treated as separate headers
            // @ts-expect-error getAll is added to the Headers prototype by
            // importing @miniflare/core
            headers["set-cookie"] = response.headers.getAll("set-cookie");
          } else {
            headers[key] = value;
          }
        }

        // If a Content-Encoding is set, and the user hasn't encoded the body,
        // we're responsible for doing so.
        const encoders: Transform[] = [];
        if (headers["content-encoding"] && response.encodeBody === "auto") {
          // Content-Length will be wrong as it's for the decoded length
          delete headers["content-length"];
          // Reverse of https://github.com/nodejs/undici/blob/48d9578f431cbbd6e74f77455ba92184f57096cf/lib/fetch/index.js#L1660
          const codings = headers["content-encoding"]
            .toString()
            .toLowerCase()
            .split(",")
            .map((x) => x.trim());
          for (const coding of codings) {
            if (/(x-)?gzip/.test(coding)) {
              encoders.push(zlib.createGzip());
            } else if (/(x-)?deflate/.test(coding)) {
              encoders.push(zlib.createDeflate());
            } else if (coding === "br") {
              encoders.push(zlib.createBrotliCompress());
            } else {
              // Unknown encoding, don't do any encoding at all
              mf.log.warn(
                `Unknown encoding \"${coding}\", sending plain response...`
              );
              delete headers["content-encoding"];
              encoders.length = 0;
              break;
            }
          }
        }

        // Add live reload script if enabled, this isn't an already encoded
        // response, and it's HTML
        const liveReloadEnabled =
          HTTPPlugin.liveReload &&
          response.encodeBody === "auto" &&
          response.headers
            .get("content-type")
            ?.toLowerCase()
            .includes("text/html");

        // If Content-Length is specified, and we're live-reloading, we'll
        // need to adjust it to make room for the live reload script
        const contentLength = response.headers.get("content-length");
        if (liveReloadEnabled && contentLength !== null) {
          const length = parseInt(contentLength);
          if (!isNaN(length)) {
            // Append length of live reload script
            headers["content-length"] = length + liveReloadScriptLength;
          }
        }

        res?.writeHead(status, headers);

        // Response body may be null if empty
        if (res) {
          // `initialStream` is the stream we'll write the response to. It
          // should end up as the first encoder, piping to the next encoder,
          // and finally piping to the response:
          //
          // encoders[0] (initialStream) -> encoders[1] -> res
          //
          // Not using `pipeline(passThrough, ...encoders, res)` here as that
          // gives a premature close error with server sent events. This also
          // avoids creating an extra stream even when we're not encoding.
          let initialStream: Writable = res;
          for (let i = encoders.length - 1; i >= 0; i--) {
            encoders[i].pipe(initialStream);
            initialStream = encoders[i];
          }

          if (response.body) {
            for await (const chunk of response.body) {
              if (chunk) initialStream.write(chunk);
            }

            if (liveReloadEnabled) {
              initialStream.write(liveReloadScript);
            }
          }

          initialStream.end();
        }
      } catch (e: any) {
        // MIME types aren't case sensitive
        const accept = req.headers.accept?.toLowerCase() ?? "";
        if (
          accept.includes("text/html") ||
          accept.includes("*/*") ||
          accept.includes("text/*")
        ) {
          // Send pretty HTML error page if client accepts it
          const Youch: typeof import("youch").default = require("youch");
          const youch = new Youch(e, req);
          youch.addLink(() => {
            const links = [
              '<a href="https://developers.cloudflare.com/workers/" target="_blank" style="text-decoration:none">📚 Workers Docs</a>',
              '<a href="https://discord.gg/cloudflaredev" target="_blank" style="text-decoration:none">💬 Workers Discord</a>',
              '<a href="https://miniflare.dev" target="_blank" style="text-decoration:none">🔥 Miniflare Docs</a>',
            ];
            // Live reload is basically a link right?
            if (HTTPPlugin.liveReload) links.push(liveReloadScript);
            return links.join("");
          });
          const errorHtml = await youch.toHTML();
          res?.writeHead(500, { "Content-Type": "text/html; charset=UTF-8" });
          res?.end(errorHtml, "utf8");
        } else {
          // Otherwise, send plaintext stack trace
          res?.writeHead(500, { "Content-Type": "text/plain; charset=UTF-8" });
          res?.end(e.stack, "utf8");
        }

        // Add method and URL to stack trace
        mf.log.error(prefixError(`${req.method} ${req.url}`, e));
      }
    }

    assert(req.method && req.url);
    await logResponse(mf.log, {
      start,
      method: req.method,
      url: req.url,
      status,
      waitUntil,
    });
    return response;
  };
}

export async function createServer<Plugins extends HTTPPluginSignatures>(
  mf: MiniflareCore<Plugins>,
  options?: http.ServerOptions & https.ServerOptions
): Promise<http.Server | https.Server> {
  const plugins = await mf.getPlugins();
  const listener = createRequestListener(mf);

  // Setup HTTP server
  let server: http.Server | https.Server;
  if (plugins.HTTPPlugin.httpsEnabled) {
    const httpsOptions = plugins.HTTPPlugin.httpsOptions;
    assert(httpsOptions);
    server = https.createServer({ ...httpsOptions, ...options }, listener);
  } else {
    server = http.createServer(options ?? {}, listener);
  }

  const { WebSocketServer }: typeof import("ws") = require("ws");

  // Setup WebSocket servers
  const webSocketServer = new WebSocketServer({ noServer: true });
  const liveReloadServer = new WebSocketServer({ noServer: true });
  server.on("upgrade", async (request, socket, head) => {
    // Only interested in pathname so base URL doesn't matter
    const { pathname } = new URL(request.url ?? "", "http://localhost");
    if (pathname === "/cdn-cgi/mf/reload") {
      // If this is the for live-reload, handle the request ourselves
      liveReloadServer.handleUpgrade(request, socket as any, head, (ws) => {
        liveReloadServer.emit("connection", ws, request);
      });
    } else {
      // Otherwise, handle the request in the worker
      const response = await listener(request);

      // Check web socket response was returned
      const webSocket = response?.webSocket;
      if (response?.status !== 101 || !webSocket) {
        socket.write("HTTP/1.1 500 Internal Server Error\r\n\r\n");
        socket.destroy();
        mf.log.error(
          new TypeError(
            "Web Socket request did not return status 101 Switching Protocols response with Web Socket"
          )
        );
        return;
      }

      // Accept and couple the Web Socket
      webSocketServer.handleUpgrade(request, socket as any, head, (ws) => {
        void coupleWebSocket(ws, webSocket);
        webSocketServer.emit("connection", ws, request);
      });
    }
  });
  const reloadListener = () => {
    // Reload all connected live reload clients
    for (const ws of liveReloadServer.clients) {
      ws.close(1012, "Service Restart");
    }
    // Close all existing web sockets on reload
    for (const ws of webSocketServer.clients) {
      ws.close(1012, "Service Restart");
    }
  };
  mf.addEventListener("reload", reloadListener);
  server.on("close", () => mf.removeEventListener("reload", reloadListener));

  return server;
}

export async function startServer<Plugins extends HTTPPluginSignatures>(
  mf: MiniflareCore<Plugins>,
  options?: http.ServerOptions & https.ServerOptions
): Promise<http.Server | https.Server> {
  const server = await createServer(mf, options);
  const plugins = await mf.getPlugins();
  const { httpsEnabled, host, port = DEFAULT_PORT } = plugins.HTTPPlugin;
  return new Promise((resolve) => {
    server.listen(port, host, () => {
      const log = mf.log;
      const protocol = httpsEnabled ? "https" : "http";
      const accessibleHosts = host ? [host] : getAccessibleHosts(true);
      log.info(`Listening on ${host ?? ""}:${port}`);
      for (const accessibleHost of accessibleHosts) {
        log.info(`- ${protocol}://${accessibleHost}:${port}`);
      }
      resolve(server);
    });
  });
}