feat: support running on CF Workers

Switches to limited number of node modules that Workers support.
Adds workarounds to mismatches between Deno and Node.

- [deps]: uses simpler check for `config_dir` to avoid `node:os`.
- [deps]: switches to `@sntran/html-rewriter` for cross runtime.
- [mod]: fallback for undefined `import.meta.url` in Workers.
- [backend/drive/auth]: move `reveal` out of global scope.
- [backend/local]: switch to dynamic import for `node:fs/promises`.
- [cmd/config]: switch to dynamic import for `node:fs/promises`.
- [cmd/lsf]: creates new `Headers` instead of spreading.
- [cmd/serve/http]: switches to `@sntran/serve` for cross runtime.

Added a `_worker.js` script to run as example on CF Workers.

.gitignore

@@ -1,3 +1,4 @@
 .env
 node_modules
 .DS_Store
+.wrangler

_worker.js

@@ -0,0 +1,76 @@
+import * as backends from "./backend/main.js";
+
+/**
+ * A handler
+ *
+ * @callback Handler
+ * @param {Request} request
+ * @param {Object} env Environment variables.
+ * @returns {Response|Promise<Response>}
+ */
+
+/**
+ * Serves a bare remote, i.e., `/:memory:/path/to/file`
+ *
+ * All configuration must be passed as query parameters.
+ *
+ * @param {Request} request
+ * @param {Object} env
+ * @param {Object} params
+ * @param {string} params.remote
+ * @param {string} [params.path]
+ * @returns {Promise<Response}
+ */
+function remote(request, _env, params) {
+  let { remote, path = "/" } = params;
+
+  const backend = backends[remote];
+  if (!backend) {
+    return new Response("Remote not found.", { status: 404 });
+  }
+
+  if (!path) {
+    path = "/";
+  }
+
+  const url = new URL(request.url);
+  url.pathname = path;
+
+  request = new Request(url, request);
+
+  return backend.fetch(request);
+}
+
+const routes = {
+  "/\\::remote\\:/": remote,
+  "/\\::remote\\:/:path*": remote,
+};
+
+/**
+ * Routes request to the appropriate handler.
+ * @param {Object} routes
+ * @returns {Handler}
+ */
+function router(routes = {}) {
+  return function (request, env) {
+    const url = new URL(request.url);
+
+    for (const [route, handler] of Object.entries(routes)) {
+      const [pathname, method] = route.split("@").reverse();
+
+      if (method && request.method !== method) continue;
+
+      const pattern = new URLPattern({ pathname });
+      if (!pattern.test(url)) continue;
+
+      const params = pattern.exec(url)?.pathname?.groups || {};
+      return handler(request, env, params);
+    }
+
+    return env.ASSETS.fetch(request);
+  };
+}
+
+export default {
+  fetch: router(routes),
+};

backend/alias/main.js

@@ -26,7 +26,7 @@ import { fetch } from "../../mod.js";
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-function router(request) {
+function alias(request) {
   const { pathname, searchParams } = new URL(request.url);
   const remote = searchParams.get("remote");
 
@@ -39,5 +39,5 @@ function router(request) {
 }
 
 export default {
-  fetch: router,
+  fetch: alias,
 };

backend/chunker/main.js

@@ -145,7 +145,7 @@ export const options = {
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-async function router(request) {
+async function chunker(request) {
   const { method, url } = request;
   const { pathname, searchParams } = new URL(url);
 
@@ -385,5 +385,5 @@ async function upload(url, init) {
 }
 
 export default {
-  fetch: router,
+  fetch: chunker,
 };

backend/crypt/main.js

@@ -138,7 +138,7 @@ const SECRETBOX_OPTIONS = {
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-async function router(request) {
+async function crypt(request) {
   let { pathname, searchParams } = new URL(request.url);
 
   let remote = searchParams.get("remote");
@@ -341,5 +341,5 @@ async function deriveKey(encPass, encSalt) {
 }
 
 export default {
-  fetch: router,
+  fetch: crypt,
 };

backend/drive/auth.js

@@ -5,9 +5,8 @@ import { reveal } from "../../cmd/obscure/main.js";
 const TOKEN_URL = "https://oauth2.googleapis.com/token";
 
 const CLIENT_ID = "202264815644.apps.googleusercontent.com";
-const CLIENT_SECRET = await reveal(
-  "eX8GpZTVx3vxMWVkuuBdDWmAUE6rGhTwVrvG9GhllYccSdj2-mvHVg",
-).then((r) => r.text());
+// This is actually an obscured value. Must use `reveal`.
+const CLIENT_SECRET = "eX8GpZTVx3vxMWVkuuBdDWmAUE6rGhTwVrvG9GhllYccSdj2-mvHVg";
 const SCOPE = "drive";
 
 const encoder = new TextEncoder();
@@ -71,7 +70,10 @@ export async function auth(request) {
     body.set("assertion", jwt);
   } else {
     const client_id = searchParams.get("client_id") || CLIENT_ID;
-    const client_secret = searchParams.get("client_secret") || CLIENT_SECRET;
+    let client_secret = searchParams.get("client_secret");
+    if (!client_secret) {
+      client_secret = await reveal(CLIENT_SECRET).then((r) => r.text());
+    }
     let token = searchParams.get("token") || "";
     try {
       // Refresh token can be passed inside a JSON (rclone style) or the token itself.

backend/drive/main.js

@@ -21,7 +21,7 @@ const FILE_HEADERS = new Headers({
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-async function router(request) {
+async function drive(request) {
   //#region Auth
   const response = await auth(request);
   if (!response.ok) {
@@ -207,5 +207,5 @@ async function router(request) {
 }
 
 export default {
-  fetch: router,
+  fetch: drive,
 };

backend/fshare/main.js

@@ -46,20 +46,12 @@ const APP_KEY = "dMnqMMZMUnN5YpvKENaEhdQQ5jxDqddt";
  * @property {number} [modified]
  */
 
-const authResponse = new Response("401 Unauthorized", {
-  status: 401,
-  statusText: "Unauthorized",
-  headers: {
-    "WWW-Authenticate": `Basic realm="Login", charset="UTF-8"`,
-  },
-});
-
 /**
  * Serves an FShare remote
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-async function router(request) {
+async function fshare(request) {
   const { method, url } = request;
   let { pathname, searchParams } = new URL(url);
 
@@ -298,6 +290,14 @@ async function authFetch(request, init) {
  * @returns {Promise<Response>}
  */
 export async function auth(request) {
+  const authResponse = new Response("401 Unauthorized", {
+    status: 401,
+    statusText: "Unauthorized",
+    headers: {
+      "WWW-Authenticate": `Basic realm="Login", charset="UTF-8"`,
+    },
+  });
+
   const headers = request.headers;
   const authorization = headers.get("Authorization");
   if (!authorization) {
@@ -410,7 +410,13 @@ export async function download(config, url, init = {}) {
   const { location } = await response.json();
 
   if (!location) {
-    return authResponse;
+    return new Response("401 Unauthorized", {
+      status: 401,
+      statusText: "Unauthorized",
+      headers: {
+        "WWW-Authenticate": `Basic realm="Login", charset="UTF-8"`,
+      },
+    });
   }
 
   if (redirect === "manual") {
@@ -424,5 +430,5 @@ export async function download(config, url, init = {}) {
 }
 
 export default {
-  fetch: router,
+  fetch: fshare,
 };

backend/http/main.js

@@ -48,7 +48,7 @@ export const options = {
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-async function router(request) {
+async function http(request) {
   const { url, body } = request;
   const { pathname, searchParams } = new URL(url);
 
@@ -218,5 +218,5 @@ async function router(request) {
 }
 
 export default {
-  fetch: router,
+  fetch: http,
 };

backend/local/main.js

@@ -1,18 +1,21 @@
 #!/usr/bin/env -S deno serve --allow-all
 
-import { cwd } from "node:process";
-import { mkdir, open, readdir, rm, stat } from "node:fs/promises";
+import process from "node:process";
 import { contentType, extname, formatBytes, join } from "../../deps.js";
 
 /**
  * Serves a local remote
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-async function router(request) {
+async function local(request) {
   const { method, url } = request;
   const { pathname, searchParams } = new URL(url);
-  const absolutePath = join(cwd(), pathname);
+  const absolutePath = join(process.cwd?.() || ".", pathname);
+
+  // Have to use dynamic import here because `fs/promises` is not available in
+  // Worker environments.
+  const { mkdir, open, readdir, rm, stat } = await import("node:fs/promises");
 
   let stats;
 
@@ -23,7 +26,6 @@ async function router(request) {
     stats = await stat(absolutePath);
 
     if (stats.isDirectory()) {
-      // TODO: refactor to use `node:fs`
       /**
        * @type {import("node:fs").Dirent[]}
        */
@@ -70,7 +72,6 @@ async function router(request) {
                 filePath += "/";
               }
 
-              // TODO: refactor to use `node:fs`
               const { size, mtime } = await stat(
                 join(absolutePath, filePath),
               );
@@ -145,14 +146,16 @@ async function router(request) {
       await mkdir(absolutePath, { recursive: true });
     } else {
       const file = await open(absolutePath, "w");
-      await request.body.pipeTo(new WritableStream({
-        async write(chunk) {
-          await file.write(chunk);
-        },
-        async close() {
-          await file.close();
-        },
-      }));
+      await request.body.pipeTo(
+        new WritableStream({
+          async write(chunk) {
+            await file.write(chunk);
+          },
+          async close() {
+            await file.close();
+          },
+        }),
+      );
     }
 
     status = 201;
@@ -171,5 +174,5 @@ async function router(request) {
 }
 
 export default {
-  fetch: router,
+  fetch: local,
 };

backend/memory/main.js

@@ -23,7 +23,7 @@ cache.set("/", null);
  * @param {Request} request
  * @returns {Promise<Response>}
  */
-async function router(request) {
+async function memory(request) {
   const { method, url } = request;
   const { pathname, searchParams } = new URL(url);
 
@@ -189,5 +189,5 @@ async function router(request) {
 }
 
 export default {
-  fetch: router,
+  fetch: memory,
 };

cmd/config/main.js

@@ -1,5 +1,4 @@
 import { env } from "node:process";
-import { readFile } from "node:fs/promises";
 
 import { config_dir, INI, join } from "../../deps.js";
 
@@ -39,6 +38,8 @@ const NAME_REGEX = /^[\w.][\w.\s-]*$/;
  * @returns {Promise<Response>} The response.
  */
 export async function config(subcommand, name, options, init) {
+  const { readFile } = await import("node:fs/promises");
+
   let file = "", ini = "";
   // Order as specified at https://rclone.org/docs/#config-config-file.
   const PATHS = [

cmd/lsf/main.js

@@ -125,13 +125,16 @@ export async function lsf(location, flags = {}) {
   } = flags;
 
   const response = await lsjson(location, flags);
-  const { headers, ok } = response;
+  let { ok, headers, body } = response;
 
   if (!ok) {
     return response;
   }
 
-  const body = response.body
+  headers = new Headers(response.headers);
+  headers.set("Content-Type", "text/plain");
+
+  body = body
     .pipeThrough(new TextDecoderStream())
     .pipeThrough(
       new TransformStream({
@@ -169,9 +172,6 @@ export async function lsf(location, flags = {}) {
     .pipeThrough(new TextEncoderStream());
 
   return new Response(body, {
-    headers: {
-      ...headers,
-      "Content-Type": "text/plain",
-    },
+    headers,
   });
 }