Fix local demo server connection refused on port 8080

PLAN.md

@@ -0,0 +1,54 @@
+# Plan: Fix local demo server connection refused on port 8080
+
+## Problem Analysis
+
+The `server.js` file has two issues preventing the demo from working:
+
+### Issue 1: IPv6/IPv4 Binding
+`server.listen(port)` (line 10) is called without a host argument. Per [Node.js docs](https://nodejs.org/api/net.html#serverlistenport-host-backlog-callback), when host is omitted the server binds to `::` (IPv6 unspecified address) when IPv6 is available. While most OSes support dual-stack (accepting both IPv4 and IPv6 on `::`), some environments (including containers and sandboxes) may have IPv6 disabled or `localhost` resolving only to `127.0.0.1`, causing "connection refused".
+
+**Fix**: Pass `'0.0.0.0'` as the host to `server.listen()` to explicitly bind to all IPv4 interfaces.
+
+### Issue 2: No Static File Serving
+The current server handler only returns a plain text response (`"Hello from mogterm2!"`). It doesn't serve the HTML, CSS, or JS files that make up the demo (`demo/index.html`, `src/*.js`, `src/*.css`, `index.html`). Even if the binding issue were fixed, navigating to `http://localhost:8080` would show plain text, not the demo page.
+
+**Fix**: Replace the stub handler with a static file server that:
+- Serves files from the project root directory
+- Maps `/` to `index.html` (the project already has one at root)
+- Returns correct `Content-Type` headers based on file extension
+- Returns 404 for missing files
+- Uses only Node.js built-in modules (`node:fs`, `node:path`, `node:http`) — no new dependencies
+
+## Scope
+
+This is a **single-agent** task. Both fixes are in the same file (`server.js`) and are tightly coupled — you can't meaningfully test one without the other.
+
+## Files to Change
+
+- `server.js` — the only file that needs modification
+
+## Implementation Steps
+
+1. Add imports for `node:fs` and `node:path`
+2. Define a MIME type map for file extensions used in the project (`.html`, `.css`, `.js`, `.json`, `.ts`)
+3. Replace the request handler to:
+   - Resolve the requested URL path to a filesystem path relative to the project root
+   - Default `/` to `/index.html`
+   - Prevent path traversal (reject paths containing `..`)
+   - Read the file and serve it with the correct Content-Type
+   - Return 404 for missing files
+4. Change `server.listen(port, ...)` to `server.listen(port, '0.0.0.0', ...)`
+5. Update the console.log to show the full URL including `http://0.0.0.0:${port}`
+
+## Validation
+
+- Start the server with `node server.js`
+- Verify `curl http://127.0.0.1:8080/` returns HTML content
+- Verify `curl http://127.0.0.1:8080/demo/index.html` returns the demo page
+- Verify `curl http://127.0.0.1:8080/src/terminal.js` returns JavaScript
+- Run existing tests: `npx tsx --test test/**/*.test.ts` to ensure no regressions
+
+## Sources
+
+- [Node.js net.Server.listen() docs](https://nodejs.org/api/net.html#serverlistenport-host-backlog-callback) — confirms `::` default binding behavior
+- [Node.js http.createServer() docs](https://nodejs.org/api/http.html#httpcreateserveroptions-requestlistener) — static file serving pattern

server.js

@@ -1,12 +1,43 @@
 import { createServer } from "node:http";
+import { readFile } from "node:fs";
+import { dirname, join, extname } from "node:path";
+import { fileURLToPath } from "node:url";
 
+const __dirname = dirname(fileURLToPath(import.meta.url));
 const port = process.env.PORT || 8080;
 
+const mimeTypes = {
+  ".html": "text/html",
+  ".css": "text/css",
+  ".js": "application/javascript",
+  ".json": "application/json",
+  ".ts": "text/plain",
+};
+
 const server = createServer((req, res) => {
-  res.writeHead(200, { "Content-Type": "text/plain" });
-  res.end("Hello from mogterm2!\n");
+  const pathname = new URL(req.url, "http://localhost").pathname;
+
+  if (pathname.includes("..")) {
+    res.writeHead(403);
+    res.end("Forbidden");
+    return;
+  }
+
+  const filePath = join(__dirname, pathname === "/" ? "/index.html" : pathname);
+  const ext = extname(filePath);
+  const contentType = mimeTypes[ext] || "application/octet-stream";
+
+  readFile(filePath, (err, data) => {
+    if (err) {
+      res.writeHead(404);
+      res.end("Not Found");
+      return;
+    }
+    res.writeHead(200, { "Content-Type": contentType });
+    res.end(data);
+  });
 });
 
-server.listen(port, () => {
-  console.log(`Server listening on port ${port}`);
+server.listen(port, "0.0.0.0", () => {
+  console.log(`Server listening on http://0.0.0.0:${port}`);
 });

tasks.json

@@ -0,0 +1,6 @@
+{
+  "mode": "single",
+  "claudeMd": "# Project Context\n\nYou are fixing `server.js` in a Node.js terminal emulator project (mogterm2). The project uses `\"type\": \"module\"` in package.json, so all imports must use ESM syntax (`import ... from ...`).\n\n## Bug\n\nThe demo server has two problems:\n1. `server.listen(port)` binds to `::` (IPv6 only) — must bind to `0.0.0.0` for IPv4 access\n2. The request handler only returns plain text — must serve static files from the project root\n\n## What to Change\n\nOnly modify `server.js`. The current file is:\n```js\nimport { createServer } from \"node:http\";\n\nconst port = process.env.PORT || 8080;\n\nconst server = createServer((req, res) => {\n  res.writeHead(200, { \"Content-Type\": \"text/plain\" });\n  res.end(\"Hello from mogterm2!\\n\");\n});\n\nserver.listen(port, () => {\n  console.log(`Server listening on port ${port}`);\n});\n```\n\n## Requirements\n\n1. Add ESM imports for `node:fs`, `node:path`, and `node:url` (for `fileURLToPath` to get `__dirname` equivalent)\n2. Compute the project root using `path.dirname(fileURLToPath(import.meta.url))`\n3. Define a MIME type map: `.html` → `text/html`, `.css` → `text/css`, `.js` → `application/javascript`, `.json` → `application/json`, `.ts` → `text/plain`, default → `application/octet-stream`\n4. Replace the request handler to serve static files:\n   - Parse `req.url` to get the pathname\n   - Map `/` to `/index.html`\n   - Reject paths containing `..` with a 403\n   - Resolve the path relative to project root\n   - Read the file with `fs.readFile`\n   - Serve with correct Content-Type; 404 if file not found\n5. Change `server.listen(port, ...)` to `server.listen(port, '0.0.0.0', ...)`\n6. Update the console.log to show `http://0.0.0.0:${port}`\n\n## Conventions\n- ESM imports only (the project has `\"type\": \"module\"`)\n- Use `node:` protocol prefix for built-in modules (matches existing code)\n- Keep it minimal — no dependencies, no over-engineering\n- Conventional Commits for the commit message: `fix(server): bind to 0.0.0.0 and serve static files`\n\n## Validation\n- Start server: `node server.js &`\n- Test: `curl -s http://127.0.0.1:8080/ | head -5` should return HTML\n- Test: `curl -s http://127.0.0.1:8080/demo/index.html | head -5` should return HTML\n- Test: `curl -s -o /dev/null -w '%{http_code}' http://127.0.0.1:8080/nonexistent` should return 404\n- Kill the server after testing\n- Run existing tests: `npx tsx --test test/**/*.test.ts`\n\n## Gotchas\n- Must use `fileURLToPath(import.meta.url)` instead of `__dirname` (ESM has no `__dirname`)\n- `fs.readFile` callback-style is fine; no need for promises\n- URL pathname may include query strings — use `new URL(req.url, 'http://localhost').pathname` to extract just the path",
+  "subtasks": [],
+  "integration": null
+}