Files
paperclip/server/src/routes/plugin-ui-static.ts
2026-03-13 16:22:34 -05:00

497 lines
17 KiB
TypeScript

/**
* @fileoverview Plugin UI static file serving route
*
* Serves plugin UI bundles from the plugin's dist/ui/ directory under the
* `/_plugins/:pluginId/ui/*` namespace. This is specified in PLUGIN_SPEC.md
* §19.0.3 (Bundle Serving).
*
* Plugin UI bundles are pre-built ESM that the host serves as static assets.
* The host dynamically imports the plugin's UI entry module from this path,
* resolves the named export declared in `ui.slots[].exportName`, and mounts
* it into the extension slot.
*
* Security:
* - Path traversal is prevented by resolving the requested path and verifying
* it stays within the plugin's UI directory.
* - Only plugins in 'ready' status have their UI served.
* - Only plugins that declare `entrypoints.ui` serve UI bundles.
*
* Cache Headers:
* - Files with content-hash patterns in their name (e.g., `index-a1b2c3d4.js`)
* receive `Cache-Control: public, max-age=31536000, immutable`.
* - Other files receive `Cache-Control: public, max-age=0, must-revalidate`
* with ETag-based conditional request support.
*
* @module server/routes/plugin-ui-static
* @see doc/plugins/PLUGIN_SPEC.md §19.0.3 — Bundle Serving
* @see doc/plugins/PLUGIN_SPEC.md §25.4.5 — Frontend Cache Invalidation
*/
import { Router } from "express";
import path from "node:path";
import fs from "node:fs";
import crypto from "node:crypto";
import type { Db } from "@paperclipai/db";
import { pluginRegistryService } from "../services/plugin-registry.js";
import { logger } from "../middleware/logger.js";
// ---------------------------------------------------------------------------
// Constants
// ---------------------------------------------------------------------------
/**
* Regex to detect content-hashed filenames.
*
* Matches patterns like:
* - `index-a1b2c3d4.js`
* - `styles.abc123def.css`
* - `chunk-ABCDEF01.mjs`
*
* The hash portion must be at least 8 hex characters to avoid false positives.
*/
const CONTENT_HASH_PATTERN = /[.-][a-fA-F0-9]{8,}\.\w+$/;
/**
* Cache-Control header for content-hashed files.
* These files are immutable by definition (the hash changes when content changes).
*/
/** 1 year in seconds — standard for content-hashed immutable resources. */
const ONE_YEAR_SECONDS = 365 * 24 * 60 * 60; // 31_536_000
const CACHE_CONTROL_IMMUTABLE = `public, max-age=${ONE_YEAR_SECONDS}, immutable`;
/**
* Cache-Control header for non-hashed files.
* These files must be revalidated on each request (ETag-based).
*/
const CACHE_CONTROL_REVALIDATE = "public, max-age=0, must-revalidate";
/**
* MIME types for common plugin UI bundle file extensions.
*/
const MIME_TYPES: Record<string, string> = {
".js": "application/javascript; charset=utf-8",
".mjs": "application/javascript; charset=utf-8",
".css": "text/css; charset=utf-8",
".json": "application/json; charset=utf-8",
".map": "application/json; charset=utf-8",
".html": "text/html; charset=utf-8",
".svg": "image/svg+xml",
".png": "image/png",
".jpg": "image/jpeg",
".jpeg": "image/jpeg",
".gif": "image/gif",
".webp": "image/webp",
".woff": "font/woff",
".woff2": "font/woff2",
".ttf": "font/ttf",
".eot": "application/vnd.ms-fontobject",
".ico": "image/x-icon",
".txt": "text/plain; charset=utf-8",
};
// ---------------------------------------------------------------------------
// Helper
// ---------------------------------------------------------------------------
/**
* Resolve a plugin's UI directory from its package location.
*
* The plugin's `packageName` is stored in the DB. We resolve the package path
* from the local plugin directory (DEFAULT_LOCAL_PLUGIN_DIR) by looking in
* `node_modules`. If the plugin was installed from a local path, the manifest
* `entrypoints.ui` path is resolved relative to the package directory.
*
* @param localPluginDir - The plugin installation directory
* @param packageName - The npm package name
* @param entrypointsUi - The UI entrypoint path from the manifest (e.g., "./dist/ui/")
* @returns Absolute path to the UI directory, or null if not found
*/
export function resolvePluginUiDir(
localPluginDir: string,
packageName: string,
entrypointsUi: string,
packagePath?: string | null,
): string | null {
// For local-path installs, prefer the persisted package path.
if (packagePath) {
const resolvedPackagePath = path.resolve(packagePath);
if (fs.existsSync(resolvedPackagePath)) {
const uiDirFromPackagePath = path.resolve(resolvedPackagePath, entrypointsUi);
if (
uiDirFromPackagePath.startsWith(resolvedPackagePath)
&& fs.existsSync(uiDirFromPackagePath)
) {
return uiDirFromPackagePath;
}
}
}
// Resolve the package root within the local plugin directory's node_modules.
// npm installs go to <localPluginDir>/node_modules/<packageName>/
let packageRoot: string;
if (packageName.startsWith("@")) {
// Scoped package: @scope/name -> node_modules/@scope/name
packageRoot = path.join(localPluginDir, "node_modules", ...packageName.split("/"));
} else {
packageRoot = path.join(localPluginDir, "node_modules", packageName);
}
// If the standard location doesn't exist, the plugin may have been installed
// from a local path. Try to check if the package.json is accessible at the
// computed path or if the package is found elsewhere.
if (!fs.existsSync(packageRoot)) {
// For local-path installs, the packageName may be a directory that doesn't
// live inside node_modules. Check if the package exists directly at the
// localPluginDir level.
const directPath = path.join(localPluginDir, packageName);
if (fs.existsSync(directPath)) {
packageRoot = directPath;
} else {
return null;
}
}
// Resolve the UI directory relative to the package root
const uiDir = path.resolve(packageRoot, entrypointsUi);
// Verify the resolved UI directory exists and is actually inside the package
if (!fs.existsSync(uiDir)) {
return null;
}
return uiDir;
}
/**
* Compute an ETag from file stat (size + mtime).
* This is a lightweight approach that avoids reading the file content.
*/
function computeETag(size: number, mtimeMs: number): string {
const ETAG_VERSION = "v2";
const hash = crypto
.createHash("md5")
.update(`${ETAG_VERSION}:${size}-${mtimeMs}`)
.digest("hex")
.slice(0, 16);
return `"${hash}"`;
}
// ---------------------------------------------------------------------------
// Route factory
// ---------------------------------------------------------------------------
/**
* Options for the plugin UI static route.
*/
export interface PluginUiStaticRouteOptions {
/**
* The local plugin installation directory.
* This is where plugins are installed via `npm install --prefix`.
* Defaults to the standard `~/.paperclip/plugins/` location.
*/
localPluginDir: string;
}
/**
* Create an Express router that serves plugin UI static files.
*
* This route handles `GET /_plugins/:pluginId/ui/*` requests by:
* 1. Looking up the plugin in the registry by ID or key
* 2. Verifying the plugin is in 'ready' status with UI declared
* 3. Resolving the file path within the plugin's dist/ui/ directory
* 4. Serving the file with appropriate cache headers
*
* @param db - Database connection for plugin registry lookups
* @param options - Configuration options
* @returns Express router
*/
export function pluginUiStaticRoutes(db: Db, options: PluginUiStaticRouteOptions) {
const router = Router();
const registry = pluginRegistryService(db);
const log = logger.child({ service: "plugin-ui-static" });
/**
* GET /_plugins/:pluginId/ui/*
*
* Serve a static file from a plugin's UI bundle directory.
*
* The :pluginId parameter accepts either:
* - Database UUID
* - Plugin key (e.g., "acme.linear")
*
* The wildcard captures the relative file path within the UI directory.
*
* Cache strategy:
* - Content-hashed filenames → immutable, 1-year max-age
* - Other files → must-revalidate with ETag
*/
router.get("/_plugins/:pluginId/ui/*filePath", async (req, res) => {
const { pluginId } = req.params;
// Extract the relative file path from the named wildcard.
// In Express 5 with path-to-regexp v8, named wildcards may return
// an array of path segments or a single string.
const rawParam = req.params.filePath;
const rawFilePath = Array.isArray(rawParam)
? rawParam.join("/")
: rawParam as string | undefined;
if (!rawFilePath || rawFilePath.length === 0) {
res.status(400).json({ error: "File path is required" });
return;
}
// Step 1: Look up the plugin
let plugin = null;
try {
plugin = await registry.getById(pluginId);
} catch (error) {
const maybeCode =
typeof error === "object" && error !== null && "code" in error
? (error as { code?: unknown }).code
: undefined;
if (maybeCode !== "22P02") {
throw error;
}
}
if (!plugin) {
plugin = await registry.getByKey(pluginId);
}
if (!plugin) {
res.status(404).json({ error: "Plugin not found" });
return;
}
// Step 2: Verify the plugin is ready and has UI declared
if (plugin.status !== "ready") {
res.status(403).json({
error: `Plugin UI is not available (status: ${plugin.status})`,
});
return;
}
const manifest = plugin.manifestJson;
if (!manifest?.entrypoints?.ui) {
res.status(404).json({ error: "Plugin does not declare a UI bundle" });
return;
}
// Step 2b: Check for devUiUrl in plugin config — proxy to local dev server
// when a plugin author has configured a dev server URL for hot-reload.
// See PLUGIN_SPEC.md §27.2 — Local Development Workflow
try {
const configRow = await registry.getConfig(plugin.id);
const devUiUrl =
configRow &&
typeof configRow === "object" &&
"configJson" in configRow &&
(configRow as { configJson: Record<string, unknown> }).configJson?.devUiUrl;
if (typeof devUiUrl === "string" && devUiUrl.length > 0) {
// Dev proxy is only available in development mode
if (process.env.NODE_ENV === "production") {
log.warn(
{ pluginId: plugin.id },
"plugin-ui-static: devUiUrl ignored in production",
);
// Fall through to static file serving below
} else {
// Guard against rawFilePath overriding the base URL via protocol
// scheme (e.g. "https://evil.com/x") or protocol-relative paths
// (e.g. "//evil.com/x") which cause `new URL(path, base)` to
// ignore the base entirely.
// Normalize percent-encoding so encoded slashes (%2F) can't bypass
// the protocol/path checks below.
let decodedPath: string;
try {
decodedPath = decodeURIComponent(rawFilePath);
} catch {
res.status(400).json({ error: "Invalid file path" });
return;
}
if (
decodedPath.includes("://") ||
decodedPath.startsWith("//") ||
decodedPath.startsWith("\\\\")
) {
res.status(400).json({ error: "Invalid file path" });
return;
}
// Proxy the request to the dev server
const targetUrl = new URL(rawFilePath, devUiUrl.endsWith("/") ? devUiUrl : devUiUrl + "/");
// SSRF protection: only allow http/https and localhost targets for dev proxy
if (targetUrl.protocol !== "http:" && targetUrl.protocol !== "https:") {
res.status(400).json({ error: "devUiUrl must use http or https protocol" });
return;
}
// Dev proxy is restricted to loopback addresses only.
// Validate the *constructed* targetUrl hostname (not the base) to
// catch any path-based override that slipped past the checks above.
const devHost = targetUrl.hostname;
const isLoopback =
devHost === "localhost" ||
devHost === "127.0.0.1" ||
devHost === "::1" ||
devHost === "[::1]";
if (!isLoopback) {
log.warn(
{ pluginId: plugin.id, devUiUrl, host: devHost },
"plugin-ui-static: devUiUrl must target localhost, rejecting proxy",
);
res.status(400).json({ error: "devUiUrl must target localhost" });
return;
}
log.debug(
{ pluginId: plugin.id, devUiUrl, targetUrl: targetUrl.href },
"plugin-ui-static: proxying to devUiUrl",
);
try {
const controller = new AbortController();
const timeout = setTimeout(() => controller.abort(), 10_000);
try {
const upstream = await fetch(targetUrl.href, { signal: controller.signal });
if (!upstream.ok) {
res.status(upstream.status).json({
error: `Dev server returned ${upstream.status}`,
});
return;
}
const contentType = upstream.headers.get("content-type");
if (contentType) res.set("Content-Type", contentType);
res.set("Cache-Control", "no-cache, no-store, must-revalidate");
const body = await upstream.arrayBuffer();
res.send(Buffer.from(body));
return;
} finally {
clearTimeout(timeout);
}
} catch (proxyErr) {
log.warn(
{
pluginId: plugin.id,
devUiUrl,
err: proxyErr instanceof Error ? proxyErr.message : String(proxyErr),
},
"plugin-ui-static: failed to proxy to devUiUrl, falling back to static",
);
// Fall through to static serving below
}
}
}
} catch {
// Config lookup failure is non-fatal — fall through to static serving
}
// Step 3: Resolve the plugin's UI directory
const uiDir = resolvePluginUiDir(
options.localPluginDir,
plugin.packageName,
manifest.entrypoints.ui,
plugin.packagePath,
);
if (!uiDir) {
log.warn(
{ pluginId: plugin.id, pluginKey: plugin.pluginKey, packageName: plugin.packageName },
"plugin-ui-static: UI directory not found on disk",
);
res.status(404).json({ error: "Plugin UI directory not found" });
return;
}
// Step 4: Resolve the requested file path and prevent traversal (including symlinks)
const resolvedFilePath = path.resolve(uiDir, rawFilePath);
// Step 5: Check that the file exists and is a regular file
let fileStat: fs.Stats;
try {
fileStat = fs.statSync(resolvedFilePath);
} catch {
res.status(404).json({ error: "File not found" });
return;
}
// Security: resolve symlinks via realpathSync and verify containment.
// This prevents symlink-based traversal that string-based startsWith misses.
let realFilePath: string;
let realUiDir: string;
try {
realFilePath = fs.realpathSync(resolvedFilePath);
realUiDir = fs.realpathSync(uiDir);
} catch {
res.status(404).json({ error: "File not found" });
return;
}
const relative = path.relative(realUiDir, realFilePath);
if (relative.startsWith("..") || path.isAbsolute(relative)) {
res.status(403).json({ error: "Access denied" });
return;
}
if (!fileStat.isFile()) {
res.status(404).json({ error: "File not found" });
return;
}
// Step 6: Determine cache strategy based on filename
const basename = path.basename(resolvedFilePath);
const isContentHashed = CONTENT_HASH_PATTERN.test(basename);
// Step 7: Set cache headers
if (isContentHashed) {
res.set("Cache-Control", CACHE_CONTROL_IMMUTABLE);
} else {
res.set("Cache-Control", CACHE_CONTROL_REVALIDATE);
// Compute and set ETag for conditional request support
const etag = computeETag(fileStat.size, fileStat.mtimeMs);
res.set("ETag", etag);
// Check If-None-Match for 304 Not Modified
const ifNoneMatch = req.headers["if-none-match"];
if (ifNoneMatch === etag) {
res.status(304).end();
return;
}
}
// Step 8: Set Content-Type
const ext = path.extname(resolvedFilePath).toLowerCase();
const contentType = MIME_TYPES[ext];
if (contentType) {
res.set("Content-Type", contentType);
}
// Step 9: Set CORS headers (plugin UI may be loaded from different origin in dev)
res.set("Access-Control-Allow-Origin", "*");
// Step 10: Send the file
// The plugin source can live in Git worktrees (e.g. ".worktrees/...").
// `send` defaults to dotfiles:"ignore", which treats dot-directories as
// not found. We already enforce traversal safety above, so allow dot paths.
res.sendFile(resolvedFilePath, { dotfiles: "allow" }, (err) => {
if (err) {
log.error(
{ err, pluginId: plugin.id, filePath: resolvedFilePath },
"plugin-ui-static: error sending file",
);
// Only send error if headers haven't been sent yet
if (!res.headersSent) {
res.status(500).json({ error: "Failed to serve file" });
}
}
});
});
return router;
}