feat: add desktop repo (#1071)

packages/desktop/app/javascripts/Main/ExtensionsServer.ts

@@ -0,0 +1,115 @@
+import fs from 'fs'
+import http, { IncomingMessage, ServerResponse } from 'http'
+import mime from 'mime-types'
+import path from 'path'
+import { URL } from 'url'
+import { FileDoesNotExist } from './Utils/FileUtils'
+import { Paths } from './Types/Paths'
+import { extensions as str } from './Strings'
+
+const Protocol = 'http'
+
+function logError(...message: any) {
+  console.error('extServer:', ...message)
+}
+
+function log(...message: any) {
+  console.log('extServer:', ...message)
+}
+
+export function normalizeFilePath(requestUrl: string, host: string): string {
+  const isThirdPartyComponent = requestUrl.startsWith('/Extensions')
+  const isNativeComponent = requestUrl.startsWith('/components')
+  if (!isThirdPartyComponent && !isNativeComponent) {
+    throw new Error(`URL '${requestUrl}' falls outside of the extensions/features domain.`)
+  }
+
+  const removedPrefix = requestUrl.replace('/components', '').replace('/Extensions', '')
+
+  const base = `${Protocol}://${host}`
+  const url = new URL(removedPrefix, base)
+
+  /**
+   * Normalize path (parse '..' and '.') so that we prevent path traversal by
+   * joining a fully resolved path to the Extensions dir.
+   */
+  const modifiedReqUrl = path.normalize(url.pathname)
+  if (isThirdPartyComponent) {
+    return path.join(Paths.extensionsDir, modifiedReqUrl)
+  } else {
+    return path.join(Paths.components, modifiedReqUrl)
+  }
+}
+
+async function handleRequest(request: IncomingMessage, response: ServerResponse) {
+  try {
+    if (!request.url) {
+      throw new Error('No url.')
+    }
+    if (!request.headers.host) {
+      throw new Error('No `host` header.')
+    }
+
+    const filePath = normalizeFilePath(request.url, request.headers.host)
+
+    const stat = await fs.promises.lstat(filePath)
+
+    if (!stat.isFile()) {
+      throw new Error('Client requested something that is not a file.')
+    }
+
+    const mimeType = mime.lookup(path.parse(filePath).ext)
+
+    response.setHeader('Access-Control-Allow-Origin', '*')
+    response.setHeader('Cache-Control', 'max-age=604800')
+    response.setHeader('Content-Type', `${mimeType}; charset=utf-8`)
+
+    const data = fs.readFileSync(filePath)
+
+    response.writeHead(200)
+
+    response.end(data)
+  } catch (error: any) {
+    onRequestError(error, response)
+  }
+}
+
+function onRequestError(error: Error | { code: string }, response: ServerResponse) {
+  let responseCode: number
+  let message: string
+
+  if ('code' in error && error.code === FileDoesNotExist) {
+    responseCode = 404
+    message = str().missingExtension
+  } else {
+    logError(error)
+    responseCode = 500
+    message = str().unableToLoadExtension
+  }
+
+  response.writeHead(responseCode)
+  response.end(message)
+}
+
+export function createExtensionsServer(): string {
+  const port = 45653
+  const ip = '127.0.0.1'
+  const host = `${Protocol}://${ip}:${port}`
+
+  const initCallback = () => {
+    log(`Server started at ${host}`)
+  }
+
+  try {
+    http
+      .createServer(handleRequest)
+      .listen(port, ip, initCallback)
+      .on('error', (err) => {
+        console.error('Error listening on extServer', err)
+      })
+  } catch (error) {
+    console.error('Error creating ext server', error)
+  }
+
+  return host
+}