feature: support range requests

src/parts/CreateWebViewServerHandler/CreateWebViewServerHandler.ts

@@ -1,8 +1,8 @@
 import type { IncomingMessage, ServerResponse } from 'node:http'
+import { emptyResponse } from '../EmptyResponse/EmptyResponse.ts'
 import * as GetPathName from '../GetPathName/GetPathName.ts'
 import * as GetResponse from '../GetResponse/GetResponse.ts'
 import * as SendResponse from '../SendResponse/SendResponse.ts'
-import * as GetResponseInfo from '../GetResponseInfo/GetResponseInfo.ts'
 
 // TODO deprecated frame ancestors
 export const createHandler = (
@@ -16,7 +16,19 @@ export const createHandler = (
     if (pathName === '/') {
       pathName += 'index.html'
     }
-    const result = await GetResponse.getResponse(pathName, frameAncestors, webViewRoot, contentSecurityPolicy, iframeContent)
+    const range = request.headers.range
+    const result = await GetResponse.getResponse(
+      pathName,
+      frameAncestors,
+      webViewRoot,
+      contentSecurityPolicy,
+      iframeContent,
+      range,
+      response,
+    )
+    if (result === emptyResponse) {
+      return
+    }
     await SendResponse.sendResponse(response, result)
   }
 

src/parts/EmptyResponse/EmptyResponse.ts

@@ -0,0 +1 @@
+export const emptyResponse = new Response()

src/parts/GetResponse/GetResponse.ts

@@ -1,3 +1,4 @@
+import { ServerResponse } from 'node:http'
 import * as HandleIndexHtml from '../HandleIndexHtml/HandleIndexHtml.ts'
 import * as HandleOther from '../HandleOther/HandleOther.ts'
 import * as HandlePreviewInjected from '../HandlePreviewInjected/HandlePreviewInjected.ts'
@@ -9,6 +10,8 @@ export const getResponse = async (
   webViewRoot: string,
   contentSecurityPolicy: string,
   iframeContent: string,
+  range: any,
+  response: ServerResponse,
 ): Promise<Response> => {
   const filePath = ResolveFilePath.resolveFilePath(pathName, webViewRoot)
   const isHtml = filePath.endsWith('index.html')
@@ -18,5 +21,5 @@ export const getResponse = async (
   if (filePath.endsWith('preview-injected.js')) {
     return HandlePreviewInjected.handlePreviewInjected()
   }
-  return HandleOther.handleOther(filePath)
+  return HandleOther.handleOther(filePath, range, response)
 }

src/parts/HandleOther/HandleOther.ts

@@ -1,11 +1,18 @@
+import { ServerResponse } from 'node:http'
+import { emptyResponse } from '../EmptyResponse/EmptyResponse.ts'
 import * as FileSystem from '../FileSystem/FileSystem.ts'
 import * as GetContentType from '../GetContentType/GetContentType.ts'
+import * as HandleRangeRequest from '../HandleRangeRequest/HandleRangeRequest.ts'
 import * as HttpHeader from '../HttpHeader/HttpHeader.ts'
 import * as HttpStatusCode from '../HttpStatusCode/HttpStatusCode.ts'
 import * as IsEnoentError from '../IsEnoentError/IsEnoentError.ts'
 
-export const handleOther = async (filePath: string) => {
+export const handleOther = async (filePath: string, range: any, res: ServerResponse) => {
   try {
+    if (range) {
+      await HandleRangeRequest.handleRangeRequest(filePath, range, res)
+      return emptyResponse
+    }
     const contentType = GetContentType.getContentType(filePath)
     // TODO figure out which of these headers are actually needed
     const content = await FileSystem.readFile(filePath)

src/parts/HandleRangeRequest/HandleRangeRequest.ts

@@ -0,0 +1,47 @@
+import { createReadStream } from 'node:fs'
+import { stat } from 'node:fs/promises'
+import { ServerResponse } from 'node:http'
+import { pipeline } from 'node:stream/promises'
+import * as HttpHeader from '../HttpHeader/HttpHeader.ts'
+import * as HttpStatusCode from '../HttpStatusCode/HttpStatusCode.ts'
+import * as IsStreamPrematureCloseError from '../IsStreamPrematureCloseError/IsStreamPrematureCloseError.ts'
+
+// TODO add lots of tests for this
+export const handleRangeRequest = async (filePath: string, range: string, res: ServerResponse) => {
+  const stats = await stat(filePath)
+  let code = 206
+  let [x, y] = range.replace('bytes=', '').split('-')
+  let end = parseInt(y, 10) || stats.size - 1
+  let start = parseInt(x, 10) || 0
+
+  const options = {
+    start,
+    end,
+  }
+
+  if (end >= stats.size) {
+    end = stats.size - 1
+  }
+
+  if (start >= stats.size) {
+    res.setHeader(HttpHeader.ContentRange, `bytes */${stats.size}`)
+    res.statusCode = HttpStatusCode.OtherError
+    return res.end()
+  }
+  const headers: any = {}
+
+  headers[HttpHeader.ContentRange] = `bytes ${start}-${end}/${stats.size}`
+  headers[HttpHeader.ContentLength] = end - start + 1
+  headers[HttpHeader.AcceptRanges] = 'bytes'
+
+  res.writeHead(code, headers)
+  const readStream = createReadStream(filePath, options)
+  try {
+    await pipeline(readStream, res)
+  } catch (error) {
+    if (IsStreamPrematureCloseError.isStreamPrematureCloseError(error)) {
+      return
+    }
+    console.error(`[preview-process] ${error}`)
+  }
+}

src/parts/HttpHeader/HttpHeader.ts

@@ -1,9 +1,12 @@
+export const AcceptRanges = 'Accept-Ranges'
+export const AccessControlAllowOrigin = 'Access-Control-Allow-Origin'
 export const CacheControl = 'Cache-Control'
-export const ContentType = 'Content-Type'
+export const ContentLength = 'Content-Length'
+export const ContentRange = 'Content-Range'
 export const ContentSecurityPolicy = 'Content-Security-Policy'
+export const ContentType = 'Content-Type'
 export const CrossOriginEmbedderPolicy = 'Cross-Origin-Embedder-Policy'
 export const CrossOriginOpenerPolicy = 'Cross-Origin-Opener-Policy'
 export const CrossOriginResourcePolicy = 'Cross-Origin-Resource-Policy'
-export const AccessControlAllowOrigin = 'Access-Control-Allow-Origin'
 export const Etag = 'Etag'
 export const IfNotMatch = 'if-none-match'

src/parts/HttpStatusCode/HttpStatusCode.ts

@@ -4,3 +4,4 @@ export const NotFound = 404
 export const NotModifed = 304
 export const Ok = 200
 export const ServerError = 500
+export const OtherError = 416

test/HandleOther.test.ts

@@ -1,4 +1,5 @@
 import { beforeEach, expect, jest, test } from '@jest/globals'
+import { ServerResponse } from 'http'
 
 beforeEach(() => {
   jest.resetAllMocks()
@@ -23,14 +24,18 @@ class FileNotFoundError extends Error {
 
 test('not found', async () => {
   jest.spyOn(FileSystem, 'readFile').mockRejectedValue(new FileNotFoundError())
-  const response = await HandleOther.handleOther('/test/not-found.txt')
+  const range = ''
+  const res = new ServerResponse({} as any)
+  const response = await HandleOther.handleOther('/test/not-found.txt', range, res)
   expect(response.status).toBe(404)
   expect(await response.text()).toBe('not found')
 })
 
 test('normal file', async () => {
   jest.spyOn(FileSystem, 'readFile').mockResolvedValue(Buffer.from('ok'))
-  const response = await HandleOther.handleOther('/test/not-found.txt')
+  const range = ''
+  const res = new ServerResponse({} as any)
+  const response = await HandleOther.handleOther('/test/not-found.txt', range, res)
   expect(response.status).toBe(200)
   expect(await response.text()).toBe('ok')
 })