@typespec/http-server-js

// Copyright (c) Microsoft Corporation // Licensed under the MIT license. import { Module } from "../../src/ctx.js"; export let module: Module = undefined as any; // prettier-ignore const lines = [ "// Copyright (c) Microsoft Corporation", "// Licensed under the MIT license.", "", "import type * as http from \"node:http\";", "", "export interface HttpPart {", " headers: { [k: string]: string | undefined };", " body: ReadableStream<Buffer>;", "}", "", "/**", " * Consumes a stream of incoming data and splits it into individual streams for each part of a multipart request, using", " * the provided `boundary` value.", " */", "function MultipartBoundaryTransformStream(", " boundary: string,", "): ReadableWritablePair<ReadableStream<Buffer>, Buffer> {", " let buffer: Buffer = Buffer.alloc(0);", " // Initialize subcontroller to an object that does nothing. Multipart bodies may contain a preamble before the first", " // boundary, so this dummy controller will discard it.", " let subController: { enqueue(chunk: Buffer): void; close(): void } | null = {", " enqueue() {},", " close() {},", " };", "", " let boundarySplit = Buffer.from(`--${boundary}`);", " let initialized = false;", "", " // We need to keep at least the length of the boundary split plus room for CRLFCRLF in the buffer to detect the boundaries.", " // We subtract one from this length because if the whole thing were in the buffer, we would detect it and move past it.", " const bufferKeepLength = boundarySplit.length + BUF_CRLFCRLF.length - 1;", " let _readableController: ReadableStreamDefaultController<ReadableStream<Buffer>> = null as any;", "", " const readable = new ReadableStream<ReadableStream<Buffer>>({", " start(controller) {", " _readableController = controller;", " },", " });", "", " const readableController = _readableController;", "", " const writable = new WritableStream<Buffer>({", " write: async (chunk) => {", " buffer = Buffer.concat([buffer, chunk]);", "", " let index: number;", "", " while ((index = buffer.indexOf(boundarySplit)) !== -1) {", " // We found a boundary, emit everything before it and initialize a new stream for the next part.", "", " // We are initialized if we have found the boundary at least once.", " //", " // Cases", " // 1. If the index is zero and we aren't initialized, there was no preamble.", " // 2. If the index is zero and we are initialized, then we had to have found \\r\\n--boundary, nothing special to do.", " // 3. If the index is not zero, and we are initialized, then we found \\r\\n--boundary somewhere in the middle,", " // nothing special to do.", " // 4. If the index is not zero and we aren't initialized, then we need to check that boundarySplit was preceded", " // by \\r\\n for validity, because the preamble must end with \\r\\n.", "", " if (index > 0) {", " if (!initialized) {", " if (!buffer.subarray(index - 2, index).equals(Buffer.from(\"\\r\\n\"))) {", " readableController.error(new Error(\"Invalid preamble in multipart body.\"));", " } else {", " await enqueueSub(buffer.subarray(0, index - 2));", " }", " } else {", " await enqueueSub(buffer.subarray(0, index));", " }", " }", "", " // We enqueued everything before the boundary, so we clear the buffer past the boundary", " buffer = buffer.subarray(index + boundarySplit.length);", "", " // We're done with the current part, so close the stream. If this is the opening boundary, there won't be a", " // subcontroller yet.", " subController?.close();", " subController = null;", "", " if (!initialized) {", " initialized = true;", " boundarySplit = Buffer.from(`\\r\\n${boundarySplit}`);", " }", " }", "", " if (buffer.length > bufferKeepLength) {", " await enqueueSub(buffer.subarray(0, -bufferKeepLength));", " buffer = buffer.subarray(-bufferKeepLength);", " }", " },", " close() {", " if (!/--(\\r\\n)?/.test(buffer.toString(\"utf-8\"))) {", " readableController.error(new Error(\"Unexpected characters after final boundary.\"));", " }", "", " subController?.close();", "", " readableController.close();", " },", " });", "", " async function enqueueSub(s: Buffer) {", " subController ??= await new Promise<ReadableStreamDefaultController>((resolve) => {", " readableController.enqueue(", " new ReadableStream<Buffer>({", " start: (controller) => resolve(controller),", " }),", " );", " });", "", " subController.enqueue(s);", " }", "", " return { readable, writable };", "}", "", "const BUF_CRLFCRLF = Buffer.from(\"\\r\\n\\r\\n\");", "", "/**", " * Consumes a stream of the contents of a single part of a multipart request and emits an `HttpPart` object for each part.", " * This consumes just enough of the stream to read the headers, and then forwards the rest of the stream as the body.", " */", "class HttpPartTransform extends TransformStream<ReadableStream<Buffer>, HttpPart> {", " constructor() {", " super({", " transform: async (partRaw, controller) => {", " const reader = partRaw.getReader();", "", " let buf = Buffer.alloc(0);", " let idx;", "", " while ((idx = buf.indexOf(BUF_CRLFCRLF)) === -1) {", " const { done, value } = await reader.read();", " if (done) {", " throw new Error(\"Unexpected end of part.\");", " }", " buf = Buffer.concat([buf, value]);", " }", "", " const headerText = buf.subarray(0, idx).toString(\"utf-8\").trim();", "", " const headers = Object.fromEntries(", " headerText.split(\"\\r\\n\").map((line) => {", " const [name, value] = line.split(\": \", 2);", "", " return [name.toLowerCase(), value];", " }),", " ) as { [k: string]: string };", "", " const body = new ReadableStream<Buffer>({", " start(controller) {", " controller.enqueue(buf.subarray(idx + BUF_CRLFCRLF.length));", " },", " async pull(controller) {", " const { done, value } = await reader.read();", "", " if (done) {", " controller.close();", " } else {", " controller.enqueue(value);", " }", " },", " });", "", " controller.enqueue({ headers, body });", " },", " });", " }", "}", "", "/**", " * Processes a request as a multipart request, returning a stream of `HttpPart` objects, each representing an individual", " * part in the multipart request.", " *", " * Only call this function if you have already validated the content type of the request and confirmed that it is a", " * multipart request.", " *", " * @throws Error if the content-type header is missing or does not contain a boundary field.", " *", " * @param request - the incoming request to parse as multipart", " * @returns a stream of HttpPart objects, each representing an individual part in the multipart request", " */", "export function createMultipartReadable(request: http.IncomingMessage): ReadableStream<HttpPart> {", " const boundary = request.headers[\"content-type\"]", " ?.split(\";\")", " .find((s) => s.includes(\"boundary=\"))", " ?.split(\"=\", 2)[1];", " if (!boundary) {", " throw new Error(\"Invalid request: missing boundary in content-type.\");", " }", "", " const bodyStream = new ReadableStream<Uint8Array>({", " start(controller) {", " request.on(\"data\", (chunk: Buffer) => {", " controller.enqueue(chunk);", " });", " request.on(\"end\", () => controller.close());", " },", " });", "", " return bodyStream", " .pipeThrough(MultipartBoundaryTransformStream(boundary))", " .pipeThrough(new HttpPartTransform());", "}", "", "// Gross polyfill because Safari doesn't support this yet.", "//", "// https://bugs.webkit.org/show_bug.cgi?id=194379", "// https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream#browser_compatibility", "(ReadableStream.prototype as any)[Symbol.asyncIterator] ??= async function* () {", " const reader = this.getReader();", " try {", " while (true) {", " const { done, value } = await reader.read();", " if (done) return value;", " yield value;", " }", " } finally {", " reader.releaseLock();", " }", "};", "", "declare global {", " interface ReadableStream<R> {", " [Symbol.asyncIterator](): AsyncIterableIterator<R>;", " }", "}", "", ]; export async function createModule(parent: Module): Promise<Module> { if (module) return module; module = { name: "multipart", cursor: parent.cursor.enter("multipart"), imports: [], declarations: [], }; module.declarations.push(lines); parent.declarations.push(module); return module; }