Revert "Respond with 400 on request parse failure" (denoland#4593)

readRequest should not write a response.

This reverts commit 017a611.

std/http/io.ts

@@ -342,38 +342,17 @@ export function parseHTTPVersion(vers: string): [number, number] {
 
 export async function readRequest(
  conn: Deno.Conn,
- // The reader and writer buffers may be constructed externally so they can be
- // shared by requests on the same connection -- see `Server`.
- reader?: BufReader,
- writer?: BufWriter
+ bufr: BufReader
 ): Promise<ServerRequest | Deno.EOF> {
- reader = reader ?? new BufReader(conn);
- writer = writer ?? new BufWriter(conn);
- const tp = new TextProtoReader(reader);
- let firstLine: string | Deno.EOF;
- let headers: Headers | Deno.EOF;
- try {
- firstLine = await tp.readLine(); // e.g. GET /index.html HTTP/1.0
- if (firstLine == Deno.EOF) {
- return Deno.EOF;
- }
- headers = await tp.readMIMEHeader();
- if (headers == Deno.EOF) {
- throw new Deno.errors.UnexpectedEof();
- }
- } catch (error) {
- // An error was thrown while parsing request headers.
- await writeResponse(writer, {
- status: 400,
- body: encoder.encode(`${error.message}\r\n\r\n`),
- });
- throw error;
- }
+ const tp = new TextProtoReader(bufr);
+ const firstLine = await tp.readLine(); // e.g. GET /index.html HTTP/1.0
+ if (firstLine === Deno.EOF) return Deno.EOF;
+ const headers = await tp.readMIMEHeader();
+ if (headers === Deno.EOF) throw new Deno.errors.UnexpectedEof();
 
  const req = new ServerRequest();
  req.conn = conn;
- req.r = reader;
- req.w = writer;
+ req.r = bufr;
  [req.method, req.url, req.proto] = firstLine.split(" ", 3);
  [req.protoMinor, req.protoMajor] = parseHTTPVersion(req.proto);
  req.headers = headers;

std/http/io_test.ts

@@ -5,7 +5,6 @@ import {
  assert,
  assertNotEOF,
  assertNotEquals,
- assertMatch,
 } from "../testing/asserts.ts";
 import {
  bodyReader,
@@ -350,28 +349,13 @@ malformedHeader
 `;
  const reader = new BufReader(new StringReader(input));
  let err;
- let responseString: string;
  try {
- // Capture whatever `readRequest()` attempts to write to the connection on
- // error. We expect it to be a 400 response.
- await readRequest(
- mockConn({
- write(p: Uint8Array): Promise<number> {
- responseString = decode(p);
- return Promise.resolve(p.length);
- },
- }),
- reader
- );
+ await readRequest(mockConn(), reader);
  } catch (e) {
  err = e;
  }
  assert(err instanceof Error);
  assertEquals(err.message, "malformed MIME header line: malformedHeader");
- assertMatch(
- responseString!,
- /^HTTP\/1\.1 400 Bad Request\r\ncontent-length: \d+\r\n\r\n.*\r\n\r\n$/ms
- );
 });
 
 // Ported from Go

std/http/mock.ts

@@ -17,8 +17,8 @@ export function mockConn(base: Partial<Deno.Conn> = {}): Deno.Conn {
  read: (): Promise<number | Deno.EOF> => {
  return Promise.resolve(0);
  },
- write: (p: Uint8Array): Promise<number> => {
- return Promise.resolve(p.length);
+ write: (): Promise<number> => {
+ return Promise.resolve(-1);
  },
  close: (): void => {},
  ...base,

std/http/server.ts

@@ -146,21 +146,22 @@ export class Server implements AsyncIterable<ServerRequest> {
  private async *iterateHttpRequests(
  conn: Conn
  ): AsyncIterableIterator<ServerRequest> {
- const reader = new BufReader(conn);
- const writer = new BufWriter(conn);
+ const bufr = new BufReader(conn);
+ const w = new BufWriter(conn);
  let req: ServerRequest | Deno.EOF = Deno.EOF;
  let err: Error | undefined;
 
  while (!this.closing) {
  try {
- req = await readRequest(conn, reader, writer);
+ req = await readRequest(conn, bufr);
  } catch (e) {
  err = e;
  }
  if (err != null || req === Deno.EOF) {
  break;
  }
 
+ req.w = w;
  yield req;
 
  // Wait for the request to be processed before we accept a new request on