7 files changed, 554 insertions, 246 deletions

diff --git a/cli/test_runner.rs b/cli/test_runner.rs
index 3d177f60e..b2eea3480 100644
--- a/cli/test_runner.rs
+++ b/cli/test_runner.rs
@@ -131,6 +131,7 @@ mod tests {
     let expected: Vec<Url> = vec![
       format!("{}/cookie_test.ts", root_url),
       format!("{}/file_server_test.ts", root_url),
+      format!("{}/io_test.ts", root_url),
       format!("{}/racing_server_test.ts", root_url),
       format!("{}/server_test.ts", root_url),
     ]
diff --git a/std/http/io.ts b/std/http/io.ts
new file mode 100644
index 000000000..a51fada54
--- /dev/null
+++ b/std/http/io.ts
@@ -0,0 +1,213 @@
+import { BufReader, UnexpectedEOFError, BufWriter } from "../io/bufio.ts";
+import { TextProtoReader } from "../textproto/mod.ts";
+import { assert } from "../testing/asserts.ts";
+import { encoder } from "../strings/mod.ts";
+
+export function emptyReader(): Deno.Reader {
+  return {
+    async read(_: Uint8Array): Promise<number | Deno.EOF> {
+      return Deno.EOF;
+    }
+  };
+}
+
+export function bodyReader(contentLength: number, r: BufReader): Deno.Reader {
+  let totalRead = 0;
+  let finished = false;
+  async function read(buf: Uint8Array): Promise<number | Deno.EOF> {
+    if (finished) return Deno.EOF;
+    let result: number | Deno.EOF;
+    const remaining = contentLength - totalRead;
+    if (remaining >= buf.byteLength) {
+      result = await r.read(buf);
+    } else {
+      const readBuf = buf.subarray(0, remaining);
+      result = await r.read(readBuf);
+    }
+    if (result !== Deno.EOF) {
+      totalRead += result;
+    }
+    finished = totalRead === contentLength;
+    return result;
+  }
+  return { read };
+}
+
+export function chunkedBodyReader(h: Headers, r: BufReader): Deno.Reader {
+  // Based on https://tools.ietf.org/html/rfc2616#section-19.4.6
+  const tp = new TextProtoReader(r);
+  let finished = false;
+  const chunks: Array<{
+    offset: number;
+    data: Uint8Array;
+  }> = [];
+  async function read(buf: Uint8Array): Promise<number | Deno.EOF> {
+    if (finished) return Deno.EOF;
+    const [chunk] = chunks;
+    if (chunk) {
+      const chunkRemaining = chunk.data.byteLength - chunk.offset;
+      const readLength = Math.min(chunkRemaining, buf.byteLength);
+      for (let i = 0; i < readLength; i++) {
+        buf[i] = chunk.data[chunk.offset + i];
+      }
+      chunk.offset += readLength;
+      if (chunk.offset === chunk.data.byteLength) {
+        chunks.shift();
+        // Consume \r\n;
+        if ((await tp.readLine()) === Deno.EOF) {
+          throw new UnexpectedEOFError();
+        }
+      }
+      return readLength;
+    }
+    const line = await tp.readLine();
+    if (line === Deno.EOF) throw new UnexpectedEOFError();
+    // TODO: handle chunk extension
+    const [chunkSizeString] = line.split(";");
+    const chunkSize = parseInt(chunkSizeString, 16);
+    if (Number.isNaN(chunkSize) || chunkSize < 0) {
+      throw new Error("Invalid chunk size");
+    }
+    if (chunkSize > 0) {
+      if (chunkSize > buf.byteLength) {
+        let eof = await r.readFull(buf);
+        if (eof === Deno.EOF) {
+          throw new UnexpectedEOFError();
+        }
+        const restChunk = new Uint8Array(chunkSize - buf.byteLength);
+        eof = await r.readFull(restChunk);
+        if (eof === Deno.EOF) {
+          throw new UnexpectedEOFError();
+        } else {
+          chunks.push({
+            offset: 0,
+            data: restChunk
+          });
+        }
+        return buf.byteLength;
+      } else {
+        const bufToFill = buf.subarray(0, chunkSize);
+        const eof = await r.readFull(bufToFill);
+        if (eof === Deno.EOF) {
+          throw new UnexpectedEOFError();
+        }
+        // Consume \r\n
+        if ((await tp.readLine()) === Deno.EOF) {
+          throw new UnexpectedEOFError();
+        }
+        return chunkSize;
+      }
+    } else {
+      assert(chunkSize === 0);
+      // Consume \r\n
+      if ((await r.readLine()) === Deno.EOF) {
+        throw new UnexpectedEOFError();
+      }
+      await readTrailers(h, r);
+      finished = true;
+      return Deno.EOF;
+    }
+  }
+  return { read };
+}
+
+const kProhibitedTrailerHeaders = [
+  "transfer-encoding",
+  "content-length",
+  "trailer"
+];
+
+/**
+ * Read trailer headers from reader and append values to headers.
+ * "trailer" field will be deleted.
+ * */
+export async function readTrailers(
+  headers: Headers,
+  r: BufReader
+): Promise<void> {
+  const keys = parseTrailer(headers.get("trailer"));
+  if (!keys) return;
+  const tp = new TextProtoReader(r);
+  const result = await tp.readMIMEHeader();
+  assert(result != Deno.EOF, "trailer must be set");
+  for (const [k, v] of result) {
+    if (!keys.has(k)) {
+      throw new Error("Undeclared trailer field");
+    }
+    keys.delete(k);
+    headers.append(k, v);
+  }
+  assert(keys.size === 0, "Missing trailers");
+  headers.delete("trailer");
+}
+
+function parseTrailer(field: string | null): Set<string> | undefined {
+  if (field == null) {
+    return undefined;
+  }
+  const keys = field.split(",").map(v => v.trim());
+  if (keys.length === 0) {
+    throw new Error("Empty trailer");
+  }
+  for (const invalid of kProhibitedTrailerHeaders) {
+    if (keys.includes(invalid)) {
+      throw new Error(`Prohibited field for trailer`);
+    }
+  }
+  return new Set(keys);
+}
+
+export async function writeChunkedBody(
+  w: Deno.Writer,
+  r: Deno.Reader
+): Promise<void> {
+  const writer = BufWriter.create(w);
+  for await (const chunk of Deno.toAsyncIterator(r)) {
+    if (chunk.byteLength <= 0) continue;
+    const start = encoder.encode(`${chunk.byteLength.toString(16)}\r\n`);
+    const end = encoder.encode("\r\n");
+    await writer.write(start);
+    await writer.write(chunk);
+    await writer.write(end);
+  }
+
+  const endChunk = encoder.encode("0\r\n\r\n");
+  await writer.write(endChunk);
+}
+
+/** write trailer headers to writer. it mostly should be called after writeResponse */
+export async function writeTrailers(
+  w: Deno.Writer,
+  headers: Headers,
+  trailers: Headers
+): Promise<void> {
+  const trailer = headers.get("trailer");
+  if (trailer === null) {
+    throw new Error('response headers must have "trailer" header field');
+  }
+  const transferEncoding = headers.get("transfer-encoding");
+  if (transferEncoding === null || !transferEncoding.match(/^chunked/)) {
+    throw new Error(
+      `trailer headers is only allowed for "transfer-encoding: chunked": got "${transferEncoding}"`
+    );
+  }
+  const writer = BufWriter.create(w);
+  const trailerHeaderFields = trailer
+    .split(",")
+    .map(s => s.trim().toLowerCase());
+  for (const f of trailerHeaderFields) {
+    assert(
+      !kProhibitedTrailerHeaders.includes(f),
+      `"${f}" is prohibited for trailer header`
+    );
+  }
+  for (const [key, value] of trailers) {
+    assert(
+      trailerHeaderFields.includes(key),
+      `Not trailer header field: ${key}`
+    );
+    await writer.write(encoder.encode(`${key}: ${value}\r\n`));
+  }
+  await writer.write(encoder.encode("\r\n"));
+  await writer.flush();
+}
diff --git a/std/http/io_test.ts b/std/http/io_test.ts
new file mode 100644
index 000000000..7e7701596
--- /dev/null
+++ b/std/http/io_test.ts
@@ -0,0 +1,167 @@
+import {
+  AssertionError,
+  assertThrowsAsync,
+  assertEquals
+} from "../testing/asserts.ts";
+import { bodyReader, writeTrailers, readTrailers } from "./io.ts";
+import { encode, decode } from "../strings/mod.ts";
+import { BufReader } from "../io/bufio.ts";
+import { chunkedBodyReader } from "./io.ts";
+const { test, Buffer } = Deno;
+
+test("bodyReader", async () => {
+  const text = "Hello, Deno";
+  const r = bodyReader(text.length, new BufReader(new Buffer(encode(text))));
+  assertEquals(decode(await Deno.readAll(r)), text);
+});
+function chunkify(n: number, char: string): string {
+  const v = Array.from({ length: n })
+    .map(() => `${char}`)
+    .join("");
+  return `${n.toString(16)}\r\n${v}\r\n`;
+}
+test("chunkedBodyReader", async () => {
+  const body = [
+    chunkify(3, "a"),
+    chunkify(5, "b"),
+    chunkify(11, "c"),
+    chunkify(22, "d"),
+    chunkify(0, "")
+  ].join("");
+  const h = new Headers();
+  const r = chunkedBodyReader(h, new BufReader(new Buffer(encode(body))));
+  let result: number | Deno.EOF;
+  // Use small buffer as some chunks exceed buffer size
+  const buf = new Uint8Array(5);
+  const dest = new Buffer();
+  while ((result = await r.read(buf)) !== Deno.EOF) {
+    const len = Math.min(buf.byteLength, result);
+    await dest.write(buf.subarray(0, len));
+  }
+  const exp = "aaabbbbbcccccccccccdddddddddddddddddddddd";
+  assertEquals(dest.toString(), exp);
+});
+
+test("chunkedBodyReader with trailers", async () => {
+  const body = [
+    chunkify(3, "a"),
+    chunkify(5, "b"),
+    chunkify(11, "c"),
+    chunkify(22, "d"),
+    chunkify(0, ""),
+    "deno: land\r\n",
+    "node: js\r\n",
+    "\r\n"
+  ].join("");
+  const h = new Headers({
+    trailer: "deno,node"
+  });
+  const r = chunkedBodyReader(h, new BufReader(new Buffer(encode(body))));
+  assertEquals(h.has("trailer"), true);
+  assertEquals(h.has("deno"), false);
+  assertEquals(h.has("node"), false);
+  const act = decode(await Deno.readAll(r));
+  const exp = "aaabbbbbcccccccccccdddddddddddddddddddddd";
+  assertEquals(act, exp);
+  assertEquals(h.has("trailer"), false);
+  assertEquals(h.get("deno"), "land");
+  assertEquals(h.get("node"), "js");
+});
+
+test("readTrailers", async () => {
+  const h = new Headers({
+    trailer: "deno,node"
+  });
+  const trailer = ["deno: land", "node: js", "", ""].join("\r\n");
+  await readTrailers(h, new BufReader(new Buffer(encode(trailer))));
+  assertEquals(h.has("trailer"), false);
+  assertEquals(h.get("deno"), "land");
+  assertEquals(h.get("node"), "js");
+});
+
+test("readTrailer should throw if undeclared headers found in trailer", async () => {
+  const patterns = [
+    ["deno,node", "deno: land\r\nnode: js\r\ngo: lang\r\n\r\n"],
+    ["deno", "node: js\r\n\r\n"],
+    ["deno", "node:js\r\ngo: lang\r\n\r\n"]
+  ];
+  for (const [header, trailer] of patterns) {
+    const h = new Headers({
+      trailer: header
+    });
+    await assertThrowsAsync(
+      async () => {
+        await readTrailers(h, new BufReader(new Buffer(encode(trailer))));
+      },
+      Error,
+      "Undeclared trailer field"
+    );
+  }
+});
+
+test("readTrailer should throw if trailer contains prohibited fields", async () => {
+  for (const f of ["content-length", "trailer", "transfer-encoding"]) {
+    const h = new Headers({
+      trailer: f
+    });
+    await assertThrowsAsync(
+      async () => {
+        await readTrailers(h, new BufReader(new Buffer()));
+      },
+      Error,
+      "Prohibited field for trailer"
+    );
+  }
+});
+
+test("writeTrailer", async () => {
+  const w = new Buffer();
+  await writeTrailers(
+    w,
+    new Headers({ "transfer-encoding": "chunked", trailer: "deno,node" }),
+    new Headers({ deno: "land", node: "js" })
+  );
+  assertEquals(w.toString(), "deno: land\r\nnode: js\r\n\r\n");
+});
+
+test("writeTrailer should throw", async () => {
+  const w = new Buffer();
+  await assertThrowsAsync(
+    () => {
+      return writeTrailers(w, new Headers(), new Headers());
+    },
+    Error,
+    'must have "trailer"'
+  );
+  await assertThrowsAsync(
+    () => {
+      return writeTrailers(w, new Headers({ trailer: "deno" }), new Headers());
+    },
+    Error,
+    "only allowed"
+  );
+  for (const f of ["content-length", "trailer", "transfer-encoding"]) {
+    await assertThrowsAsync(
+      () => {
+        return writeTrailers(
+          w,
+          new Headers({ "transfer-encoding": "chunked", trailer: f }),
+          new Headers({ [f]: "1" })
+        );
+      },
+      AssertionError,
+      "prohibited"
+    );
+  }
+  await assertThrowsAsync(
+    () => {
+      return writeTrailers(
+        w,
+        new Headers({ "transfer-encoding": "chunked", trailer: "deno" }),
+        new Headers({ node: "js" })
+      );
+    },
+    AssertionError,
+    "Not trailer"
+  );
+});
diff --git a/std/http/racing_server.ts b/std/http/racing_server.ts
index 629fef2db..0b0e5a8a5 100644
--- a/std/http/racing_server.ts
+++ b/std/http/racing_server.ts
@@ -5,12 +5,15 @@ import { delay } from "../util/async.ts";
 const addr = Deno.args[1] || "127.0.0.1:4501";
 const server = serve(addr);
 
-const body = new TextEncoder().encode("Hello 1\n");
-const body4 = new TextEncoder().encode("World 4\n");
-
-async function delayedRespond(request: ServerRequest): Promise<void> {
+function body(i: number): string {
+  return `Step${i}\n`;
+}
+async function delayedRespond(
+  request: ServerRequest,
+  step: number
+): Promise<void> {
   await delay(3000);
-  await request.respond({ status: 200, body });
+  await request.respond({ status: 200, body: body(step) });
 }
 
 async function largeRespond(request: ServerRequest, c: string): Promise<void> {
@@ -19,6 +22,13 @@ async function largeRespond(request: ServerRequest, c: string): Promise<void> {
   await request.respond({ status: 200, body: b });
 }
 
+async function ignoreToConsume(
+  request: ServerRequest,
+  step: number
+): Promise<void> {
+  await request.respond({ status: 200, body: body(step) });
+}
+
 console.log("Racing server listening...\n");
 
 let step = 1;
@@ -28,7 +38,7 @@ for await (const request of server) {
       // Try to wait long enough.
       // For pipelining, this should cause all the following response
       // to block.
-      delayedRespond(request);
+      delayedRespond(request, step);
       break;
     case 2:
       // HUGE body.
@@ -38,8 +48,20 @@ for await (const request of server) {
       // HUGE body.
       largeRespond(request, "b");
       break;
+    case 4:
+      // Ignore to consume body (content-length)
+      ignoreToConsume(request, step);
+      break;
+    case 5:
+      // Ignore to consume body (chunked)
+      ignoreToConsume(request, step);
+      break;
+    case 6:
+      // Ignore to consume body (chunked + trailers)
+      ignoreToConsume(request, step);
+      break;
     default:
-      request.respond({ status: 200, body: body4 });
+      request.respond({ status: 200, body: body(step) });
       break;
   }
   step++;
diff --git a/std/http/racing_server_test.ts b/std/http/racing_server_test.ts
index 639935339..07df92bae 100644
--- a/std/http/racing_server_test.ts
+++ b/std/http/racing_server_test.ts
@@ -1,7 +1,7 @@
 const { connect, run } = Deno;
 
 import { assert, assertEquals } from "../testing/asserts.ts";
-import { BufReader } from "../io/bufio.ts";
+import { BufReader, BufWriter } from "../io/bufio.ts";
 import { TextProtoReader } from "../textproto/mod.ts";
 
 let server: Deno.Process;
@@ -21,20 +21,20 @@ function killServer(): void {
   server.stdout?.close();
 }
 
-const input = `GET / HTTP/1.1
-
-GET / HTTP/1.1
-
-GET / HTTP/1.1
-
-GET / HTTP/1.1
-
-`;
+const input = [
+  "GET / HTTP/1.1\r\n\r\n",
+  "GET / HTTP/1.1\r\n\r\n",
+  "GET / HTTP/1.1\r\n\r\n",
+  "POST / HTTP/1.1\r\ncontent-length: 4\r\n\r\ndeno",
+  "POST / HTTP/1.1\r\ntransfer-encoding: chunked\r\n\r\n4\r\ndeno\r\n0\r\n\r\n",
+  "POST / HTTP/1.1\r\ntransfer-encoding: chunked\r\ntrailer: deno\r\n\r\n4\r\ndeno\r\n0\r\n\r\ndeno: land\r\n\r\n",
+  "GET / HTTP/1.1\r\n\r\n"
+].join("");
 const HUGE_BODY_SIZE = 1024 * 1024;
 const output = `HTTP/1.1 200 OK
-content-length: 8
+content-length: 6
 
-Hello 1
+Step1
 HTTP/1.1 200 OK
 content-length: ${HUGE_BODY_SIZE}
 
@@ -42,9 +42,21 @@ ${"a".repeat(HUGE_BODY_SIZE)}HTTP/1.1 200 OK
 content-length: ${HUGE_BODY_SIZE}
 
 ${"b".repeat(HUGE_BODY_SIZE)}HTTP/1.1 200 OK
-content-length: 8
+content-length: 6
+
+Step4
+HTTP/1.1 200 OK
+content-length: 6
+
+Step5
+HTTP/1.1 200 OK
+content-length: 6
+
+Step6
+HTTP/1.1 200 OK
+content-length: 6
 
-World 4
+Step7
 `;
 
 Deno.test(async function serverPipelineRace(): Promise<void> {
@@ -52,7 +64,9 @@ Deno.test(async function serverPipelineRace(): Promise<void> {
 
   const conn = await connect({ port: 4501 });
   const r = new TextProtoReader(new BufReader(conn));
-  await conn.write(new TextEncoder().encode(input));
+  const w = new BufWriter(conn);
+  await w.write(new TextEncoder().encode(input));
+  await w.flush();
   const outLines = output.split("\n");
   // length - 1 to disregard last empty line
   for (let i = 0; i < outLines.length - 1; i++) {
diff --git a/std/http/server.ts b/std/http/server.ts
index 9e9cde016..e7d6bd598 100644
--- a/std/http/server.ts
+++ b/std/http/server.ts
@@ -1,5 +1,5 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
-const { listen, listenTLS, copy, toAsyncIterator } = Deno;
+const { listen, listenTLS, copy } = Deno;
 type Listener = Deno.Listener;
 type Conn = Deno.Conn;
 type Reader = Deno.Reader;
@@ -9,6 +9,13 @@ import { TextProtoReader } from "../textproto/mod.ts";
 import { STATUS_TEXT } from "./http_status.ts";
 import { assert } from "../testing/asserts.ts";
 import { deferred, Deferred, MuxAsyncIterator } from "../util/async.ts";
+import {
+  bodyReader,
+  chunkedBodyReader,
+  writeChunkedBody,
+  writeTrailers,
+  emptyReader
+} from "./io.ts";
 
 const encoder = new TextEncoder();
 
@@ -30,64 +37,6 @@ export function setContentLength(r: Response): void {
   }
 }
 
-async function writeChunkedBody(w: Writer, r: Reader): Promise<void> {
-  const writer = BufWriter.create(w);
-
-  for await (const chunk of toAsyncIterator(r)) {
-    if (chunk.byteLength <= 0) continue;
-    const start = encoder.encode(`${chunk.byteLength.toString(16)}\r\n`);
-    const end = encoder.encode("\r\n");
-    await writer.write(start);
-    await writer.write(chunk);
-    await writer.write(end);
-  }
-
-  const endChunk = encoder.encode("0\r\n\r\n");
-  await writer.write(endChunk);
-}
-const kProhibitedTrailerHeaders = [
-  "transfer-encoding",
-  "content-length",
-  "trailer"
-];
-
-/** write trailer headers to writer. it mostly should be called after writeResponse */
-export async function writeTrailers(
-  w: Writer,
-  headers: Headers,
-  trailers: Headers
-): Promise<void> {
-  const trailer = headers.get("trailer");
-  if (trailer === null) {
-    throw new Error('response headers must have "trailer" header field');
-  }
-  const transferEncoding = headers.get("transfer-encoding");
-  if (transferEncoding === null || !transferEncoding.match(/^chunked/)) {
-    throw new Error(
-      `trailer headers is only allowed for "transfer-encoding: chunked": got "${transferEncoding}"`
-    );
-  }
-  const writer = BufWriter.create(w);
-  const trailerHeaderFields = trailer
-    .split(",")
-    .map(s => s.trim().toLowerCase());
-  for (const f of trailerHeaderFields) {
-    assert(
-      !kProhibitedTrailerHeaders.includes(f),
-      `"${f}" is prohibited for trailer header`
-    );
-  }
-  for (const [key, value] of trailers) {
-    assert(
-      trailerHeaderFields.includes(key),
-      `Not trailer header field: ${key}`
-    );
-    await writer.write(encoder.encode(`${key}: ${value}\r\n`));
-  }
-  await writer.write(encoder.encode("\r\n"));
-  await writer.flush();
-}
-
 export async function writeResponse(w: Writer, r: Response): Promise<void> {
   const protoMajor = 1;
   const protoMinor = 1;
@@ -138,17 +87,6 @@ export async function writeResponse(w: Writer, r: Response): Promise<void> {
   await writer.flush();
 }
 
-export class ServerRequestBody implements Reader {
-  constructor(private it: AsyncIterator<number, undefined, Uint8Array>) {}
-  async read(p: Uint8Array): Promise<number | Deno.EOF> {
-    const res = await this.it.next(p);
-    if (res.done) {
-      return Deno.EOF;
-    }
-    return res.value;
-  }
-}
-
 export class ServerRequest {
   url!: string;
   method!: string;
@@ -184,7 +122,7 @@ export class ServerRequest {
     return this._contentLength;
   }
 
-  private _body: ServerRequestBody | null = null;
+  private _body: Deno.Reader | null = null;
 
   /**
    * Body of the request.
@@ -200,100 +138,28 @@ export class ServerRequest {
    *       bufSlice = bufSlice.subarray(nread);
    *     }
    */
-  get body(): ServerRequestBody {
+  get body(): Deno.Reader {
     if (!this._body) {
-      const stream = this._bodyStream();
-      stream.next(); // drop dummy such that first read is not empty.
-      this._body = new ServerRequestBody(stream);
-    }
-    return this._body;
-  }
-
-  /**
-   * Internal: actually reading body. Each step, buf to use is passed
-   * in through yield result.
-   * Returns on no more data to read or error.
-   */
-  private async *_bodyStream(): AsyncIterator<number, undefined, Uint8Array> {
-    let buf = yield 0; // dummy yield to retrieve user provided buf.
-    if (this.headers.has("content-length")) {
-      const len = this.contentLength;
-      if (len === null) {
-        return;
-      }
-      let rr = await this.r.read(buf);
-      let nread = rr === Deno.EOF ? 0 : rr;
-      let nreadTotal = nread;
-      while (rr !== Deno.EOF && nreadTotal < len) {
-        buf = yield nread;
-        rr = await this.r.read(buf);
-        nread = rr === Deno.EOF ? 0 : rr;
-        nreadTotal += nread;
-      }
-      yield nread;
-    } else {
-      const transferEncoding = this.headers.get("transfer-encoding");
-      if (transferEncoding) {
-        const parts = transferEncoding
-          .split(",")
-          .map((e): string => e.trim().toLowerCase());
-        if (parts.includes("chunked")) {
-          // Based on https://tools.ietf.org/html/rfc2616#section-19.4.6
-          const tp = new TextProtoReader(this.r);
-          let line = await tp.readLine();
-          if (line === Deno.EOF) throw new UnexpectedEOFError();
-          // TODO: handle chunk extension
-          const [chunkSizeString] = line.split(";");
-          let chunkSize = parseInt(chunkSizeString, 16);
-          if (Number.isNaN(chunkSize) || chunkSize < 0) {
-            throw new Error("Invalid chunk size");
-          }
-          while (chunkSize > 0) {
-            let currChunkOffset = 0;
-            // Since given readBuffer might be smaller, loop.
-            while (currChunkOffset < chunkSize) {
-              // Try to be as large as chunkSize. Might be smaller though.
-              const bufferToFill = buf.subarray(0, chunkSize);
-              if ((await this.r.readFull(bufferToFill)) === Deno.EOF) {
-                throw new UnexpectedEOFError();
-              }
-              currChunkOffset += bufferToFill.length;
-              buf = yield bufferToFill.length;
-            }
-            await this.r.readLine(); // Consume \r\n
-            line = await tp.readLine();
-            if (line === Deno.EOF) throw new UnexpectedEOFError();
-            chunkSize = parseInt(line, 16);
-          }
-          const entityHeaders = await tp.readMIMEHeader();
-          if (entityHeaders !== Deno.EOF) {
-            for (const [k, v] of entityHeaders) {
-              this.headers.set(k, v);
-            }
-          }
-          /* Pseudo code from https://tools.ietf.org/html/rfc2616#section-19.4.6
-          length := 0
-          read chunk-size, chunk-extension (if any) and CRLF
-          while (chunk-size > 0) {
-            read chunk-data and CRLF
-            append chunk-data to entity-body
-            length := length + chunk-size
-            read chunk-size and CRLF
-          }
-          read entity-header
-          while (entity-header not empty) {
-            append entity-header to existing header fields
-            read entity-header
-          }
-          Content-Length := length
-          Remove "chunked" from Transfer-Encoding
-          */
-          return; // Must return here to avoid fall through
+      if (this.contentLength != null) {
+        this._body = bodyReader(this.contentLength, this.r);
+      } else {
+        const transferEncoding = this.headers.get("transfer-encoding");
+        if (transferEncoding != null) {
+          const parts = transferEncoding
+            .split(",")
+            .map((e): string => e.trim().toLowerCase());
+          assert(
+            parts.includes("chunked"),
+            'transfer-encoding must include "chunked" if content-length is not set'
+          );
+          this._body = chunkedBodyReader(this.headers, this.r);
+        } else {
+          // Neither content-length nor transfer-encoding: chunked
+          this._body = emptyReader();
         }
-        // TODO: handle other transfer-encoding types
       }
-      // Otherwise... Do nothing
     }
+    return this._body;
   }
 
   async respond(r: Response): Promise<void> {
@@ -316,6 +182,16 @@ export class ServerRequest {
       throw err;
     }
   }
+
+  private finalized = false;
+  async finalize(): Promise<void> {
+    if (this.finalized) return;
+    // Consume unread body
+    const body = this.body;
+    const buf = new Uint8Array(1024);
+    while ((await body.read(buf)) !== Deno.EOF) {}
+    this.finalized = true;
+  }
 }
 
 function fixLength(req: ServerRequest): void {
@@ -462,6 +338,8 @@ export class Server implements AsyncIterable<ServerRequest> {
         // req.done implies this connection already closed, so we can just return.
         return;
       }
+      // Consume unread body and trailers if receiver didn't consume those data
+      await req.finalize();
     }
 
     if (req === Deno.EOF) {
diff --git a/std/http/server_test.ts b/std/http/server_test.ts
index b145b8353..70ce5f2f1 100644
--- a/std/http/server_test.ts
+++ b/std/http/server_test.ts
@@ -11,8 +11,6 @@ import {
   assert,
   assertEquals,
   assertNotEquals,
-  assertThrowsAsync,
-  AssertionError,
   assertNotEOF
 } from "../testing/asserts.ts";
 import {
@@ -21,8 +19,7 @@ import {
   writeResponse,
   serve,
   readRequest,
-  parseHTTPVersion,
-  writeTrailers
+  parseHTTPVersion
 } from "./server.ts";
 import {
   BufReader,
@@ -32,6 +29,7 @@ import {
 } from "../io/bufio.ts";
 import { delay, deferred } from "../util/async.ts";
 import { StringReader } from "../io/readers.ts";
+import { encode } from "../strings/mod.ts";
 
 interface ResponseTest {
   response: Response;
@@ -43,7 +41,7 @@ const dec = new TextDecoder();
 
 type Handler = () => void;
 
-const mockConn = {
+const mockConn = (): Deno.Conn => ({
   localAddr: {
     transport: "tcp",
     hostname: "",
@@ -64,7 +62,7 @@ const mockConn = {
     return -1;
   },
   close: (): void => {}
-};
+});
 
 const responseTests: ResponseTest[] = [
   // Default response
@@ -100,7 +98,7 @@ test(async function responseWrite(): Promise<void> {
     const request = new ServerRequest();
     request.w = bufw;
 
-    request.conn = mockConn as Deno.Conn;
+    request.conn = mockConn();
 
     await request.respond(testCase.response);
     assertEquals(buf.toString(), testCase.raw);
@@ -142,6 +140,25 @@ test(async function requestContentLength(): Promise<void> {
   }
 });
 
+interface TotalReader extends Deno.Reader {
+  total: number;
+}
+function totalReader(r: Deno.Reader): TotalReader {
+  let _total = 0;
+  async function read(p: Uint8Array): Promise<number | Deno.EOF> {
+    const result = await r.read(p);
+    if (typeof result === "number") {
+      _total += result;
+    }
+    return result;
+  }
+  return {
+    read,
+    get total(): number {
+      return _total;
+    }
+  };
+}
 test(async function requestBodyWithContentLength(): Promise<void> {
   {
     const req = new ServerRequest();
@@ -164,8 +181,53 @@ test(async function requestBodyWithContentLength(): Promise<void> {
     const body = dec.decode(await Deno.readAll(req.body));
     assertEquals(body, longText);
   }
+  // Handler ignored to consume body
+});
+test("ServerRequest.finalize() should consume unread body / content-length", async () => {
+  const text = "deno.land";
+  const req = new ServerRequest();
+  req.headers = new Headers();
+  req.headers.set("content-length", "" + text.length);
+  const tr = totalReader(new Buffer(encode(text)));
+  req.r = new BufReader(tr);
+  req.w = new BufWriter(new Buffer());
+  await req.respond({ status: 200, body: "ok" });
+  assertEquals(tr.total, 0);
+  await req.finalize();
+  assertEquals(tr.total, text.length);
+});
+test("ServerRequest.finalize() should consume unread body / chunked, trailers", async () => {
+  const text = [
+    "5",
+    "Hello",
+    "4",
+    "Deno",
+    "0",
+    "",
+    "deno: land",
+    "node: js",
+    "",
+    ""
+  ].join("\r\n");
+  const req = new ServerRequest();
+  req.headers = new Headers();
+  req.headers.set("transfer-encoding", "chunked");
+  req.headers.set("trailer", "deno,node");
+  const body = encode(text);
+  const tr = totalReader(new Buffer(body));
+  req.r = new BufReader(tr);
+  req.w = new BufWriter(new Buffer());
+  await req.respond({ status: 200, body: "ok" });
+  assertEquals(tr.total, 0);
+  assertEquals(req.headers.has("trailer"), true);
+  assertEquals(req.headers.has("deno"), false);
+  assertEquals(req.headers.has("node"), false);
+  await req.finalize();
+  assertEquals(tr.total, body.byteLength);
+  assertEquals(req.headers.has("trailer"), false);
+  assertEquals(req.headers.get("deno"), "land");
+  assertEquals(req.headers.get("node"), "js");
 });
-
 test(async function requestBodyWithTransferEncoding(): Promise<void> {
   {
     const shortText = "Hello";
@@ -465,7 +527,7 @@ malformedHeader
   const reader = new BufReader(new StringReader(input));
   let err;
   try {
-    await readRequest(mockConn as Deno.Conn, reader);
+    await readRequest(mockConn(), reader);
   } catch (e) {
     err = e;
   }
@@ -543,7 +605,7 @@ test(async function testReadRequestError(): Promise<void> {
     let err;
     let req: ServerRequest | Deno.EOF | undefined;
     try {
-      req = await readRequest(mockConn as Deno.Conn, reader);
+      req = await readRequest(mockConn(), reader);
     } catch (e) {
       err = e;
     }
@@ -655,7 +717,10 @@ test({
     try {
       const r = new TextProtoReader(new BufReader(p.stdout!));
       const s = await r.readLine();
-      assert(s !== Deno.EOF && s.includes("server listening"));
+      assert(
+        s !== Deno.EOF && s.includes("server listening"),
+        "server must be started"
+      );
 
       let serverIsRunning = true;
       p.status()
@@ -765,55 +830,3 @@ if (Deno.build.os !== "win") {
     }
   });
 }
-
-test("writeTrailer", async () => {
-  const w = new Buffer();
-  await writeTrailers(
-    w,
-    new Headers({ "transfer-encoding": "chunked", trailer: "deno,node" }),
-    new Headers({ deno: "land", node: "js" })
-  );
-  assertEquals(w.toString(), "deno: land\r\nnode: js\r\n\r\n");
-});
-
-test("writeTrailer should throw", async () => {
-  const w = new Buffer();
-  await assertThrowsAsync(
-    () => {
-      return writeTrailers(w, new Headers(), new Headers());
-    },
-    Error,
-    'must have "trailer"'
-  );
-  await assertThrowsAsync(
-    () => {
-      return writeTrailers(w, new Headers({ trailer: "deno" }), new Headers());
-    },
-    Error,
-    "only allowed"
-  );
-  for (const f of ["content-length", "trailer", "transfer-encoding"]) {
-    await assertThrowsAsync(
-      () => {
-        return writeTrailers(
-          w,
-          new Headers({ "transfer-encoding": "chunked", trailer: f }),
-          new Headers({ [f]: "1" })
-        );
-      },
-      AssertionError,
-      "prohibited"
-    );
-  }
-  await assertThrowsAsync(
-    () => {
-      return writeTrailers(
-        w,
-        new Headers({ "transfer-encoding": "chunked", trailer: "deno" }),
-        new Headers({ node: "js" })
-      );
-    },
-    AssertionError,
-    "Not trailer"
-  );
-});