Add support for fetch() headers (#727)

6 files changed, 104 insertions, 16 deletions

diff --git a/js/deno.ts b/js/deno.ts
index 6f71ee499..187d0f27f 100644
--- a/js/deno.ts
+++ b/js/deno.ts
@@ -1,11 +1,7 @@
 // Copyright 2018 the Deno authors. All rights reserved. MIT license.
 // Public deno module.
 /// <amd-module name="deno"/>
-export {
-  env,
-  exit,
-  makeTempDirSync
-} from "./os";
+export { env, exit, makeTempDirSync } from "./os";
 export { mkdirSync, mkdir } from "./mkdir";
 export { removeSync, remove, removeAllSync, removeAll } from "./remove";
 export { readFileSync, readFile } from "./read_file";
diff --git a/js/fetch.ts b/js/fetch.ts
index e3aa052f9..24905694e 100644
--- a/js/fetch.ts
+++ b/js/fetch.ts
@@ -16,19 +16,75 @@ import {
   Response,
   Blob,
   RequestInit,
+  HeadersInit,
   FormData
 } from "./fetch_types";
 import { TextDecoder } from "./text_encoding";
 
-class DenoHeaders implements Headers {
+interface Header {
+  name: string;
+  value: string;
+}
+
+export class DenoHeaders implements Headers {
+  private readonly headerList: Header[] = [];
+
+  constructor(init?: HeadersInit) {
+    if (init) {
+      this._fill(init);
+    }
+  }
+
+  private _append(header: Header): void {
+    // TODO(qti3e) Check header based on the fetch spec.
+    this._appendToHeaderList(header);
+  }
+
+  private _appendToHeaderList(header: Header): void {
+    const lowerCaseName = header.name.toLowerCase();
+    for (let i = 0; i < this.headerList.length; ++i) {
+      if (this.headerList[i].name.toLowerCase() === lowerCaseName) {
+        header.name = this.headerList[i].name;
+      }
+    }
+    this.headerList.push(header);
+  }
+
+  private _fill(init: HeadersInit): void {
+    if (Array.isArray(init)) {
+      for (let i = 0; i < init.length; ++i) {
+        const header = init[i];
+        if (header.length !== 2) {
+          throw new TypeError("Failed to construct 'Headers': Invalid value");
+        }
+        this._append({
+          name: header[0],
+          value: header[1]
+        });
+      }
+    } else {
+      for (const key in init) {
+        this._append({
+          name: key,
+          value: init[key]
+        });
+      }
+    }
+  }
+
   append(name: string, value: string): void {
-    assert(false, "Implement me");
+    this._appendToHeaderList({ name, value });
   }
+
   delete(name: string): void {
     assert(false, "Implement me");
   }
   get(name: string): string | null {
-    assert(false, "Implement me");
+    for (const header of this.headerList) {
+      if (header.name.toLowerCase() === name.toLowerCase()) {
+        return header.value;
+      }
+    }
     return null;
   }
   has(name: string): boolean {
@@ -54,15 +110,20 @@ class FetchResponse implements Response {
   statusText = "FIXME"; // TODO
   readonly type = "basic"; // TODO
   redirected = false; // TODO
-  headers = new DenoHeaders();
+  headers: DenoHeaders;
   readonly trailer: Promise<Headers>;
   //private bodyChunks: Uint8Array[] = [];
   private first = true;
   private bodyWaiter: Resolvable<ArrayBuffer>;
 
-  constructor(readonly status: number, readonly body_: ArrayBuffer) {
+  constructor(
+    readonly status: number,
+    readonly body_: ArrayBuffer,
+    headersList: Array<[string, string]>
+  ) {
     this.bodyWaiter = createResolvable();
     this.trailer = createResolvable();
+    this.headers = new DenoHeaders(headersList);
     setTimeout(() => {
       this.bodyWaiter.resolve(body_);
     }, 0);
@@ -149,6 +210,14 @@ export async function fetch(
   assert(bodyArray != null);
   const body = typedArrayToArrayBuffer(bodyArray!);
 
-  const response = new FetchResponse(status, body);
+  const headersList: Array<[string, string]> = [];
+  const len = msg.headerKeyLength();
+  for (let i = 0; i < len; ++i) {
+    const key = msg.headerKey(i);
+    const value = msg.headerValue(i);
+    headersList.push([key, value]);
+  }
+
+  const response = new FetchResponse(status, body, headersList);
   return response;
 }
diff --git a/js/fetch_test.ts b/js/fetch_test.ts
index 1af3bc2eb..2b7f32099 100644
--- a/js/fetch_test.ts
+++ b/js/fetch_test.ts
@@ -18,3 +18,20 @@ test(async function fetchPerm() {
   assertEqual(err.kind, deno.ErrorKind.PermissionDenied);
   assertEqual(err.name, "PermissionDenied");
 });
+
+testPerm({ net: true }, async function fetchHeaders() {
+  const response = await fetch("http://localhost:4545/package.json");
+  const headers = response.headers;
+  assertEqual(headers.get("Content-Type"), "application/json");
+  assert(headers.get("Server").startsWith("SimpleHTTP"));
+});
+
+test(async function headersAppend() {
+  let err;
+  try {
+    const headers = new Headers([["foo", "bar", "baz"]]);
+  } catch (e) {
+    err = e;
+  }
+  assert(err instanceof TypeError);
+});
diff --git a/js/fetch_types.d.ts b/js/fetch_types.d.ts
index f00bdd3c5..9d4082c35 100644
--- a/js/fetch_types.d.ts
+++ b/js/fetch_types.d.ts
@@ -13,7 +13,7 @@ See the Apache Version 2.0 License for specific language governing permissions
 and limitations under the License.
 *******************************************************************************/
 
-type HeadersInit = Headers | string[][] | Record<string, string>;
+type HeadersInit = string[][] | Record<string, string>;
 type BodyInit =
   | Blob
   | BufferSource
diff --git a/js/globals.ts b/js/globals.ts
index cd29d34c7..3805f12f5 100644
--- a/js/globals.ts
+++ b/js/globals.ts
@@ -6,6 +6,7 @@ import * as textEncoding from "./text_encoding";
 import * as fetch_ from "./fetch";
 import { libdeno } from "./libdeno";
 import { globalEval } from "./global-eval";
+import { DenoHeaders } from "./fetch";
 
 declare global {
   interface Window {
@@ -23,6 +24,8 @@ declare global {
 
     TextEncoder: typeof TextEncoder;
     TextDecoder: typeof TextDecoder;
+
+    Headers: typeof Headers;
   }
 
   const clearTimeout: typeof timers.clearTimer;
@@ -38,6 +41,7 @@ declare global {
   // tslint:disable:variable-name
   const TextEncoder: typeof textEncoding.TextEncoder;
   const TextDecoder: typeof textEncoding.TextDecoder;
+  const Headers: typeof DenoHeaders;
   // tslint:enable:variable-name
 }
 
@@ -57,3 +61,5 @@ window.TextEncoder = textEncoding.TextEncoder;
 window.TextDecoder = textEncoding.TextDecoder;
 
 window.fetch = fetch_.fetch;
+
+window.Headers = DenoHeaders;
diff --git a/js/rename.ts b/js/rename.ts
index 241e27490..5917912f5 100644
--- a/js/rename.ts
+++ b/js/rename.ts
@@ -4,8 +4,8 @@ import { flatbuffers } from "flatbuffers";
 import * as dispatch from "./dispatch";
 
 /**
- * Synchronously renames (moves) oldpath to newpath. If newpath already exists 
- * and is not a directory, Rename replaces it. OS-specific restrictions may 
+ * Synchronously renames (moves) oldpath to newpath. If newpath already exists
+ * and is not a directory, Rename replaces it. OS-specific restrictions may
  * apply when oldpath and newpath are in different directories.
  *
  *     import { renameSync } from "deno";
@@ -16,8 +16,8 @@ export function renameSync(oldpath: string, newpath: string): void {
 }
 
 /**
- * Renames (moves) oldpath to newpath. If newpath already exists 
- * and is not a directory, Rename replaces it. OS-specific restrictions may 
+ * Renames (moves) oldpath to newpath. If newpath already exists
+ * and is not a directory, Rename replaces it. OS-specific restrictions may
  * apply when oldpath and newpath are in different directories.
  *
  *     import { rename } from "deno";