src/hero.mjs: Add writeHead() and its helper functions

2 files changed, 93 insertions, 0 deletions

diff --git a/src/hero.mjs b/src/hero.mjs
index b47d459..75c9a88 100644
--- a/src/hero.mjs
+++ b/src/hero.mjs
@@ -380,6 +380,23 @@ export const extractQueryParams = s => {
 	return ret;
 };
 
+export const renderStatus = code =>
+	`HTTP/1.1 ${code} ${http.STATUS_CODES[code]}`
+
+export const renderHeaders = obj =>
+	Object.keys(obj)
+		.sort(u.strSortFn)
+		.map(name => `${name}: ${obj[name]}`);
+
+export const buildHeader = (status, headers) =>
+	[renderStatus(status)]
+		.concat(renderHeaders(headers))
+		.concat(["\r\n"])
+		.join("\r\n");
+
+export const writeHead = (socket, status, headers) =>
+	socket.write(buildHeader(status, headers));
+
 export const handle404 = _req => ({
 	status: 404,
 	body: "Not Found\n",
diff --git a/tests/js/hero.mjs b/tests/js/hero.mjs
index 468f4a8..33403d0 100644
--- a/tests/js/hero.mjs
+++ b/tests/js/hero.mjs
@@ -33,6 +33,10 @@ import {
 	findDynamicHandler,
 	findHandler,
 	extractQueryParams,
+	renderStatus,
+	renderHeaders,
+	buildHeader,
+	writeHead,
 	handle404,
 	make404Handler,
 	handleRequest,
@@ -1331,6 +1335,74 @@ const test_extractQueryParams = async t => {
 	});
 };
 
+const test_renderStatus = async t => {
+	t.start("renderStatus()");
+
+	await t.test("good statuses", () => {
+		assert.equal(renderStatus(101), "HTTP/1.1 101 Switching Protocols");
+		assert.equal(renderStatus(202), "HTTP/1.1 202 Accepted");
+		assert.equal(renderStatus(409), "HTTP/1.1 409 Conflict");
+	});
+};
+
+const test_renderHeaders = async t => {
+	t.start("renderHeaders()");
+
+	await t.test("empty values", () => {
+		assert.deepEqual(renderHeaders({}), []);
+	})
+
+	await t.test("values are rendered and sorted", () => {
+		assert.deepEqual(renderHeaders({ a: "one", Z: "two" }), [
+			"a: one",
+			"Z: two",
+		]);
+	});
+
+	await t.test("GIGO for newlines", () => {
+		assert.deepEqual(renderHeaders({ a: "\nx: 1\r\n", }), [
+			"a: \nx: 1\r\n",
+		]);
+	});
+};
+
+const test_buildHeader = async t => {
+	t.start("buildHeader()");
+
+	await t.test("empty values", () => {
+		assert.equal(
+			buildHeader(200, {}),
+			"HTTP/1.1 200 OK\r\n" +
+			"\r\n",
+		);
+	});
+
+	await t.test("we compose the status line and the headers", () => {
+		assert.equal(
+			buildHeader(201, { a: "1", b: "2" }),
+			"HTTP/1.1 201 Created\r\n" +
+			"a: 1\r\n" +
+			"b: 2\r\n" +
+			"\r\n",
+		);
+	});
+};
+
+const test_writeHead = async t => {
+	t.start("writeHead()");
+
+	await t.test("we simply write what buildHeader() gives us", () => {
+		const contents = [];
+		const socket = { write: x => contents.push(x) };
+		writeHead(socket, 202, { "Key": "Value" });
+		assert.deepEqual(contents, [
+			"HTTP/1.1 202 Accepted\r\n" +
+			"Key: Value\r\n" +
+			"\r\n",
+		]);
+	});
+};
+
 const test_make404Handler = async t => {
 	t.start("make404Handler");
 
@@ -2146,6 +2218,10 @@ await runner.runTests([
 	test_findDynamicHandler,
 	test_findHandler,
 	test_extractQueryParams,
+	test_renderStatus,
+	test_renderHeaders,
+	test_buildHeader,
+	test_writeHead,
 	test_make404Handler,
 	test_handleRequest,
 	test_makeRequestListener,