src/hero.mjs: Add buildHttpPayload()

2 files changed, 67 insertions, 0 deletions

diff --git a/src/hero.mjs b/src/hero.mjs
index a9397ef..daf8141 100644
--- a/src/hero.mjs
+++ b/src/hero.mjs
@@ -285,6 +285,25 @@ export const emitHeaders = obj =>
 		.map(name => `${name}: ${obj[name]}`)
 		.join("\r\n");
 
+const STATUS_CODES = {
+	404: "Not Found",
+	405: "Method Not Allowed",
+};
+
+export const buildHttpPayload = (code, {
+	headers = {},
+	message = `${STATUS_CODES[code]}\n`,
+} = {}) =>
+	`HTTP/1.1 ${code} ${STATUS_CODES[code]}\r\n` +
+	emitHeaders({
+		"Connection": "close",
+		"Content-Type": "text/plain; charset=UTF-8",
+		"Content-Length": Buffer.byteLength(message),
+		...headers,
+	}) +
+	"\r\n\r\n" +
+	message;
+
 export const makeRequestListener = table => async (req, res) => {
 	const { status, headers, body } = await handleRequest(table, req);
 	res.writeHead(status, headers);
diff --git a/tests/js/hero.mjs b/tests/js/hero.mjs
index d57152f..627aa33 100644
--- a/tests/js/hero.mjs
+++ b/tests/js/hero.mjs
@@ -32,6 +32,7 @@ import {
 	make404Handler,
 	handleRequest,
 	emitHeaders,
+	buildHttpPayload,
 	makeRequestListener,
 	actionsFn,
 	lineHandlerFn,
@@ -1165,6 +1166,52 @@ const test_emitHeaders = async t => {
 	});
 };
 
+const test_buildHttpPayload = async t => {
+	t.start("buildHttpPayload()");
+
+	await t.test("empty values", () => {
+		assert.equal(
+			buildHttpPayload(404),
+			"HTTP/1.1 404 Not Found\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 10\r\n" +
+			"Content-Type: text/plain; charset=UTF-8\r\n" +
+			"\r\n" +
+			"Not Found\n",
+		);
+		assert.equal(
+			buildHttpPayload(405),
+			"HTTP/1.1 405 Method Not Allowed\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 19\r\n" +
+			"Content-Type: text/plain; charset=UTF-8\r\n" +
+			"\r\n" +
+			"Method Not Allowed\n",
+		);
+	});
+
+	await t.test("we can add headers and customise the message", () => {
+		assert.equal(
+			buildHttpPayload(404, {
+				headers: {
+					"X-Something": "something",
+					"Aaaa": "ZzZz",
+					"Content-Type": "text/plain",
+				},
+				message: "the message\n"
+			}),
+			"HTTP/1.1 404 Not Found\r\n" +
+			"Aaaa: ZzZz\r\n" +
+			"Connection: close\r\n" +
+			"Content-Length: 12\r\n" +
+			"Content-Type: text/plain\r\n" +
+			"X-Something: something\r\n" +
+			"\r\n" +
+			"the message\n",
+		);
+	});
+};
+
 const test_makeRequestListener = async t => {
 	t.start("makeRequestListener()");
 
@@ -1858,6 +1905,7 @@ await runner.runTests([
 	test_make404Handler,
 	test_handleRequest,
 	test_emitHeaders,
+	test_buildHttpPayload,
 	test_makeRequestListener,
 	test_actionsFn,
 	test_lineHandlerFn,