Headers cleanup

packages/kit/src/core/adapt/prerender.js

@@ -3,6 +3,7 @@ import { dirname, join, resolve as resolve_path, sep as path_separator } from 'p
 import { parse, pathToFileURL, resolve, URLSearchParams } from 'url';
 import glob from 'tiny-glob/sync.js';
 import { mkdirp } from '@sveltejs/app-utils/files';
+import { Headers } from '../../runtime/app/headers.js';
 
 /** @param {string} html */
 function clean_html(html) {
@@ -83,14 +84,15 @@ export async function prerender({ cwd, out, log, config, force }) {
 		if (seen.has(path)) return;
 		seen.add(path);
 
-		const rendered = await app.render(
+		const rendered = app.render(
 			{
 				host: config.kit.host,
 				method: 'GET',
-				headers: {},
+				headers: new Headers(),
 				path,
 				body: null,
-				query: new URLSearchParams()
+				query: new URLSearchParams(),
+				params: null
 			},
 			{
 				local: true,
@@ -102,7 +104,7 @@ export async function prerender({ cwd, out, log, config, force }) {
 		if (rendered) {
 			const response_type = Math.floor(rendered.status / 100);
 			const headers = rendered.headers;
-			const type = headers && headers['content-type'];
+			const type = headers && headers.get('content-type');
 			const is_html = response_type === REDIRECT || type === 'text/html';
 
 			const parts = path.split('/');
@@ -114,7 +116,7 @@ export async function prerender({ cwd, out, log, config, force }) {
 			mkdirp(dirname(file));
 
 			if (response_type === REDIRECT) {
-				const { location } = headers;
+				const location = headers.get('location');
 
 				log.warn(`${rendered.status} ${path} -> ${location}`);
 				writeFileSync(file, `<meta http-equiv="refresh" content="0;url=${encodeURI(location)}">`);
@@ -136,7 +138,7 @@ export async function prerender({ cwd, out, log, config, force }) {
 					const result = dependencies[path];
 					const response_type = Math.floor(result.status / 100);
 
-					const is_html = result.headers['content-type'] === 'text/html';
+					const is_html = result.headers.get('content-type') === 'text/html';
 
 					const parts = path.split('/');
 					if (is_html && parts[parts.length - 1] !== 'index.html') {

packages/kit/src/core/dev/index.js

@@ -9,6 +9,7 @@ import vite from 'vite';
 import create_manifest_data from '../../core/create_manifest_data/index.js';
 import { create_app } from '../../core/create_app/index.js';
 import { rimraf } from '@sveltejs/app-utils/files';
+import { Headers } from '../../runtime/app/headers.js';
 import { ssr } from '../../runtime/server/index.js';
 import { get_body } from '@sveltejs/app-utils/http';
 import { copy_assets } from '../utils.js';
@@ -126,12 +127,13 @@ class Watcher extends EventEmitter {
 
 					const rendered = await ssr(
 						{
-							headers: req.headers,
+							headers: new Headers(req.headers),
 							method: req.method,
 							host: null,
 							path: parsed.pathname,
 							query: new URLSearchParams(parsed.query),
-							body
+							body,
+							params: null
 						},
 						{
 							paths: this.config.kit.paths,
@@ -208,7 +210,7 @@ class Watcher extends EventEmitter {
 					);
 
 					if (rendered) {
-						res.writeHead(rendered.status, rendered.headers);
+						res.writeHead(rendered.status, rendered.headers.asMap());
 						res.end(rendered.body);
 					} else {
 						res.statusCode = 404;

packages/kit/src/core/start/index.js

@@ -4,6 +4,7 @@ import { parse, pathToFileURL, URLSearchParams } from 'url';
 import sirv from 'sirv';
 import { get_body } from '@sveltejs/app-utils/http';
 import { join, resolve } from 'path';
+import { Headers } from '../../runtime/app/headers.js';
 
 /** @param {string} dir */
 const mutable = (dir) =>
@@ -45,10 +46,12 @@ export async function start({ port, config, cwd = process.cwd() }) {
 					const rendered = await app.render(
 						{
 							method: req.method,
-							headers: req.headers,
+							headers: new Headers(req.headers),
 							path: parsed.pathname,
 							body: await get_body(req),
-							query: new URLSearchParams(parsed.query || '')
+							query: new URLSearchParams(parsed.query || ''),
+							params: null,
+							host: null
 						},
 						{
 							paths: {
@@ -61,7 +64,7 @@ export async function start({ port, config, cwd = process.cwd() }) {
 					);
 
 					if (rendered) {
-						res.writeHead(rendered.status, rendered.headers);
+						res.writeHead(rendered.status, rendered.headers.asMap());
 						res.end(rendered.body);
 					} else {
 						res.statusCode = 404;

packages/kit/src/runtime/app/headers.js

@@ -0,0 +1,80 @@
+/**
+ * @type {import("../../../types.internal").Headers}
+ */
+export class Headers {
+	/**
+	 * @param {Record<string,string|string[]>} [headers]
+	 */
+	constructor(headers) {
+		this.headers = lowercase_keys(headers) || {};
+	}
+
+	/**
+	 * @param {string} key
+	 * @param {string} value
+	 */
+	set(key, value) {
+		this.headers[key.toLowerCase()] = value;
+	}
+
+	/**
+	 * @param {string} key
+	 * @returns {string}
+	 */
+	get(key) {
+		key = key.toLowerCase();
+		if (Array.isArray(this.headers[key])) {
+			if (this.headers[key].length > 1) {
+				throw new Error(`Called get but multiple headers found for ${key}`);
+			}
+			return this.headers[key][0];
+		}
+		return /** @type {string} */ (this.headers[key]);
+	}
+
+	/**
+	 * @param {string} key
+	 * @returns {string[]}
+	 */
+	getAll(key) {
+		key = key.toLowerCase();
+		if (typeof this.headers[key] === 'string') {
+			return [/** @type {string} */ (this.headers[key])];
+		}
+		if (typeof this.headers[key] === 'undefined') {
+			return [];
+		}
+		return /** @type {string[]} */ (this.headers[key]);
+	}
+
+	/**
+	 * @returns {Record<string,string|string[]>}
+	 */
+	asMap() {
+		return this.headers;
+	}
+
+	/**
+	 * @returns {Record<string,string>}
+	 */
+	asSingleValuedMap() {
+		/** @type {Record<string,string>} */
+		const result = {};
+		for (const key of Object.keys(this.headers)) {
+			result[key] = this.get(key);
+		}
+		return result;
+	}
+}
+
+/** @param {Record<string, string|string[]>} obj */
+function lowercase_keys(obj) {
+	/** @type {Record<string, string|string[]>} */
+	const clone = {};
+
+	for (const key in obj) {
+		clone[key.toLowerCase()] = obj[key];
+	}
+
+	return clone;
+}

packages/kit/src/runtime/server/endpoint.js

@@ -1,3 +1,5 @@
+import { Headers } from '../app/headers.js';
+
 /**
  * @param {import('../../../types.internal').Request} request
  * @param {*} context // TODO
@@ -18,7 +20,7 @@ export default function render_route(request, context, options) {
 
 			const response = await handler(
 				{
-					host: options.host || request.headers[options.host_header || 'host'],
+					host: options.host || request.headers.get(options.host_header || 'host'),
 					path: request.path,
 					headers: request.headers,
 					query: request.query,
@@ -34,19 +36,17 @@ export default function render_route(request, context, options) {
 					body: `Invalid response from route ${request.path}; ${
 						response.body == null ? 'body is missing' : `expected an object, got ${typeof response}`
 					}`,
-					headers: {}
+					headers: new Headers()
 				};
 			}
 
-			let { status = 200, body, headers = {} } = response;
-
-			headers = lowercase_keys(headers);
+			let { status = 200, body, headers = new Headers() } = response;
 
 			if (
 				(typeof body === 'object' && !('content-type' in headers)) ||
-				headers['content-type'] === 'application/json'
+				headers.get('content-type') === 'application/json'
 			) {
-				headers = { ...headers, 'content-type': 'application/json' };
+				headers.set('content-type', 'application/json');
 				body = JSON.stringify(body);
 			}
 
@@ -55,20 +55,8 @@ export default function render_route(request, context, options) {
 			return {
 				status: 501,
 				body: `${request.method} is not implemented for ${request.path}`,
-				headers: {}
+				headers: new Headers()
 			};
 		}
 	});
 }
-
-/** @param {Record<string, string>} obj */
-function lowercase_keys(obj) {
-	/** @type {Record<string, string>} */
-	const clone = {};
-
-	for (const key in obj) {
-		clone[key.toLowerCase()] = obj[key];
-	}
-
-	return clone;
-}

packages/kit/src/runtime/server/index.js

@@ -1,4 +1,5 @@
 import { createHash } from 'crypto';
+import { Headers } from '../app/headers.js';
 import render_page from './page.js';
 import render_endpoint from './endpoint.js';
 
@@ -17,13 +18,13 @@ export async function ssr(request, options) {
 
 		return {
 			status: 301,
-			headers: {
+			headers: new Headers({
 				location: request.path.slice(0, -1) + (q ? `?${q}` : '')
-			}
+			})
 		};
 	}
 
-	const { context, headers = {} } =
+	const { context, headers = new Headers({}) } =
 		(await (options.setup.prepare && options.setup.prepare({ headers: request.headers }))) || {};
 
 	try {
@@ -33,24 +34,24 @@ export async function ssr(request, options) {
 		if (response) {
 			// inject ETags for 200 responses
 			if (response.status === 200) {
-				if (!/(no-store|immutable)/.test(response.headers['cache-control'])) {
+				if (!/(no-store|immutable)/.test(response.headers.get('cache-control'))) {
 					const etag = `"${md5(response.body)}"`;
 
-					if (request.headers['if-none-match'] === etag) {
+					if (request.headers.get('if-none-match') === etag) {
 						return {
 							status: 304,
-							headers: {},
+							headers: new Headers({}),
 							body: null
 						};
 					}
 
-					response.headers['etag'] = etag;
+					response.headers.set('etag', etag);
 				}
 			}
 
 			return {
 				status: response.status,
-				headers: { ...headers, ...response.headers },
+				headers: new Headers({ ...headers.asMap(), ...response.headers.asMap() }),
 				body: response.body,
 				dependencies: response.dependencies
 			};