astro/dist/core/request.js

Astro is a modern site builder with web best practices, performance, and DX front-of-mind.

/**
* Used by astro internals to create a web standard request object.
*
* The user of this function may provide the data in a runtime-agnostic way.
*
* This is used by the static build to create fake requests for prerendering, and by the dev server to convert node requests into the standard request object.
*/
export function createRequest({ url, headers, method = "GET", body = undefined, logger, isPrerendered = false, routePattern, init }) {
	// headers are made available on the created request only if the request is for a page that will be on-demand rendered
	const headersObj = isPrerendered ? undefined : headers instanceof Headers ? headers : new Headers(
		// Filter out HTTP/2 pseudo-headers. These are internally-generated headers added to all HTTP/2 requests with trusted metadata about the request.
		// Examples include `:method`, `:scheme`, `:authority`, and `:path`.
		// They are always prefixed with a colon to distinguish them from other headers, and it is an error to add the to a Headers object manually.
		// See https://httpwg.org/specs/rfc7540.html#HttpRequest
		Object.entries(headers).filter(([name]) => !name.startsWith(":"))
	);
	if (typeof url === "string") url = new URL(url);
	// Remove search parameters if the request is for a page that will be on-demand rendered
	if (isPrerendered) {
		url.search = "";
	}
	const request = new Request(url, {
		method,
		headers: headersObj,
		// body is made available only if the request is for a page that will be on-demand rendered
		body: isPrerendered ? null : body,
		...init
	});
	if (isPrerendered) {
		// Warn when accessing headers in SSG mode
		let _headers = request.headers;
		// We need to remove descriptor's value and writable properties because we're adding getters and setters.
		const { value, writable, ...headersDesc } = Object.getOwnPropertyDescriptor(request, "headers") || {};
		Object.defineProperty(request, "headers", {
			...headersDesc,
			get() {
				logger.warn(null, `\`Astro.request.headers\` was used when rendering the route \`${routePattern}'\`. \`Astro.request.headers\` is not available on prerendered pages. If you need access to request headers, make sure that the page is server-rendered using \`export const prerender = false;\` or by setting \`output\` to \`"server"\` in your Astro config to make all your pages server-rendered by default.`);
				return _headers;
			},
			set(newHeaders) {
				_headers = newHeaders;
			}
		});
	}
	return request;
}