createRedirectRoutes() — astro Function Reference

Source Code

packages/astro/src/core/routing/manifest/create.ts lines 321–401

function createRedirectRoutes(
	{ settings }: CreateRouteManifestParams,
	routeMap: Map<string, RouteData>,
): RouteData[] {
	const { config } = settings;
	const trailingSlash = config.trailingSlash;

	const routes: RouteData[] = [];

	for (const [from, to] of Object.entries(settings.config.redirects)) {
		const segments = removeLeadingForwardSlash(from)
			.split(path.posix.sep)
			.filter(Boolean)
			.map((s: string) => {
				validateSegment(s);
				return getParts(s, from);
			});

		const pattern = getPattern(segments, settings.config.base, trailingSlash);
		const pathname = segments.every((segment) => segment.length === 1 && !segment[0].dynamic)
			? `/${segments.map((segment) => segment[0].content).join('/')}`
			: null;
		const params = segments
			.flat()
			.filter((p) => p.dynamic)
			.map((p) => p.content);
		const route = joinSegments(segments);

		let destination: string;
		if (typeof to === 'string') {
			destination = to;
		} else {
			destination = to.destination;
		}

		// check if the link starts with http or https; if not, throw an error
		if (URL.canParse(destination) && !/^https?:\/\//.test(destination)) {
			throw new AstroError({
				...UnsupportedExternalRedirect,
				message: UnsupportedExternalRedirect.message(from, destination),
			});
		}

		const redirectRoute = routeMap.get(destination);

		// If the source has dynamic params and the redirect will be prerendered,
		// we need a valid redirectRoute to map them. Without it, the build will fail
		// later with a misleading error. Catch this early and provide a clear error message.
		if (
			params.length > 0 &&
			!redirectRoute &&
			!URL.canParse(destination) &&
			getPrerenderDefault(config)
		) {
			throw new AstroError({
				...InvalidRedirectDestination,
				message: InvalidRedirectDestination.message(from, destination),
			});
		}

		routes.push({
			type: 'redirect',
			// For backwards compatibility, a redirect is never considered an index route.
			isIndex: false,
			route,
			pattern,
			segments,
			params,
			component: from,
			pathname: pathname || void 0,
			prerender: getPrerenderDefault(config),
			redirect: to,
			redirectRoute,
			fallbackRoutes: [],
			distURL: [],
			origin: 'project',
		});
	}

	return routes;
}