findRouteToRewrite() — astro Function Reference

Source Code

packages/astro/src/core/routing/rewrite.ts lines 39–145

export function findRouteToRewrite({
	payload,
	routes,
	request,
	trailingSlash,
	buildFormat,
	base,
	outDir,
}: FindRouteToRewrite): FindRouteToRewriteResult {
	let newUrl: URL | undefined = undefined;
	if (payload instanceof URL) {
		newUrl = payload;
	} else if (payload instanceof Request) {
		newUrl = new URL(payload.url);
	} else {
		newUrl = new URL(payload, new URL(request.url).origin);
	}

	let pathname = newUrl.pathname;
	const shouldAppendSlash = shouldAppendForwardSlash(trailingSlash, buildFormat);

	// Special handling for base path
	if (base !== '/') {
		// Check if this is a request to the base path
		const isBasePathRequest =
			newUrl.pathname === base || newUrl.pathname === removeTrailingForwardSlash(base);

		if (isBasePathRequest) {
			// For root path requests at the base URL
			// When trailingSlash is 'never', we should match '' (empty string pathname)
			// When trailingSlash is 'always', we should match '/' pathname
			pathname = shouldAppendSlash ? '/' : '';
		} else if (newUrl.pathname.startsWith(base)) {
			// For non-root paths under the base
			pathname = shouldAppendSlash
				? appendForwardSlash(newUrl.pathname)
				: removeTrailingForwardSlash(newUrl.pathname);
			pathname = pathname.slice(base.length);
		}
	}

	// Ensure pathname starts with '/' when needed
	if (!pathname.startsWith('/') && shouldAppendSlash && newUrl.pathname.endsWith('/')) {
		pathname = prependForwardSlash(pathname);
	}

	// Convert '/' to '' for trailingSlash: 'never'
	if (pathname === '/' && base !== '/' && !shouldAppendSlash) {
		pathname = '';
	}
	// If config.build.format = 'file' then pathname includes .html, so we need to remove it
	if (buildFormat === 'file') {
		pathname = pathname.replace(/\.html$/, '');
	}
	// Set the final URL pathname
	if (base !== '/' && (pathname === '' || pathname === '/') && !shouldAppendSlash) {
		// Special case for root path at base URL with trailingSlash: 'never'
		newUrl.pathname = removeTrailingForwardSlash(base);
	} else {
		newUrl.pathname = joinPaths(...[base, pathname].filter(Boolean));
	}

	const decodedPathname = decodeURI(pathname);
	let foundRoute;
	for (const route of routes) {
		if (route.pattern.test(decodedPathname)) {
			// If it's a dynamic route, make sure it actually generates the pathname
			// Checking for params to make sure it's a dynamic route
			if (
				route.params &&
				route.params.length !== 0 &&
				route.distURL &&
				route.distURL.length !== 0
			) {
				// Remove outDir from beginning of distURL
				// Remove /index.html or .html from end of distURL and compare with pathname
				// Use pathname (encoded) instead of decodedPathname because url.href is encoded
				if (
					!route.distURL.find(
						(url) =>
							url.href.replace(outDir.toString(), '').replace(/(?:\/index\.html|\.html)$/, '') ==