astro/dist/vite-plugin-astro-server/trailing-slash.js

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

import { collapseDuplicateTrailingSlashes, hasFileExtension, isInternalPath } from "@astrojs/internal-helpers/path";
import { trailingSlashMismatchTemplate } from "../template/4xx.js";
import { writeHtmlResponse, writeRedirectResponse } from "./response.js";
/**
* Pure decision function for trailing-slash dev-server behavior.
*
* Evaluates a decoded `pathname`, the query-string portion (including leading
* `?`), and the project's `trailingSlash` config and returns the action the
* middleware should take. The middleware is responsible for translating the
* decision into an HTTP response.
*/
export function evaluateTrailingSlash(pathname, search, trailingSlash) {
	if (isInternalPath(pathname)) {
		return { action: "next" };
	}
	const collapsed = collapseDuplicateTrailingSlashes(pathname, true);
	if (pathname && collapsed !== pathname) {
		return {
			action: "redirect",
			status: 301,
			location: `${collapsed}${search}`
		};
	}
	if (trailingSlash === "never" && pathname.endsWith("/") && pathname !== "/" || trailingSlash === "always" && !pathname.endsWith("/") && !hasFileExtension(pathname)) {
		return {
			action: "reject",
			status: 404,
			pathname
		};
	}
	return { action: "next" };
}
export function trailingSlashMiddleware(settings) {
	const { trailingSlash } = settings.config;
	return function devTrailingSlash(req, res, next) {
		const url = new URL(`http://localhost${req.url}`);
		let pathname;
		try {
			pathname = decodeURI(url.pathname);
		} catch (e) {
			/* malformed uri */
			return next(e);
		}
		const decision = evaluateTrailingSlash(pathname, url.search, trailingSlash);
		switch (decision.action) {
			case "redirect": return writeRedirectResponse(res, decision.status, decision.location);
			case "reject": {
				const html = trailingSlashMismatchTemplate(decision.pathname, trailingSlash);
				return writeHtmlResponse(res, decision.status, html);
			}
			case "next": return next();
		}
	};
}