astro/dist/core/preview/index.js

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

import fs from "node:fs";
import { createRequire } from "node:module";
import { fileURLToPath, pathToFileURL } from "node:url";
import { AstroIntegrationLogger } from "../logger/core.js";
import { telemetry } from "../../events/index.js";
import { eventCliSession } from "../../events/session.js";
import { runHookConfigDone, runHookConfigSetup } from "../../integrations/hooks.js";
import { resolveConfig } from "../config/config.js";
import { loadOrCreateNodeLogger } from "../logger/load.js";
import { createSettings } from "../config/settings.js";
import { createRoutesList } from "../routing/create-manifest.js";
import { getClientOutputDirectory, getPrerenderDefault } from "../../prerender/utils.js";
import { ensureProcessNodeEnv } from "../util.js";
import createStaticPreviewServer from "./static-preview-server.js";
import { getResolvedHostForHttpServer } from "./util.js";
/**
* Starts a local server to serve your static dist/ directory. This command is useful for previewing
* your build locally, before deploying it. It is not designed to be run in production.
*
* @experimental The JavaScript API is experimental
*/
export default async function preview(inlineConfig) {
	ensureProcessNodeEnv("production");
	const { userConfig, astroConfig } = await resolveConfig(inlineConfig ?? {}, "preview");
	const logger = await loadOrCreateNodeLogger(astroConfig, inlineConfig ?? {});
	telemetry.record(eventCliSession("preview", userConfig));
	const _settings = await createSettings(astroConfig, inlineConfig.logLevel, fileURLToPath(astroConfig.root));
	const settings = await runHookConfigSetup({
		settings: _settings,
		command: "preview",
		logger
	});
	// Create a route manifest and determine buildOutput from actual routes.
	// Route scanning sets settings.buildOutput to 'server' if any route is non-prerendered.
	settings.buildOutput = getPrerenderDefault(settings.config) ? "static" : "server";
	await createRoutesList({
		settings,
		cwd: inlineConfig.root
	}, logger);
	await runHookConfigDone({
		settings,
		logger,
		command: "preview"
	});
	if (settings.buildOutput === "static" && !settings.adapter?.previewEntrypoint) {
		const clientOutDir = getClientOutputDirectory(settings);
		if (!fs.existsSync(clientOutDir)) {
			const outDirPath = fileURLToPath(clientOutDir);
			throw new Error(`[preview] The output directory ${outDirPath} does not exist. Did you run \`astro build\`?`);
		}
		const server = await createStaticPreviewServer(settings, logger);
		return server;
	}
	if (!settings.adapter) {
		throw new Error(`[preview] No adapter found.`);
	}
	if (!settings.adapter.previewEntrypoint) {
		throw new Error(`[preview] The ${settings.adapter.name} adapter does not support the preview command.`);
	}
	// We need to use require.resolve() here so that advanced package managers like pnpm
	// don't treat this as a dependency of Astro itself. This correctly resolves the
	// preview entrypoint of the integration package, relative to the user's project root.
	const require = createRequire(settings.config.root);
	const previewEntrypointUrl = pathToFileURL(require.resolve(settings.adapter.previewEntrypoint.toString())).href;
	const previewModule = await import(previewEntrypointUrl);
	if (typeof previewModule.default !== "function") {
		throw new Error(`[preview] ${settings.adapter.name} cannot preview your app.`);
	}
	const server = await previewModule.default({
		outDir: settings.config.outDir,
		client: settings.config.build.client,
		server: settings.config.build.server,
		serverEntrypoint: new URL(settings.config.build.serverEntry, settings.config.build.server),
		host: getResolvedHostForHttpServer(settings.config.server.host),
		port: settings.config.server.port,
		base: settings.config.base,
		logger: new AstroIntegrationLogger(logger.options, settings.adapter.name),
		headers: settings.config.server.headers,
		allowedHosts: settings.config.server.allowedHosts,
		open: settings.config.server.open,
		root: settings.config.root
	});
	return server;
}