Files
Portfolio/scripts/prerender.mjs

284 lines
12 KiB
JavaScript

import { constants } from 'node:fs';
import { createHash, randomUUID } from 'node:crypto';
import { lstat, mkdir, mkdtemp, open, readFile, readdir, realpath, rename, rm, writeFile } from 'node:fs/promises';
import { dirname, relative, resolve, sep } from 'node:path';
import { fileURLToPath, pathToFileURL } from 'node:url';
import { loadProductionInputs } from '../src/content/load-production-inputs.ts';
import { createPageMetadata, createStaticHostArtifacts } from '../src/content/metadata.ts';
import { serializeJsonLd } from '../src/security/serialize-json-ld.ts';
import {
createArtifactContract,
createBuildAuthority,
resolveViteAssetClosure,
serializeBuildAuthority,
} from './build-contract.mjs';
import { parseExactConfigArgument } from './config-argument.mjs';
import { captureDirectoryIdentity, publishStagedDirectory } from './safe-publication.mjs';
import { verifyArtifactDirectory } from './verify-artifacts.mjs';
export { parseExactConfigArgument } from './config-argument.mjs';
const scriptPath = fileURLToPath(import.meta.url);
const repositoryRoot = resolve(dirname(scriptPath), '..');
const escapeHtml = (value) => value
.replace(/&/gu, '&')
.replace(/</gu, '&lt;')
.replace(/>/gu, '&gt;')
.replace(/"/gu, '&quot;');
const exactlyOne = (source, expression, label) => {
const matches = source.match(expression) ?? [];
if (matches.length !== 1) throw new Error(`Expected exactly one ${label}.`);
};
const metadataMarkup = (metadata) => {
const image = metadata.openGraph.image === undefined
? ''
: `\n <meta property="og:image" content="${escapeHtml(metadata.openGraph.image)}" />`;
return [
` <meta name="description" content="${escapeHtml(metadata.description)}" />`,
` <meta name="robots" content="${escapeHtml(metadata.robots)}" />`,
` <link rel="canonical" href="${escapeHtml(metadata.canonicalUrl)}" />`,
` <meta property="og:type" content="${metadata.openGraph.type}" />`,
` <meta property="og:title" content="${escapeHtml(metadata.openGraph.title)}" />`,
` <meta property="og:description" content="${escapeHtml(metadata.openGraph.description)}" />`,
` <meta property="og:url" content="${escapeHtml(metadata.openGraph.url)}" />${image}`,
` <script type="application/ld+json">${metadata.serializedJsonLd}</script>`,
].join('\n');
};
export const assemblePrerenderedHtml = (template, manifest, markup, inputs) => {
const closure = resolveViteAssetClosure(manifest);
const entryUrl = `/${closure.entryModule}`;
exactlyOne(template, /<title>[^<]*<\/title>/gu, 'title');
exactlyOne(template, /<div id="app"><\/div>/gu, 'empty app root');
exactlyOne(template, /<script type="module"[^>]*><\/script>/gu, 'client module script');
exactlyOne(template, /<!--portfolio-head-->/gu, 'portfolio head marker');
exactlyOne(template, /<!--portfolio-body-->/gu, 'portfolio body marker');
const metadata = createPageMetadata(inputs.content, inputs.manifest, inputs.site);
const snapshot = serializeJsonLd(inputs);
const preloads = closure.modulePreloads
.map((file) => ` <link rel="modulepreload" href="/${file}" />`)
.join('\n');
const withoutModule = template.replace(/\s*<script type="module"[^>]*><\/script>/u, '');
const withHead = withoutModule
.replace(/<title>[^<]*<\/title>/u, `<title>${escapeHtml(metadata.title)}</title>`)
.replace('<!--portfolio-head-->', `${preloads}\n${metadataMarkup(metadata)}`)
.replace('<div id="app"></div>', `<div id="app">${markup}</div>`);
const clientBootstrap = [
`<script id="portfolio-inputs" type="application/json">${snapshot}</script>`,
`<script type="module" crossorigin src="${entryUrl}"></script>`,
].join('\n ');
return withHead.replace('<!--portfolio-body-->', clientBootstrap);
};
const assertInsideRepository = (path) => {
const pathRelativeToRoot = relative(repositoryRoot, path);
if (pathRelativeToRoot === '..' || pathRelativeToRoot.startsWith(`..${sep}`)) {
throw new Error('Build input escaped the repository root.');
}
};
const isMissing = (error) =>
typeof error === 'object' && error !== null && 'code' in error && error.code === 'ENOENT';
const fileIdentity = (stats) => ({
dev: stats.dev,
ino: stats.ino,
size: stats.size,
mtimeMs: stats.mtimeMs,
});
const sameFileIdentity = (left, right) =>
left.dev === right.dev && left.ino === right.ino && left.size === right.size && left.mtimeMs === right.mtimeMs;
const assertRegularFile = async (path, label) => {
const stats = await lstat(path);
if (stats.isSymbolicLink() || !stats.isFile() || stats.nlink !== 1) {
throw new Error(`${label} must be one regular, non-linked file.`);
}
return fileIdentity(stats);
};
const readSafeRegularFile = async (path, label) => {
const initialIdentity = await assertRegularFile(path, label);
const handle = await open(path, constants.O_RDONLY | (constants.O_NOFOLLOW ?? 0));
try {
const openedStats = await handle.stat();
if (!openedStats.isFile() || openedStats.nlink !== 1 ||
!sameFileIdentity(initialIdentity, fileIdentity(openedStats))) {
throw new Error(`${label} identity changed while opening.`);
}
const bytes = await handle.readFile();
if (!sameFileIdentity(initialIdentity, await assertRegularFile(path, label))) {
throw new Error(`${label} identity changed while reading.`);
}
return bytes;
} finally {
await handle.close();
}
};
const assertExactDirectoryMembers = async (root, expectedNames, label) => {
await captureDirectoryIdentity(root);
const entries = await readdir(root, { withFileTypes: true });
const actualNames = entries.map((entry) => entry.name).sort();
const expected = [...expectedNames].sort();
if (JSON.stringify(actualNames) !== JSON.stringify(expected)) {
throw new Error(`${label} inventory is not exact.`);
}
if (entries.some((entry) => entry.isSymbolicLink())) throw new Error(`${label} contains a symlink.`);
return entries;
};
const loadTrustedClientBuild = async (clientRoot) => {
await assertExactDirectoryMembers(clientRoot, ['.vite', 'assets', 'index.html'], 'Client build');
const viteRoot = resolve(clientRoot, '.vite');
const assetsRoot = resolve(clientRoot, 'assets');
await assertExactDirectoryMembers(viteRoot, ['manifest.json'], 'Client Vite metadata');
await captureDirectoryIdentity(assetsRoot);
const template = (await readSafeRegularFile(resolve(clientRoot, 'index.html'), 'Built client template')).toString('utf8');
const manifestSource = (await readSafeRegularFile(resolve(viteRoot, 'manifest.json'), 'Vite manifest')).toString('utf8');
const manifest = JSON.parse(manifestSource);
const closure = resolveViteAssetClosure(manifest);
const clientPaths = [...new Set([
...closure.executableModules,
...closure.styles,
...closure.viteAssets,
])].sort();
await assertExactDirectoryMembers(
assetsRoot,
clientPaths.map((path) => path.slice('assets/'.length)),
'Client assets',
);
const bytesByPath = {};
for (const path of clientPaths) {
bytesByPath[path] = await readSafeRegularFile(resolve(clientRoot, path), `Client asset ${path}`);
}
return { template, manifest, closure, bytesByPath };
};
const loadPreparedPublicAssets = async (inputs) => {
const preparedRoot = resolve(repositoryRoot, 'inputs/prepared-assets');
await captureDirectoryIdentity(preparedRoot);
const bytesByPath = {};
for (const asset of inputs.manifest.assets) {
bytesByPath[`assets/${asset.fileName}`] = await readSafeRegularFile(
resolve(preparedRoot, asset.fileName),
`Prepared public asset ${asset.fileName}`,
);
}
return bytesByPath;
};
const writeFreshStagingArtifacts = async (stagingRoot, html, artifacts, bytesByPath) => {
await mkdir(resolve(stagingRoot, 'assets'));
for (const [path, bytes] of Object.entries(bytesByPath)) {
await writeFile(resolve(stagingRoot, path), bytes, { flag: 'wx' });
}
await Promise.all([
writeFile(resolve(stagingRoot, 'index.html'), html, { flag: 'wx' }),
writeFile(resolve(stagingRoot, 'robots.txt'), artifacts.robots, { flag: 'wx' }),
writeFile(resolve(stagingRoot, '_headers.example'), artifacts.headers, { flag: 'wx' }),
writeFile(resolve(stagingRoot, '_redirects.example'), artifacts.redirects, { flag: 'wx' }),
...(artifacts.sitemap === undefined
? []
: [writeFile(resolve(stagingRoot, 'sitemap.xml'), artifacts.sitemap, { flag: 'wx' })]),
]);
};
const removeOwnedStaging = async (stagingRoot) => {
if (dirname(stagingRoot) !== repositoryRoot || !stagingRoot.startsWith(resolve(repositoryRoot, '.dist-stage-'))) {
throw new Error('Refusing to remove an unowned staging path.');
}
try {
await captureDirectoryIdentity(stagingRoot);
} catch (error) {
if (isMissing(error) || /existing safe directory/iu.test(String(error))) return;
throw error;
}
await rm(stagingRoot, { recursive: true });
};
const writeAuthorityAtomically = async (authority) => {
const serverRoot = resolve(repositoryRoot, 'dist-ssr');
await captureDirectoryIdentity(serverRoot);
const authorityPath = resolve(serverRoot, 'artifact-authority.json');
try {
await assertRegularFile(authorityPath, 'Existing artifact authority');
} catch (error) {
if (!isMissing(error)) throw error;
}
const temporaryPath = resolve(serverRoot, `.artifact-authority-${randomUUID()}.tmp`);
try {
await writeFile(temporaryPath, serializeBuildAuthority(authority), { flag: 'wx' });
await assertRegularFile(temporaryPath, 'Temporary artifact authority');
await rename(temporaryPath, authorityPath);
} catch (error) {
await rm(temporaryPath, { force: true });
throw error;
}
};
export const prerender = async (configPath) => {
const distRoot = resolve(repositoryRoot, 'dist');
const clientRoot = resolve(repositoryRoot, 'dist-client');
const configAbsolutePath = resolve(repositoryRoot, configPath);
assertInsideRepository(configAbsolutePath);
if (await realpath(repositoryRoot) !== repositoryRoot) throw new Error('Repository root has a symlinked ancestor.');
const inputs = await loadProductionInputs({
contentJson: pathToFileURL(resolve(repositoryRoot, 'content/public/portfolio-content.json')),
assetManifestJson: pathToFileURL(resolve(repositoryRoot, 'content/public/asset-manifest.json')),
preparedAssetRoot: pathToFileURL(`${resolve(repositoryRoot, 'inputs/prepared-assets')}${sep}`),
siteConfigJson: pathToFileURL(configAbsolutePath),
});
const clientBuild = await loadTrustedClientBuild(clientRoot);
const serverEntryPath = resolve(repositoryRoot, 'dist-ssr/entry-server.js');
const serverEntryIdentity = await assertRegularFile(serverEntryPath, 'SSR entry');
const { render } = await import(`${pathToFileURL(serverEntryPath).href}?build=${encodeURIComponent(inputs.site.buildId)}`);
if (typeof render !== 'function') throw new Error('SSR entry does not export render().');
if (!sameFileIdentity(serverEntryIdentity, await assertRegularFile(serverEntryPath, 'SSR entry'))) {
throw new Error('SSR entry identity changed during import.');
}
const markup = await render('/', inputs);
const html = assemblePrerenderedHtml(clientBuild.template, clientBuild.manifest, markup, inputs);
const metadata = createPageMetadata(inputs.content, inputs.manifest, inputs.site);
const artifacts = createStaticHostArtifacts(metadata, inputs.site);
const publicBytes = await loadPreparedPublicAssets(inputs);
const bytesByPath = { ...clientBuild.bytesByPath, ...publicBytes };
const digestByPath = Object.fromEntries(Object.entries(bytesByPath).map(([path, bytes]) => [
path,
createHash('sha256').update(bytes).digest('hex'),
]));
const contract = createArtifactContract(
clientBuild.closure,
inputs.manifest,
digestByPath,
inputs.site.buildId,
);
const authority = createBuildAuthority(clientBuild.manifest, contract);
const stagingRoot = await mkdtemp(resolve(repositoryRoot, '.dist-stage-'));
try {
await writeFreshStagingArtifacts(stagingRoot, html, artifacts, bytesByPath);
await verifyArtifactDirectory(stagingRoot, inputs, contract);
const stagingIdentity = await captureDirectoryIdentity(stagingRoot);
await publishStagedDirectory({
repositoryRoot,
finalRoot: distRoot,
stagingRoot,
expectedStagingIdentity: stagingIdentity,
beforeCommit: async () => writeAuthorityAtomically(authority),
});
} catch (error) {
await removeOwnedStaging(stagingRoot);
throw error;
}
};
if (process.argv[1] !== undefined && resolve(process.argv[1]) === scriptPath) {
const configPath = parseExactConfigArgument(process.argv.slice(2));
await prerender(configPath);
}