mirror of
https://github.com/kevin-DL/sapper.git
synced 2026-01-12 19:25:10 +00:00
Adds a sapper extract CLI command, which scrapes the server to run as a static website starting at the site's root.
TESTED=Basic unit test ensuring relevant routes are added.
This commit is contained in:
freedmand
223
lib/utils/extract.js
Normal file
223
lib/utils/extract.js
Normal file
@@ -0,0 +1,223 @@
|
||||
const fs = require('fs-extra');
|
||||
const app = require('express')();
|
||||
const compression = require('compression');
|
||||
const sapper = require('../index.js');
|
||||
const static = require('serve-static');
|
||||
const Spider = require('node-spider');
|
||||
const path = require('path');
|
||||
|
||||
const { PORT = 3000, OUTPUT_DIR = 'dist' } = process.env;
|
||||
const { dest = sapperDest } = require('../config.js');
|
||||
|
||||
const prefix = `http://localhost:${PORT}`;
|
||||
|
||||
/**
|
||||
* Returns the full URL of the specified path in the server.
|
||||
* @param {string} url The path for which to get the complete URL.
|
||||
* @return {string} The full URL.
|
||||
*/
|
||||
function getFullUrl(url) {
|
||||
if (url.startsWith(prefix)) return url;
|
||||
return `${prefix}${url}`;
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns the extension on the URL or '' if there is none.
|
||||
* @param {string} url The URL.
|
||||
* @return {string} The URL's extension or the empty string if the URL has no
|
||||
* extension.
|
||||
*/
|
||||
function getExtension(url) {
|
||||
const splits = url.split('.');
|
||||
let extension = splits[splits.length - 1].trim();
|
||||
if (!/^[a-zA-Z0-9]+$/.test(extension) || extension.length > 10) {
|
||||
// Clear the extension if it is not alphanumeric or is long enough to
|
||||
// signify it may just be a hash value or something.
|
||||
extension = '';
|
||||
}
|
||||
return extension;
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns the relative path for the specified URL, adding index.html if the URL
|
||||
* ends in `/`. This makes the URL function well in a static site.
|
||||
* @param {string} url The URL for which to retrieve the relative path.
|
||||
* @return {string} A URL that starts with / that is relative to the server
|
||||
* root. The URL will add index.html if it ends with `/`.
|
||||
*/
|
||||
function relativePath(url) {
|
||||
if (url.startsWith(prefix)) return relativePath(url.substr(prefix.length));
|
||||
if (url.endsWith('/')) url += 'index.html';
|
||||
if (getExtension(url) == '') url += '/index.html';
|
||||
if (url.startsWith('/')) return url;
|
||||
throw new Error('Bad url');
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns the Sapper API route for the specified URL path.
|
||||
* @param {string} url The absolute or relative URL.
|
||||
* @return {string} The URL with /api/ in front.
|
||||
*/
|
||||
function apiPath(url) {
|
||||
if (url.startsWith(prefix)) {
|
||||
return `${prefix}/api${url.substr(prefix.length)}`;
|
||||
}
|
||||
return `/api${url}`;
|
||||
}
|
||||
|
||||
/**
|
||||
* Returns whether the specified URL is on the server or an external link.
|
||||
* @param {string} url The URL.
|
||||
* @return {boolean} True if the URL is on the server.
|
||||
*/
|
||||
function filter(url) {
|
||||
return url.startsWith('/') || url.startsWith(getFullUrl('/'));
|
||||
}
|
||||
|
||||
/**
|
||||
* Retrieves chunk files that are normally cached for offline use in the service
|
||||
* worker.
|
||||
* @return {!Array<string>}
|
||||
*/
|
||||
function getChunkFiles() {
|
||||
const clientInfo =
|
||||
fs.readJsonSync(path.join(sapperDest, 'stats.client.json'));
|
||||
const chunkFiles = clientInfo.assets.map(chunk => `/client/${chunk.name}`);
|
||||
return chunkFiles;
|
||||
}
|
||||
|
||||
/**
|
||||
* Exports the Sapper app as a static website by starting at the root and
|
||||
* crawling pages that are linked, their /api/ pages, and webpack routes, as
|
||||
* well as copying assets.
|
||||
* @param {?Array<string>=} includeUrls If non-null, a set of additional URLs to
|
||||
* scrape in the extraction. This should only be set if there are routes
|
||||
* that cannot be reached from the root.
|
||||
* @param {?Array<string>=} excludeUrls If non-null, a set of URLs to avoid
|
||||
* scraping in the extraction.
|
||||
* @param {number=} extractionDir The directory in which to place the extracted
|
||||
* output.
|
||||
*/
|
||||
module.exports = async function(includeUrls = null, excludeUrls = null,
|
||||
extractionDir = OUTPUT_DIR) {
|
||||
// Set up the server.
|
||||
|
||||
// this allows us to do e.g. `fetch('/api/blog')` on the server
|
||||
const fetch = require('node-fetch');
|
||||
global.fetch = (url, opts) => {
|
||||
if (url[0] === '/') url = `http://localhost:${PORT}${url}`;
|
||||
return fetch(url, opts);
|
||||
};
|
||||
|
||||
app.use(compression({ threshold: 0 }));
|
||||
|
||||
app.use(static('assets'));
|
||||
|
||||
app.use(sapper());
|
||||
|
||||
// Clean the output directory and copy assets in.
|
||||
fs.removeSync(extractionDir);
|
||||
fs.copySync('assets', extractionDir);
|
||||
|
||||
// If exclude URLs are set, normalize them.
|
||||
if (excludeUrls == null) excludeUrls = [];
|
||||
excludeUrls = excludeUrls.map((url) => getFullUrl(url));
|
||||
|
||||
// The crux of the extraction, chaining the traditional server call with a web
|
||||
// scraper. The program automatically exits after all the static pages have
|
||||
// been scraped from the server that are accessible from the root page (`/`).
|
||||
const extractedFiles = []; // keep track of extracted files.
|
||||
const server = await app.listen(PORT);
|
||||
console.log(`listening on port ${PORT} and beginning extraction`);
|
||||
|
||||
return new Promise((resolve, reject) => {
|
||||
const spider = new Spider({
|
||||
concurrent: 5,
|
||||
delay: 0,
|
||||
logs: process.stderr,
|
||||
allowDuplicates: false,
|
||||
catchErrors: true,
|
||||
addReferrer: false,
|
||||
xhr: false,
|
||||
keepAlive: false,
|
||||
error: (err, url) => {
|
||||
console.error(`ERROR ${err} at ${url}`);
|
||||
reject();
|
||||
},
|
||||
// Called when there are no more requests
|
||||
done: async () => {
|
||||
await server.close();
|
||||
console.log('Done!');
|
||||
resolve();
|
||||
},
|
||||
|
||||
headers: { 'user-agent': 'node-spider' },
|
||||
// Use a binary encoding to preserve image files.
|
||||
encoding: 'binary'
|
||||
});
|
||||
|
||||
// The primary logic to handle a scraped page.
|
||||
const handleRequest = (doc) => {
|
||||
// Only deal with the page if it is on the server, i.e. it is not an
|
||||
// external link.
|
||||
if (!filter(doc.url)) return;
|
||||
// Skip URL if it is in the exclude list.
|
||||
if (excludeUrls.includes(getFullUrl(doc.url))) return;
|
||||
|
||||
// Grab the page's relative path and write the page contents to a local
|
||||
// file.
|
||||
const relPath = relativePath(doc.url);
|
||||
extractedFiles.push(relPath);
|
||||
console.log(`GOT ${relPath}`); // static page url
|
||||
fs.outputFileSync(path.join(extractionDir, relPath), doc.res.body,
|
||||
{encoding: 'binary'});
|
||||
|
||||
/**
|
||||
* Resolves and checks if a given URL is local; if so, adds it to the
|
||||
* scraping queue.
|
||||
* @param {string} url The URL to process.
|
||||
*/
|
||||
const process = (url) => {
|
||||
// Remove trailing hash if relevant.
|
||||
url = url.split('#')[0];
|
||||
// Resolve URL relative to server root.
|
||||
url = doc.resolve(url);
|
||||
// Crawl more if the URL is on the server.
|
||||
if (filter(url)) spider.queue(url, handleRequest);
|
||||
};
|
||||
|
||||
const extension = getExtension(relPath);
|
||||
if (extension == 'html') {
|
||||
// Grab src and href attributes from html pages.
|
||||
doc.$('[src]').each((i, elem) => {
|
||||
process(doc.$(elem).attr('src'));
|
||||
});
|
||||
doc.$('[href]').each((i, elem) => {
|
||||
process(doc.$(elem).attr('href'));
|
||||
});
|
||||
}
|
||||
|
||||
if (doc.url.endsWith('/service-worker.js')) {
|
||||
// Grab additional routes.
|
||||
const chunkFiles = getChunkFiles();
|
||||
chunkFiles.forEach(
|
||||
(url) => spider.queue(getFullUrl(url), handleRequest));
|
||||
}
|
||||
|
||||
if (relPath.endsWith('/index.html') && !relPath.startsWith('/api/')) {
|
||||
// Attempt to grab the /api/ version of a page that seems to be a
|
||||
// basic route.
|
||||
spider.queue(apiPath(doc.url), handleRequest);
|
||||
}
|
||||
};
|
||||
|
||||
// Start crawling with the document root and the service worker.
|
||||
spider.queue(getFullUrl('/'), handleRequest);
|
||||
spider.queue(getFullUrl('/service-worker.js'), handleRequest);
|
||||
|
||||
if (includeUrls !== null) {
|
||||
includeUrls.forEach(
|
||||
(url) => spider.queue(getFullUrl(url), handleRequest));
|
||||
}
|
||||
});
|
||||
}
|
||||
Reference in New Issue
Block a user