playwright: auto-start a web server for the special URL localhost:5000

To make it easier to run the tests locally (or in the near future, in
every PullRequest), let's add a minimal node.js script that serves the
static webpages in as similar a manner to GitHub Pages as is needed for
the tests to validate the site.

This server will be started automatically when running with the
environment variable PLAYWRIGHT_TEST_URL set to http://localhost:5000/.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

playwright.config.js

@@ -74,11 +74,14 @@ module.exports = defineConfig({
     // },
   ],
 
-  /* Run your local dev server before starting the tests */
-  // webServer: {
-  //   command: 'npm run start',
-  //   url: 'http://127.0.0.1:3000',
-  //   reuseExistingServer: !process.env.CI,
-  // },
+  /* Run a local web server before starting the tests as needed */
+  webServer:
+    process.env.PLAYWRIGHT_TEST_URL !== 'http://localhost:5000/'
+    ? undefined
+    : {
+      command: 'node script/serve-public.js',
+      url: process.env.PLAYWRIGHT_TEST_URL,
+      reuseExistingServer: true,
+    },
 });
 

script/serve-public.js

@@ -0,0 +1,56 @@
+#!/usr/bin/env node
+
+const http = require('http');
+const url = require('url');
+const fs = require('fs');
+const path = require('path');
+
+const basePath = path.join(__dirname, '..', 'public');
+
+const mimeTypes = {
+     "html": "text/html",
+     "jpeg": "image/jpeg",
+     "jpg": "image/jpeg",
+     "png": "image/png",
+     "ico": "image/x-icon",
+     "js": "text/javascript",
+     "css": "text/css",
+     "json": "application/json",
+     'pf_filter': 'application/gzip',
+     'pf_fragment': 'application/gzip',
+     'pf_index': 'application/gzip',
+     'pf_meta': 'application/gzip',
+     'pagefind': 'application/gzip',
+};
+
+const handler = (request, response) => {
+    const pathname = url.parse(request.url).pathname;
+    let filename = path.join(basePath, pathname === "/" ? "index.html" : pathname);
+
+    let stats = fs.statSync(filename, { throwIfNoEntry: false });
+    if (!stats?.isFile() && !filename.match(/\.[A-Za-z0-9]{1,11}$/)) {
+	    filename += ".html";
+	    stats = fs.statSync(filename, { throwIfNoEntry: false });
+    }
+    try{
+        if (!stats?.isFile()) throw new Error(`Not a file: ${filename}`);
+        const fileStream = fs.createReadStream(filename);
+        let mimeType = mimeTypes[path.extname(filename).split(".")[1]];
+        if (!mimeType) throw new Error(`Could not get mime type for '${filename}'`)
+        response.writeHead(200, {'Content-Type':mimeType});
+        fileStream.pipe(response);
+    } catch(e) {
+        console.log(`Could not read ${filename}`);
+        response.writeHead(404, {'Content-Type': 'text/plain'});
+        response.write('404 Not Found\n');
+        response.end();
+        return;
+    }
+};
+
+const server = http.createServer(handler);
+
+server.on("listening", () => {
+    console.log(`Now listening on: http://localhost:${server.address().port}/`);
+});
+server.listen(5000);