New "browse" UI

Also, separated out browse, ?meta, and ?module request handlers.

Fixes #82

modules/createServer.js

@@ -1,49 +1,148 @@
 import express from 'express';
 
+import serveDirectoryBrowser from './actions/serveDirectoryBrowser.js';
+import serveDirectoryMetadata from './actions/serveDirectoryMetadata.js';
+import serveFileBrowser from './actions/serveFileBrowser.js';
+import serveFileMetadata from './actions/serveFileMetadata.js';
 import serveFile from './actions/serveFile.js';
 import serveMainPage from './actions/serveMainPage.js';
+import serveModule from './actions/serveModule.js';
 import serveStats from './actions/serveStats.js';
 
 import cors from './middleware/cors.js';
-import fetchPackage from './middleware/fetchPackage.js';
-import findFile from './middleware/findFile.js';
+import findEntry from './middleware/findEntry.js';
 import logger from './middleware/logger.js';
 import redirectLegacyURLs from './middleware/redirectLegacyURLs.js';
 import staticFiles from './middleware/staticFiles.js';
+import validateFilename from './middleware/validateFilename.js';
 import validatePackageURL from './middleware/validatePackageURL.js';
 import validatePackageName from './middleware/validatePackageName.js';
 import validateQuery from './middleware/validateQuery.js';
+import validateVersion from './middleware/validateVersion.js';
 
-export default function createServer() {
+function createApp(callback) {
   const app = express();
-
-  app.disable('x-powered-by');
-  app.enable('trust proxy');
-
-  app.use(logger);
-  app.use(cors);
-  app.use(staticFiles);
-
-  // Special startup request from App Engine
-  // https://cloud.google.com/appengine/docs/standard/nodejs/how-instances-are-managed
-  app.get('/_ah/start', (req, res) => {
-    res.status(200).end();
-  });
-
-  app.get('/', serveMainPage);
-  app.get('/api/stats', serveStats);
-
-  app.use(redirectLegacyURLs);
-
-  app.get(
-    '*',
-    validatePackageURL,
-    validatePackageName,
-    validateQuery,
-    fetchPackage,
-    findFile,
-    serveFile
-  );
-
+  callback(app);
   return app;
 }
+
+export default function createServer() {
+  return createApp(app => {
+    app.disable('x-powered-by');
+    app.enable('trust proxy');
+    app.enable('strict routing');
+
+    app.use(logger);
+    app.use(cors);
+    app.use(staticFiles);
+
+    // Special startup request from App Engine
+    // https://cloud.google.com/appengine/docs/standard/nodejs/how-instances-are-managed
+    app.get('/_ah/start', (req, res) => {
+      res.status(200).end();
+    });
+
+    app.get('/', serveMainPage);
+    app.get('/api/stats', serveStats);
+
+    app.use(redirectLegacyURLs);
+
+    app.use(
+      '/browse',
+      createApp(app => {
+        app.enable('strict routing');
+
+        app.get(
+          '*/',
+          validatePackageURL,
+          validatePackageName,
+          validateQuery,
+          validateVersion,
+          serveDirectoryBrowser
+        );
+
+        app.get(
+          '*',
+          validatePackageURL,
+          validatePackageName,
+          validateQuery,
+          validateVersion,
+          serveFileBrowser
+        );
+      })
+    );
+
+    // We need to route in this weird way because Express
+    // doesn't have a way to route based on query params.
+    const metadataApp = createApp(app => {
+      app.enable('strict routing');
+
+      app.get(
+        '*/',
+        validatePackageURL,
+        validatePackageName,
+        validateQuery,
+        validateVersion,
+        validateFilename,
+        serveDirectoryMetadata
+      );
+
+      app.get(
+        '*',
+        validatePackageURL,
+        validatePackageName,
+        validateQuery,
+        validateVersion,
+        validateFilename,
+        serveFileMetadata
+      );
+    });
+
+    app.use((req, res, next) => {
+      if (req.query.meta != null) {
+        metadataApp(req, res);
+      } else {
+        next();
+      }
+    });
+
+    const moduleApp = createApp(app => {
+      app.enable('strict routing');
+
+      app.get(
+        '*',
+        validatePackageURL,
+        validatePackageName,
+        validateQuery,
+        validateVersion,
+        validateFilename,
+        findEntry,
+        serveModule
+      );
+    });
+
+    app.use((req, res, next) => {
+      if (req.query.module != null) {
+        moduleApp(req, res);
+      } else {
+        next();
+      }
+    });
+
+    // Send old */ requests to the new /browse UI.
+    app.get('*/', (req, res) => {
+      res.redirect(302, '/browse' + req.url);
+    });
+
+    app.get(
+      '*',
+      validatePackageURL,
+      validatePackageName,
+      validateQuery,
+      validateVersion,
+      validateFilename,
+      findEntry,
+      serveFile
+    );
+  });
+}