[FEATURE] Server: Add handling for custom middleware (#200)

As per RFC 0005: SAP/ui5-tooling#151

README.md

@@ -15,8 +15,8 @@
 ## Server
 Provides server capabilities for the [UI5 Tooling](https://github.com/SAP/ui5-tooling).
 
-### Middlewares
-The development server has already a set of middlewares which supports the developer with the following features:
+### Middleware
+The development server has already a set of middleware which supports the developer with the following features:
 
 * Translation files with `.properties` extension are properly encoded with **ISO-8859-1**.
 * Changes on files with `.less` extension triggers a theme build and delivers the compiled CSS files.

index.js

@@ -5,13 +5,33 @@
 module.exports = {
 	server: require("./lib/server"),
 	sslUtil: require("./lib/sslUtil"),
+	middlewareRepository: require("./lib/middleware/middlewareRepository"),
+
+	// Legacy middleware export. Still private.
 	middleware: {
 		csp: require("./lib/middleware/csp"),
-		discovery: require("./lib/middleware/discovery"),
-		nonReadRequests: require("./lib/middleware/discovery"),
-		serveIndex: require("./lib/middleware/serveIndex"),
-		serveResources: require("./lib/middleware/serveResources"),
-		serveThemes: require("./lib/middleware/serveThemes"),
-		versionInfo: require("./lib/middleware/versionInfo"),
+		discovery: mapLegacyMiddlewareArguments(require("./lib/middleware/discovery")),
+		nonReadRequests: mapLegacyMiddlewareArguments(require("./lib/middleware/discovery")),
+		serveIndex: mapLegacyMiddlewareArguments(require("./lib/middleware/serveIndex")),
+		serveResources: mapLegacyMiddlewareArguments(require("./lib/middleware/serveResources")),
+		serveThemes: mapLegacyMiddlewareArguments(require("./lib/middleware/serveThemes")),
+		versionInfo: mapLegacyMiddlewareArguments(require("./lib/middleware/versionInfo")),
 	}
 };
+
+function mapLegacyMiddlewareArguments(module) {
+	// Old arguments was a single object with optional properties
+	// - resourceCollections
+	// - tree
+	return function({resourceCollections, tree} = {}) {
+		const resources = {};
+		resources.all = resourceCollections.combo;
+		resources.rootProject = resourceCollections.source;
+		resources.dependencies = resourceCollections.dependencies;
+
+		return module({
+			resources,
+			tree
+		});
+	};
+}

lib/middleware/MiddlewareManager.js

@@ -0,0 +1,178 @@
+const middlewareRepository = require("./middlewareRepository");
+/**
+ *
+ *
+ * @memberof module:@ui5/server.middleware
+ */
+class MiddlewareManager {
+	constructor({tree, resources, options = {
+		sendSAPTargetCSP: false
+	}}) {
+		if (!tree || !resources || !resources.all || !resources.rootProject || !resources.dependencies) {
+			throw new Error("[MiddlewareManager]: One or more mandatory parameters not provided");
+		}
+		this.tree = tree;
+		this.resources = resources;
+		this.options = options;
+
+		this.middleware = {};
+		this.middlewareExecutionOrder = [];
+	}
+
+	async applyMiddleware(app) {
+		await this.addStandardMiddleware();
+		await this.addCustomMiddleware();
+
+		return this.middlewareExecutionOrder.map((name) => {
+			const m = this.middleware[name];
+			app.use(m.mountPath, m.middleware);
+		});
+	}
+
+	async addMiddleware(middlewareName, {
+		wrapperCallback, mountPath = "/",
+		beforeMiddleware, afterMiddleware
+	} = {}) {
+		let middlewareCallback = middlewareRepository.getMiddleware(middlewareName);
+		if (wrapperCallback) {
+			middlewareCallback = wrapperCallback(middlewareCallback);
+		}
+		if (this.middleware[middlewareName] || this.middlewareExecutionOrder.includes(middlewareName)) {
+			throw new Error(`Failed to add duplicate middleware ${middlewareName}`);
+		}
+
+		if (beforeMiddleware || afterMiddleware) {
+			const refMiddlewareName = beforeMiddleware || afterMiddleware;
+			let refMiddlewareIdx = this.middlewareExecutionOrder.indexOf(refMiddlewareName);
+			if (refMiddlewareIdx === -1) {
+				throw new Error(`Could not find middleware ${refMiddlewareName}, referenced by custom ` +
+					`middleware ${middlewareName}`);
+			}
+			if (afterMiddleware) {
+				// Insert after index of referenced middleware
+				refMiddlewareIdx++;
+			}
+			this.middlewareExecutionOrder.splice(refMiddlewareIdx, 0, middlewareName);
+		} else {
+			this.middlewareExecutionOrder.push(middlewareName);
+		}
+
+		this.middleware[middlewareName] = {
+			middleware: await Promise.resolve(middlewareCallback({resources: this.resources})),
+			mountPath
+		};
+	}
+
+	async addStandardMiddleware() {
+		await this.addMiddleware("csp", {
+			wrapperCallback: (cspModule) => {
+				const oCspConfig = {
+					allowDynamicPolicySelection: true,
+					allowDynamicPolicyDefinition: true,
+					definedPolicies: {
+						"sap-target-level-1":
+							"default-src 'self'; " +
+							"script-src  'self' 'unsafe-eval'; " +
+							"style-src   'self' 'unsafe-inline'; " +
+							"font-src    'self' data:; " +
+							"img-src     'self' * data: blob:; " +
+							"frame-src   'self' https: data: blob:; " +
+							"child-src   'self' https: data: blob:; " +
+							"connect-src 'self' https: wss:;",
+						"sap-target-level-2":
+							"default-src 'self'; " +
+							"script-src  'self'; " +
+							"style-src   'self' 'unsafe-inline'; " +
+							"font-src    'self' data:; " +
+							"img-src     'self' * data: blob:; " +
+							"frame-src   'self' https: data: blob:; " +
+							"child-src   'self' https: data: blob:; " +
+							"connect-src 'self' https: wss:;"
+					}
+				};
+				if (this.options.sendSAPTargetCSP) {
+					Object.assign(oCspConfig, {
+						defaultPolicy: "sap-target-level-1",
+						defaultPolicyIsReportOnly: true,
+						defaultPolicy2: "sap-target-level-2",
+						defaultPolicy2IsReportOnly: true,
+					});
+				}
+				return () => {
+					return cspModule("sap-ui-xx-csp-policy", oCspConfig);
+				};
+			}
+		});
+		await this.addMiddleware("compression");
+		await this.addMiddleware("cors");
+		await this.addMiddleware("discovery", {
+			mountPath: "/discovery"
+		});
+		await this.addMiddleware("serveResources");
+		await this.addMiddleware("serveThemes");
+		await this.addMiddleware("versionInfo", {
+			mountPath: "/resources/sap-ui-version.json",
+			wrapperCallback: (versionInfoModule) => {
+				return ({resources}) => {
+					return versionInfoModule({
+						resources,
+						tree: this.tree
+					});
+				};
+			}
+		});
+		await this.addMiddleware("connectUi5Proxy", {
+			mountPath: "/proxy"
+		});
+		// Handle anything but read operations *before* the serveIndex middleware
+		//	as it will reject them with a 405 (Method not allowed) instead of 404 like our old tooling
+		await this.addMiddleware("nonReadRequests");
+		await this.addMiddleware("serveIndex");
+	}
+
+	async addCustomMiddleware() {
+		const project = this.tree;
+		const projectCustomMiddleware = project.server && project.server.customMiddleware;
+		if (!projectCustomMiddleware || projectCustomMiddleware.length === 0) {
+			return; // No custom middleware defined
+		}
+
+		for (let i = 0; i < projectCustomMiddleware.length; i++) {
+			const middlewareDef = projectCustomMiddleware[i];
+			if (!middlewareDef.name) {
+				throw new Error(`Missing name for custom middleware definition of project ${project.metadata.name} ` +
+					`at index ${i}`);
+			}
+			if (middlewareDef.beforeMiddleware && middlewareDef.afterMiddleware) {
+				throw new Error(
+					`Custom middleware definition ${middlewareDef.name} of project ${project.metadata.name} ` +
+					`defines both "beforeMiddleware" and "afterMiddleware" parameters. Only one must be defined.`);
+			}
+			if (!middlewareDef.beforeMiddleware && !middlewareDef.afterMiddleware) {
+				throw new Error(
+					`Custom middleware definition ${middlewareDef.name} of project ${project.metadata.name} ` +
+					`defines neither a "beforeMiddleware" nor an "afterMiddleware" parameter. One must be defined.`);
+			}
+
+			if (this.middleware[middlewareDef.name]) {
+				// Middleware is already known
+				throw new Error(`Failed to add custom middleware ${middlewareDef.name}. ` +
+					`A middleware with the same name is already known.`);
+			}
+			await this.addMiddleware(middlewareDef.name, {
+				wrapperCallback: (middleware) => {
+					return ({resources}) => {
+						const options = {
+							configuration: middlewareDef.configuration
+						};
+						return middleware({resources, options});
+					};
+				},
+				mountPath: middlewareDef.mountPath,
+				beforeMiddleware: middlewareDef.beforeMiddleware,
+				afterMiddleware: middlewareDef.afterMiddleware
+			});
+		}
+	}
+}
+module.exports = MiddlewareManager;

lib/middleware/connectUi5Proxy.js

@@ -0,0 +1,9 @@
+const ui5connect = require("connect-openui5");
+
+function createMiddleware() {
+	return ui5connect.proxy({
+		secure: false
+	});
+}
+
+module.exports = createMiddleware;

lib/middleware/discovery.js

@@ -13,12 +13,14 @@ const urlPattern = /\/(app_pages|all_libs|all_tests)(?:[?#].*)?$/;
  * </ul>
  *
  * @module @ui5/server/middleware/discovery
- * @param {Object} resourceCollections Contains the resource reader or collection to access project related files
- * @param {module:@ui5/fs.AbstractReader} resourceCollections.source Resource reader or collection for the source project
- * @param {module:@ui5/fs.AbstractReader} resourceCollections.combo Resource collection which contains the workspace and the project dependencies
+ * @param {Object} parameters Parameters
+ * @param {module:@ui5/fs.AbstractReader} parameters.resources.all Reader or Collection to read resources of the
+ *                                        root project and its dependencies
+ * @param {module:@ui5/fs.AbstractReader} parameters.resources.rootProject Reader or Collection to read resources of
+ *                                        the project the server is started in
  * @returns {Function} Returns a server middleware closure.
  */
-function createMiddleware({resourceCollections}) {
+function createMiddleware({resources}) {
 	return function discoveryMiddleware(req, res, next) {
 		const parts = urlPattern.exec(req.url);
 		const type = parts && parts[1];
@@ -46,7 +48,7 @@ function createMiddleware({resourceCollections}) {
 		}
 
 		if (type === "app_pages") {
-			resourceCollections.source.byGlob("/**/*.{html,htm}").then(function(resources) {
+			resources.rootProject.byGlob("/**/*.{html,htm}").then(function(resources) {
 				resources.forEach(function(resource) {
 					const relPath = resource.getPath().substr(1); // cut off leading "/"
 					response.push({
@@ -56,7 +58,7 @@ function createMiddleware({resourceCollections}) {
 				sendResponse();
 			});
 		} else if (type === "all_libs") {
-			resourceCollections.combo.byGlob([
+			resources.all.byGlob([
 				"/resources/**/*.library"
 			]).then(function(resources) {
 				resources.forEach(function(resource) {
@@ -72,8 +74,8 @@ function createMiddleware({resourceCollections}) {
 			});
 		} else if (type === "all_tests") {
 			Promise.all([
-				resourceCollections.combo.byGlob("/resources/**/*.library"),
-				resourceCollections.combo.byGlob("/test-resources/**/*.{html,htm}")
+				resources.all.byGlob("/resources/**/*.library"),
+				resources.all.byGlob("/test-resources/**/*.{html,htm}")
 			]).then(function(results) {
 				const libraryResources = results[0];
 				const testPageResources = results[1];

lib/middleware/middlewareRepository.js

@@ -0,0 +1,33 @@
+const middlewares = {
+	compression: "compression",
+	cors: "cors",
+	csp: "./csp",
+	serveResources: "./serveResources",
+	serveIndex: "./serveIndex",
+	discovery: "./discovery",
+	versionInfo: "./versionInfo",
+	connectUi5Proxy: "./connectUi5Proxy",
+	serveThemes: "./serveThemes",
+	nonReadRequests: "./nonReadRequests"
+};
+
+function getMiddleware(middlewareName) {
+	const middlewarePath = middlewares[middlewareName];
+
+	if (!middlewarePath) {
+		throw new Error(`middlewareRepository: Unknown Middleware ${middlewareName}`);
+	}
+	return require(middlewarePath);
+}
+
+function addMiddleware(name, middlewarePath) {
+	if (middlewares[name]) {
+		throw new Error(`middlewareRepository: Middleware ${name} already registered`);
+	}
+	middlewares[name] = middlewarePath;
+}
+
+module.exports = {
+	getMiddleware: getMiddleware,
+	addMiddleware: addMiddleware
+};

lib/middleware/serveIndex.js

@@ -133,16 +133,16 @@ function createContent(path, resourceInfos) {
  * Creates and returns the middleware to serve a resource index.
  *
  * @module @ui5/server/middleware/serveIndex
- * @param {Object} resourceCollections Contains the resource reader or collection to access project related files
- * @param {module:@ui5/fs.AbstractReader} resourceCollections.combo Resource collection which contains the workspace and the project dependencies
+ * @param {Object} resources Contains the resource reader or collection to access project related files
+ * @param {module:@ui5/fs.AbstractReader} resources.all Resource collection which contains the workspace and the project dependencies
  * @returns {Function} Returns a server middleware closure.
  */
-function createMiddleware({resourceCollections}) {
+function createMiddleware({resources}) {
 	return function serveIndex(req, res, next) {
 		const pathname = parseurl(req).pathname;
 		log.verbose("\n Listing index of " + pathname);
 		const glob = pathname + (pathname.endsWith("/") ? "*" : "/*");
-		resourceCollections.combo.byGlob(glob, {nodir: false}).then((resources) => {
+		resources.all.byGlob(glob, {nodir: false}).then((resources) => {
 			if (!resources || resources.length == 0) { // Not found
 				next();
 				return;

lib/middleware/serveResources.js

@@ -19,14 +19,14 @@ function isFresh(req, res) {
  * Creates and returns the middleware to serve application resources.
  *
  * @module @ui5/server/middleware/serveResources
- * @param {Object} resourceCollections Contains the resource reader or collection to access project related files
- * @param {module:@ui5/fs.AbstractReader} resourceCollections.combo Resource collection which contains the workspace and the project dependencies
+ * @param {Object} resources Contains the resource reader or collection to access project related files
+ * @param {module:@ui5/fs.AbstractReader} resources.all Resource collection which contains the workspace and the project dependencies
  * @returns {Function} Returns a server middleware closure.
  */
-function createMiddleware({resourceCollections}) {
+function createMiddleware({resources}) {
 	return function serveResources(req, res, next) {
 		const pathname = parseurl(req).pathname;
-		resourceCollections.combo.byPath(pathname).then(function(resource) {
+		resources.all.byPath(pathname).then(function(resource) {
 			if (!resource) { // Not found
 				next();
 				return;

lib/middleware/serveThemes.js

@@ -18,13 +18,13 @@ const themeRequest = /^(.*\/)library(?:(\.css)|(-RTL\.css)|(-parameters\.json))$
  * The theme is built in realtime. If a less file was modified, the theme build is triggered to rebuild the theme.
  *
  * @module @ui5/server/middleware/serveThemes
- * @param {Object} resourceCollections Contains the resource reader or collection to access project related files
- * @param {module:@ui5/fs.AbstractReader} resourceCollections.combo Resource collection which contains the workspace and the project dependencies
+ * @param {Object} resources Contains the resource reader or collection to access project related files
+ * @param {module:@ui5/fs.AbstractReader} resources.all Resource collection which contains the workspace and the project dependencies
  * @returns {Function} Returns a server middleware closure.
  */
-function createMiddleware({resourceCollections}) {
+function createMiddleware({resources}) {
 	const builder = new themeBuilder.ThemeBuilder({
-		fs: fsInterface(resourceCollections.combo)
+		fs: fsInterface(resources.all)
 	});
 
 	return function theme(req, res, next) {
@@ -46,7 +46,7 @@ function createMiddleware({resourceCollections}) {
 		}
 
 		const sourceLessPath = themeReq[1] + "library.source.less";
-		resourceCollections.combo.byPath(sourceLessPath).then((sourceLessResource) => {
+		resources.all.byPath(sourceLessPath).then((sourceLessResource) => {
 			if (!sourceLessResource) { // Not found
 				next();
 				return;