Add grouping of routes by path prefix (#58)

Sources/Alchemy/Routing/Application+GroupedRoutes.swift

@@ -0,0 +1,20 @@
+extension Application {
+    /// Groups a set of endpoints by a path prefix.
+    /// All endpoints added in the `configure` closure will
+    /// be prefixed, but none in the handler chain that continues
+    /// after the `.grouped`.
+    ///
+    /// - Parameters:
+    ///   - pathPrefix: The path prefix for all routes
+    ///     defined in the `configure` closure.
+    ///   - configure: A closure for adding routes that will be
+    ///     prefixed by the given path prefix.
+    /// - Returns: This application for chaining handlers.
+    @discardableResult
+    public func grouped(_ pathPrefix: String, configure: (Application) -> Void) -> Self {
+        Services.router.pathPrefixes.append(pathPrefix)
+        configure(self)
+        _ = Services.router.pathPrefixes.popLast()
+        return self
+    }
+}

Sources/Alchemy/Routing/Router.swift

@@ -22,6 +22,8 @@ public final class Router {
 
     /// Current middleware of this router.
     var middlewares: [Middleware] = []
+
+    var pathPrefixes: [String] = []
 
     /// A trie that holds all the handlers.
     private let trie = RouterTrieNode<HTTPMethod, RouterHandler>()
@@ -42,7 +44,8 @@ public final class Router {
         for method: HTTPMethod,
         path: String
     ) {
-        let splitPath = path.split(separator: "/").map(String.init)
+        let pathPrefixes = self.pathPrefixes.map { $0.hasPrefix("/") ? String($0.dropFirst()) : $0 }
+        let splitPath = pathPrefixes + path.split(separator: "/").map(String.init)
         let middlewareClosures = self.middlewares.reversed().map(Middleware.intercept)
         self.trie.insert(path: splitPath, storageKey: method) {
             var next = { request in

Tests/AlchemyTests/Routing/RouterTests.swift

@@ -167,6 +167,53 @@ final class RouterTests: XCTestCase {
         // Could update the router to automatically add "/" if URI strings are missing them,
         // automatically add/remove trailing "/", etc.
     }
+
+    func testGroupedPathPrefix() throws {
+        self.app
+            .grouped("group") { app in
+                app
+                    .register(.get1)
+                    .register(.get2)
+                    .grouped("nested") { app in
+                        app.register(.post1)
+                    }
+                    .register(.post2)
+            }
+            .register(.get3)
+
+        XCTAssertEqual(try self.app.request(TestRequest(
+            method: .GET,
+            path: "/group\(TestRequest.get1.path)",
+            response: TestRequest.get1.path
+        )), TestRequest.get1.response)
+
+        XCTAssertEqual(try self.app.request(TestRequest(
+            method: .GET,
+            path: "/group\(TestRequest.get2.path)",
+            response: TestRequest.get2.path
+        )), TestRequest.get2.response)
+
+        XCTAssertEqual(try self.app.request(TestRequest(
+            method: .POST,
+            path: "/group/nested\(TestRequest.post1.path)",
+            response: TestRequest.post1.path
+        )), TestRequest.post1.response)
+
+        XCTAssertEqual(try self.app.request(TestRequest(
+            method: .POST,
+            path: "/group\(TestRequest.post2.path)",
+            response: TestRequest.post2.path
+        )), TestRequest.post2.response)
+
+        // only available under group prefix
+        XCTAssertNil(try self.app.request(TestRequest.get1))
+        XCTAssertNil(try self.app.request(TestRequest.get2))
+        XCTAssertNil(try self.app.request(TestRequest.post1))
+        XCTAssertNil(try self.app.request(TestRequest.post2))
+
+        // defined outside group --> still available without group prefix
+        XCTAssertEqual(try self.app.request(TestRequest.get3), TestRequest.get3.response)
+    }
 }
 
 /// Runs the specified callback on a request / response.