make URLParameter keys type aware

khanlou · Sep 6, 2020 · c4e2120 · c4e2120
1 parent e5b57c7
commit c4e2120
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Showing 9 changed files with 112 additions and 68 deletions.
diff --git a/Demo/Todos.swift b/Demo/Todos.swift
@@ -11,6 +11,16 @@ import Meridian
 // Specs
 // https://www.todobackend.com/specs/index.html?https://meridian-demo.herokuapp.com/todos
 
+struct IDParameter: URLParameterKey {
+    public typealias DecodeType = String
+}
+
+extension ParameterKeys {
+    var id: IDParameter {
+        IDParameter()
+    }
+}
+
 struct ListTodos: Route {
 
     static let route: RouteMatcher = .get(.root)
@@ -52,9 +62,9 @@ struct CreateTodo: Route {
 }
 
 struct ShowTodo: Route {
-    static let route: RouteMatcher = .get("/\(.id)")
+    static let route: RouteMatcher = .get("/\(\.id)")
 
-    @URLParameter(.id) var id: String
+    @URLParameter(\.id) var id
 
     @EnvironmentObject var database: Database
 
@@ -74,9 +84,9 @@ struct TodoPatch: Codable {
 }
 
 struct EditTodo: Route {
-    static let route: RouteMatcher = .patch("/\(.id)")
+    static let route: RouteMatcher = .patch("/\(\.id)")
 
-    @URLParameter(.id) var id: String
+    @URLParameter(\.id) var id
 
     @JSONBody var patch: TodoPatch
 
@@ -100,9 +110,9 @@ struct EditTodo: Route {
 }
 
 struct DeleteTodo: Route {
-    static let route: RouteMatcher = .delete("/\(.id)")
+    static let route: RouteMatcher = .delete("/\(\.id)")
 
-    @URLParameter(.id) var id: String
+    @URLParameter(\.id) var id
 
     @EnvironmentObject var database: Database
 

diff --git a/Meridian/HTTPHandler.swift b/Meridian/HTTPHandler.swift
@@ -14,12 +14,12 @@ let RequestErrorsKey = "RequestErrors"
 
 public struct RequestContext {
     public let header: RequestHeader
-    public let urlParameters: [URLParameterKey: Substring]
+    public let matchedRoute: MatchedRoute
     public let postBody: Data
 
-    public init(header: RequestHeader, urlParameters: [URLParameterKey: Substring] = [:], postBody: Data = Data()) {
+    public init(header: RequestHeader, matchedRoute: MatchedRoute, postBody: Data = Data()) {
         self.header = header
-        self.urlParameters = urlParameters
+        self.matchedRoute = matchedRoute
         self.postBody = postBody
     }
 
@@ -98,7 +98,7 @@ final class HTTPHandler: ChannelInboundHandler {
 
                 let requestContext = RequestContext(
                     header: header,
-                    urlParameters: matchedRoute.parameters,
+                    matchedRoute: matchedRoute,
                     postBody: body
                 )
 

diff --git a/Meridian/Property Wrappers/URLParameter.swift b/Meridian/Property Wrappers/URLParameter.swift
@@ -7,21 +7,10 @@
 
 import Foundation
 
-public typealias URLParameter<Type: LosslessStringConvertible> = CustomWithParameters<URLParameterExtractor<Type>>
+public typealias URLParameter<SpecificURLParameterKey: URLParameterKey> = CustomWithParameters<URLParameterExtractor<SpecificURLParameterKey>>
 
-public struct URLParameterExtractor<Type: LosslessStringConvertible>: ParameterizedExtractor {
-
-    public static func extract(from context: RequestContext, parameters: URLParameterKey) throws -> Type {
-        guard let substring = _currentRequest.urlParameters[parameters] else {
-            throw MissingURLParameterError()
-        }
-        let value = String(substring)
-        if Type.self == String.self {
-            return value as! Type
-        } else if let finalValue = Type(value) {
-            return finalValue
-        } else {
-            throw URLParameterDecodingError(type: Type.self)
-        }
+public struct URLParameterExtractor<SpecificURLParameterKey: URLParameterKey>: ParameterizedExtractor {
+    public static func extract(from context: RequestContext, parameters: KeyPath<ParameterKeys, SpecificURLParameterKey>) throws -> SpecificURLParameterKey.DecodeType {
+        try _currentRequest.matchedRoute.parameter(for: SpecificURLParameterKey.self)
     }
 }
diff --git a/Meridian/RouteMatcher.swift b/Meridian/RouteMatcher.swift
@@ -8,11 +8,26 @@
 import Foundation
 
 public struct MatchedRoute {
-    public let parameters: [URLParameterKey: Substring]
+    let parameters: [String: Substring]
 
-    public init(parameters: [URLParameterKey: Substring] = [:]) {
+    public init(parameters: [String: Substring] = [:]) {
         self.parameters = parameters
     }
+
+    public func parameter<Key: URLParameterKey>(for key: Key.Type) throws -> Key.DecodeType {
+        guard let substring = self.parameters[Key.stringKey] else {
+            throw MissingURLParameterError()
+        }
+        let value = String(substring)
+        if Key.DecodeType.self == String.self {
+            return value as! Key.DecodeType
+        } else if let finalValue = Key.DecodeType(value) {
+            return finalValue
+        } else {
+            throw URLParameterDecodingError(type: Key.DecodeType.self)
+        }
+
+    }
 }
 
 public struct RouteMatcher {
@@ -58,25 +73,13 @@ public struct RouteMatcher {
     }
 }
 
-public struct URLParameterKey: Hashable {
-
-    public let id = UUID()
-
-    public init() {
-
-    }
-
-    public static let id = URLParameterKey()
-}
-
-
 extension RouteMatcher: ExpressibleByStringInterpolation {
 
     public struct RegexMatcher: StringInterpolationProtocol {
 
         var regexString = ""
 
-        var mapping: [URLParameterKey] = []
+        var mapping: [String] = []
 
         public init(literalCapacity: Int, interpolationCount: Int) {
 
@@ -86,11 +89,11 @@ extension RouteMatcher: ExpressibleByStringInterpolation {
             regexString.append(literal) // escape for regex
         }
 
-        public mutating func appendInterpolation(_ urlParameter: URLParameterKey) {
+        public mutating func appendInterpolation<SpecificKey: URLParameterKey>(_ urlParameter: KeyPath<ParameterKeys, SpecificKey>) {
 
             regexString.append("([^/]+)")
 
-            mapping.append(urlParameter)
+            mapping.append(SpecificKey.stringKey)
         }
     }
 
@@ -108,16 +111,16 @@ extension RouteMatcher: ExpressibleByStringInterpolation {
                 return nil
             }
 
-            var result: [URLParameterKey: Substring] = [:]
+            var result: [String: Substring] = [:]
 
             for match in matches {
                 let ranges = (0..<match.numberOfRanges)
                     .dropFirst() /*ignore the first match*/
                     .map({ match.range(at: $0) })
 
-                zip(stringInterpolation.mapping, ranges).forEach({ urlParameter, range in
+                zip(stringInterpolation.mapping, ranges).forEach({ urlParameterName, range in
                     guard let betterRange = Range(range, in: header.path) else { fatalError("Should be able to convert ranges") }
-                    result[urlParameter] = header.path[betterRange]
+                    result[urlParameterName] = header.path[betterRange]
                 })
             }
 

diff --git a/Meridian/URLParameterKey.swift b/Meridian/URLParameterKey.swift
@@ -0,0 +1,22 @@
+//
+//  URLParameterKey.swift
+//  
+//
+//  Created by Soroush Khanlou on 9/6/20.
+//
+
+import Foundation
+
+public enum ParameterKeys {
+
+}
+
+public protocol URLParameterKey {
+    associatedtype DecodeType: LosslessStringConvertible
+}
+
+extension URLParameterKey {
+    static var stringKey: String {
+        String(reflecting: Self.self) 
+    }
+}
diff --git a/MeridianTests/RoutingTests.swift b/MeridianTests/RoutingTests.swift
@@ -64,27 +64,27 @@ final class RoutingTests: XCTestCase {
     }
 
     func testURLParameters() {
-        let matcher: RouteMatcher = "/testing/\(.tester)"
+        let matcher: RouteMatcher = "/testing/\(\.tester)"
 
         let matchedRoute = matcher.matches(RequestHeader(method: .GET, uri: "/testing/123", headers: []))
 
         XCTAssertNotNil(matchedRoute)
 
-        XCTAssertEqual(matchedRoute?.parameters[.tester], "123")
+        XCTAssertEqual(try matchedRoute?.parameter(for: TesterParameterKey.self), "123")
 
         XCTAssertNil(matcher.matches(RequestHeader(method: .GET, uri: "/testing/", headers: [])))
         XCTAssertNil(matcher.matches(RequestHeader(method: .GET, uri: "/testing/123/456", headers: [])))
     }
 
     func testTwoURLParameters() {
-        let matcher: RouteMatcher = "/testing/\(.tester)/sub/\(.secondTester)"
+        let matcher: RouteMatcher = "/testing/\(\.tester)/sub/\(\.secondTester)"
 
         let matchedRoute = matcher.matches(RequestHeader(method: .GET, uri: "/testing/123/sub/hello", headers: []))
 
         XCTAssertNotNil(matchedRoute)
 
-        XCTAssertEqual(matchedRoute?.parameters[.tester], "123")
-        XCTAssertEqual(matchedRoute?.parameters[.secondTester], "hello")
+        XCTAssertEqual(try matchedRoute?.parameter(for: TesterParameterKey.self), "123")
+        XCTAssertEqual(try matchedRoute?.parameter(for: SecondTesterParameterKey.self), "hello")
 
         XCTAssertNil(matcher.matches(RequestHeader(method: .GET, uri: "/testing/123", headers: [])))
         XCTAssertNil(matcher.matches(RequestHeader(method: .GET, uri: "/testing/123", headers: [])))

diff --git a/MeridianTests/TestHelpers.swift b/MeridianTests/TestHelpers.swift
@@ -12,11 +12,6 @@ import Meridian
 
 let http11 = HTTPVersion.init(major: 1, minor: 1)
 
-extension URLParameterKey {
-    static let tester = URLParameterKey()
-    static let secondTester = URLParameterKey()
-}
-
 struct HTTPRequestBuilder {
     let uri: String
     let method: NIOHTTP1.HTTPMethod
@@ -103,6 +98,31 @@ enum MusicNote: String, Decodable {
     }
 }
 
-extension URLParameterKey {
-    static let letter = URLParameterKey()
+struct LetterParameterKey: URLParameterKey {
+    typealias DecodeType = LetterGrade
+}
+
+struct TesterParameterKey: URLParameterKey {
+    typealias DecodeType = String
 }
+
+struct SecondTesterParameterKey: URLParameterKey {
+    typealias DecodeType = String
+}
+
+struct StringIDParameter: URLParameterKey {
+    public typealias DecodeType = String
+}
+
+struct NumberParameter: URLParameterKey {
+    public typealias DecodeType = Int
+}
+
+extension ParameterKeys {
+    var letter: LetterParameterKey { .init() }
+    var tester: TesterParameterKey { .init() }
+    var secondTester: SecondTesterParameterKey { .init() }
+    var id: StringIDParameter { .init() }
+    var number: NumberParameter { .init() }
+}
+
diff --git a/MeridianTests/URLParameterRouteTests.swift b/MeridianTests/URLParameterRouteTests.swift
@@ -19,40 +19,40 @@ struct NoURLParameterRoute: Route {
 }
 
 struct StringURLParameterRoute: Route {
-    static let route: RouteMatcher = "/string/\(.id)"
+    static let route: RouteMatcher = "/string/\(\.id)"
 
-    @URLParameter(.id) var id: String
+    @URLParameter(\.id) var id
 
     func execute() throws -> Response {
         "The ID is \(id)"
     }
 }
 
 struct IntURLParameterRoute: Route {
-    static let route: RouteMatcher = "/int/\(.id)"
+    static let route: RouteMatcher = "/int/\(\.number)"
 
-    @URLParameter(.id) var id: Int
+    @URLParameter(\.number) var id
 
     func execute() throws -> Response {
         "The ID+1 is \(id+1)"
     }
 }
 
 struct MultipleURLParameterRoute: Route {
-    static let route: RouteMatcher = "/int/\(.id)/letter/\(.letter)"
+    static let route: RouteMatcher = "/int/\(\.number)/letter/\(\.letter)"
 
-    @URLParameter(.id) var id: Int
-    @URLParameter(.letter) var letter: LetterGrade
+    @URLParameter(\.number) var id
+    @URLParameter(\.letter) var letter
 
     func execute() throws -> Response {
         "The ID+2 is \(id+2) and the letter is \(letter)"
     }
 }
 
 struct LetterURLParameterRoute: Route {
-    static let route: RouteMatcher = "/letter/\(.letter)"
+    static let route: RouteMatcher = "/letter/\(\.letter)"
 
-    @URLParameter(.letter) var grade: LetterGrade
+    @URLParameter(\.letter) var grade
 
     func execute() throws -> Response {
         "The letter grade is \(grade)"

diff --git a/README.md b/README.md
@@ -11,11 +11,11 @@ extension URLParameters {
 
 struct SampleEndpoint: Route {
   
-    static let path: RouteMatcher = "/api/users/\(.id))/followers"
+    static let path: RouteMatcher = "/api/users/\(\.id))/followers"
   
     @QueryParameter("sort_direction") var sortDirection: SortDirection
   
-    @URLParameter(.id) var userID: String
+    @URLParameter(\.id) var userID
     
     @EnivronmentObject var database: Database