[Bugfix] Communications (#7)

This PR contains the work done to implement some bugfixes to the existing source code related to the `Communications` library of this package.

To provide further details about the work done:
- [x] removed an unnecessary function from the `Client` public protocol;
- [x] moved the `MakeURLRequestError` public error to its own file;
- [x] added the `parameters` property to the `Endpoint` public protocol;
- [x] added support for the parameters handling in the `MakeURLRequestUseCase` use case.

Co-authored-by: Javier Cicchelli <javier@rock-n-code.com>
Reviewed-on: #7

Sources/Communications/Errors/MakeURLRequestError.swift

@@ -0,0 +1,17 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftLibs open source project
+//
+// Copyright (c) 2023 Röck+Cöde VoF. and the SwiftLibs project authors
+// Licensed under the EUPL 1.2 or later.
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftLibs project authors
+//
+//===----------------------------------------------------------------------===//
+
+/// Errors generated out of the `MakeURLRequestUseCase` use case.
+public enum MakeURLRequestError: Error {
+    /// An expected URL was not created.
+    case urlNotCreated
+}

Sources/Communications/Protocols/Client.swift

@@ -27,9 +27,4 @@ public protocol Client {
         as model: Model.Type
     ) async throws -> Model
     
-    /// Makes a request to a remote location based on a given endpoint and expects to return an original, uncasted response.
-    /// - Parameter endpoint: The endpoint for which to make a remote call.
-    /// - Returns: An original data response from a call to a remote endpoint.
-    @discardableResult func request(endpoint: some Endpoint) async throws -> Data
-
 }

Sources/Communications/Protocols/Endpoint.swift

@@ -15,6 +15,11 @@ import Foundation
 /// This protocol defines an endpoint to be used in a remote call.
 public protocol Endpoint {
     
+    // MARK: Type aliases
+    
+    typealias Parameters = [String : String?]
+    typealias Headers = [String : String]
+    
     // MARK: Properties
     
     /// The scheme subcomponent for the endpoint.
@@ -29,11 +34,14 @@ public protocol Endpoint {
     /// The path subcomponent for the endpoint.
     var path: String { get }
     
+    /// The query parameter subcomponents for the endpoint.
+    var parameters: Parameters { get }
+    
     /// The HTTP request method for the endpoint.
     var method: HTTPRequestMethod { get }
     
     /// The HTTP header fields as a dictionary for the endpoint.
-    var headers: [String: String] { get }
+    var headers: Headers { get }
     
     /// The message body as data for a request.
     var body: Data? { get }

Sources/Communications/Use Cases/MakeURLRequestUseCase.swift

@@ -35,6 +35,12 @@ public struct MakeURLRequestUseCase {
             urlComponents.port = port
         }
         
+        if !endpoint.parameters.isEmpty {
+            urlComponents.queryItems = endpoint.parameters
+                .map(URLQueryItem.init)
+                .sorted(by: { $0.name < $1.name })
+        }
+
         guard let url = urlComponents.url else {
             throw MakeURLRequestError.urlNotCreated
         }
@@ -49,10 +55,3 @@ public struct MakeURLRequestUseCase {
     }
 
 }
-
-// MARK: - Errors
-
-enum MakeURLRequestError: Error {
-    case urlNotCreated
-}
-

Tests/Communications/Use Cases/MakeURLRequestUseCaseTests.swift

@@ -52,6 +52,25 @@ final class MakeURLRequestUseCaseTests: XCTestCase {
         XCTAssertNil(result.httpBody)
     }
     
+    func test_withEndpoint_initialisedWithParameters() throws {
+        // GIVEN
+        let endpoint = TestEndpoint(parameters: [
+            "someParameter": "someValue",
+            "anotherParameter": nil,
+            "otherParameter": "yetAnotherValue"
+        ])
+        
+        // WHEN
+        let result = try makeURLRequest(endpoint: endpoint)
+        
+        // THEN
+        XCTAssertNotNil(result)
+        XCTAssertEqual(result.url?.absoluteString, "http://www.something.com/path/to/endpoint?anotherParameter&otherParameter=yetAnotherValue&someParameter=someValue")
+        XCTAssertEqual(result.httpMethod, HTTPRequestMethod.get.rawValue)
+        XCTAssertEqual(result.allHTTPHeaderFields, [:])
+        XCTAssertNil(result.httpBody)
+    }
+    
     func test_withEndpoint_initialisedWithHeaders() throws {
         // GIVEN
         let endpoint = TestEndpoint(headers: [
@@ -100,23 +119,25 @@ private struct TestEndpoint: Endpoint {
     
     let scheme: String = "http"
     let host: String = "www.something.com"
+    let port: Int?
     let path: String = "/path/to/endpoint"
+    let parameters: Parameters
     let method: HTTPRequestMethod = .get
-    
+    let headers: Headers
-    var port: Int?
+    let body: Data?
-    var headers: [String : String]
-    var body: Data?
 
     // MARK: Initialisers
     
     init(
         port: Int? = nil,
-        headers: [String : String] = [:],
+        parameters: Parameters = [:],
+        headers: Headers = [:],
         body: Data? = nil
     ) {
         self.port = port
-        self.body = body
+        self.parameters = parameters
         self.headers = headers
+        self.body = body
     }
 
 }