Add QueryParameters protocol to provide interface for URL query.

APIKit.xcodeproj/project.pbxproj

@@ -7,6 +7,9 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		0ED17E891E229EC700EC1114 /* QueryParameters.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0ED17E881E229EC700EC1114 /* QueryParameters.swift */; };
+		0ED17E8B1E22A22900EC1114 /* URLEncodedQueryParameters.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0ED17E8A1E22A22900EC1114 /* URLEncodedQueryParameters.swift */; };
+		0ED17E8E1E22AC8300EC1114 /* URLEncodedQueryParametersTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0ED17E8D1E22AC8300EC1114 /* URLEncodedQueryParametersTests.swift */; };
 		141F12201C1C9ABE0026D415 /* Result.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = CD5115241B1FFBA900514240 /* Result.framework */; };
 		141F12311C1C9AC70026D415 /* Result.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = CD5115241B1FFBA900514240 /* Result.framework */; };
 		141F12361C1C9AC70026D415 /* Result.framework in Copy Frameworks */ = {isa = PBXBuildFile; fileRef = CD5115241B1FFBA900514240 /* Result.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
@@ -80,6 +83,9 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		0ED17E881E229EC700EC1114 /* QueryParameters.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = QueryParameters.swift; sourceTree = "<group>"; };
+		0ED17E8A1E22A22900EC1114 /* URLEncodedQueryParameters.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = URLEncodedQueryParameters.swift; sourceTree = "<group>"; };
+		0ED17E8D1E22AC8300EC1114 /* URLEncodedQueryParametersTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = URLEncodedQueryParametersTests.swift; sourceTree = "<group>"; };
 		141F120F1C1C96820026D415 /* Base.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; name = Base.xcconfig; path = Configurations/Base.xcconfig; sourceTree = "<group>"; };
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@@ -156,6 +162,24 @@
 /* End PBXFrameworksBuildPhase section */
 
 /* Begin PBXGroup section */
+		0ED17E871E229EAC00EC1114 /* QueryParameters */ = {
+			isa = PBXGroup;
+			children = (
+				0ED17E881E229EC700EC1114 /* QueryParameters.swift */,
+				0ED17E8A1E22A22900EC1114 /* URLEncodedQueryParameters.swift */,
+			);
+			name = QueryParameters;
+			path = APIKit/QueryParameters;
+			sourceTree = "<group>";
+		};
+		0ED17E8C1E22AC5D00EC1114 /* QueryParameters */ = {
+			isa = PBXGroup;
+			children = (
+				0ED17E8D1E22AC8300EC1114 /* URLEncodedQueryParametersTests.swift */,
+			);
+			path = QueryParameters;
+			sourceTree = "<group>";
+		};
 		141F120E1C1C96690026D415 /* Configurations */ = {
 			isa = PBXGroup;
 			children = (
@@ -224,6 +248,7 @@
 				7F698E451D9D680C00F1561D /* RequestTests.swift */,
 				7F698E491D9D680C00F1561D /* SessionCallbackQueueTests.swift */,
 				7F698E4A1D9D680C00F1561D /* SessionTests.swift */,
+				0ED17E8C1E22AC5D00EC1114 /* QueryParameters */,
 				7F698E3B1D9D680C00F1561D /* BodyParametersType */,
 				7F698E401D9D680C00F1561D /* DataParserType */,
 				7F698E461D9D680C00F1561D /* SessionAdapterType */,
@@ -294,6 +319,7 @@
 				7F7048CB1D9D89BE003C99F6 /* Session.swift */,
 				7F7048CC1D9D89BE003C99F6 /* Unavailable.swift */,
 				7F85FB8B1C9D317300CEE132 /* SessionAdapter */,
+				0ED17E871E229EAC00EC1114 /* QueryParameters */,
 				7F18BD0D1C972C38003A31DF /* BodyParameters */,
 				7FA19A441C9CC9A2005D25AE /* DataParser */,
 				7F18BD161C9730ED003A31DF /* Serializations */,
@@ -457,12 +483,14 @@
 			files = (
 				7F7048D31D9D89BE003C99F6 /* Unavailable.swift in Sources */,
 				7F7048D11D9D89BE003C99F6 /* Request.swift in Sources */,
+				0ED17E891E229EC700EC1114 /* QueryParameters.swift in Sources */,
 				7F7048E81D9D8A08003C99F6 /* DataParser.swift in Sources */,
 				7F7048CE1D9D89BE003C99F6 /* CallbackQueue.swift in Sources */,
 				7F7048DE1D9D89FB003C99F6 /* AbstractInputStream.m in Sources */,
 				7F7048E31D9D89FB003C99F6 /* MultipartFormDataBodyParameters.swift in Sources */,
 				7F7048F01D9D8A12003C99F6 /* ResponseError.swift in Sources */,
 				7F7048EA1D9D8A08003C99F6 /* JSONDataParser.swift in Sources */,
+				0ED17E8B1E22A22900EC1114 /* URLEncodedQueryParameters.swift in Sources */,
 				7F7048D21D9D89BE003C99F6 /* Session.swift in Sources */,
 				7F7048E01D9D89FB003C99F6 /* Data+InputStream.swift in Sources */,
 				7F7048DF1D9D89FB003C99F6 /* BodyParameters.swift in Sources */,
@@ -491,6 +519,7 @@
 				7F698E501D9D680C00F1561D /* FormURLEncodedBodyParametersTests.swift in Sources */,
 				7F698E581D9D680C00F1561D /* RequestTests.swift in Sources */,
 				ECA8314A1DE4DEBE004EB1B5 /* ProtobufDataParserTests.swift in Sources */,
+				0ED17E8E1E22AC8300EC1114 /* URLEncodedQueryParametersTests.swift in Sources */,
 				7F698E5E1D9D680C00F1561D /* TestRequest.swift in Sources */,
 				7F698E601D9D680C00F1561D /* TestSessionTask.swift in Sources */,
 				7FA1690D1D9D8C80006C982B /* HTTPStub.swift in Sources */,

Sources/APIKit/BodyParameters/BodyParameters.swift

@@ -15,6 +15,6 @@ public protocol BodyParameters {
     var contentType: String { get }
 
     /// Builds `RequestBodyEntity`.
-    /// Throws: `ErrorType`
+    /// Throws: `Error`
     func buildEntity() throws -> RequestBodyEntity
 }

Sources/APIKit/DataParser/DataParser.swift

@@ -6,6 +6,6 @@ public protocol DataParser {
     var contentType: String? { get }
 
     /// Return `Any` that expresses structure of response such as JSON and XML.
-    /// - Throws: `ErrorType` when parser encountered invalid format data.
+    /// - Throws: `Error` when parser encountered invalid format data.
     func parse(data: Data) throws -> Any
 }

Sources/APIKit/QueryParameters/QueryParameters.swift

@@ -0,0 +1,7 @@
+import Foundation
+
+/// `QueryParameters` provides interface to generate HTTP URL query strings.
+public protocol QueryParameters {
+    /// Generate URL query strings.
+    func encode() -> String?
+}

Sources/APIKit/QueryParameters/URLEncodedQueryParameters.swift

@@ -0,0 +1,20 @@
+import Foundation
+
+/// `URLEncodedQueryParameters` serializes form object for HTTP URL query.
+public struct URLEncodedQueryParameters: QueryParameters {
+    /// The parameters to be url encoded.
+    public let parameters: Any
+
+    /// Returns `URLEncodedQueryParameters` that is initialized with parameters.
+    public init(parameters: Any) {
+        self.parameters = parameters
+    }
+
+    /// Generate url encoded `String`.
+    public func encode() -> String? {
+        guard let parameters = parameters as? [String: Any], !parameters.isEmpty else {
+            return nil
+        }
+        return URLEncodedSerialization.string(from: parameters)
+    }
+}

Sources/APIKit/Request.swift

@@ -29,7 +29,7 @@ public protocol Request {
     /// The actual parameters for the URL query. The values of this property will be escaped using `URLEncodedSerialization`.
     /// If this property is not implemented and `method.prefersQueryParameter` is `true`, the value of this property
     /// will be computed from `parameters`.
-    var queryParameters: [String: Any]? { get }
+    var queryParameters: QueryParameters? { get }
 
     /// The actual parameters for the HTTP body. If this property is not implemented and `method.prefersQueryParameter` is `false`,
     /// the value of this property will be computed from `parameters` using `JSONBodyParameters`.
@@ -45,19 +45,19 @@ public protocol Request {
 
     /// Intercepts `URLRequest` which is created by `Request.buildURLRequest()`. If an error is
     /// thrown in this method, the result of `Session.send()` turns `.failure(.requestError(error))`.
-    /// - Throws: `ErrorType`
+    /// - Throws: `Error`
     func intercept(urlRequest: URLRequest) throws -> URLRequest
 
     /// Intercepts response `Any` and `HTTPURLResponse`. If an error is thrown in this method,
     /// the result of `Session.send()` turns `.failure(.responseError(error))`.
     /// The default implementation of this method is provided to throw `RequestError.unacceptableStatusCode`
     /// if the HTTP status code is not in `200..<300`.
-    /// - Throws: `ErrorType`
+    /// - Throws: `Error`
     func intercept(object: Any, urlResponse: HTTPURLResponse) throws -> Any
 
     /// Build `Response` instance from raw response object. This method is called after
     /// `intercept(object:urlResponse:)` if it does not throw any error.
-    /// - Throws: `ErrorType`
+    /// - Throws: `Error`
     func response(from object: Any, urlResponse: HTTPURLResponse) throws -> Response
 }
 
@@ -66,12 +66,12 @@ public extension Request {
         return nil
     }
 
-    public var queryParameters: [String: Any]? {
-        guard let parameters = parameters as? [String: Any], method.prefersQueryParameters else {
+    public var queryParameters: QueryParameters? {
+        guard let parameters = parameters, method.prefersQueryParameters else {
             return nil
         }
 
-        return parameters
+        return URLEncodedQueryParameters(parameters: parameters)
     }
 
     public var bodyParameters: BodyParameters? {
@@ -102,7 +102,7 @@ public extension Request {
     }
 
     /// Builds `URLRequest` from properties of `self`.
-    /// - Throws: `RequestError`, `ErrorType`
+    /// - Throws: `RequestError`, `Error`
     public func buildURLRequest() throws -> URLRequest {
         let url = path.isEmpty ? baseURL : baseURL.appendingPathComponent(path)
         guard var components = URLComponents(url: url, resolvingAgainstBaseURL: true) else {
@@ -111,8 +111,8 @@ public extension Request {
 
         var urlRequest = URLRequest(url: url)
 
-        if let queryParameters = queryParameters, !queryParameters.isEmpty {
-            components.percentEncodedQuery = URLEncodedSerialization.string(from: queryParameters)
+        if let queryString = queryParameters?.encode(), !queryString.isEmpty {
+            components.percentEncodedQuery = queryString
         }
 
         if let bodyParameters = bodyParameters {
@@ -139,7 +139,7 @@ public extension Request {
     }
 
     /// Builds `Response` from response `Data`.
-    /// - Throws: `ResponseError`, `ErrorType`
+    /// - Throws: `ResponseError`, `Error`
     public func parse(data: Data, urlResponse: HTTPURLResponse) throws -> Response {
         let parsedObject = try dataParser.parse(data: data)
         let passedObject = try intercept(object: parsedObject, urlResponse: urlResponse)

Sources/APIKit/Serializations/URLEncodedSerialization.swift

@@ -87,7 +87,7 @@ public final class URLEncodedSerialization {
         return data
     }
 
-    /// Returns urlencoded `Data` from the string.
+    /// Returns urlencoded `String` from the dictionary.
     public static func string(from dictionary: [String: Any]) -> String {
         let pairs = dictionary.map { key, value -> String in
             if value is NSNull {

Tests/APIKitTests/QueryParameters/URLEncodedQueryParametersTests.swift

@@ -0,0 +1,19 @@
+import XCTest
+import APIKit
+
+class URLEncodedQueryParametersTests: XCTestCase {
+    func testURLEncodedSuccess() {
+        let object: [String: Any] = ["foo": "string", "bar": 1, "q": "こんにちは"]
+        let parameters = URLEncodedQueryParameters(parameters: object)
+        guard let query = parameters.encode() else {
+            XCTFail()
+            return
+        }
+
+        let items = query.components(separatedBy: "&")
+        XCTAssertEqual(items.count, 3)
+        XCTAssertTrue(items.contains("foo=string"))
+        XCTAssertTrue(items.contains("bar=1"))
+        XCTAssertTrue(items.contains("q=%E3%81%93%E3%82%93%E3%81%AB%E3%81%A1%E3%81%AF"))
+    }
+}