allow EmptyResponse to be used with CodableParser when API call response does not contain valid JSON.

Author: DenTelezhkin

Diff for: CHANGELOG.md

@@ -3,6 +3,8 @@ All notable changes to this project will be documented in this file.
 
 # Next
 
+* Allow `EmptyResponse` to be used with CodableParser when network response does not contain valid JSON.
+
 ## [4.1.0](https://github.com/MLSDev/TRON/releases/tag/4.1.0)
 
 * Deprecate TRON level headerBuilder in favor of Alamofire.requestAdapter.

Diff for: Source/EmptyResponse.swift

@@ -27,8 +27,14 @@ import Foundation
 
 #if swift(>=4.0)
     /// Struct, that can be used as Model generic constraint in cases, where you don't care about response type.
-    public struct EmptyResponse: Codable {}
+    public struct EmptyResponse: Codable {
+        /// Creates `EmptyResponse`.
+        public init() {}
+    }
 #else
     /// Struct, that can be used as Model generic constraint in cases, where you don't care about response type.
-    public struct EmptyResponse {}
+    public struct EmptyResponse {
+        /// Creates `EmptyResponse`.
+        public init() {}
+    }
 #endif

Diff for: Source/TRONCodable.swift

@@ -49,6 +49,10 @@ open class CodableParser<Model: Decodable, ErrorModel: Decodable> : ErrorHandlin
     open var serializeResponse: (URLRequest?, HTTPURLResponse?, Data?, Error?) -> Result<Model> {
         return { [weak self] request, response, data, error in
             do {
+                if Model.self is EmptyResponse.Type {
+                    // swiftlint:disable:next force_cast
+                    return Result.success(EmptyResponse() as! Model)
+                }
                 let model = try (self?.modelDecoder ?? JSONDecoder()).decode(Model.self, from: data ?? Data())
                 return Result.success(model)
             } catch {
@@ -96,6 +100,10 @@ open class CodableDownloadParser<Model: Decodable, ErrorModel: Decodable> : Erro
         return { [weak self] request, response, url, error in
             if let url = url, let data = try? Data(contentsOf: url) {
                 do {
+                    if Model.self is EmptyResponse.Type {
+                        // swiftlint:disable:next force_cast
+                        return Result.success(EmptyResponse() as! Model)
+                    }
                     let model = try (self?.modelDecoder ?? JSONDecoder()).decode(Model.self, from: data)
                     return Result.success(model)
                 } catch {

Diff for: Tests/TRONTests/CodableTestCase.swift

@@ -62,6 +62,20 @@ class CodableTestCase: XCTestCase {
         waitForExpectations(timeout: 5, handler: nil)
     }
 
+    func testEmptyResponseStillCallsSuccessBlock() {
+        let tron = TRON(baseURL: "http://httpbin.org")
+        let request : APIRequest<EmptyResponse, CodableError> = tron.codable.request("headers")
+        request.method = .head
+        let expectation = self.expectation(description: "Empty response")
+        request.perform(withSuccess: { _ in
+            expectation.fulfill()
+        }, failure: { _ in
+            XCTFail()
+            }
+        )
+        waitForExpectations(timeout: 1, handler: nil)
+    }
+    
 }
 
 #endif