feat: added convenience decoding strategies (#38)

README.md

@@ -487,6 +487,51 @@ struct Request: Postie.Request {
 }
 ```
 
+#### Response parsing strategies
+
+As the response body might differ depending on various factors, you can control the parsing using "decoding strategies".
+
+By default if you use `ResponseBody` to parse the response body, it will use the `DefaultBodyStrategy` (which expects an HTTP status code 2XX or 3XX).
+
+The same applies to the `ResponseErrorBody` to parse the response body for a status code of 400 or above, which is using the `DefaultErrorBodyStrategy`.
+
+For your convenience we added a couple of convenience strategies in `ResponseBody` and `ResponseErrorBody`, you can use with the `ResponseBodyWrapper` and `ResponseErrorBodyWrapper`.
+
+If you want to implement a custom decoding strategy, all you need to do is define a struct implementing the protocol `ResponseBodyDecodingStrategy` or `ResponseErrorBodyDecodingStrategy`.
+
+**Example:***
+
+```swift
+struct CustomBodyDecodingStrategy {
+    public static func allowsEmptyContent(for _: Int) -> Bool {
+        return false
+    }
+
+    public static func validate(statusCode: Int) -> Bool {
+        // e.g. only decode if the status code is 999
+        statusCode == 999
+    }
+}
+
+struct Request: Postie.Request {
+    struct Response: Decodable {
+        struct CreatedResponseBody: JSONDecodable {
+            ...
+        }
+
+        @ResponseBody<CreatedResponseBody>.Status201 var createdBody: CreatedResponseBody
+
+        struct CustomResponseBody: JSONDecodable {
+            ...
+        }
+
+        @ResponseBodyWrapper<CustomResponseBody, CustomBodyDecodingStrategy> var customBody
+    }
+}
+```
+
+Note: Due to technical limitations of the `Codable` protocol in Swift, it is currently not possible to have a non-static/dynamic decoding strategy.  
+
 #### Response headers
 
 Use the property wrapper `@ResponseHeader<Strategy>` inside the response type.

Sources/Postie/Responses/ResponseBody/ResponseBody+DecodingStrategies.swift

@@ -1,4 +1,7 @@
 public extension ResponseBody {
-
     typealias OptionalContent = ResponseBodyWrapper<Body, OptionalContentStrategy>
+
+    typealias Status200 = ResponseBodyWrapper<Body, ValidateStatus200BodyStrategy>
+    typealias Status201 = ResponseBodyWrapper<Body, ValidateStatus201BodyStrategy>
+    typealias Status303 = ResponseBodyWrapper<Body, ValidateStatus303BodyStrategy>
 }

Sources/Postie/Responses/ResponseErrorBody/ResponseErrorBody+DecodingStrategies.swift

@@ -0,0 +1,8 @@
+public extension ResponseErrorBody {
+    typealias Status400 = ResponseErrorBodyWrapper<Body, ValidateStatus400ErrorBodyStrategy>
+    typealias Status401 = ResponseErrorBodyWrapper<Body, ValidateStatus401ErrorBodyStrategy>
+    typealias Status403 = ResponseErrorBodyWrapper<Body, ValidateStatus403ErrorBodyStrategy>
+    typealias Status404 = ResponseErrorBodyWrapper<Body, ValidateStatus404ErrorBodyStrategy>
+    typealias Status410 = ResponseErrorBodyWrapper<Body, ValidateStatus410ErrorBodyStrategy>
+    typealias Status422 = ResponseErrorBodyWrapper<Body, ValidateStatus422ErrorBodyStrategy>
+}

Sources/Postie/Strategies/Body/ValidateStatus200BodyStrategy.swift

@@ -0,0 +1,9 @@
+public struct ValidateStatus200BodyStrategy: ResponseBodyDecodingStrategy {
+    public static func allowsEmptyContent(for _: Int) -> Bool {
+        return false
+    }
+
+    public static func validate(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.ok.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus201BodyStrategy.swift

@@ -0,0 +1,9 @@
+public struct ValidateStatus201BodyStrategy: ResponseBodyDecodingStrategy {
+    public static func allowsEmptyContent(for _: Int) -> Bool {
+        return false
+    }
+
+    public static func validate(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.created.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus303BodyStrategy.swift

@@ -0,0 +1,9 @@
+public struct ValidateStatus303BodyStrategy: ResponseBodyDecodingStrategy {
+    public static func allowsEmptyContent(for _: Int) -> Bool {
+        return true
+    }
+
+    public static func validate(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.seeOther.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus400ErrorBodyStrategy.swift

@@ -0,0 +1,5 @@
+public struct ValidateStatus400ErrorBodyStrategy: ResponseErrorBodyDecodingStrategy {
+    public static func isError(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.badRequest.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus401ErrorBodyStrategy.swift

@@ -0,0 +1,5 @@
+public struct ValidateStatus401ErrorBodyStrategy: ResponseErrorBodyDecodingStrategy {
+    public static func isError(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.unauthorized.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus403ErrorBodyStrategy.swift

@@ -0,0 +1,5 @@
+public struct ValidateStatus403ErrorBodyStrategy: ResponseErrorBodyDecodingStrategy {
+    public static func isError(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.forbidden.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus404ErrorBodyStrategy.swift

@@ -0,0 +1,5 @@
+public struct ValidateStatus404ErrorBodyStrategy: ResponseErrorBodyDecodingStrategy {
+    public static func isError(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.notFound.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus410ErrorBodyStrategy.swift

@@ -0,0 +1,5 @@
+public struct ValidateStatus410ErrorBodyStrategy: ResponseErrorBodyDecodingStrategy {
+    public static func isError(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.gone.rawValue
+    }
+}

Sources/Postie/Strategies/Body/ValidateStatus422ErrorBodyStrategy.swift

@@ -0,0 +1,5 @@
+public struct ValidateStatus422ErrorBodyStrategy: ResponseErrorBodyDecodingStrategy {
+    public static func isError(statusCode: Int) -> Bool {
+        statusCode == HTTPStatusCode.unprocessableEntity.rawValue
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus200BodyStrategyTests.swift

@@ -0,0 +1,20 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus200BodyStrategyTests: XCTestCase {
+    func testAllowsEmptyContent_statusIs200_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus200BodyStrategy.allowsEmptyContent(for: 200))
+    }
+
+    func testAllowsEmptyContent_statusIsNot200_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus200BodyStrategy.allowsEmptyContent(for: 999))
+    }
+
+    func testValidate_statusIs200_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus200BodyStrategy.validate(statusCode: 200))
+    }
+
+    func testValidate_statusIsNot200_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus200BodyStrategy.validate(statusCode: 999))
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus201BodyStrategyTests.swift

@@ -0,0 +1,20 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus201BodyStrategyTests: XCTestCase {
+    func testAllowsEmptyContent_statusIs201_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus201BodyStrategy.allowsEmptyContent(for: 201))
+    }
+
+    func testAllowsEmptyContent_statusIsNot201_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus201BodyStrategy.allowsEmptyContent(for: 999))
+    }
+
+    func testValidate_statusIs201_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus201BodyStrategy.validate(statusCode: 201))
+    }
+
+    func testValidate_statusIsNot201_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus201BodyStrategy.validate(statusCode: 999))
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus400ErrorBodyStrategyTests.swift

@@ -0,0 +1,12 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus400ErrorBodyStrategyTests: XCTestCase {
+    func testIsError_statusIs400_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus400ErrorBodyStrategy.isError(statusCode: 400))
+    }
+
+    func testIsError_statusIsNot400_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus400ErrorBodyStrategy.isError(statusCode: 999))
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus401ErrorBodyStrategyTests.swift

@@ -0,0 +1,12 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus401ErrorBodyStrategyTests: XCTestCase {
+    func testIsError_statusIs401_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus401ErrorBodyStrategy.isError(statusCode: 401))
+    }
+
+    func testIsError_statusIsNot401_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus401ErrorBodyStrategy.isError(statusCode: 999))
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus403ErrorBodyStrategyTests.swift

@@ -0,0 +1,12 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus403ErrorBodyStrategyTests: XCTestCase {
+    func testIsError_statusIs403_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus403ErrorBodyStrategy.isError(statusCode: 403))
+    }
+
+    func testIsError_statusIsNot403_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus403ErrorBodyStrategy.isError(statusCode: 999))
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus404ErrorBodyStrategyTests.swift

@@ -0,0 +1,12 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus404ErrorBodyStrategyTests: XCTestCase {
+    func testIsError_statusIs404_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus404ErrorBodyStrategy.isError(statusCode: 404))
+    }
+
+    func testIsError_statusIsNot404_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus404ErrorBodyStrategy.isError(statusCode: 999))
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus410ErrorBodyStrategyTests.swift

@@ -0,0 +1,12 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus410ErrorBodyStrategyTests: XCTestCase {
+    func testIsError_statusIs410_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus410ErrorBodyStrategy.isError(statusCode: 410))
+    }
+
+    func testIsError_statusIsNot410_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus410ErrorBodyStrategy.isError(statusCode: 999))
+    }
+}

Tests/PostieTests/Strategies/Body/ValidateStatus422ErrorBodyStrategyTests.swift

@@ -0,0 +1,12 @@
+@testable import Postie
+import XCTest
+
+class ValidateStatus422ErrorBodyStrategyTests: XCTestCase {
+    func testIsError_statusIs422_shouldBeTrue() {
+        XCTAssertTrue(ValidateStatus422ErrorBodyStrategy.isError(statusCode: 422))
+    }
+
+    func testIsError_statusIsNot422_shouldBeFalse() {
+        XCTAssertFalse(ValidateStatus422ErrorBodyStrategy.isError(statusCode: 999))
+    }
+}