Custom JSON encoding options

Sources/OpenAPIRuntime/Conversion/Configuration.swift

@@ -114,7 +114,27 @@ public protocol CustomCoder: Sendable {
     /// - Returns: A value of the requested type.
     /// - Throws: An error if decoding fails.
     func customDecode<T: Decodable>(_ type: T.Type, from data: Data) throws -> T
+}
+
+/// The options that control the encoded JSON data.
+public struct JSONEncodingOptions: OptionSet, Sendable {
+
+    /// The format's default value.
+    public let rawValue: UInt
+
+    /// Creates a JSONEncodingOptions value with the given raw value.
+    public init(rawValue: UInt) { self.rawValue = rawValue }
 
+    /// Include newlines and indentation to make the output more human-readable.
+    public static let prettyPrinted: JSONEncodingOptions = .init(rawValue: 1 << 0)
+
+    /// Serialize JSON objects with field keys sorted in lexicographic order.
+    public static let sortedKeys: JSONEncodingOptions = .init(rawValue: 1 << 1)
+
+    /// Omit escaping forward slashes with backslashes.
+    ///
+    /// Important: Only use this option when the output is not embedded in HTML/XML.
+    public static let withoutEscapingSlashes: JSONEncodingOptions = .init(rawValue: 1 << 2)
 }
 
 /// A set of configuration values used by the generated client and server types.
@@ -123,6 +143,9 @@ public struct Configuration: Sendable {
     /// The transcoder used when converting between date and string values.
     public var dateTranscoder: any DateTranscoder
 
+    /// The options for the underlying JSON encoder.
+    public var jsonEncodingOptions: JSONEncodingOptions
+
     /// The generator to use when creating mutlipart bodies.
     public var multipartBoundaryGenerator: any MultipartBoundaryGenerator
 
@@ -134,14 +157,17 @@ public struct Configuration: Sendable {
     /// - Parameters:
     ///   - dateTranscoder: The transcoder to use when converting between date
     ///   and string values.
+    ///   - jsonEncodingOptions: The options for the underlying JSON encoder.
     ///   - multipartBoundaryGenerator: The generator to use when creating mutlipart bodies.
     ///   - xmlCoder: Custom XML coder for encoding and decoding xml bodies. Only required when using XML body payloads.
     public init(
         dateTranscoder: any DateTranscoder = .iso8601,
+        jsonEncodingOptions: JSONEncodingOptions = [.sortedKeys, .prettyPrinted],
         multipartBoundaryGenerator: any MultipartBoundaryGenerator = .random,
         xmlCoder: (any CustomCoder)? = nil
     ) {
         self.dateTranscoder = dateTranscoder
+        self.jsonEncodingOptions = jsonEncodingOptions
         self.multipartBoundaryGenerator = multipartBoundaryGenerator
         self.xmlCoder = xmlCoder
     }

Sources/OpenAPIRuntime/Conversion/Converter.swift

@@ -38,7 +38,7 @@ import class Foundation.JSONDecoder
         self.configuration = configuration
 
         self.encoder = JSONEncoder()
-        self.encoder.outputFormatting = [.sortedKeys, .prettyPrinted]
+        self.encoder.outputFormatting = .init(configuration.jsonEncodingOptions)
         self.encoder.dateEncodingStrategy = .from(dateTranscoder: configuration.dateTranscoder)
 
         self.headerFieldEncoder = JSONEncoder()
@@ -49,3 +49,14 @@ import class Foundation.JSONDecoder
         self.decoder.dateDecodingStrategy = .from(dateTranscoder: configuration.dateTranscoder)
     }
 }
+
+extension JSONEncoder.OutputFormatting {
+    /// Creates a new value.
+    /// - Parameter options: The JSON encoding options to represent.
+    init(_ options: JSONEncodingOptions) {
+        self.init()
+        if options.contains(.prettyPrinted) { formUnion(.prettyPrinted) }
+        if options.contains(.sortedKeys) { formUnion(.sortedKeys) }
+        if options.contains(.withoutEscapingSlashes) { formUnion(.withoutEscapingSlashes) }
+    }
+}

Sources/OpenAPIRuntime/Deprecated/Deprecated.swift

@@ -37,4 +37,25 @@ extension Configuration {
     ) {
         self.init(dateTranscoder: dateTranscoder, multipartBoundaryGenerator: multipartBoundaryGenerator, xmlCoder: nil)
     }
+
+    /// Creates a new configuration with the specified values.
+    ///
+    /// - Parameters:
+    ///   - dateTranscoder: The transcoder to use when converting between date
+    ///   and string values.
+    ///   - multipartBoundaryGenerator: The generator to use when creating mutlipart bodies.
+    ///   - xmlCoder: Custom XML coder for encoding and decoding xml bodies. Only required when using XML body payloads.
+    @available(*, deprecated, renamed: "init(dateTranscoder:jsonEncodingOptions:multipartBoundaryGenerator:xmlCoder:)")
+    @_disfavoredOverload public init(
+        dateTranscoder: any DateTranscoder = .iso8601,
+        multipartBoundaryGenerator: any MultipartBoundaryGenerator = .random,
+        xmlCoder: (any CustomCoder)? = nil
+    ) {
+        self.init(
+            dateTranscoder: dateTranscoder,
+            jsonEncodingOptions: [.sortedKeys, .prettyPrinted],
+            multipartBoundaryGenerator: multipartBoundaryGenerator,
+            xmlCoder: xmlCoder
+        )
+    }
 }

Tests/OpenAPIRuntimeTests/Conversion/Test_Configuration.swift

@@ -12,6 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 import XCTest
+import HTTPTypes
+import Foundation
 @_spi(Generated) import OpenAPIRuntime
 
 final class Test_Configuration: Test_Runtime {
@@ -27,4 +29,36 @@ final class Test_Configuration: Test_Runtime {
         XCTAssertEqual(try transcoder.encode(testDateWithFractionalSeconds), testDateWithFractionalSecondsString)
         XCTAssertEqual(testDateWithFractionalSeconds, try transcoder.decode(testDateWithFractionalSecondsString))
     }
+
+    func _testJSON(configuration: Configuration, expected: String) async throws {
+        let converter = Converter(configuration: configuration)
+        var headerFields: HTTPFields = [:]
+        let body = try converter.setResponseBodyAsJSON(
+            testPetWithPath,
+            headerFields: &headerFields,
+            contentType: "application/json"
+        )
+        let data = try await Data(collecting: body, upTo: 1024)
+        XCTAssertEqualStringifiedData(data, expected)
+    }
+
+    func testJSONEncodingOptions_default() async throws {
+        try await _testJSON(configuration: Configuration(), expected: testPetWithPathPrettifiedWithEscapingSlashes)
+    }
+
+    func testJSONEncodingOptions_empty() async throws {
+        try await _testJSON(
+            configuration: Configuration(jsonEncodingOptions: [
+                .sortedKeys  // without sorted keys, this test would be unreliable
+            ]),
+            expected: testPetWithPathMinifiedWithEscapingSlashes
+        )
+    }
+
+    func testJSONEncodingOptions_prettyWithoutEscapingSlashes() async throws {
+        try await _testJSON(
+            configuration: Configuration(jsonEncodingOptions: [.prettyPrinted, .sortedKeys, .withoutEscapingSlashes]),
+            expected: testPetWithPathPrettifiedWithoutEscapingSlashes
+        )
+    }
 }

Tests/OpenAPIRuntimeTests/Test_Runtime.swift

@@ -117,6 +117,28 @@ class Test_Runtime: XCTestCase {
 
     var testStructPrettyData: Data { Data(testStructPrettyString.utf8) }
 
+    var testPetWithPath: TestPetWithPath { .init(name: "Fluffz", path: URL(string: "/land/forest")!) }
+
+    var testPetWithPathMinifiedWithEscapingSlashes: String { #"{"name":"Fluffz","path":"\/land\/forest"}"# }
+
+    var testPetWithPathPrettifiedWithEscapingSlashes: String {
+        #"""
+        {
+          "name" : "Fluffz",
+          "path" : "\/land\/forest"
+        }
+        """#
+    }
+
+    var testPetWithPathPrettifiedWithoutEscapingSlashes: String {
+        #"""
+        {
+          "name" : "Fluffz",
+          "path" : "/land/forest"
+        }
+        """#
+    }
+
     var testStructURLFormData: Data { Data(testStructURLFormString.utf8) }
 
     var testEvents: [TestPet] { [.init(name: "Rover"), .init(name: "Pancake")] }
@@ -247,6 +269,11 @@ public func XCTAssertEqualURLString(_ lhs: URL?, _ rhs: String, file: StaticStri
 
 struct TestPet: Codable, Equatable { var name: String }
 
+struct TestPetWithPath: Codable, Equatable {
+    var name: String
+    var path: URL
+}
+
 struct TestPetDetailed: Codable, Equatable {
     var name: String
     var type: String