Add OpenAPIFetchRuntime for Web APIs via JS interop

Package.swift

@@ -24,20 +24,26 @@ let swiftSettings: [SwiftSetting] = [
 let package = Package(
     name: "swift-openapi-runtime",
     platforms: [
-        .macOS(.v10_15), .macCatalyst(.v13), .iOS(.v13), .tvOS(.v13), .watchOS(.v6), .visionOS(.v1)
+        .macOS(.v13), .macCatalyst(.v13), .iOS(.v13), .tvOS(.v13), .watchOS(.v6), .visionOS(.v1)
     ],
     products: [
         .library(
             name: "OpenAPIRuntime",
             targets: ["OpenAPIRuntime"]
+        ),
+        .library(
+            name: "OpenAPIFetchRuntime",
+            targets: ["OpenAPIFetchRuntime"]
         )
     ],
     traits: [
         .trait(name: "FullFoundation"),
+        .trait(name: "JavaScriptFetch"),
         .default(enabledTraits: ["FullFoundation"])
     ],
     dependencies: [
         .package(url: "https://github.com/apple/swift-http-types", from: "1.0.0"),
+        .package(url: "https://github.com/swiftwasm/JavaScriptKit", .upToNextMinor(from: "0.50.2")),
     ],
     targets: [
         .target(
@@ -52,6 +58,19 @@ let package = Package(
             dependencies: ["OpenAPIRuntime"],
             swiftSettings: swiftSettings
         ),
+        .target(
+            name: "OpenAPIFetchRuntime",
+            dependencies: [
+                .product(
+                    name: "JavaScriptKit",
+                    package: "JavaScriptKit",
+                    condition: .when(traits: ["JavaScriptFetch"])
+                ),
+            ],
+            swiftSettings: [
+                .enableExperimentalFeature("Extern"),
+            ]
+        ),
     ]
 )
 

Sources/OpenAPIFetchRuntime/ClientError.swift

@@ -0,0 +1,20 @@
+#if JavaScriptFetch
+@_spi(BridgeJS) public import JavaScriptKit
+
+public enum ClientError: Error {
+    case transportFailure(JSException)
+    case unexpectedStatus(statusCode: Int, operationID: String)
+    case deserializationFailure(String)
+
+    public func toJSException() -> JSException {
+        switch self {
+        case .transportFailure(let exception):
+            return exception
+        case .unexpectedStatus(statusCode: let code, operationID: let op):
+            return JSException(message: "Unexpected status \(code) for \(op)")
+        case .deserializationFailure(let detail):
+            return JSException(message: "Deserialization failure: \(detail)")
+        }
+    }
+}
+#endif

Sources/OpenAPIFetchRuntime/ClientHelpers.swift

@@ -0,0 +1,96 @@
+#if JavaScriptFetch
+@_spi(BridgeJS) public import JavaScriptKit
+
+public func makeHeaders(contentType: String? = nil) throws(ClientError) -> Headers {
+    do {
+        let h = try Headers()
+        if let contentType { try h.set("Content-Type", contentType) }
+        return h
+    } catch {
+        throw .transportFailure(error)
+    }
+}
+
+public func checkOk(_ response: Response, operationID: String) throws(ClientError) {
+    let ok: Bool
+    let status: Double
+    do {
+        ok = try response.ok
+        status = try response.status
+    } catch {
+        throw .transportFailure(error)
+    }
+    if !ok {
+        throw .unexpectedStatus(statusCode: Int(status), operationID: operationID)
+    }
+}
+
+public func deserialize<T: _JSBridgedClass>(_ response: Response) async throws(ClientError) -> T {
+    let jsValue: JSValue
+    do {
+        jsValue = try await response.json()
+    } catch {
+        throw .transportFailure(error)
+    }
+    guard let object = jsValue.object else {
+        throw .deserializationFailure("Expected JS object for deserialization")
+    }
+    return T(unsafelyWrapping: object)
+}
+
+public func deserializeArray<T: _JSBridgedClass>(_ response: Response) async throws(ClientError) -> [T] {
+    let jsValue: JSValue
+    do {
+        jsValue = try await response.json()
+    } catch {
+        throw .transportFailure(error)
+    }
+    guard let object = jsValue.object else {
+        throw .deserializationFailure("Expected JS object for array deserialization")
+    }
+    guard let jsArray = JSArray(object) else {
+        throw .deserializationFailure("Expected JS Array, got non-array object")
+    }
+    var result: [T] = []
+    for element in jsArray {
+        guard let object = element.object else {
+            throw .deserializationFailure("Expected JS object in array element")
+        }
+        result.append(T(unsafelyWrapping: object))
+    }
+    return result
+}
+
+public func deserializeOneOf(
+    _ response: Response,
+    discriminatorProperty: String
+) async throws(ClientError) -> (String, JSObject) {
+    let jsValue: JSValue
+    do {
+        jsValue = try await response.json()
+    } catch {
+        throw .transportFailure(error)
+    }
+    guard let object = jsValue.object else {
+        throw .deserializationFailure("Expected JS object for oneOf response")
+    }
+    let discriminatorJSValue = object[discriminatorProperty]
+    guard let stringValue = discriminatorJSValue.string else {
+        throw .deserializationFailure("Discriminator property is not a string")
+    }
+    return (stringValue, object)
+}
+
+public func appendQueryParam(_ url: String, name: String, value: String) throws(ClientError) -> String {
+    let encodedName: String
+    let encodedValue: String
+    do {
+        encodedName = try encodeURIComponent(name)
+        encodedValue = try encodeURIComponent(value)
+    } catch {
+        throw .transportFailure(error)
+    }
+    let separator = url.contains("?") ? "&" : "?"
+    return url + separator + encodedName + "=" + encodedValue
+}
+#endif

Sources/OpenAPIFetchRuntime/ClientTransport.swift

@@ -0,0 +1,23 @@
+#if JavaScriptFetch
+@_spi(BridgeJS) public import JavaScriptKit
+
+public enum HTTPMethod: String, Sendable {
+    case get = "GET"
+    case post = "POST"
+    case put = "PUT"
+    case delete = "DELETE"
+    case patch = "PATCH"
+    case head = "HEAD"
+    case options = "OPTIONS"
+}
+extension HTTPMethod: _BridgedSwiftEnumNoPayload, _BridgedSwiftRawValueEnum {}
+
+public protocol ClientTransport: Sendable {
+    func send(
+        method: HTTPMethod,
+        url: String,
+        headers: consuming Headers,
+        body: JSObject?
+    ) async throws(ClientError) -> Response
+}
+#endif

Sources/OpenAPIFetchRuntime/FetchTransport.swift

@@ -0,0 +1,21 @@
+#if JavaScriptFetch
+@_spi(BridgeJS) public import JavaScriptKit
+
+public struct FetchTransport: ClientTransport, Sendable {
+    public init() {}
+
+    public func send(
+        method: HTTPMethod,
+        url: String,
+        headers: consuming Headers,
+        body: JSObject?
+    ) async throws(ClientError) -> Response {
+        do {
+            let requestInit = try RequestInit(method, headers, body)
+            return try await fetch(url, requestInit)
+        } catch {
+            throw .transportFailure(error)
+        }
+    }
+}
+#endif

Sources/OpenAPIFetchRuntime/WebAPIs.swift

@@ -0,0 +1,42 @@
+#if JavaScriptFetch
+@_spi(BridgeJS) public import JavaScriptKit
+
+@JSClass(from: .global) public struct Headers {
+    @JSFunction public init() throws(JSException)
+    @JSFunction public func append(_ name: String, _ value: String) throws(JSException) -> Void
+    @JSFunction public func delete(_ name: String) throws(JSException) -> Void
+    @JSFunction public func get(_ name: String) throws(JSException) -> Optional<String>
+    @JSFunction public func has(_ name: String) throws(JSException) -> Bool
+    @JSFunction public func set(_ name: String, _ value: String) throws(JSException) -> Void
+}
+
+@JSClass(from: .global) public struct Response {
+    @JSGetter public var headers: Headers
+    @JSGetter public var ok: Bool
+    @JSGetter public var status: Double
+    @JSGetter public var statusText: String
+    @JSGetter public var url: String
+    @JSFunction public func json() async throws(JSException) -> JSValue
+    @JSFunction public func text() async throws(JSException) -> String
+}
+
+@JSFunction(from: .global) public func fetch(_ input: String, _ options: RequestInit) async throws(JSException) -> Response
+
+@JSClass public struct RequestInit {
+    @JSFunction public init(_ method: HTTPMethod, _ headers: Headers, _ body: JSObject?) throws(JSException)
+}
+
+@JSClass(from: .global) public struct URL {
+    @JSFunction public init(_ path: String, _ base: String) throws(JSException)
+    @JSGetter public var href: String
+    @JSGetter public var searchParams: URLSearchParams
+}
+
+@JSClass(from: .global) public struct URLSearchParams {
+    @JSFunction public func set(_ name: String, _ value: String) throws(JSException) -> Void
+    @JSFunction public func append(_ name: String, _ value: String) throws(JSException) -> Void
+    @JSFunction public func delete(_ name: String) throws(JSException) -> Void
+}
+
+@JSFunction(from: .global) public func encodeURIComponent(_ string: String) throws(JSException) -> String
+#endif

Sources/OpenAPIFetchRuntime/bridge-js.config.json

@@ -0,0 +1,3 @@
+{
+  "exposeToGlobal": false
+}