Add initial implementation of FunctionsClient

Author: grdsdev

Package.swift

@@ -19,9 +19,11 @@ let package = Package(
   targets: [
     .target(
       name: "Functions",
-      dependencies: []),
+      dependencies: []
+    ),
     .testTarget(
       name: "FunctionsTests",
-      dependencies: ["Functions"]),
+      dependencies: ["Functions"]
+    ),
   ]
 )

Sources/Functions/FunctionsClient.swift

@@ -1,6 +1,93 @@
-public struct functions_swift {
-    public private(set) var text = "Hello, World!"
+import Foundation
 
-    public init() {
+public final class FunctionsClient {
+  let url: URL
+  var headers: [String: String]
+
+  private let session: URLSession = .shared
+
+  public init(url: URL, headers: [String: String] = [:]) {
+    self.url = url
+    self.headers = headers
+    self.headers["X-Client-Info"] = "functions-swift/\(version)"
+  }
+
+  /// Updates the authorization header.
+  /// - Parameter token: the new JWT token sent in the authorization header
+  public func setAuth(token: String) {
+    headers["Authorization"] = "Bearer \(token)"
+  }
+
+  /// Invokes a function.
+  /// - Parameters:
+  ///   - functionName: the name of the function to invoke.
+  public func invoke<Response>(
+    functionName: String,
+    invokeOptions: FunctionInvokeOptions = .init(),
+    decode: (Data, HTTPURLResponse) throws -> Response
+  ) async throws -> Response {
+    let (data, response) = try await rawInvoke(
+      functionName: functionName,
+      invokeOptions: invokeOptions
+    )
+    return try decode(data, response)
+  }
+
+  /// Invokes a function.
+  /// - Parameters:
+  ///   - functionName: the name of the function to invoke.
+  public func invoke<T: Decodable>(
+    functionName: String,
+    invokeOptions: FunctionInvokeOptions = .init(),
+    decoder: JSONDecoder = JSONDecoder()
+  ) async throws -> T {
+    try await invoke(
+      functionName: functionName,
+      invokeOptions: invokeOptions,
+      decode: { data, _ in try decoder.decode(T.self, from: data) }
+    )
+  }
+
+  /// Invokes a function.
+  /// - Parameters:
+  ///   - functionName: the name of the function to invoke.
+  public func invoke(
+    functionName: String,
+    invokeOptions: FunctionInvokeOptions = .init()
+  ) async throws {
+    try await invoke(
+      functionName: functionName,
+      invokeOptions: invokeOptions,
+      decode: { _, _ in () }
+    )
+  }
+
+  private func rawInvoke(
+    functionName: String,
+    invokeOptions: FunctionInvokeOptions
+  ) async throws -> (Data, HTTPURLResponse) {
+    let body = invokeOptions.body
+    let invokeHeaders = invokeOptions.headers
+
+    var request = URLRequest(url: url.appendingPathComponent(functionName))
+    request.httpMethod = "POST"
+    request.httpBody = body
+    request.allHTTPHeaderFields = invokeHeaders.merging(headers) { invokeHeader, _ in invokeHeader }
+
+    let (data, response) = try await session.data(for: request)
+    guard let httpResponse = response as? HTTPURLResponse else {
+      throw URLError(.badServerResponse)
+    }
+
+    guard 200 ..< 300 ~= httpResponse.statusCode else {
+      throw FunctionsError.httpError(code: httpResponse.statusCode, data: data)
     }
+
+    let isRelayError = httpResponse.value(forHTTPHeaderField: "x-relay-error") == "true"
+    if isRelayError {
+      throw FunctionsError.relayError
+    }
+
+    return (data, httpResponse)
+  }
 }

Sources/Functions/Types.swift

@@ -0,0 +1,42 @@
+import Foundation
+
+public enum FunctionsError: Error, LocalizedError {
+  case relayError
+  case httpError(code: Int, data: Data)
+
+  public var errorDescription: String? {
+    switch self {
+    case .relayError: return "Relay Error invoking the Edge Function"
+    case let .httpError(code, _): return "Edge Function returned a non-2xx status code: \(code)"
+    }
+  }
+}
+
+public struct FunctionInvokeOptions {
+  let headers: [String: String]
+  let body: Data?
+
+  public init<T: Encodable>(headers: [String: String] = [:], body: T) {
+    var headers = headers
+
+    switch body {
+    case let string as String:
+      headers["Content-Type"] = "text/plain"
+      self.body = string.data(using: .utf8)
+    case let data as Data:
+      headers["Content-Type"] = "application/octet-stream"
+      self.body = data
+    default:
+      // default, assume this is JSON
+      headers["Content-Type"] = "application/json"
+      self.body = try? JSONEncoder().encode(body)
+    }
+
+    self.headers = headers
+  }
+
+  public init(headers: [String: String] = [:]) {
+    self.headers = headers
+    body = nil
+  }
+}

Sources/Functions/Version.swift

@@ -0,0 +1 @@
+let version = "0.0.1"

Tests/FunctionsTests/FunctionsTests.swift

@@ -1,7 +1,4 @@
-import XCTest
 @testable import Functions
+import XCTest
 
-final class functions_swiftTests: XCTestCase {
-    func testExample() throws {
-    }
-}
+final class FunctionsTests: XCTestCase {}