Renaming and removal of force unwrap/try

Sources/Examples/EchoNIO/main.swift

@@ -29,11 +29,17 @@ let messageOption = Option("message",
                            default: "Testing 1 2 3",
                            description: "message to send")
 
-func makeEchoClient(address: String, port: Int) throws -> EchoClient {
+/// Create en `EchoClient` and wait for it to initialize. Returns nil if initialisation fails.
+func makeEchoClient(address: String, port: Int) -> EchoClient? {
   let eventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: 1)
-  return try GRPCClient.start(host: address, port: port, eventLoopGroup: eventLoopGroup)
-    .map { client in EchoClient(client: client) }
-    .wait()
+  do {
+    return try GRPCClient.start(host: address, port: port, eventLoopGroup: eventLoopGroup)
+      .map { client in EchoClient(client: client) }
+      .wait()
+  } catch {
+    print("Unable to create an EchoClient: \(error)")
+    return nil
+  }
 }
 
 Group {
@@ -66,7 +72,7 @@ Group {
     description: "Perform a unary get()."
   ) { address, port, message in
     print("calling get")
-    let echo = try! makeEchoClient(address: address, port: port)
+    guard let echo = makeEchoClient(address: address, port: port) else { return }
 
     var requestMessage = Echo_EchoRequest()
     requestMessage.text = message
@@ -77,7 +83,17 @@ Group {
       print("get received: \(response.text)")
     }
 
-    _ = try! get.response.wait()
+    get.response.whenFailure { error in
+      print("get response failed with error: \(error)")
+    }
+
+    // wait() on the status to stop the program from exiting.
+    do {
+      let status = try get.status.wait()
+      print("get completed with status: \(status)")
+    } catch {
+      print("get status failed with error: \(error)")
+    }
   }
 
   $0.command(
@@ -88,7 +104,7 @@ Group {
     description: "Perform a server-streaming expand()."
   ) { address, port, message in
     print("calling expand")
-    let echo = try! makeEchoClient(address: address, port: port)
+    guard let echo = makeEchoClient(address: address, port: port) else { return }
 
     var requestMessage = Echo_EchoRequest()
     requestMessage.text = message
@@ -98,7 +114,13 @@ Group {
       print("expand received: \(response.text)")
     }
 
-    _ = try! expand.status.wait()
+    // wait() on the status to stop the program from exiting.
+    do {
+      let status = try expand.status.wait()
+      print("expand completed with status: \(status)")
+    } catch {
+      print("expand status failed with error: \(error)")
+    }
   }
 
   $0.command(
@@ -109,7 +131,7 @@ Group {
     description: "Perform a client-streaming collect()."
   ) { address, port, message in
     print("calling collect")
-    let echo = try! makeEchoClient(address: address, port: port)
+    guard let echo = makeEchoClient(address: address, port: port) else { return }
 
     let collect = echo.collect()
 
@@ -125,7 +147,17 @@ Group {
       print("collect received: \(resposne.text)")
     }
 
-    _ = try! collect.status.wait()
+    collect.response.whenFailure { error in
+      print("collect response failed with error: \(error)")
+    }
+
+    // wait() on the status to stop the program from exiting.
+    do {
+      let status = try collect.status.wait()
+      print("collect completed with status: \(status)")
+    } catch {
+      print("collect status failed with error: \(error)")
+    }
   }
 
   $0.command(
@@ -136,7 +168,7 @@ Group {
     description: "Perform a bidirectional-streaming update()."
   ) { address, port, message in
     print("calling update")
-    let echo = try! makeEchoClient(address: address, port: port)
+    guard let echo = makeEchoClient(address: address, port: port) else { return }
 
     let update = echo.update { response in
       print("update received: \(response.text)")
@@ -150,6 +182,12 @@ Group {
     }
     update.send(.end)
 
-    _ = try! update.status.wait()
+    // wait() on the status to stop the program from exiting.
+    do {
+      let status = try update.status.wait()
+      print("update completed with status: \(status)")
+    } catch {
+      print("update status failed with error: \(error)")
+    }
   }
 }.run()

Sources/SwiftGRPCNIO/ClientCalls/BaseClientCall.swift

@@ -27,7 +27,7 @@ public protocol ClientCall {
   var subchannel: EventLoopFuture<Channel> { get }
 
   /// Initial response metadata.
-  var metadata: EventLoopFuture<HTTPHeaders> { get }
+  var initialMetadata: EventLoopFuture<HTTPHeaders> { get }
 
   /// Response status.
   var status: EventLoopFuture<GRPCStatus> { get }
@@ -78,7 +78,7 @@ public protocol UnaryResponseClientCall: ClientCall {
 
 public class BaseClientCall<RequestMessage: Message, ResponseMessage: Message>: ClientCall {
   public let subchannel: EventLoopFuture<Channel>
-  public let metadata: EventLoopFuture<HTTPHeaders>
+  public let initialMetadata: EventLoopFuture<HTTPHeaders>
   public let status: EventLoopFuture<GRPCStatus>
 
   /// Sets up a gRPC call.
@@ -113,14 +113,16 @@ public class BaseClientCall<RequestMessage: Message, ResponseMessage: Message>:
     }
 
     self.subchannel = subchannelPromise.futureResult
-    self.metadata = metadataPromise.futureResult
+    self.initialMetadata = metadataPromise.futureResult
     self.status = statusPromise.futureResult
   }
 
   internal func makeRequestHead(path: String, host: String) -> HTTPRequestHead {
     var requestHead = HTTPRequestHead(version: .init(major: 2, minor: 0), method: .POST, uri: path)
     requestHead.headers.add(name: "host", value: host)
     requestHead.headers.add(name: "content-type", value: "application/grpc")
+    requestHead.headers.add(name: "te", value: "trailers")
+    requestHead.headers.add(name: "user-agent", value: "grpc-swift-nio")
     return requestHead
   }
 }

Sources/SwiftGRPCNIO/ClientCalls/ServerStreamingClientCall.swift

@@ -18,7 +18,6 @@ import SwiftProtobuf
 import NIO
 
 public class ServerStreamingClientCall<RequestMessage: Message, ResponseMessage: Message>: BaseClientCall<RequestMessage, ResponseMessage> {
-
   public init(client: GRPCClient, path: String, request: RequestMessage, handler: @escaping (ResponseMessage) -> Void) {
     super.init(channel: client.channel, multiplexer: client.multiplexer, responseHandler: .callback(handler: handler))
 

Sources/SwiftGRPCNIO/ClientCalls/UnaryClientCall.swift

@@ -17,20 +17,20 @@ import Foundation
 import SwiftProtobuf
 import NIO
 
-public class UnaryClientCall<Request: Message, Response: Message>: BaseClientCall<Request, Response>, UnaryResponseClientCall {
-  public let response: EventLoopFuture<Response>
+public class UnaryClientCall<RequestMessage: Message, ResponseMessage: Message>: BaseClientCall<RequestMessage, ResponseMessage>, UnaryResponseClientCall {
+  public let response: EventLoopFuture<ResponseMessage>
 
-  public init(client: GRPCClient, path: String, request: Request) {
-    let responsePromise: EventLoopPromise<Response> = client.channel.eventLoop.newPromise()
+  public init(client: GRPCClient, path: String, request: RequestMessage) {
+    let responsePromise: EventLoopPromise<ResponseMessage> = client.channel.eventLoop.newPromise()
     self.response = responsePromise.futureResult
 
     super.init(channel: client.channel, multiplexer: client.multiplexer, responseHandler: .fulfill(promise: responsePromise))
 
     let requestHead = makeRequestHead(path: path, host: client.host)
     subchannel.whenSuccess { channel in
-      channel.write(GRPCClientRequestPart<Request>.head(requestHead), promise: nil)
-      channel.write(GRPCClientRequestPart<Request>.message(request), promise: nil)
-      channel.writeAndFlush(GRPCClientRequestPart<Request>.end, promise: nil)
+      channel.write(GRPCClientRequestPart<RequestMessage>.head(requestHead), promise: nil)
+      channel.write(GRPCClientRequestPart<RequestMessage>.message(request), promise: nil)
+      channel.writeAndFlush(GRPCClientRequestPart<RequestMessage>.end, promise: nil)
     }
   }
 }

Sources/SwiftGRPCNIO/GRPCClient.swift

@@ -18,7 +18,6 @@ import NIO
 import NIOHTTP2
 
 public final class GRPCClient {
-
   public static func start(
     host: String,
     port: Int,