xref: /aosp_15_r20/external/flatbuffers/grpc/examples/swift/Greeter/Sources/client/main.swift (revision 890232f25432b36107d06881e0a25aaa6b473652)
1 /*
2  * Copyright 2021 Google Inc. All rights reserved.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 import FlatBuffers
18 import GRPC
19 import Logging
20 import Model
21 import NIO
22 
23 // Quieten the logs.
24 LoggingSystem.bootstrap {
25   var handler = StreamLogHandler.standardOutput(label: $0)
26   handler.logLevel = .critical
27   return handler
28 }
29 
greetnull30 func greet(name: String, client greeter: models_GreeterServiceClient) {
31   // Form the request with the name, if one was provided.
32   var builder = FlatBufferBuilder()
33   let nameOff = builder.create(string: name)
34   let root = models_HelloRequest.createHelloRequest(
35     &builder,
36     nameOffset: nameOff)
37   builder.finish(offset: root)
38 
39   // Make the RPC call to the server.
40   let sayHello = greeter
41     .SayHello(Message<models_HelloRequest>(builder: &builder))
42 
43   // wait() on the response to stop the program from exiting before the response is received.
44   do {
45     let response = try sayHello.response.wait()
46     print("Greeter SayHello received: \(response.object.message ?? "Unknown")")
47   } catch {
48     print("Greeter failed: \(error)")
49   }
50 
51   let surname = builder.create(string: name)
52   let manyRoot = models_HelloRequest.createHelloRequest(
53     &builder,
54     nameOffset: surname)
55   builder.finish(offset: manyRoot)
56 
57   let call = greeter.SayManyHellos(Message(builder: &builder)) { message in
58     print(
59       "Greeter SayManyHellos received: \(message.object.message  ?? "Unknown")")
60   }
61 
62   let status = try! call.status.recover { _ in .processingError }.wait()
63   if status.code != .ok {
64     print("RPC failed: \(status)")
65   }
66 }
67 
mainnull68 func main(args: [String]) {
69   // arg0 (dropped) is the program name. We expect arg1 to be the port, and arg2 (optional) to be
70   // the name sent in the request.
71   let arg1 = args.dropFirst(1).first
72   let arg2 = args.dropFirst(2).first
73 
74   switch (arg1.flatMap(Int.init), arg2) {
75   case (.none, _):
76     print("Usage: PORT [NAME]")
77     exit(1)
78 
79   case let (.some(port), name):
80     // Setup an `EventLoopGroup` for the connection to run on.
81     //
82     // See: https://github.com/apple/swift-nio#eventloops-and-eventloopgroups
83     let group = MultiThreadedEventLoopGroup(numberOfThreads: 1)
84 
85     // Make sure the group is shutdown when we're done with it.
86     defer {
87       try! group.syncShutdownGracefully()
88     }
89 
90     // Configure the channel, we're not using TLS so the connection is `insecure`.
91     let channel = ClientConnection.insecure(group: group)
92       .connect(host: "localhost", port: port)
93 
94     // Close the connection when we're done with it.
95     defer {
96       try! channel.close().wait()
97     }
98 
99     // Provide the connection to the generated client.
100     let greeter = models_GreeterServiceClient(channel: channel)
101 
102     // Do the greeting.
103     greet(name: name ?? "FlatBuffers!", client: greeter)
104   }
105 }
106 
107 main(args: CommandLine.arguments)
108