grpc-swift/Examples/Echo/Swift/Echo/EchoServer.swift

/*
 *
 * Copyright 2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
import Foundation
import gRPC

class EchoGetSession : Session {
  var handler : Handler
  var server : EchoGetServer

  init(handler:Handler, server: EchoGetServer) {
    self.handler = handler
    self.server = server
  }

  func run() {
    do {
      try handler.receiveMessage(initialMetadata:Metadata()) {(requestData) in
        if let requestData = requestData {
          let requestMessage = try! Echo_EchoRequest(protobuf:requestData)
          if let replyMessage = self.server.handle(message:requestMessage) { // calling stub
            try self.handler.sendResponse(message:replyMessage.serializeProtobuf(),
                                          statusCode: 0,
                                          statusMessage: "OK",
                                          trailingMetadata:Metadata())
          }
        }
      }
    } catch (let callError) {
      print("grpc error: \(callError)")
    }
  }
}

class EchoUpdateSession : Session {
  var handler : Handler
  var server : EchoUpdateServer

  init(handler:Handler, server: EchoUpdateServer) {
    self.handler = handler
    self.server = server
  }

  func sendMessage(message:Echo_EchoResponse) -> Void {
    try! handler.sendResponse(message:message.serializeProtobuf()) {}
  }

  func waitForMessage() {
    do {
      try handler.receiveMessage() {(requestData) in
        if let requestData = requestData {

          let requestMessage = try! Echo_EchoRequest(protobuf:requestData)
          self.waitForMessage()
          self.server.handle(session:self, message:requestMessage)

        } else {
          // if we get an empty message (requestData == nil), we close the connection
          try self.handler.sendStatus(statusCode: 0,
                                      statusMessage: "OK",
                                      trailingMetadata: Metadata())
          {
            self.handler.shutdown()
          }
        }
      }
    } catch (let error) {
      print(error)
    }
  }

  func run() {
    do {
      try self.handler.sendMetadata(initialMetadata:Metadata()) {
        self.waitForMessage()
      }
    } catch (let callError) {
      print("grpc error: \(callError)")
    }
  }
}

class EchoServer {
  private var address: String
  private var server: Server

  init(address:String, secure:Bool) {
    gRPC.initialize()
    self.address = address
    if secure {
      let certificateURL = Bundle.main.url(forResource: "ssl", withExtension: "crt")!
      let certificate = try! String(contentsOf: certificateURL)
      let keyURL = Bundle.main.url(forResource: "ssl", withExtension: "key")!
      let key = try! String(contentsOf: keyURL)
      self.server = gRPC.Server(address:address, key:key, certs:certificate)
    } else {
      self.server = gRPC.Server(address:address)
    }
  }

  func start() {
    print("Server Starting")
    print("GRPC version " + gRPC.version())

    server.run {(handler) in
      print("Server received request to " + handler.host
        + " calling " + handler.method
        + " from " + handler.caller)

      if (handler.method == "/echo.Echo/Get") {
        handler.session = EchoGetSession(handler:handler,
                                         server:EchoGetServer())
        handler.session.run()
      }

      if (handler.method == "/echo.Echo/Update") {
        handler.session = EchoUpdateSession(handler:handler,
                                            server:EchoUpdateServer())
        handler.session.run()
      }
    }
  }
}

// The following code is for developer/users to edit.
// Everything above these lines is intended to be preexisting or generated.

class EchoGetServer {

  func handle(message:Echo_EchoRequest) -> Echo_EchoResponse? {
    var reply = Echo_EchoResponse()
    reply.text = "Swift nonstreaming echo " + message.text
    return reply
  }

}

class EchoUpdateServer {

  func handle(session:EchoUpdateSession, message:Echo_EchoRequest) -> Void {
    var reply = Echo_EchoResponse()
    reply.text = "Swift streaming echo " + message.text
    session.sendMessage(message:reply)
  }
  
}