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

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 *
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 * in the documentation and/or other materials provided with the
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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import Foundation
import gRPC
import QuickProto

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() {
    let fileDescriptorSet = FileDescriptorSet(filename:"echo.out")
    print("Server Starting")
    print("GRPC version " + gRPC.version())

    server.run {(requestHandler) in
      print("Received request to " + requestHandler.host
        + " calling " + requestHandler.method
        + " from " + requestHandler.caller)

      // NONSTREAMING
      if (requestHandler.method == "/echo.Echo/Get") {

        do {
          try requestHandler.receiveMessage(initialMetadata:Metadata())
          {(requestData) in
            if let requestData = requestData,
              let requestMessage =
              fileDescriptorSet.readMessage("EchoRequest", data: requestData) {
              try requestMessage.forOneField("text") {(field) in
                let replyMessage = fileDescriptorSet.makeMessage("EchoResponse")!
                replyMessage.addField("text", value:"Swift nonstreaming echo " + field.string())

                do {
                  try requestHandler.sendResponse(message:replyMessage.data(),
                                                  trailingMetadata:Metadata())
                } catch (let callError) {

                }
              }
            }
          }
        } catch (let callError) {

        }
      }

      // STREAMING
      if (requestHandler.method == "/echo.Echo/Update") {
        do {
          try requestHandler.sendMetadata(
            initialMetadata: Metadata(),
            completion: {

              try self.handleMessage(
                fileDescriptorSet: fileDescriptorSet,
                requestHandler: requestHandler)

              // we seem to never get this, but I'm told it's what we're supposed to do
              try requestHandler.receiveClose() {
                try requestHandler.sendStatus(trailingMetadata: Metadata(), completion: {
                  print("status sent")
                  requestHandler.shutdown()
                })
              }
            }
          )
        } catch (let callError) {

        }
      }
    }
  }

  func handleMessage(fileDescriptorSet: FileDescriptorSet,
                     requestHandler: Handler) throws -> Void {
    try requestHandler.receiveMessage()
      {(requestData) in
        if let requestData = requestData,
          let requestMessage = fileDescriptorSet.readMessage("EchoRequest", data:requestData) {
          try requestMessage.forOneField("text") {(field) in
            let replyMessage = fileDescriptorSet.makeMessage("EchoResponse")!
            replyMessage.addField("text", value:"Swift streaming echo " + field.string())
            try requestHandler.sendResponse(message:replyMessage.data()) {
              // after we've sent our response, prepare to handle another message
              try self.handleMessage(fileDescriptorSet:fileDescriptorSet, requestHandler:requestHandler)
            }
          }
        } else {
          // if we get an empty message (nil buffer), we close the connection
          try requestHandler.sendStatus(trailingMetadata: Metadata(), completion: {
            print("status sent")
            requestHandler.shutdown()
          })
        }
    }
  }
}