grpc-swift/Examples/Google/Datastore/Sources/main.swift

/*
 * Copyright 2017, gRPC Authors All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import Foundation
import gRPC
import OAuth2
import Commander

// Convert Encodable objects to dictionaries of property-value pairs.
class PropertiesEncoder {
  static func encode<T : Encodable>(_ value : T) throws -> [String:Any]? {
    let plist = try PropertyListEncoder().encode(value)
    let properties = try PropertyListSerialization.propertyList(from:plist, options:[], format:nil)
    return properties as? [String:Any]
  }
}

// Create Decodable objects from dictionaries of property-value pairs.
class PropertiesDecoder {
  static func decode<T: Decodable>(_ type: T.Type, from: [String:Any]) throws -> T {
    let plist = try PropertyListSerialization.data(fromPropertyList: from, format: .binary, options:0)
    return try PropertyListDecoder().decode(type, from: plist)
  }
}

// a Swift interface to the Google Cloud Datastore API
class Datastore {
  var projectID : String
  var service : Google_Datastore_V1_DatastoreService!
  
  let scopes = ["https://www.googleapis.com/auth/datastore"]
  
  init(projectID:String) {
    self.projectID = projectID
  }
  
  func authenticate() throws {
    var authToken : String!
    if let provider = DefaultTokenProvider(scopes:scopes) {
      let sem = DispatchSemaphore(value: 0)
      try provider.withToken() {(token, error) -> Void in
        if let token = token {
          authToken = token.AccessToken
        }
        sem.signal()
      }
      sem.wait()
    }
    if authToken == nil {
      print("ERROR: No OAuth token is available. Did you set GOOGLE_APPLICATION_CREDENTIALS?")
      exit(-1)
    }
    // Initialize gRPC service
    gRPC.initialize()
    service = Google_Datastore_V1_DatastoreService(address:"datastore.googleapis.com")
    service.metadata = Metadata(["authorization":"Bearer " + authToken])
  }
  
  func performList<T: Codable>(type: T.Type) throws -> [Int64 : T]{
    var request = Google_Datastore_V1_RunQueryRequest()
    request.projectID = projectID
    var query = Google_Datastore_V1_GqlQuery()
    query.queryString = "select * from " + String(describing: type)
    request.gqlQuery = query
    let result = try service.runquery(request)
    var entities : [Int64 : T] = [:]
    for entityResult in result.batch.entityResults {
      var properties : [String:Any] = [:]
      for property in entityResult.entity.properties {
        let key = property.key
        switch property.value.valueType! {
        case .integerValue(let v):
          properties[key] = v
        case .stringValue(let v):
          properties[key] = v
        default:
          print("?")
        }
      }
      let entity = try PropertiesDecoder.decode(type, from:properties)
      entities[entityResult.entity.key.path[0].id] = entity
    }
    return entities
  }
  
  func performInsert<T: Codable>(thing: T) throws {
    var request = Google_Datastore_V1_CommitRequest()
    request.projectID = projectID
    request.mode = .nonTransactional
    var pathElement = Google_Datastore_V1_Key.PathElement()
    pathElement.kind = String(describing: type(of: thing))
    var key = Google_Datastore_V1_Key()
    key.path = [pathElement]
    var entity = Google_Datastore_V1_Entity()
    entity.key = key
    let properties = try PropertiesEncoder.encode(thing)!
    for (k,v) in properties {
      var value = Google_Datastore_V1_Value()
      switch v {
      case let v as String:
        value.stringValue = v
      case let v as Int:
        value.integerValue = Int64(v)
      default:
        break
      }
      entity.properties[k] = value
    }
    var mutation = Google_Datastore_V1_Mutation()
    mutation.insert = entity
    request.mutations.append(mutation)
    let result = try service.commit(request)
    for mutationResult in result.mutationResults {
      print("\(mutationResult)")
    }
  }
  
  func performDelete(kind: String,
                     id: Int64) throws {
    var request = Google_Datastore_V1_CommitRequest()
    request.projectID = projectID
    request.mode = .nonTransactional
    var pathElement = Google_Datastore_V1_Key.PathElement()
    pathElement.kind = kind
    pathElement.id = id
    var key = Google_Datastore_V1_Key()
    key.path = [pathElement]
    var mutation = Google_Datastore_V1_Mutation()
    mutation.delete = key
    request.mutations.append(mutation)
    let result = try service.commit(request)
    for mutationResult in result.mutationResults {
      print("\(mutationResult)")
    }
  }
}

let projectID = "your-project-identifier"

struct Thing : Codable {
  var name: String
  var number: Int
}

Group {
  $0.command("insert") { (number:Int) in
    let datastore = Datastore(projectID: projectID)
    try datastore.authenticate()
    let thing = Thing(name:"Thing", number:number)
    try datastore.performInsert(thing:thing)
  }
  
  $0.command("delete") { (id:Int) in
    let datastore = Datastore(projectID: projectID)
    try datastore.authenticate()
    try datastore.performDelete(kind:"Thing", id:Int64(id))
  }
  
  $0.command("list") {
    let datastore = Datastore(projectID: projectID)
    try datastore.authenticate()
    let entities = try datastore.performList(type: Thing.self)
    print("\(entities)")
  }
  
  }.run()