Added structure to datastore client example.

Examples/Datastore/PackageManager/Sources/main.swift

@@ -18,14 +18,6 @@ import gRPC
 import OAuth2
 import Commander
 
-let projectID = "your-project-identifier"
-let scopes = ["https://www.googleapis.com/auth/datastore"]
-
-struct Thing : Codable {
-  var name: String
-  var number: Int
-}
-
 // Convert Encodable objects to dictionaries of property-value pairs.
 class PropertiesEncoder {
   static func encode<T : Encodable>(_ value : T) throws -> [String:Any]? {
@@ -38,135 +30,149 @@ class PropertiesEncoder {
 // 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)
+    let plist = try PropertyListSerialization.data(fromPropertyList: from, format: .binary, options:0)
     return try PropertyListDecoder().decode(type, from: plist)
   }
 }
 
-func prepareService() throws -> Google_Datastore_V1_DatastoreService? {
-  // Get an OAuth token
-  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
+// 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.signal()
+      sem.wait()
+    }
+    if authToken == nil {
+      print("ERROR: No OAuth token is available. Did you set GOOGLE_APPLICATION_CREDENTIALS?")
+      exit(-1)
     }
-    sem.wait()
+    // Initialize gRPC service
+    gRPC.initialize()
+    service = Google_Datastore_V1_DatastoreService(address:"datastore.googleapis.com")
+    service.metadata = Metadata(["authorization":"Bearer " + authToken])
   }
-  if authToken == nil {
-    print("ERROR: No OAuth token is available. Did you set GOOGLE_APPLICATION_CREDENTIALS?")
-    exit(-1)
+  
+  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
   }
-  // Initialize gRPC service
-  gRPC.initialize()
-  let service = Google_Datastore_V1_DatastoreService(address:"datastore.googleapis.com")
-  service.metadata = Metadata(["authorization":"Bearer " + authToken])
-  return service
-}
-
-func performList<T: Codable>(service: Google_Datastore_V1_DatastoreService, 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
+  
+  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:
-        print("?")
+        break
       }
+      entity.properties[k] = value
     }
-    let entity = try PropertiesDecoder.decode(type, from:properties)
-    entities[entityResult.entity.key.path[0].id] = entity
-  }
-  return entities
-}
-
-func performInsert<T: Codable>(service: Google_Datastore_V1_DatastoreService,
-                               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
+    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)")
     }
-    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)")
+    }
   }
 }
 
-func performDelete(service: Google_Datastore_V1_DatastoreService,
-                   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
-    if let service = try prepareService() {
-      let thing = Thing(name:"Thing", number:number)
-      try performInsert(service:service, thing:thing)
-    }
+    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
-    if let service = try prepareService() {
-      try performDelete(service:service, kind:"Thing", id:Int64(id))
-    }
+    let datastore = Datastore(projectID: projectID)
+    try datastore.authenticate()
+    try datastore.performDelete(kind:"Thing", id:Int64(id))
   }
   
   $0.command("list") {
-    if let service = try prepareService() {
-      let entities = try performList(service:service, type: Thing.self)
-      print("\(entities)")
-    }
+    let datastore = Datastore(projectID: projectID)
+    try datastore.authenticate()
+    let entities = try datastore.performList(type: Thing.self)
+    print("\(entities)")
   }
   
   }.run()