ios - 在 Firebase 中保存数组

Question

我使用 Firebase 3.0 作为我的后端，我需要将我的每个 user.uid 保存在一个单独的子项中，它需要是一个 NSArray，然后使用 for 循环检索该数组!

这就是我保存数据的方式:我为 FIRController 创建了一个单独的类，它处理数据库和存储的所有存储和检索。

func signUpUserWithBasicInfo(emailId : String! , password : String!, username : String!, age : String, gender : String!, backpackerType : String, info : [String : AnyObject], completionBlock : (() -> Void)){

    print("fir signup did recieve")
    FIRAuth.auth()?.createUserWithEmail(emailId, password: password, completion: {
        user,error in

        if error != nil{
            print("error encountered while backend email signup Handshake : \(error)")
            print("")
            self.delegate.firShowAlert("Error signing you up", Message: "Please check your network or this email already exist!")

        }else{
            print("uploading database")
            self.profilePictureUploading(info, completionBlock: {

                FIRControllerClass.ref.child("UserProfile").child(user!.uid).setValue([
                    "username" : username,
                    "email" : emailId,
                    "age" : age,
                    "gender" : gender,
                    "password" : password,
                    "typeOfBackpacker" : backpackerType
                    ])

                completionBlock()

            })
        }
    })
}

func profilePictureUploading(infoOnThePicture : [String : AnyObject],completionBlock : (()->Void)) {

    if let referenceUrl = infoOnThePicture[UIImagePickerControllerReferenceURL] {
        print(referenceUrl)
        let assets = PHAsset.fetchAssetsWithALAssetURLs([referenceUrl as! NSURL], options: nil)
        print(assets)
        let asset = assets.firstObject
        print(asset)
        asset?.requestContentEditingInputWithOptions(nil, completionHandler: { (ContentEditingInput, infoOfThePicture)  in

            let imageFile = ContentEditingInput?.fullSizeImageURL
            print("imagefile : \(imageFile)")

            let filePath = FIRAuth.auth()!.currentUser!.uid +  "/\(Int(NSDate.timeIntervalSinceReferenceDate() * 1000))/\(imageFile!.lastPathComponent!)"
            print("filePath : \(filePath)")

                FIRControllerClass.storageRef.child("ProfilePictures").child(filePath).putFile(imageFile!, metadata: nil, completion: { (metadata, error) in

                         if error != nil{

                            print("error in uploading image : \(error)")
                            self.delegate.firShowAlert("Error Uploading Your Profile Pic", Message: "Please check your network!")
                         }

                          else{

                                print("metadata in : \(metadata!)")
                                print(metadata?.downloadURL())
                                print("The pic has been uploaded")
                                print("download url : \(metadata?.downloadURL())")

                                self.uploadSuccess(metadata!, storagePath: filePath)

                                completionBlock()

                }

            })
        })

    } else {
            print("No reference URL found!")
    }
}

我如何在后端创建一个用作数组的子项，以及如何检索该数组？

我的 firebase JSON 结构:-

{
  "UserId" : [ 1, 
    "Sq5EDvVOsQWkLylEx3GrBdEsIN92",
    "xC4jCJmobUcqghq8C3SI1XT0UPk1",
    "D8QmnOSH6vRYiMujKNXngzhdn992",
    "riHjon6wknOmALwf0Z0Ri5aOMA82",
    "fKqlb88MKsYCE43xy7D51qH6jqH3",
    "aCgAFAGDIgWRSUu9a2aMo9HtnnD3",
    "iicKACGo8RaeTSEggKPB0sU2Bme2",
    "qJ2c8AcEYzVkJKLl13N92tyKnbz2"
    ],
  "UserProfile" : {
    "D8QmnOSH6vRYiMujKNXngzhdn992" : {
      "age" : "12",
      "email" : "dummy1@gmail.com",
      "gender" : "f",
      "password" : "123454321",
      "typeOfBackpacker" : "dummy",
      "username" : "duummyy1"
    },
    "Sq5EDvVOsQWkLylEx3GrBdEsIN92" : {
      "age" : "121",
      "email" : "ghfgh@gnag.com",
      "gender" : "gjhg",
      "password" : "123454321",
      "typeOfBackpacker" : "chef",
      "username" : "hgfgh"
    },
    "aCgAFAGDIgWRSUu9a2aMo9HtnnD3" : {
      "age" : "24",
      "email" : "cathydurrant@gmail.com",
      "gender" : "F",
      "password" : "123454321",
      "typeOfBackpacker" : "Group",
      "username" : "Cathy"
      },
      etc
}

我还需要在我的数据库(数组)中添加一个no of friends数组。我使用for循环的唯一原因是我可以向我的用户显示每个用户的详细信息(除了来自他/她自己)使用我在我的数据库中创建的 userId 数组，这实际上是我的每个用户数据库的父节点。

这就是我在数据库中附加 UserId 的方式:-

func retrieveUserIdsArray(completionBlock : ((appendedArr : NSMutableArray) -> Void)){

    var appendedArray : NSMutableArray = []

    FIRControllerClass.ref.child("UserId").observeEventType(FIRDataEventType.Value, withBlock: {(snapshot) in

        if let userIdDetails = snapshot.value as? NSMutableArray{

        userIdDetails.addObject((FIRAuth.auth()?.currentUser?.uid)!)
        appendedArray = userIdDetails

        completionBlock(appendedArr: appendedArray)

        }
    })
} 

在此函数中调用:-

    func signUpUserWithBasicInfo(emailId : String! , password : String!, username : String!, age : String, gender : String!, backpackerType : String, info : [String : AnyObject], completionBlock : (() -> Void)){

    print("fir signup did recieve")

    FIRAuth.auth()?.createUserWithEmail(emailId, password: password, completion: {
        user,error in

        if error != nil{

            print("error encountered while backend email signup Handshake : \(error)")

            print("")

            self.delegate.firShowAlert("Error signing you up", Message: "Please check your network or this email already exist!")

        }else{

            print("uploading database")

            self.profilePictureUploading(info, completionBlock: {

                FIRControllerClass.ref.child("UserProfile").child(user!.uid).setValue([
                    "username" : username,
                    "email" : emailId,
                    "age" : age,
                    "gender" : gender,
                    "password" : password,
                    "typeOfBackpacker" : backpackerType
                    ])


                var a = 0

                self.retrieveUserIdsArray({ (appendedArr) in

                    a += 1

                    print("The appended array is : \(appendedArr)")

                    if a == 1{

                        FIRControllerClass.ref.child("UserId").setValue(appendedArr)

                    }else{

                        completionBlock()

                    }
                })
            })
        }
    })
}

我使用 a 变量的原因是为了解决它引起的无限循环(我知道它只是一个 hack，现在..)

欢迎任何更好的方法来解决这个问题!..

Answer 1

数组在 Firebase 中可能具有挑战性，因为不能直接访问或修改单个元素。您要么读取整个数组，要么写入整个数组。

我建议更改结构以更好地匹配您想要的数据并完全避免数组:

"UserProfile" : {
    "D8QmnOSH6vRYiMujKNXngzhdn992" : {
      "age" : "12",
      "email" : "dummy1@gmail.com",
      "gender" : "f",
      "password" : "123454321",
      "typeOfBackpacker" : "dummy",
      "username" : "duummyy1"
      "friend_count": 10
      "friend_of"
         "aCgAFAGDIgWRSUu9a2aMo9HtnnD3": true
    },

然后一个简单的深度查询将返回您需要的一切(Firebase v2)

let myUid = "aCgAFAGDIgWRSUu9a2aMo9HtnnD3"
let path = ("friend_of/\(myUid)") // equals friend_of/aCgAFAGDIgWRSUu9a2aMo9HtnnD3
var userIdArray = [String]()
userProfileRef.queryOrderedByChild(path)
              .queryEqualToValue(true)
              .observeSingleEventOfType(.Value, withBlock: { snapshot in
   for child in snapshot.children {
      let userId = child.key as String
      userIdArray.append(userId)
   }
   //loop is done, now we have an array of userIds that are friends
})

代码返回我的 friend 的每个用户 (myUid)

我还添加了一个“ friend 计数”节点，它只记录该用户的 friend 数量。添加 friend 时，增加值，删除时减少值。很快

myUid.child("friend_count").setValue(updated_count)

此代码还避免了循环、回调和额外的完成 block ，因为它依赖于 Firebase 来获取数据，并在完成时通知我们。

如果你真的非常想读取一个数组节点(不推荐)

    let myRef = self.myRootRef.child("array_node")
    myRef.observeSingleEventOfType(.Value, withBlock: { snapshot in

        let a = snapshot.value as! NSArray
        print(a) //a an NSArray

        let b = (a as Array).filter {$0 is String}

        print(b) //b is a Swift Array

        print( b[1] )
    })