AWS DynamoDB 批量获取请求 - iOS

Question

我可以在 AWS dynamoDB 中对单个 table 执行简单的 Get 请求，但是当我将其扩展为跨多个 table 的批处理请求时，我继续收到错误消息

validation error detected: Value null at 'requestItems.rip.member.keys' failed to satisfy constraint

我理解这是因为值没有被正确传递，但我看不出我的代码有什么问题

//Create Request Values
AWSDynamoDBGetItemInput *getItem = [AWSDynamoDBGetItemInput new];
AWSDynamoDBAttributeValue *hashValue = [AWSDynamoDBAttributeValue new];
hashValue.S = @"User Test";
getItem.key = @{@"ripId": hashValue};

//Create Request Values 2 
AWSDynamoDBGetItemInput *getItem2 = [AWSDynamoDBGetItemInput new];
AWSDynamoDBAttributeValue *hashValue2 = [AWSDynamoDBAttributeValue new];
hashValue2.S = @"User Test";
getItem2.key = @{@"chat": hashValue2};

//Combine to Batch Request
AWSDynamoDBBatchGetItemInput * batchFetch = [AWSDynamoDBBatchGetItemInput new];
batchFetch.requestItems = @{ @"rip": getItem,
                             @"chat": getItem,};

[[dynamoDB batchGetItem:batchFetch] continueWithBlock:^id(BFTask *task) {
    if (!task.error) {

        NSLog(@"BOY SUCCES");

    } else {
        NSLog(@" NO BOY SUCCESS %@",task.error);
    }
    return nil;
}];

在互联网上到处搜索，但看不到使用 iOS Objective C（或 swift 的批处理请求的工作示例）。

我已经在单个 Get 请求中测试了两个变量，它们都有效。

Answer 1

您忘记在 AWSDynamoDBKeysAndAttributes 中环绕 AWSDynamoDBAttributeValue。这是来自 AWSDynamoDBTests.m 的一个简单示例：

AWSDynamoDBKeysAndAttributes *keysAndAttributes = [AWSDynamoDBKeysAndAttributes new];
keysAndAttributes.keys = @[@{@"hashKey" : attributeValue1},
                           @{@"hashKey" : attributeValue2}];
keysAndAttributes.consistentRead = @YES;

AWSDynamoDBBatchGetItemInput *batchGetItemInput = [AWSDynamoDBBatchGetItemInput new];
batchGetItemInput.requestItems = @{table1Name: keysAndAttributes};

Answer 2

由于批量获取没有映射到 class 我通过这样做解决了它。

我这样做解决了，

    let dynamoDBObjectMapper = AWSDynamoDBObjectMapper.defaultDynamoDBObjectMapper()
    let task1 = dynamoDBObjectMapper.load(User.self, hashKey: "rtP1oQ5DJG", rangeKey: nil)
    let task2 = dynamoDBObjectMapper.load(User.self, hashKey: "dbqb1zyUq1", rangeKey: nil)

    AWSTask.init(forCompletionOfAllTasksWithResults: [task1, task2]).continueWithBlock { (task) -> AnyObject? in
        if let users = task.result as? [User] {
            print(users.count)
            print(users[0].firstName)
            print(users[1].firstName)
        }
        else if let error = task.error {
            print(error.localizedDescription)
        }
        return nil
    }

Answer 3

Swift 3

我能够使用以下代码获得 BatchGet 请求。希望这可以帮助其他因缺少 Swift 文档而苦苦挣扎的人。

此代码假定您已在 AppDelegate 应用程序 didFinishLaunchingWithOptions 方法中配置了 AWSServiceConfiguration。

let DynamoDB = AWSDynamoDB.default()

    // define your primary hash keys
    let hashAttribute1 = AWSDynamoDBAttributeValue()
    hashAttribute1?.s = "NDlFRTdDODEtQzNCOC00QUI5LUFFMzUtRkIyNTJFNERFOTBF"

    let hashAttribute2 = AWSDynamoDBAttributeValue()
    hashAttribute2?.s = "MjVCNzU3MUQtMEM0NC00NEJELTk5M0YtRTM0QjVDQ0Q1NjlF"

    let keys: Array = [["userID": hashAttribute1], ["userID": hashAttribute2]]

    let keysAndAttributesMap = AWSDynamoDBKeysAndAttributes()
    keysAndAttributesMap?.keys = keys as? [[String : AWSDynamoDBAttributeValue]]
    keysAndAttributesMap?.consistentRead = true
    let tableMap = ["Your-Table-Name" : keysAndAttributesMap]
    let request = AWSDynamoDBBatchGetItemInput()
    request?.requestItems = tableMap as? [String : AWSDynamoDBKeysAndAttributes]
    request?.returnConsumedCapacity = AWSDynamoDBReturnConsumedCapacity.total
    DynamoDB.batchGetItem(request!) { (output, error) in
        if output != nil {
            print("Batch Query output?.responses?.count:", output!.responses!)
        }
        if error != nil {
            print("Batch Query error:", error!)
        }
    }

AWS DynamoDB 批量获取请求 - iOS

AWS DynamoDB Batch Get Request - iOS

objective-c

amazon-web-services

ios

amazon-dynamodb

Swift 3