Cant Unmarshall dynamodb属性 [英] Cant unmarshall dynamodb attribute

问题描述

我正在使用带有DynamoDB API的AWS-SDK-GO进行实验...

I'm experimenting with AWS-SDK-GO with the DynamoDB API...

我正在尝试查询数据库并返回一个字符串.但是我在解决返回值问题上遇到了一些问题....

I'm trying to query the db and return a string. But I'm having some issues unmarshelling the return value....

结构

type Item struct {
     slug string
     destination string
}

查询功能

input := &dynamodb.GetItemInput{
    Key: map[string]*dynamodb.AttributeValue{
        "slug": {
            S: aws.String(slug),
        },
    },
    TableName: db.TableName,
}

result, err := db.dynamo.GetItem(input)
if err != nil {
    return "",  err
}

n := Item{}
err = dynamodbattribute.UnmarshalMap(result.Item, &n)

if err != nil {
    log.Printf("Failed to unmarshal Record, %v", err)
    return "", err
}
log.Printf("dump %+v", n)
log.Printf("echo %s", n.slug)
log.Printf("echo %s", n.destination)
log.Printf("orig %v", result.Item)

结果

2017/10/11 14:21:34 dump {slug: destination:}
2017/10/11 14:21:34 echo 
2017/10/11 14:21:34 echo 
2017/10/11 14:21:34 orig map[destination:{
  S: "http://example.com"
} slug:{
  S: "abcde"
}]

为什么将商品退回为空?

Why is Item being returned empty?

我尝试到处寻找，但找不到解决方法....

I've tried to look everywhere but find no solution....

推荐答案

我不确定您是否尝试过此方法.我认为，如果您可以按以下所述更改结构，则可以解决问题.

I am not sure whether you have tried this. I think if you can change the struct as mentioned below, it may resolve the problem.

我假设 slug 和 destination 都已定义/保存为DynamoDB表中的String属性.

I assumed that both slug and destination are defined/saved as String attribute in DynamoDB table.

type Item struct {
     Slug string`json:"slug"`
     Destination string`json:"destination"`
}

将打印内容更改为:-

log.Printf("echo %s", n.Slug)
log.Printf("echo %s", n.Destination)

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