dynamodb 地图的 AWS API 网关主体映射模板 [英] AWS API gateway body mapping template for dynamodb map

问题描述

我试图弄清楚如何通过 AWS 中的 API 网关将动态数据插入到 dynamodb 表中.目前我有一个 dynamodb 表和一个 API 端点设置，可以接受这样的 POST.

I am trying to figure out how to insert dynamic data into a dynamodb table via an API Gateway in AWS. Currently I have a dynamodb table and an API endpoint setup that accepts a POST like so.

POST https://{unique-id}.execute-api.us.east-1.amazonaws.com/notification/events

POST https://{unique-id}.execute-api.us.east-1.amazonaws.com/notification/events

{
  "reference_number": 99,
  "purchase_date": "1/1/2017"
}

我在 API 网关中设置了一个身体映射模板，以将数据按摩到 dynamodb 中.

I've setup a body mapping template in the API gateway to massage the data into the dynamodb.

{ 
    "TableName": "Events",
    "Item": {
        "reference_number": {
            "N": "$input.path('$.reference_number')"
        },
        "purchase_date": {
            "S": "$input.path('$.purchase_date')"
        }
    }
}

上述工作并保存到表中.

The above works and saves to the table.

假设我将事件哈希添加到我的 json 中(可以根据事件进行更改).

Suppose I add the event hash to my json (which can change based on events).

{
  "reference_number": 99,
  "purchase_date": "1/1/2017",
  "event": {
     "name": "purchase",
     "items": [1,3,6],
     "info": {
       "currencyID": "USD",
       "countryID": "US"
     }
  }
}

如何使用 API Gateway Body 映射模板语法将事件属性保存到 dynamodb 中的 Map?

How do I save the event attribute to a Map in dynamodb using the API Gateway Body mapping template syntax?

{ 
    "TableName": "Events",
    "Item": {
        "reference_number": {
            "N": "$input.path('$.reference_number')"
        },
        "purchase_date": {
            "S": "$input.path('$.purchase_date')"
        },
        "event":{
            "M": "$input.path('$.event')"
        }
    }
}

上面的模板给了我以下错误."预期地图或为空"

The above template gives me the following error. "Expected map or null"

推荐答案

看起来 DynamoDB API 实际上要求 'M' 属性的值是 String 的 Map ->属性值.不幸的是，您无法传递原始 JSON.您必须手动映射整个 event 对象才能使 DDB API 满意.

It looks like DynamoDB API actually requires the value of an 'M' attribute to be a Map of String -> AttributeValue. Unfortunately you can't pass the raw JSON. You'll have to manually map the whole event object to make the DDB API happy.

http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_AttributeValue.html#DDB-Type-AttributeValue-M

一种可能的解决方法是将 event 对象字符串化并将其写入类型 S 但这当然需要读者期待这种行为.

One possible workaround would be to stringify the event object and write it as type S but that would of course require the reader to expect that behavior.

{ 
    "TableName": "Events",
    "Item": {
        "reference_number": {
            "N": "$input.path('$.reference_number')"
        },
        "purchase_date": {
            "S": "$input.path('$.purchase_date')"
        },
        "event":{
            "S": "$util.escapeJavaScript($input.json('$.event'))"
        }
    }
}

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