CODEWITHSUNDEEP
amazon-web-servicesamazon-dynamodbaws-api-gateway
Iorek
Iorek

Reputation: 581

Sort/sequence AWS API gateway output

tl;dr looking to sort API output from AWS API gateway

I have a dynamoDB table 'NP' with key 'id' and GSI 'atype-index'. There is no sort key.

Also, I have API gateway mapping template 

{
    "TableName": "NP",
    "IndexName": "atype-index",
    "KeyConditionExpression": "atype = :v1",
    "ExpressionAttributeValues": {
        ":v1": {
            "S": "$input.params('atype')"
        }
    }
}

The mapping template will extract all values in the table with GSI key matching the specified string. However, the values are extracted in no particular order, for example, the API could be:

{
  "Count": 3,
  "Items": [
    {
      "apiUrl": {
        "S": “ee”
      },
      "webTitle": {
        "S": “dd”
      },
      "atype": {
        "S": “type”
      },
      "id": {
        "S": "1a"
       }
     },
    {
      "apiUrl": {
        "S": “dd”
      },
      "webTitle": {
        "S": “cc”
      },
      "atype": {
        "S": "atype"
      },
      "id": {
        "S": “3a”
       }
     },
    {
      "apiUrl": {
        "S": “cc”
      },
      "webTitle": {
        "S": “bb”
      },
      "atype": {
        "S": "atype"
      },
      "id": {
        "S": “2a”
       }
     }
  ],
  "ScannedCount": 3
}

How do I sort the above output by the key "apiURL" for example?

Upvotes: 0

Views: 653

Answers (1)

jackko
jackko

Reputation: 7344

What you described is exactly what a sort key would accomplish, assuming you're using the Query API (rather than Scan).

If you add a sort key, the results will be sorted based on the sort key when querying a given partition key.

Edit: Just to clarify, there is no way to do the sort at the API GW layer in a mapping template.

You could put a Lambda function in between API GW and DDB if the overhead is worth it for your use case. Otherwise, probably better to just sort at client side.

Upvotes: 1

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