CODEWITHSUNDEEP
.netamazon-dynamodbaws-sdk
Rico Chan
Rico Chan

Reputation: 2396

DynamoDB .NET how to get the items JSON and directly return to client side

My code is like this, I just use a scan of DynamoDB, and change the result to JSON

var client = new AmazonDynamoDBClient();
var request = new ScanRequest
            {
                TableName = "wow_chat_msg",
            };
var response = client.Scan(request);
var jsonSerialiser = new JavaScriptSerializer();
            var json = jsonSerialiser.Serialize(response.Items);

But after that the returned JSON is like this:

[{\"Name\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"ABC\",\"SS\":[]},\"Type\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"CDE\",\"SS\":[]},\"msg_uid\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":\"1010\",\"NS\":[],\"NULL\":false,\"S\":null,\"SS\":[]},\"group_uid\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":\"1\",\"NS\":[],\"NULL\":false,\"S\":null,\"SS\":[]}},{\"Name\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"ABC\",\"SS\":[]},\"Type\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"CDE\",\"SS\":[]},\"msg_uid\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":\"3\",\"NS\":[],\"NULL\":false,\"S\":null,\"SS\":[]}},{\"Name\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"Chong\",\"SS\":[]},\"Type\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"Peter\",\"SS\":[]},\"msg_uid\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":\"2\",\"NS\":[],\"NULL\":false,\"S\":null,\"SS\":[]}},{\"Name\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"ABC\",\"SS\":[]},\"Type\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"CDE\",\"SS\":[]},\"msg_uid\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":\"1011\",\"NS\":[],\"NULL\":false,\"S\":null,\"SS\":[]}},{\"Name\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"Chan\",\"SS\":[]},\"Type\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":null,\"NS\":[],\"NULL\":false,\"S\":\"Rico\",\"SS\":[]},\"msg_uid\":{\"B\":null,\"BOOL\":false,\"IsBOOLSet\":false,\"BS\":[],\"L\":[],\"IsLSet\":false,\"M\":{},\"IsMSet\":false,\"N\":\"1\",\"NS\":[],\"NULL\":false,\"S\":null,\"SS\":[]}}]

The escape character is because I change it to string. But I want to ask how to get rid of the unnecessary attributes? Like I just want the "2" in the json value, but there are too many other attributes like "S", "SS", "BOOL" .... etc I just want a pretty JSON.

Please help, I have search a lot of documents and want to seek solution.

Upvotes: 0

Views: 3329

Answers (2)

Hector
Hector

Reputation: 221

I have a solution that returns a nice JSON. This is for a Lambda function:

public List<dynamic> GetDynamoData(string dynamoTableName, ILambdaContext context) {
    Amazon.DynamoDBv2.AmazonDynamoDBConfig amazonDynamoDBConfig = new Amazon.DynamoDBv2.AmazonDynamoDBConfig { RegionEndpoint = RegionEndpoint.XWZ};
    Amazon.DynamoDBv2.AmazonDynamoDBClient client = new Amazon.DynamoDBv2.AmazonDynamoDBClient(amazonDynamoDBConfig);
    Table myTable = Table.LoadTable(client,dynamoTableName);
    ScanFilter scanFilter = new ScanFilter();
    scanFilter.AddCondition("IDCOLULM", ScanOperator.GreaterThan, 123465); //Whatever your filter is
    Search search = myTable.Scan(scanFilter);
    List<dynamic> results = new List<dynamic>();
    do
    {
        var docList = search.GetNextSetAsync();
        docList.Result.ForEach(doc=> {
            dynamic x = Newtonsoft.Json.JsonConvert.DeserializeObject(doc.ToJson());
            results.Add(x);
        });
    } while (!search.IsDone);
    return results;
}

Upvotes: 1

Rico Chan
Rico Chan

Reputation: 2396

Just found the answer.

Using DynamoDB's low level api will return a lot of unnecessary data for low level usage. So we can use the high level document model.

http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ScanMidLevelDotNet.html

Use Table.scan, then use your own method to combine the Object of document.ToJSON(), here I use ArrayList to combine all of them.

Then after I got a list of Object, then return to the client side. Everything is beautiful.

Upvotes: 0

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