Xojo Plugin

DynamoDB - Query

See more Amazon DynamoDB Examples

The Query operation finds items based on primary key values. You can query any table or secondary index that has a composite primary key (a partition key and a sort key). Xojo Plugin

Dim success As Boolean
success = False

Dim rest As New Chilkat.Rest

// Implements the following CURL command:

// curl -X POST https://dynamodb.us-west-2.amazonaws.com/ \
//   -H "Accept-Encoding: identity" \
//   -H "Content-Type: application/x-amz-json-1.0" \
//   -H "Authorization: AWS4-HMAC-SHA256 Credential=<Credential>, SignedHeaders=<Headers>, Signature=<Signature>" \
//   -H "X-Amz-Date: <Date>" \
//   -H "X-Amz-Target: DynamoDB_20120810.Query" \
//   -d '{
//     "TableName": "Reply",
//     "IndexName": "PostedBy-Index",
//     "Limit": 3,
//     "ConsistentRead": true,
//     "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
//     "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
//     "ExpressionAttributeValues": {
//         ":v1": {"S": "Amazon DynamoDB#DynamoDB Thread 1"},
//         ":v2a": {"S": "User A"},
//         ":v2b": {"S": "User C"}
//     },
//     "ReturnConsumedCapacity": "TOTAL"
// }'

// Use the following online tool to generate REST code from a CURL command
// Convert a cURL Command to REST Source Code

Dim authAws As New Chilkat.AuthAws
authAws.AccessKey = "AWS_ACCESS_KEY"
authAws.SecretKey = "AWS_SECRET_KEY"
// Don't forget to change the region to your particular region. (Also make the same change in the call to Connect below.)
authAws.Region = "us-west-2"
authAws.ServiceName = "dynamodb"
// SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
success = rest.SetAuthAws(authAws)

// URL: https://dynamodb.us-west-2.amazonaws.com/
Dim bTls As Boolean
bTls = True
Dim port As Int32
port = 443
Dim bAutoReconnect As Boolean
bAutoReconnect = True
success = rest.Connect("dynamodb.us-west-2.amazonaws.com",port,bTls,bAutoReconnect)
If (success <> True) Then
    System.DebugLog("ConnectFailReason: " + Str(rest.ConnectFailReason))
    System.DebugLog(rest.LastErrorText)
    Return
End If

// Note: The above code does not need to be repeatedly called for each REST request.
// The rest object can be setup once, and then many requests can be sent.  Chilkat will automatically
// reconnect within a FullRequest* method as needed.  It is only the very first connection that is explicitly
// made via the Connect method.

// Use this online tool to generate code from sample JSON:
// Generate Code to Create JSON

// The following JSON is sent in the request body.

// {
//   "TableName": "Reply",
//   "IndexName": "PostedBy-Index",
//   "Limit": 3,
//   "ConsistentRead": true,
//   "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
//   "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
//   "ExpressionAttributeValues": {
//     ":v1": {
//       "S": "Amazon DynamoDB#DynamoDB Thread 1"
//     },
//     ":v2a": {
//       "S": "User A"
//     },
//     ":v2b": {
//       "S": "User C"
//     }
//   },
//   "ReturnConsumedCapacity": "TOTAL"
// }

Dim json As New Chilkat.JsonObject
success = json.UpdateString("TableName","Reply")
success = json.UpdateString("IndexName","PostedBy-Index")
success = json.UpdateInt("Limit",3)
success = json.UpdateBool("ConsistentRead",True)
success = json.UpdateString("ProjectionExpression","Id, PostedBy, ReplyDateTime")
success = json.UpdateString("KeyConditionExpression","Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b")
success = json.UpdateString("ExpressionAttributeValues.:v1.S","Amazon DynamoDB#DynamoDB Thread 1")
success = json.UpdateString("ExpressionAttributeValues.:v2a.S","User A")
success = json.UpdateString("ExpressionAttributeValues.:v2b.S","User C")
success = json.UpdateString("ReturnConsumedCapacity","TOTAL")

success = rest.AddHeader("Content-Type","application/x-amz-json-1.0")
success = rest.AddHeader("X-Amz-Target","DynamoDB_20120810.Query")
success = rest.AddHeader("Accept-Encoding","identity")

Dim sbRequestBody As New Chilkat.StringBuilder
success = json.EmitSb(sbRequestBody)
Dim sbResponseBody As New Chilkat.StringBuilder
success = rest.FullRequestSb("POST","/",sbRequestBody,sbResponseBody)
If (success <> True) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

Dim respStatusCode As Int32
respStatusCode = rest.ResponseStatusCode
System.DebugLog("response status code = " + Str(respStatusCode))
If (respStatusCode >= 400) Then
    System.DebugLog("Response Status Code = " + Str(respStatusCode))
    System.DebugLog("Response Header:")
    System.DebugLog(rest.ResponseHeader)
    System.DebugLog("Response Body:")
    System.DebugLog(sbResponseBody.GetAsString())
    Return
End If

Dim jsonResponse As New Chilkat.JsonObject
success = jsonResponse.LoadSb(sbResponseBody)

jsonResponse.EmitCompact = False
System.DebugLog(jsonResponse.Emit())

// Sample JSON response:
// (Sample code for parsing the JSON response is shown below)

// {
//   "ConsumedCapacity": {
//     "CapacityUnits": 1,
//     "TableName": "Reply"
//   },
//   "Count": 2,
//   "Items": [
//     {
//       "ReplyDateTime": {
//         "S": "2015-02-18T20:27:36.165Z"
//       },
//       "PostedBy": {
//         "S": "User A"
//       },
//       "Id": {
//         "S": "Amazon DynamoDB#DynamoDB Thread 1"
//       }
//     },
//     {
//       "ReplyDateTime": {
//         "S": "2015-02-25T20:27:36.165Z"
//       },
//       "PostedBy": {
//         "S": "User B"
//       },
//       "Id": {
//         "S": "Amazon DynamoDB#DynamoDB Thread 1"
//       }
//     }
//   ],
//   "ScannedCount": 2
// }

// Sample code for parsing the JSON response...
// Use the following online tool to generate parsing code from sample JSON:
// Generate Parsing Code from JSON

Dim ReplyDateTimeS As String
Dim PostedByS As String
Dim IdS As String

Dim ConsumedCapacityCapacityUnits As Int32
ConsumedCapacityCapacityUnits = jsonResponse.IntOf("ConsumedCapacity.CapacityUnits")
Dim ConsumedCapacityTableName As String
ConsumedCapacityTableName = jsonResponse.StringOf("ConsumedCapacity.TableName")
Dim Count As Int32
Count = jsonResponse.IntOf("Count")
Dim ScannedCount As Int32
ScannedCount = jsonResponse.IntOf("ScannedCount")
Dim i As Int32
i = 0
Dim count_i As Int32
count_i = jsonResponse.SizeOfArray("Items")
While i < count_i
    jsonResponse.I = i
    ReplyDateTimeS = jsonResponse.StringOf("Items[i].ReplyDateTime.S")
    PostedByS = jsonResponse.StringOf("Items[i].PostedBy.S")
    IdS = jsonResponse.StringOf("Items[i].Id.S")
    i = i + 1
Wend