(Visual FoxPro) DynamoDB - Query

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).

For more information, see https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Query.html

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loRest
LOCAL lnSuccess
LOCAL loAuthAws
LOCAL lnBTls
LOCAL lnPort
LOCAL lnBAutoReconnect
LOCAL loJson
LOCAL loSbRequestBody
LOCAL loSbResponseBody
LOCAL lnRespStatusCode
LOCAL loJsonResponse
LOCAL lcReplyDateTimeS
LOCAL lcPostedByS
LOCAL lcIdS
LOCAL lnConsumedCapacityCapacityUnits
LOCAL lcConsumedCapacityTableName
LOCAL lnCount
LOCAL lnScannedCount
LOCAL i
LOCAL lnCount_i

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Rest')
loRest = CreateObject('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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.AuthAws')
loAuthAws = CreateObject('Chilkat.AuthAws')
loAuthAws.AccessKey = "AWS_ACCESS_KEY"
loAuthAws.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.)
loAuthAws.Region = "us-west-2"
loAuthAws.ServiceName = "dynamodb"
* SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
loRest.SetAuthAws(loAuthAws)

* URL: https://dynamodb.us-west-2.amazonaws.com/
lnBTls = 1
lnPort = 443
lnBAutoReconnect = 1
lnSuccess = loRest.Connect("dynamodb.us-west-2.amazonaws.com",lnPort,lnBTls,lnBAutoReconnect)
IF (lnSuccess <> 1) THEN
    ? "ConnectFailReason: " + STR(loRest.ConnectFailReason)
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loAuthAws
    CANCEL
ENDIF

* 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"
* }

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJson = CreateObject('Chilkat.JsonObject')
loJson.UpdateString("TableName","Reply")
loJson.UpdateString("IndexName","PostedBy-Index")
loJson.UpdateInt("Limit",3)
loJson.UpdateBool("ConsistentRead",1)
loJson.UpdateString("ProjectionExpression","Id, PostedBy, ReplyDateTime")
loJson.UpdateString("KeyConditionExpression","Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b")
loJson.UpdateString("ExpressionAttributeValues.:v1.S","Amazon DynamoDB#DynamoDB Thread 1")
loJson.UpdateString("ExpressionAttributeValues.:v2a.S","User A")
loJson.UpdateString("ExpressionAttributeValues.:v2b.S","User C")
loJson.UpdateString("ReturnConsumedCapacity","TOTAL")

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbRequestBody = CreateObject('Chilkat.StringBuilder')
loJson.EmitSb(loSbRequestBody)
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbResponseBody = CreateObject('Chilkat.StringBuilder')
lnSuccess = loRest.FullRequestSb("POST","/",loSbRequestBody,loSbResponseBody)
IF (lnSuccess <> 1) THEN
    ? loRest.LastErrorText
    RELEASE loRest
    RELEASE loAuthAws
    RELEASE loJson
    RELEASE loSbRequestBody
    RELEASE loSbResponseBody
    CANCEL
ENDIF

lnRespStatusCode = loRest.ResponseStatusCode
? "response status code = " + STR(lnRespStatusCode)
IF (lnRespStatusCode >= 400) THEN
    ? "Response Status Code = " + STR(lnRespStatusCode)
    ? "Response Header:"
    ? loRest.ResponseHeader
    ? "Response Body:"
    ? loSbResponseBody.GetAsString()
    RELEASE loRest
    RELEASE loAuthAws
    RELEASE loJson
    RELEASE loSbRequestBody
    RELEASE loSbResponseBody
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.JsonObject')
loJsonResponse = CreateObject('Chilkat.JsonObject')
loJsonResponse.LoadSb(loSbResponseBody)

loJsonResponse.EmitCompact = 0
? loJsonResponse.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

lnConsumedCapacityCapacityUnits = loJsonResponse.IntOf("ConsumedCapacity.CapacityUnits")
lcConsumedCapacityTableName = loJsonResponse.StringOf("ConsumedCapacity.TableName")
lnCount = loJsonResponse.IntOf("Count")
lnScannedCount = loJsonResponse.IntOf("ScannedCount")
i = 0
lnCount_i = loJsonResponse.SizeOfArray("Items")
DO WHILE i < lnCount_i
    loJsonResponse.I = i
    lcReplyDateTimeS = loJsonResponse.StringOf("Items[i].ReplyDateTime.S")
    lcPostedByS = loJsonResponse.StringOf("Items[i].PostedBy.S")
    lcIdS = loJsonResponse.StringOf("Items[i].Id.S")
    i = i + 1
ENDDO

RELEASE loRest
RELEASE loAuthAws
RELEASE loJson
RELEASE loSbRequestBody
RELEASE loSbResponseBody
RELEASE loJsonResponse