(DataFlex) DynamoDB - GetItem

The GetItem operation returns a set of attributes for the item with the given primary key. If there is no matching item, GetItem does not return any data and there will be no Item element in the response.

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

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

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoRest
    Boolean iSuccess
    Variant vAuthAws
    Handle hoAuthAws
    Boolean iBTls
    Integer iPort
    Boolean iBAutoReconnect
    Handle hoJson
    Variant vSbRequestBody
    Handle hoSbRequestBody
    Variant vSbResponseBody
    Handle hoSbResponseBody
    Integer iRespStatusCode
    Handle hoJsonResponse
    String sStrVal
    Integer iConsumedCapacityCapacityUnits
    String sConsumedCapacityTableName
    String sItemLastPostDateTimeS
    String sItemMessageS
    Integer i
    Integer iCount_i
    String sTemp1
    Integer iTemp1

    Get Create (RefClass(cComChilkatRest)) To hoRest
    If (Not(IsComObjectCreated(hoRest))) Begin
        Send CreateComObject of hoRest
    End

    // 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.GetItem" \
    //   -d '{
    //     "TableName": "Thread",
    //     "Key": {
    //         "ForumName": {
    //             "S": "Amazon DynamoDB"
    //         },
    //         "Subject": {
    //             "S": "How do I update multiple items?"
    //         }
    //     },
    //     "ProjectionExpression":"LastPostDateTime, Message, Tags",
    //     "ConsistentRead": true,
    //     "ReturnConsumedCapacity": "TOTAL"
    // }'

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

    Get Create (RefClass(cComChilkatAuthAws)) To hoAuthAws
    If (Not(IsComObjectCreated(hoAuthAws))) Begin
        Send CreateComObject of hoAuthAws
    End
    Set ComAccessKey Of hoAuthAws To "AWS_ACCESS_KEY"
    Set ComSecretKey Of hoAuthAws To "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.)
    Set ComRegion Of hoAuthAws To "us-west-2"
    Set ComServiceName Of hoAuthAws To "dynamodb"
    // SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
    Get pvComObject of hoAuthAws to vAuthAws
    Get ComSetAuthAws Of hoRest vAuthAws To iSuccess

    // URL: https://dynamodb.us-west-2.amazonaws.com/
    Move True To iBTls
    Move 443 To iPort
    Move True To iBAutoReconnect
    Get ComConnect Of hoRest "dynamodb.us-west-2.amazonaws.com" iPort iBTls iBAutoReconnect To iSuccess
    If (iSuccess <> True) Begin
        Get ComConnectFailReason Of hoRest To iTemp1
        Showln "ConnectFailReason: " iTemp1
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // 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": "Thread",
    //   "Key": {
    //     "ForumName": {
    //       "S": "Amazon DynamoDB"
    //     },
    //     "Subject": {
    //       "S": "How do I update multiple items?"
    //     }
    //   },
    //   "ProjectionExpression": "LastPostDateTime, Message, Tags",
    //   "ConsistentRead": true,
    //   "ReturnConsumedCapacity": "TOTAL"
    // }

    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Get ComUpdateString Of hoJson "TableName" "Thread" To iSuccess
    Get ComUpdateString Of hoJson "Key.ForumName.S" "Amazon DynamoDB" To iSuccess
    Get ComUpdateString Of hoJson "Key.Subject.S" "How do I update multiple items?" To iSuccess
    Get ComUpdateString Of hoJson "ProjectionExpression" "LastPostDateTime, Message, Tags" To iSuccess
    Get ComUpdateBool Of hoJson "ConsistentRead" True To iSuccess
    Get ComUpdateString Of hoJson "ReturnConsumedCapacity" "TOTAL" To iSuccess

    Get ComAddHeader Of hoRest "Content-Type" "application/x-amz-json-1.0" To iSuccess
    Get ComAddHeader Of hoRest "X-Amz-Target" "DynamoDB_20120810.GetItem" To iSuccess
    Get ComAddHeader Of hoRest "Accept-Encoding" "identity" To iSuccess

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbRequestBody
    If (Not(IsComObjectCreated(hoSbRequestBody))) Begin
        Send CreateComObject of hoSbRequestBody
    End
    Get pvComObject of hoSbRequestBody to vSbRequestBody
    Get ComEmitSb Of hoJson vSbRequestBody To iSuccess
    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbResponseBody
    If (Not(IsComObjectCreated(hoSbResponseBody))) Begin
        Send CreateComObject of hoSbResponseBody
    End
    Get pvComObject of hoSbRequestBody to vSbRequestBody
    Get pvComObject of hoSbResponseBody to vSbResponseBody
    Get ComFullRequestSb Of hoRest "POST" "/" vSbRequestBody vSbResponseBody To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoRest To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get ComResponseStatusCode Of hoRest To iRespStatusCode
    Showln "response status code = " iRespStatusCode
    If (iRespStatusCode >= 400) Begin
        Showln "Response Status Code = " iRespStatusCode
        Showln "Response Header:"
        Get ComResponseHeader Of hoRest To sTemp1
        Showln sTemp1
        Showln "Response Body:"
        Get ComGetAsString Of hoSbResponseBody To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonResponse
    If (Not(IsComObjectCreated(hoJsonResponse))) Begin
        Send CreateComObject of hoJsonResponse
    End
    Get pvComObject of hoSbResponseBody to vSbResponseBody
    Get ComLoadSb Of hoJsonResponse vSbResponseBody To iSuccess

    Set ComEmitCompact Of hoJsonResponse To False
    Get ComEmit Of hoJsonResponse To sTemp1
    Showln sTemp1

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

    // {
    //   "ConsumedCapacity": {
    //     "CapacityUnits": 1,
    //     "TableName": "Thread"
    //   },
    //   "Item": {
    //     "Tags": {
    //       "SS": [
    //         "Update",
    //         "Multiple Items",
    //         "HelpMe"
    //       ]
    //     },
    //     "LastPostDateTime": {
    //       "S": "201303190436"
    //     },
    //     "Message": {
    //       "S": "I want to update multiple items in a single call. What's the best way to do that?"
    //     }
    //   }
    // }

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

    Get ComIntOf Of hoJsonResponse "ConsumedCapacity.CapacityUnits" To iConsumedCapacityCapacityUnits
    Get ComStringOf Of hoJsonResponse "ConsumedCapacity.TableName" To sConsumedCapacityTableName
    Get ComStringOf Of hoJsonResponse "Item.LastPostDateTime.S" To sItemLastPostDateTimeS
    Get ComStringOf Of hoJsonResponse "Item.Message.S" To sItemMessageS
    Move 0 To i
    Get ComSizeOfArray Of hoJsonResponse "Item.Tags.SS" To iCount_i
    While (i < iCount_i)
        Set ComI Of hoJsonResponse To i
        Get ComStringOf Of hoJsonResponse "Item.Tags.SS[i]" To sStrVal
        Move (i + 1) To i
    Loop



End_Procedure