(Unicode C) 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

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#include <C_CkRestW.h>
#include <C_CkAuthAwsW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkStringBuilderW.h>

void ChilkatSample(void)
    {
    HCkRestW rest;
    BOOL success;
    HCkAuthAwsW authAws;
    BOOL bTls;
    int port;
    BOOL bAutoReconnect;
    HCkJsonObjectW json;
    HCkStringBuilderW sbRequestBody;
    HCkStringBuilderW sbResponseBody;
    int respStatusCode;
    HCkJsonObjectW jsonResponse;
    const wchar_t *ReplyDateTimeS;
    const wchar_t *PostedByS;
    const wchar_t *IdS;
    int ConsumedCapacityCapacityUnits;
    const wchar_t *ConsumedCapacityTableName;
    int Count;
    int ScannedCount;
    int i;
    int count_i;

    rest = CkRestW_Create();

    // 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

    authAws = CkAuthAwsW_Create();
    CkAuthAwsW_putAccessKey(authAws,L"AWS_ACCESS_KEY");
    CkAuthAwsW_putSecretKey(authAws,L"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.)
    CkAuthAwsW_putRegion(authAws,L"us-west-2");
    CkAuthAwsW_putServiceName(authAws,L"dynamodb");
    // SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
    CkRestW_SetAuthAws(rest,authAws);

    // URL: https://dynamodb.us-west-2.amazonaws.com/
    bTls = TRUE;
    port = 443;
    bAutoReconnect = TRUE;
    success = CkRestW_Connect(rest,L"dynamodb.us-west-2.amazonaws.com",port,bTls,bAutoReconnect);
    if (success != TRUE) {
        wprintf(L"ConnectFailReason: %d\n",CkRestW_getConnectFailReason(rest));
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkRestW_Dispose(rest);
        CkAuthAwsW_Dispose(authAws);
        return;
    }

    // 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"
    // }

    json = CkJsonObjectW_Create();
    CkJsonObjectW_UpdateString(json,L"TableName",L"Reply");
    CkJsonObjectW_UpdateString(json,L"IndexName",L"PostedBy-Index");
    CkJsonObjectW_UpdateInt(json,L"Limit",3);
    CkJsonObjectW_UpdateBool(json,L"ConsistentRead",TRUE);
    CkJsonObjectW_UpdateString(json,L"ProjectionExpression",L"Id, PostedBy, ReplyDateTime");
    CkJsonObjectW_UpdateString(json,L"KeyConditionExpression",L"Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b");
    CkJsonObjectW_UpdateString(json,L"ExpressionAttributeValues.:v1.S",L"Amazon DynamoDB#DynamoDB Thread 1");
    CkJsonObjectW_UpdateString(json,L"ExpressionAttributeValues.:v2a.S",L"User A");
    CkJsonObjectW_UpdateString(json,L"ExpressionAttributeValues.:v2b.S",L"User C");
    CkJsonObjectW_UpdateString(json,L"ReturnConsumedCapacity",L"TOTAL");

    CkRestW_AddHeader(rest,L"Content-Type",L"application/x-amz-json-1.0");
    CkRestW_AddHeader(rest,L"X-Amz-Target",L"DynamoDB_20120810.Query");
    CkRestW_AddHeader(rest,L"Accept-Encoding",L"identity");

    sbRequestBody = CkStringBuilderW_Create();
    CkJsonObjectW_EmitSb(json,sbRequestBody);
    sbResponseBody = CkStringBuilderW_Create();
    success = CkRestW_FullRequestSb(rest,L"POST",L"/",sbRequestBody,sbResponseBody);
    if (success != TRUE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkRestW_Dispose(rest);
        CkAuthAwsW_Dispose(authAws);
        CkJsonObjectW_Dispose(json);
        CkStringBuilderW_Dispose(sbRequestBody);
        CkStringBuilderW_Dispose(sbResponseBody);
        return;
    }

    respStatusCode = CkRestW_getResponseStatusCode(rest);
    wprintf(L"response status code = %d\n",respStatusCode);
    if (respStatusCode >= 400) {
        wprintf(L"Response Status Code = %d\n",respStatusCode);
        wprintf(L"Response Header:\n");
        wprintf(L"%s\n",CkRestW_responseHeader(rest));
        wprintf(L"Response Body:\n");
        wprintf(L"%s\n",CkStringBuilderW_getAsString(sbResponseBody));
        CkRestW_Dispose(rest);
        CkAuthAwsW_Dispose(authAws);
        CkJsonObjectW_Dispose(json);
        CkStringBuilderW_Dispose(sbRequestBody);
        CkStringBuilderW_Dispose(sbResponseBody);
        return;
    }

    jsonResponse = CkJsonObjectW_Create();
    CkJsonObjectW_LoadSb(jsonResponse,sbResponseBody);

    CkJsonObjectW_putEmitCompact(jsonResponse,FALSE);
    wprintf(L"%s\n",CkJsonObjectW_emit(jsonResponse));

    // 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

    ConsumedCapacityCapacityUnits = CkJsonObjectW_IntOf(jsonResponse,L"ConsumedCapacity.CapacityUnits");
    ConsumedCapacityTableName = CkJsonObjectW_stringOf(jsonResponse,L"ConsumedCapacity.TableName");
    Count = CkJsonObjectW_IntOf(jsonResponse,L"Count");
    ScannedCount = CkJsonObjectW_IntOf(jsonResponse,L"ScannedCount");
    i = 0;
    count_i = CkJsonObjectW_SizeOfArray(jsonResponse,L"Items");
    while (i < count_i) {
        CkJsonObjectW_putI(jsonResponse,i);
        ReplyDateTimeS = CkJsonObjectW_stringOf(jsonResponse,L"Items[i].ReplyDateTime.S");
        PostedByS = CkJsonObjectW_stringOf(jsonResponse,L"Items[i].PostedBy.S");
        IdS = CkJsonObjectW_stringOf(jsonResponse,L"Items[i].Id.S");
        i = i + 1;
    }



    CkRestW_Dispose(rest);
    CkAuthAwsW_Dispose(authAws);
    CkJsonObjectW_Dispose(json);
    CkStringBuilderW_Dispose(sbRequestBody);
    CkStringBuilderW_Dispose(sbResponseBody);
    CkJsonObjectW_Dispose(jsonResponse);

    }