Unicode C
Unicode C
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).Chilkat Unicode C Downloads
#include <C_CkRestW.h>
#include <C_CkAuthAwsW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkStringBuilderW.h>
void ChilkatSample(void)
{
BOOL success;
HCkRestW rest;
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;
success = FALSE;
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);
}