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 <CkRestW.h>
#include <CkAuthAwsW.h>
#include <CkJsonObjectW.h>
#include <CkStringBuilderW.h>
void ChilkatSample(void)
{
bool success = false;
CkRestW 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
CkAuthAwsW authAws;
authAws.put_AccessKey(L"AWS_ACCESS_KEY");
authAws.put_SecretKey(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.)
authAws.put_Region(L"us-west-2");
authAws.put_ServiceName(L"dynamodb");
// SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
rest.SetAuthAws(authAws);
// URL: https://dynamodb.us-west-2.amazonaws.com/
bool bTls = true;
int port = 443;
bool bAutoReconnect = true;
success = rest.Connect(L"dynamodb.us-west-2.amazonaws.com",port,bTls,bAutoReconnect);
if (success != true) {
wprintf(L"ConnectFailReason: %d\n",rest.get_ConnectFailReason());
wprintf(L"%s\n",rest.lastErrorText());
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"
// }
CkJsonObjectW json;
json.UpdateString(L"TableName",L"Reply");
json.UpdateString(L"IndexName",L"PostedBy-Index");
json.UpdateInt(L"Limit",3);
json.UpdateBool(L"ConsistentRead",true);
json.UpdateString(L"ProjectionExpression",L"Id, PostedBy, ReplyDateTime");
json.UpdateString(L"KeyConditionExpression",L"Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b");
json.UpdateString(L"ExpressionAttributeValues.:v1.S",L"Amazon DynamoDB#DynamoDB Thread 1");
json.UpdateString(L"ExpressionAttributeValues.:v2a.S",L"User A");
json.UpdateString(L"ExpressionAttributeValues.:v2b.S",L"User C");
json.UpdateString(L"ReturnConsumedCapacity",L"TOTAL");
rest.AddHeader(L"Content-Type",L"application/x-amz-json-1.0");
rest.AddHeader(L"X-Amz-Target",L"DynamoDB_20120810.Query");
rest.AddHeader(L"Accept-Encoding",L"identity");
CkStringBuilderW sbRequestBody;
json.EmitSb(sbRequestBody);
CkStringBuilderW sbResponseBody;
success = rest.FullRequestSb(L"POST",L"/",sbRequestBody,sbResponseBody);
if (success != true) {
wprintf(L"%s\n",rest.lastErrorText());
return;
}
int respStatusCode = rest.get_ResponseStatusCode();
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",rest.responseHeader());
wprintf(L"Response Body:\n");
wprintf(L"%s\n",sbResponseBody.getAsString());
return;
}
CkJsonObjectW jsonResponse;
jsonResponse.LoadSb(sbResponseBody);
jsonResponse.put_EmitCompact(false);
wprintf(L"%s\n",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
const wchar_t *ReplyDateTimeS = 0;
const wchar_t *PostedByS = 0;
const wchar_t *IdS = 0;
int ConsumedCapacityCapacityUnits = jsonResponse.IntOf(L"ConsumedCapacity.CapacityUnits");
const wchar_t *ConsumedCapacityTableName = jsonResponse.stringOf(L"ConsumedCapacity.TableName");
int Count = jsonResponse.IntOf(L"Count");
int ScannedCount = jsonResponse.IntOf(L"ScannedCount");
int i = 0;
int count_i = jsonResponse.SizeOfArray(L"Items");
while (i < count_i) {
jsonResponse.put_I(i);
ReplyDateTimeS = jsonResponse.stringOf(L"Items[i].ReplyDateTime.S");
PostedByS = jsonResponse.stringOf(L"Items[i].PostedBy.S");
IdS = jsonResponse.stringOf(L"Items[i].Id.S");
i = i + 1;
}
}