C
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 C Downloads
#include <C_CkRest.h>
#include <C_CkAuthAws.h>
#include <C_CkJsonObject.h>
#include <C_CkStringBuilder.h>
void ChilkatSample(void)
{
BOOL success;
HCkRest rest;
HCkAuthAws authAws;
BOOL bTls;
int port;
BOOL bAutoReconnect;
HCkJsonObject json;
HCkStringBuilder sbRequestBody;
HCkStringBuilder sbResponseBody;
int respStatusCode;
HCkJsonObject jsonResponse;
const char *ReplyDateTimeS;
const char *PostedByS;
const char *IdS;
int ConsumedCapacityCapacityUnits;
const char *ConsumedCapacityTableName;
int Count;
int ScannedCount;
int i;
int count_i;
success = FALSE;
rest = CkRest_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 = CkAuthAws_Create();
CkAuthAws_putAccessKey(authAws,"AWS_ACCESS_KEY");
CkAuthAws_putSecretKey(authAws,"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.)
CkAuthAws_putRegion(authAws,"us-west-2");
CkAuthAws_putServiceName(authAws,"dynamodb");
// SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
CkRest_SetAuthAws(rest,authAws);
// URL: https://dynamodb.us-west-2.amazonaws.com/
bTls = TRUE;
port = 443;
bAutoReconnect = TRUE;
success = CkRest_Connect(rest,"dynamodb.us-west-2.amazonaws.com",port,bTls,bAutoReconnect);
if (success != TRUE) {
printf("ConnectFailReason: %d\n",CkRest_getConnectFailReason(rest));
printf("%s\n",CkRest_lastErrorText(rest));
CkRest_Dispose(rest);
CkAuthAws_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 = CkJsonObject_Create();
CkJsonObject_UpdateString(json,"TableName","Reply");
CkJsonObject_UpdateString(json,"IndexName","PostedBy-Index");
CkJsonObject_UpdateInt(json,"Limit",3);
CkJsonObject_UpdateBool(json,"ConsistentRead",TRUE);
CkJsonObject_UpdateString(json,"ProjectionExpression","Id, PostedBy, ReplyDateTime");
CkJsonObject_UpdateString(json,"KeyConditionExpression","Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b");
CkJsonObject_UpdateString(json,"ExpressionAttributeValues.:v1.S","Amazon DynamoDB#DynamoDB Thread 1");
CkJsonObject_UpdateString(json,"ExpressionAttributeValues.:v2a.S","User A");
CkJsonObject_UpdateString(json,"ExpressionAttributeValues.:v2b.S","User C");
CkJsonObject_UpdateString(json,"ReturnConsumedCapacity","TOTAL");
CkRest_AddHeader(rest,"Content-Type","application/x-amz-json-1.0");
CkRest_AddHeader(rest,"X-Amz-Target","DynamoDB_20120810.Query");
CkRest_AddHeader(rest,"Accept-Encoding","identity");
sbRequestBody = CkStringBuilder_Create();
CkJsonObject_EmitSb(json,sbRequestBody);
sbResponseBody = CkStringBuilder_Create();
success = CkRest_FullRequestSb(rest,"POST","/",sbRequestBody,sbResponseBody);
if (success != TRUE) {
printf("%s\n",CkRest_lastErrorText(rest));
CkRest_Dispose(rest);
CkAuthAws_Dispose(authAws);
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sbRequestBody);
CkStringBuilder_Dispose(sbResponseBody);
return;
}
respStatusCode = CkRest_getResponseStatusCode(rest);
printf("response status code = %d\n",respStatusCode);
if (respStatusCode >= 400) {
printf("Response Status Code = %d\n",respStatusCode);
printf("Response Header:\n");
printf("%s\n",CkRest_responseHeader(rest));
printf("Response Body:\n");
printf("%s\n",CkStringBuilder_getAsString(sbResponseBody));
CkRest_Dispose(rest);
CkAuthAws_Dispose(authAws);
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sbRequestBody);
CkStringBuilder_Dispose(sbResponseBody);
return;
}
jsonResponse = CkJsonObject_Create();
CkJsonObject_LoadSb(jsonResponse,sbResponseBody);
CkJsonObject_putEmitCompact(jsonResponse,FALSE);
printf("%s\n",CkJsonObject_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 = CkJsonObject_IntOf(jsonResponse,"ConsumedCapacity.CapacityUnits");
ConsumedCapacityTableName = CkJsonObject_stringOf(jsonResponse,"ConsumedCapacity.TableName");
Count = CkJsonObject_IntOf(jsonResponse,"Count");
ScannedCount = CkJsonObject_IntOf(jsonResponse,"ScannedCount");
i = 0;
count_i = CkJsonObject_SizeOfArray(jsonResponse,"Items");
while (i < count_i) {
CkJsonObject_putI(jsonResponse,i);
ReplyDateTimeS = CkJsonObject_stringOf(jsonResponse,"Items[i].ReplyDateTime.S");
PostedByS = CkJsonObject_stringOf(jsonResponse,"Items[i].PostedBy.S");
IdS = CkJsonObject_stringOf(jsonResponse,"Items[i].Id.S");
i = i + 1;
}
CkRest_Dispose(rest);
CkAuthAws_Dispose(authAws);
CkJsonObject_Dispose(json);
CkStringBuilder_Dispose(sbRequestBody);
CkStringBuilder_Dispose(sbResponseBody);
CkJsonObject_Dispose(jsonResponse);
}