C

DynamoDB - DeleteItem

See more Amazon DynamoDB Examples

Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute value. C

#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 *strVal;
    const char *AttributesLastPostedByS;
    const char *AttributesForumNameS;
    const char *AttributesLastPostDateTimeS;
    const char *AttributesSubjectS;
    const char *AttributesMessageS;
    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.DeleteItem" \
    //    -d '{
    //      "TableName": "Thread",
    //      "Key": {
    //          "ForumName": {
    //              "S": "Amazon DynamoDB"
    //          },
    //          "Subject": {
    //              "S": "How do I update multiple items?"
    //          }
    //      },
    //      "ConditionExpression": "attribute_not_exists(Replies)",
    //      "ReturnValues": "ALL_OLD"
    //  }'

    //  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": "Thread",
    //    "Key": {
    //      "ForumName": {
    //        "S": "Amazon DynamoDB"
    //      },
    //      "Subject": {
    //        "S": "How do I update multiple items?"
    //      }
    //    },
    //    "ConditionExpression": "attribute_not_exists(Replies)",
    //    "ReturnValues": "ALL_OLD"
    //  }

    json = CkJsonObject_Create();
    CkJsonObject_UpdateString(json,"TableName","Thread");
    CkJsonObject_UpdateString(json,"Key.ForumName.S","Amazon DynamoDB");
    CkJsonObject_UpdateString(json,"Key.Subject.S","How do I update multiple items?");
    CkJsonObject_UpdateString(json,"ConditionExpression","attribute_not_exists(Replies)");
    CkJsonObject_UpdateString(json,"ReturnValues","ALL_OLD");

    CkRest_AddHeader(rest,"Content-Type","application/x-amz-json-1.0");
    CkRest_AddHeader(rest,"X-Amz-Target","DynamoDB_20120810.DeleteItem");
    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)

    //  {
    //    "Attributes": {
    //      "LastPostedBy": {
    //        "S": "fred@example.com"
    //      },
    //      "ForumName": {
    //        "S": "Amazon DynamoDB"
    //      },
    //      "LastPostDateTime": {
    //        "S": "201303201023"
    //      },
    //      "Tags": {
    //        "SS": [
    //          "Update",
    //          "Multiple Items",
    //          "HelpMe"
    //        ]
    //      },
    //      "Subject": {
    //        "S": "How do I update multiple items?"
    //      },
    //      "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

    AttributesLastPostedByS = CkJsonObject_stringOf(jsonResponse,"Attributes.LastPostedBy.S");
    AttributesForumNameS = CkJsonObject_stringOf(jsonResponse,"Attributes.ForumName.S");
    AttributesLastPostDateTimeS = CkJsonObject_stringOf(jsonResponse,"Attributes.LastPostDateTime.S");
    AttributesSubjectS = CkJsonObject_stringOf(jsonResponse,"Attributes.Subject.S");
    AttributesMessageS = CkJsonObject_stringOf(jsonResponse,"Attributes.Message.S");
    i = 0;
    count_i = CkJsonObject_SizeOfArray(jsonResponse,"Attributes.Tags.SS");
    while (i < count_i) {
        CkJsonObject_putI(jsonResponse,i);
        strVal = CkJsonObject_stringOf(jsonResponse,"Attributes.Tags.SS[i]");
        i = i + 1;
    }



    CkRest_Dispose(rest);
    CkAuthAws_Dispose(authAws);
    CkJsonObject_Dispose(json);
    CkStringBuilder_Dispose(sbRequestBody);
    CkStringBuilder_Dispose(sbResponseBody);
    CkJsonObject_Dispose(jsonResponse);

    }