Unicode 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. Unicode C++

#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.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

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

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

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

    // {
    //   "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

    const wchar_t *strVal = 0;

    const wchar_t *AttributesLastPostedByS = jsonResponse.stringOf(L"Attributes.LastPostedBy.S");
    const wchar_t *AttributesForumNameS = jsonResponse.stringOf(L"Attributes.ForumName.S");
    const wchar_t *AttributesLastPostDateTimeS = jsonResponse.stringOf(L"Attributes.LastPostDateTime.S");
    const wchar_t *AttributesSubjectS = jsonResponse.stringOf(L"Attributes.Subject.S");
    const wchar_t *AttributesMessageS = jsonResponse.stringOf(L"Attributes.Message.S");
    int i = 0;
    int count_i = jsonResponse.SizeOfArray(L"Attributes.Tags.SS");
    while (i < count_i) {
        jsonResponse.put_I(i);
        strVal = jsonResponse.stringOf(L"Attributes.Tags.SS[i]");
        i = i + 1;
    }
    }