(Perl) DynamoDB - UpdateItem

Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values).

For more information, see https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_UpdateItem.html

Chilkat Perl Downloads Perl Module for Windows, MacOS, Linux, Alpine Linux, Solaris

use chilkat();

$rest = chilkat::CkRest->new();

# 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.UpdateItem" \
#   -d '{
#     "TableName": "Thread",
#     "Key": {
#         "ForumName": {
#             "S": "Amazon DynamoDB"
#         },
#         "Subject": {
#             "S": "Maximum number of items?"
#         }
#     },
#     "UpdateExpression": "set LastPostedBy = :val1",
#     "ConditionExpression": "LastPostedBy = :val2",
#     "ExpressionAttributeValues": {
#         ":val1": {"S": "alice@example.com"},
#         ":val2": {"S": "fred@example.com"}
#     },
#     "ReturnValues": "ALL_NEW"
# }'

# Use the following online tool to generate REST code from a CURL command
# Convert a cURL Command to REST Source Code

$authAws = chilkat::CkAuthAws->new();
$authAws->put_AccessKey("AWS_ACCESS_KEY");
$authAws->put_SecretKey("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("us-west-2");
$authAws->put_ServiceName("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/
$bTls = 1;
$port = 443;
$bAutoReconnect = 1;
$success = $rest->Connect("dynamodb.us-west-2.amazonaws.com",$port,$bTls,$bAutoReconnect);
if ($success != 1) {
    print "ConnectFailReason: " . $rest->get_ConnectFailReason() . "\r\n";
    print $rest->lastErrorText() . "\r\n";
    exit;
}

# 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": "Maximum number of items?"
#     }
#   },
#   "UpdateExpression": "set LastPostedBy = :val1",
#   "ConditionExpression": "LastPostedBy = :val2",
#   "ExpressionAttributeValues": {
#     ":val1": {
#       "S": "alice@example.com"
#     },
#     ":val2": {
#       "S": "fred@example.com"
#     }
#   },
#   "ReturnValues": "ALL_NEW"
# }

$json = chilkat::CkJsonObject->new();
$json->UpdateString("TableName","Thread");
$json->UpdateString("Key.ForumName.S","Amazon DynamoDB");
$json->UpdateString("Key.Subject.S","Maximum number of items?");
$json->UpdateString("UpdateExpression","set LastPostedBy = :val1");
$json->UpdateString("ConditionExpression","LastPostedBy = :val2");
$json->UpdateString("ExpressionAttributeValues.:val1.S",'alice@example.com');
$json->UpdateString("ExpressionAttributeValues.:val2.S",'fred@example.com');
$json->UpdateString("ReturnValues","ALL_NEW");

$rest->AddHeader("Content-Type","application/x-amz-json-1.0");
$rest->AddHeader("X-Amz-Target","DynamoDB_20120810.UpdateItem");
$rest->AddHeader("Accept-Encoding","identity");

$sbRequestBody = chilkat::CkStringBuilder->new();
$json->EmitSb($sbRequestBody);
$sbResponseBody = chilkat::CkStringBuilder->new();
$success = $rest->FullRequestSb("POST","/",$sbRequestBody,$sbResponseBody);
if ($success != 1) {
    print $rest->lastErrorText() . "\r\n";
    exit;
}

$respStatusCode = $rest->get_ResponseStatusCode();
print "response status code = " . $respStatusCode . "\r\n";
if ($respStatusCode >= 400) {
    print "Response Status Code = " . $respStatusCode . "\r\n";
    print "Response Header:" . "\r\n";
    print $rest->responseHeader() . "\r\n";
    print "Response Body:" . "\r\n";
    print $sbResponseBody->getAsString() . "\r\n";
    exit;
}

$jsonResponse = chilkat::CkJsonObject->new();
$jsonResponse->LoadSb($sbResponseBody);

$jsonResponse->put_EmitCompact(0);
print $jsonResponse->emit() . "\r\n";

# Sample JSON response:
# (Sample code for parsing the JSON response is shown below)

# {
#   "Attributes": {
#     "LastPostedBy": {
#       "S": "alice@example.com"
#     },
#     "ForumName": {
#       "S": "Amazon DynamoDB"
#     },
#     "LastPostDateTime": {
#       "S": "20130320010350"
#     },
#     "Tags": {
#       "SS": [
#         "Update",
#         "Multiple Items",
#         "HelpMe"
#       ]
#     },
#     "Subject": {
#       "S": "Maximum number of items?"
#     },
#     "Views": {
#       "N": "5"
#     },
#     "Message": {
#       "S": "I want to put 10 million data items to an Amazon DynamoDB table.  Is there an upper limit?"
#     }
#   }
# }

# 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 = $jsonResponse->stringOf("Attributes.LastPostedBy.S");
$AttributesForumNameS = $jsonResponse->stringOf("Attributes.ForumName.S");
$AttributesLastPostDateTimeS = $jsonResponse->stringOf("Attributes.LastPostDateTime.S");
$AttributesSubjectS = $jsonResponse->stringOf("Attributes.Subject.S");
$AttributesViewsN = $jsonResponse->stringOf("Attributes.Views.N");
$AttributesMessageS = $jsonResponse->stringOf("Attributes.Message.S");
$i = 0;
$count_i = $jsonResponse->SizeOfArray("Attributes.Tags.SS");
while ($i < $count_i) {
    $jsonResponse->put_I($i);
    $strVal = $jsonResponse->stringOf("Attributes.Tags.SS[i]");
    $i = $i + 1;
}