(PowerShell) 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 .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

$rest = New-Object Chilkat.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.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 = New-Object Chilkat.AuthAws
$authAws.AccessKey = "AWS_ACCESS_KEY"
$authAws.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.Region = "us-west-2"
$authAws.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 = $true
$port = 443
$bAutoReconnect = $true
$success = $rest.Connect("dynamodb.us-west-2.amazonaws.com",$port,$bTls,$bAutoReconnect)
if ($success -ne $true) {
    $("ConnectFailReason: " + $rest.ConnectFailReason)
    $($rest.LastErrorText)
    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 = New-Object Chilkat.JsonObject
$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 = New-Object Chilkat.StringBuilder
$json.EmitSb($sbRequestBody)
$sbResponseBody = New-Object Chilkat.StringBuilder
$success = $rest.FullRequestSb("POST","/",$sbRequestBody,$sbResponseBody)
if ($success -ne $true) {
    $($rest.LastErrorText)
    exit
}

$respStatusCode = $rest.ResponseStatusCode
$("response status code = " + $respStatusCode)
if ($respStatusCode -ge 400) {
    $("Response Status Code = " + $respStatusCode)
    $("Response Header:")
    $($rest.ResponseHeader)
    $("Response Body:")
    $($sbResponseBody.GetAsString())
    exit
}

$jsonResponse = New-Object Chilkat.JsonObject
$jsonResponse.LoadSb($sbResponseBody)

$jsonResponse.EmitCompact = $false
$($jsonResponse.Emit())

# 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 -lt $count_i) {
    $jsonResponse.I = $i
    $strVal = $jsonResponse.StringOf("Attributes.Tags.SS[i]")
    $i = $i + 1
}