Swift

DynamoDB - UpdateItem

See more Amazon DynamoDB Examples

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). Swift

func chilkatTest() {
    var success: Bool = false

    let rest = CkoRest()!

    // 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

    let authAws = CkoAuthAws()!
    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(authProvider: authAws)

    // URL: https://dynamodb.us-west-2.amazonaws.com/
    var bTls: Bool = true
    var port: Int = 443
    var bAutoReconnect: Bool = true
    success = rest.connect(hostname: "dynamodb.us-west-2.amazonaws.com", port: port, tls: bTls, autoReconnect: bAutoReconnect)
    if success != true {
        print("ConnectFailReason: \(rest.connectFailReason.intValue)")
        print("\(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": "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"
    // }

    let json = CkoJsonObject()!
    json.updateString(jsonPath: "TableName", value: "Thread")
    json.updateString(jsonPath: "Key.ForumName.S", value: "Amazon DynamoDB")
    json.updateString(jsonPath: "Key.Subject.S", value: "Maximum number of items?")
    json.updateString(jsonPath: "UpdateExpression", value: "set LastPostedBy = :val1")
    json.updateString(jsonPath: "ConditionExpression", value: "LastPostedBy = :val2")
    json.updateString(jsonPath: "ExpressionAttributeValues.:val1.S", value: "alice@example.com")
    json.updateString(jsonPath: "ExpressionAttributeValues.:val2.S", value: "fred@example.com")
    json.updateString(jsonPath: "ReturnValues", value: "ALL_NEW")

    rest.addHeader(name: "Content-Type", value: "application/x-amz-json-1.0")
    rest.addHeader(name: "X-Amz-Target", value: "DynamoDB_20120810.UpdateItem")
    rest.addHeader(name: "Accept-Encoding", value: "identity")

    let sbRequestBody = CkoStringBuilder()!
    json.emitSb(sb: sbRequestBody)
    let sbResponseBody = CkoStringBuilder()!
    success = rest.fullRequestSb(httpVerb: "POST", uriPath: "/", requestBody: sbRequestBody, responseBody: sbResponseBody)
    if success != true {
        print("\(rest.lastErrorText!)")
        return
    }

    var respStatusCode: Int = rest.responseStatusCode.intValue
    print("response status code = \(respStatusCode)")
    if respStatusCode >= 400 {
        print("Response Status Code = \(respStatusCode)")
        print("Response Header:")
        print("\(rest.responseHeader!)")
        print("Response Body:")
        print("\(sbResponseBody.getAsString()!)")
        return
    }

    let jsonResponse = CkoJsonObject()!
    jsonResponse.loadSb(sb: sbResponseBody)

    jsonResponse.emitCompact = false
    print("\(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

    var strVal: String?

    var AttributesLastPostedByS: String? = jsonResponse.string(of: "Attributes.LastPostedBy.S")
    var AttributesForumNameS: String? = jsonResponse.string(of: "Attributes.ForumName.S")
    var AttributesLastPostDateTimeS: String? = jsonResponse.string(of: "Attributes.LastPostDateTime.S")
    var AttributesSubjectS: String? = jsonResponse.string(of: "Attributes.Subject.S")
    var AttributesViewsN: String? = jsonResponse.string(of: "Attributes.Views.N")
    var AttributesMessageS: String? = jsonResponse.string(of: "Attributes.Message.S")
    var i: Int = 0
    var count_i: Int = jsonResponse.size(ofArray: "Attributes.Tags.SS").intValue
    while i < count_i {
        jsonResponse.i = i
        strVal = jsonResponse.string(of: "Attributes.Tags.SS[i]")
        i = i + 1
    }


}