Rust

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). Rust

let rest = chilkat::Rest::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

let auth_aws = chilkat::AuthAws::new();
auth_aws.set_access_key("AWS_ACCESS_KEY");
auth_aws.set_secret_key("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.)
auth_aws.set_region("us-west-2");
auth_aws.set_service_name("dynamodb");
// SetAuthAws causes Chilkat to automatically add the following headers: Authorization, X-Amz-Date
let _ = rest.set_auth_aws(&auth_aws);

// URL: https://dynamodb.us-west-2.amazonaws.com/
let b_tls = true;
let port = 443;
let b_auto_reconnect = true;
if rest.connect("dynamodb.us-west-2.amazonaws.com", port, b_tls, b_auto_reconnect).is_err() {
    println!("ConnectFailReason: {}", rest.connect_fail_reason());
    println!("{}", rest.last_error_text());
    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 = chilkat::JsonObject::new();
let _ = json.update_string("TableName", "Thread");
let _ = json.update_string("Key.ForumName.S", "Amazon DynamoDB");
let _ = json.update_string("Key.Subject.S", "Maximum number of items?");
let _ = json.update_string("UpdateExpression", "set LastPostedBy = :val1");
let _ = json.update_string("ConditionExpression", "LastPostedBy = :val2");
let _ = json.update_string("ExpressionAttributeValues.:val1.S", "alice@example.com");
let _ = json.update_string("ExpressionAttributeValues.:val2.S", "fred@example.com");
let _ = json.update_string("ReturnValues", "ALL_NEW");

let _ = rest.add_header("Content-Type", "application/x-amz-json-1.0");
let _ = rest.add_header("X-Amz-Target", "DynamoDB_20120810.UpdateItem");
let _ = rest.add_header("Accept-Encoding", "identity");

let sb_request_body = chilkat::StringBuilder::new();
let _ = json.emit_sb(&sb_request_body);
let sb_response_body = chilkat::StringBuilder::new();
if rest.full_request_sb("POST", "/", &sb_request_body, &sb_response_body).is_err() {
    println!("{}", rest.last_error_text());
    return;
}

let resp_status_code = rest.response_status_code();
println!("response status code = {}", resp_status_code);
if resp_status_code >= 400 {
    println!("Response Status Code = {}", resp_status_code);
    println!("Response Header:");
    println!("{}", rest.response_header());
    println!("Response Body:");
    println!("{}", sb_response_body.get_as_string().unwrap_or_default());
    return;
}

let json_response = chilkat::JsonObject::new();
let _ = json_response.load_sb(&sb_response_body);

json_response.set_emit_compact(false);
println!("{}", json_response.emit().unwrap_or_default());

// 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

let attributes_last_posted_by_s = json_response.string_of("Attributes.LastPostedBy.S").unwrap_or_default();
let attributes_forum_name_s = json_response.string_of("Attributes.ForumName.S").unwrap_or_default();
let attributes_last_post_date_time_s = json_response.string_of("Attributes.LastPostDateTime.S").unwrap_or_default();
let attributes_subject_s = json_response.string_of("Attributes.Subject.S").unwrap_or_default();
let attributes_views_n = json_response.string_of("Attributes.Views.N").unwrap_or_default();
let attributes_message_s = json_response.string_of("Attributes.Message.S").unwrap_or_default();
let mut i = 0;
let count_i = json_response.size_of_array("Attributes.Tags.SS");
while i < count_i {
    json_response.set_i(i);
    let _ = json_response.string_of("Attributes.Tags.SS[i]").unwrap_or_default();
    i = i + 1;
}