Rust

DynamoDB - Query

See more Amazon DynamoDB Examples

The Query operation finds items based on primary key values. You can query any table or secondary index that has a composite primary key (a partition key and a sort key). 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.Query" \
//   -d '{
//     "TableName": "Reply",
//     "IndexName": "PostedBy-Index",
//     "Limit": 3,
//     "ConsistentRead": true,
//     "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
//     "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
//     "ExpressionAttributeValues": {
//         ":v1": {"S": "Amazon DynamoDB#DynamoDB Thread 1"},
//         ":v2a": {"S": "User A"},
//         ":v2b": {"S": "User C"}
//     },
//     "ReturnConsumedCapacity": "TOTAL"
// }'

// 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": "Reply",
//   "IndexName": "PostedBy-Index",
//   "Limit": 3,
//   "ConsistentRead": true,
//   "ProjectionExpression": "Id, PostedBy, ReplyDateTime",
//   "KeyConditionExpression": "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b",
//   "ExpressionAttributeValues": {
//     ":v1": {
//       "S": "Amazon DynamoDB#DynamoDB Thread 1"
//     },
//     ":v2a": {
//       "S": "User A"
//     },
//     ":v2b": {
//       "S": "User C"
//     }
//   },
//   "ReturnConsumedCapacity": "TOTAL"
// }

let json = chilkat::JsonObject::new();
let _ = json.update_string("TableName", "Reply");
let _ = json.update_string("IndexName", "PostedBy-Index");
let _ = json.update_int("Limit", 3);
let _ = json.update_bool("ConsistentRead", true);
let _ = json.update_string("ProjectionExpression", "Id, PostedBy, ReplyDateTime");
let _ = json.update_string("KeyConditionExpression", "Id = :v1 AND PostedBy BETWEEN :v2a AND :v2b");
let _ = json.update_string("ExpressionAttributeValues.:v1.S", "Amazon DynamoDB#DynamoDB Thread 1");
let _ = json.update_string("ExpressionAttributeValues.:v2a.S", "User A");
let _ = json.update_string("ExpressionAttributeValues.:v2b.S", "User C");
let _ = json.update_string("ReturnConsumedCapacity", "TOTAL");

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

// {
//   "ConsumedCapacity": {
//     "CapacityUnits": 1,
//     "TableName": "Reply"
//   },
//   "Count": 2,
//   "Items": [
//     {
//       "ReplyDateTime": {
//         "S": "2015-02-18T20:27:36.165Z"
//       },
//       "PostedBy": {
//         "S": "User A"
//       },
//       "Id": {
//         "S": "Amazon DynamoDB#DynamoDB Thread 1"
//       }
//     },
//     {
//       "ReplyDateTime": {
//         "S": "2015-02-25T20:27:36.165Z"
//       },
//       "PostedBy": {
//         "S": "User B"
//       },
//       "Id": {
//         "S": "Amazon DynamoDB#DynamoDB Thread 1"
//       }
//     }
//   ],
//   "ScannedCount": 2
// }

// 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 consumed_capacity_capacity_units = json_response.int_of("ConsumedCapacity.CapacityUnits");
let consumed_capacity_table_name = json_response.string_of("ConsumedCapacity.TableName").unwrap_or_default();
let count = json_response.int_of("Count");
let scanned_count = json_response.int_of("ScannedCount");
let mut i = 0;
let count_i = json_response.size_of_array("Items");
while i < count_i {
    json_response.set_i(i);
    let _ = json_response.string_of("Items[i].ReplyDateTime.S").unwrap_or_default();
    let _ = json_response.string_of("Items[i].PostedBy.S").unwrap_or_default();
    let _ = json_response.string_of("Items[i].Id.S").unwrap_or_default();
    i = i + 1;
}