React Native

DynamoDB - GetItem

See more Amazon DynamoDB Examples

The GetItem operation returns a set of attributes for the item with the given primary key. If there is no matching item, GetItem does not return any data and there will be no Item element in the response. React Native

import { AuthAws, JsonObject, Rest, StringBuilder } from '@chilkat/react-native'

async function chilkatExample() {
  const rest = new 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.GetItem" \
  //   -d '{
  //     "TableName": "Thread",
  //     "Key": {
  //         "ForumName": {
  //             "S": "Amazon DynamoDB"
  //         },
  //         "Subject": {
  //             "S": "How do I update multiple items?"
  //         }
  //     },
  //     "ProjectionExpression":"LastPostDateTime, Message, Tags",
  //     "ConsistentRead": true,
  //     "ReturnConsumedCapacity": "TOTAL"
  // }'

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

  const authAws = new 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/
  const bTls = true;
  const port = 443;
  const bAutoReconnect = true;
  try {
    await rest.connectAsync('dynamodb.us-west-2.amazonaws.com', port, bTls, bAutoReconnect);
  } catch {
    console.log(`ConnectFailReason: ${rest.connectFailReason}`);
    console.log(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": "How do I update multiple items?"
  //     }
  //   },
  //   "ProjectionExpression": "LastPostDateTime, Message, Tags",
  //   "ConsistentRead": true,
  //   "ReturnConsumedCapacity": "TOTAL"
  // }

  const json = new JsonObject();
  json.updateString('TableName', 'Thread');
  json.updateString('Key.ForumName.S', 'Amazon DynamoDB');
  json.updateString('Key.Subject.S', 'How do I update multiple items?');
  json.updateString('ProjectionExpression', 'LastPostDateTime, Message, Tags');
  json.updateBool('ConsistentRead', true);
  json.updateString('ReturnConsumedCapacity', 'TOTAL');

  rest.addHeader('Content-Type', 'application/x-amz-json-1.0');
  rest.addHeader('X-Amz-Target', 'DynamoDB_20120810.GetItem');
  rest.addHeader('Accept-Encoding', 'identity');

  const sbRequestBody = new StringBuilder();
  json.emitSb(sbRequestBody);
  const sbResponseBody = new StringBuilder();
  try {
    await rest.fullRequestSbAsync('POST', '/', sbRequestBody, sbResponseBody);
  } catch {
    console.log(rest.lastErrorText);
    return;
  }

  const respStatusCode = rest.responseStatusCode;
  console.log(`response status code = ${respStatusCode}`);
  if (respStatusCode >= 400) {
    console.log(`Response Status Code = ${respStatusCode}`);
    console.log('Response Header:');
    console.log(rest.responseHeader);
    console.log('Response Body:');
    console.log(sbResponseBody.getAsString());
    return;
  }

  const jsonResponse = new JsonObject();
  jsonResponse.loadSb(sbResponseBody);

  jsonResponse.emitCompact = false;
  console.log(jsonResponse.emit());

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

  // {
  //   "ConsumedCapacity": {
  //     "CapacityUnits": 1,
  //     "TableName": "Thread"
  //   },
  //   "Item": {
  //     "Tags": {
  //       "SS": [
  //         "Update",
  //         "Multiple Items",
  //         "HelpMe"
  //       ]
  //     },
  //     "LastPostDateTime": {
  //       "S": "201303190436"
  //     },
  //     "Message": {
  //       "S": "I want to update multiple items in a single call. What's the best way to do that?"
  //     }
  //   }
  // }

  // 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 strVal = '';

  const consumedCapacityCapacityUnits = jsonResponse.intOf('ConsumedCapacity.CapacityUnits');
  const consumedCapacityTableName = jsonResponse.stringOf('ConsumedCapacity.TableName');
  const itemLastPostDateTimeS = jsonResponse.stringOf('Item.LastPostDateTime.S');
  const itemMessageS = jsonResponse.stringOf('Item.Message.S');
  let i = 0;
  const countI = jsonResponse.sizeOfArray('Item.Tags.SS');
  while (i < countI) {
    jsonResponse.i = i;
    strVal = jsonResponse.stringOf('Item.Tags.SS[i]');
    i++;
  }
}