AWS SDK for JavaScript QLDB Client for Node.js, Browser and React Native.
The resource management API for Amazon QLDB
To install the this package, simply type add or install @aws-sdk/client-qldb using your favorite package manager:
npm install @aws-sdk/client-qldbyarn add @aws-sdk/client-qldbpnpm add @aws-sdk/client-qldb
The AWS SDK is modulized by clients and commands.
To send a request, you only need to import the QLDBClient and
the commands you need, for example ListLedgersCommand:
// ES5 example
const { QLDBClient, ListLedgersCommand } = require("@aws-sdk/client-qldb");// ES6+ example
import { QLDBClient, ListLedgersCommand } from "@aws-sdk/client-qldb";To send a request, you:
- Initiate client with configuration (e.g. credentials, region).
- Initiate command with input parameters.
- Call
sendoperation on client with command object as input. - If you are using a custom http handler, you may call
destroy()to close open connections.
// a client can be shared by different commands.
const client = new QLDBClient({ region: "REGION" });
const params = {
/** input parameters */
};
const command = new ListLedgersCommand(params);We recommend using await operator to wait for the promise returned by send operation as follows:
// async/await.
try {
const data = await client.send(command);
// process data.
} catch (error) {
// error handling.
} finally {
// finally.
}Async-await is clean, concise, intuitive, easy to debug and has better error handling as compared to using Promise chains or callbacks.
You can also use Promise chaining to execute send operation.
client.send(command).then(
(data) => {
// process data.
},
(error) => {
// error handling.
}
);Promises can also be called using .catch() and .finally() as follows:
client
.send(command)
.then((data) => {
// process data.
})
.catch((error) => {
// error handling.
})
.finally(() => {
// finally.
});We do not recommend using callbacks because of callback hell, but they are supported by the send operation.
// callbacks.
client.send(command, (err, data) => {
// process err and data.
});The client can also send requests using v2 compatible style. However, it results in a bigger bundle size and may be dropped in next major version. More details in the blog post on modular packages in AWS SDK for JavaScript
import * as AWS from "@aws-sdk/client-qldb";
const client = new AWS.QLDB({ region: "REGION" });
// async/await.
try {
const data = await client.listLedgers(params);
// process data.
} catch (error) {
// error handling.
}
// Promises.
client
.listLedgers(params)
.then((data) => {
// process data.
})
.catch((error) => {
// error handling.
});
// callbacks.
client.listLedgers(params, (err, data) => {
// process err and data.
});When the service returns an exception, the error will include the exception information, as well as response metadata (e.g. request id).
try {
const data = await client.send(command);
// process data.
} catch (error) {
const { requestId, cfId, extendedRequestId } = error.$metadata;
console.log({ requestId, cfId, extendedRequestId });
/**
* The keys within exceptions are also parsed.
* You can access them by specifying exception names:
* if (error.name === 'SomeServiceException') {
* const value = error.specialKeyInException;
* }
*/
}Please use these community resources for getting help. We use the GitHub issues for tracking bugs and feature requests, but have limited bandwidth to address them.
- Visit Developer Guide or API Reference.
- Check out the blog posts tagged with
aws-sdk-json AWS Developer Blog. - Ask a question on StackOverflow and tag it with
aws-sdk-js. - Join the AWS JavaScript community on gitter.
- If it turns out that you may have found a bug, please open an issue.
To test your universal JavaScript code in Node.js, browser and react-native environments, visit our code samples repo.
This client code is generated automatically. Any modifications will be overwritten the next time the @aws-sdk/client-qldb package is updated.
To contribute to client you can check our generate clients scripts.
This SDK is distributed under the Apache License, Version 2.0, see LICENSE for more information.