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// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
// snippet-start:[javascript.v3.cross_service.supplement.list_widgets]
import { S3Client , ListObjectsCommand } from "@aws-sdk/client-s3" ;
// The following code uses the AWS SDK for JavaScript (v3).
// For more information, see https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/index.html.
const s3Client = new S3Client ( { } ) ;
/**
* @param {string} bucketName
*/
const listObjectNames = async ( bucketName ) => {
const command = new ListObjectsCommand ( { Bucket : bucketName } ) ;
const { Contents } = await s3Client . send ( command ) ;
if ( ! Contents . length ) {
const err = new Error ( ` No objects found in ${ bucketName } ` ) ;
err . name = "EmptyBucketError" ;
throw err ;
}
// Map the response to a list of strings representing the keys of the Amazon Simple Storage Service (Amazon S3) objects.
// Filter out any objects that don't have keys.
return Contents . map ( ( { Key } ) => Key ) . filter ( ( k ) => ! ! k ) ;
} ;
/**
* @typedef {{ httpMethod: 'GET' | 'POST' | 'PUT' | 'DELETE' | 'PATCH', path: string }} LambdaEvent
*/
/**
*
* @param {LambdaEvent} lambdaEvent
*/
const routeRequest = ( lambdaEvent ) => {
if ( lambdaEvent . httpMethod === "GET" && lambdaEvent . path === "/" ) {
return handleGetRequest ( ) ;
}
const error = new Error (
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` Unimplemented HTTP method: ${ lambdaEvent . httpMethod } ` ,
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) ;
error . name = "UnimplementedHTTPMethodError" ;
throw error ;
} ;
const handleGetRequest = async ( ) => {
if ( process . env . BUCKET === "undefined" ) {
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const err = new Error ( "No bucket name provided." ) ;
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err . name = "MissingBucketName" ;
throw err ;
}
const objects = await listObjectNames ( process . env . BUCKET ) ;
return buildResponseBody ( 200 , objects ) ;
} ;
/**
* @typedef {{statusCode: number, body: string, headers: Record<string, string> }} LambdaResponse
*/
/**
*
* @param {number} status
* @param {Record<string, string>} headers
* @param {Record<string, unknown>} body
*
* @returns {LambdaResponse}
*/
const buildResponseBody = ( status , body , headers = { } ) => {
return {
statusCode : status ,
headers ,
body ,
} ;
} ;
/**
*
* @param {LambdaEvent} event
*/
export const handler = async ( event ) => {
try {
return await routeRequest ( event ) ;
} catch ( err ) {
console . error ( err ) ;
if ( err . name === "MissingBucketName" ) {
return buildResponseBody ( 400 , err . message ) ;
}
if ( err . name === "EmptyBucketError" ) {
return buildResponseBody ( 204 , [ ] ) ;
}
if ( err . name === "UnimplementedHTTPMethodError" ) {
return buildResponseBody ( 400 , err . message ) ;
}
return buildResponseBody ( 500 , err . message || "Unknown server error" ) ;
}
} ;
// snippet-end:[javascript.v3.cross_service.supplement.list_widgets]
