s3getimage/index.js

function for checking existence of image fie on s3 and return the presigned url

'use strict';

console.log('Starting s3GetImage');
/**
import { getSignedUrl } from "@aws-sdk/s3-request-presigner";
import { S3Client } from "@aws-sdk/client-s3";
import { GetObjectCommand } from "@aws-sdk/client-s3";
import {ListObjectsV2Command } from "@aws-sdk/client-s3";
*/

const{ getSignedUrl } = require("@aws-sdk/s3-request-presigner");
const { S3Client } = require("@aws-sdk/client-s3");
const { GetObjectCommand } = require("@aws-sdk/client-s3");
const { ListObjectsV2Command } = require("@aws-sdk/client-s3");
const client = new S3Client({ region: "eu-central-1" });

async function s3getimage(event) {
  console.log('Event: ' + JSON.stringify(event));
  var s3Bucket = event.s3bucket;

  const params = {
    Bucket: s3Bucket,
    Prefix: event.userid
  }

  const command = new ListObjectsV2Command(params);
  try {
    const objectList = await client.send(command);
    
    if (objectList.Contents.length < 1) {
      console.log('there are no images with this key: ' + JSON.stringify(objectList.Contents.length));
    } else {
      let imgKey = objectList.Contents[0].Key;
      console.log('Image Key: ' + JSON.stringify(imgKey));

      const params = {
        Bucket: s3Bucket,
        Key: imgKey,
        Expires: event.expiry
      };

      const command = new GetObjectCommand(params);
      try {
        const objectUrl = await getSignedUrl(client, command);
        return objectUrl;
      } catch (err) {
        console.log('Signed URL: ' +err.statusCode + 'No user image found');
      }
    }
  } catch (err) {
    console.log('List objects: ' + err.statusCode + ' No user image found');
  }
}

module.exports = {
  s3getimage
};