get S3 Directory Index as JSON

readme.md

Bucket Policy

Make sure the bucket have the public ListBucket permission

YourBucket >> Permissions >> Bucket Policy

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "PublicListing",
            "Effect": "Allow",
            "Principal": "*",
            "Action": "s3:ListBucket",
            "Resource": "arn:aws:s3:::yourbucketname"
        }
    ]
}

Enable CORS

You can allow "*" or specific domain

YourBucket >> Permissions >> CORS configuration

<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
<CORSRule>
    <AllowedOrigin>*</AllowedOrigin>
    <AllowedMethod>GET</AllowedMethod>
    <MaxAgeSeconds>3000</MaxAgeSeconds>
    <AllowedHeader>Authorization</AllowedHeader>
</CORSRule>
</CORSConfiguration>

Configure Public Access

Enable / Disable required settings YourBucket >> Permissions >> Public access settings

directory-index.js

// source: https://gist.github.com/chinchang/8106a82c56ad007e27b1#file-xmltojson-js
function xmlToJson(xml) {
  if (typeof xml === 'string') {
    parser = new DOMParser();
    xml = parser.parseFromString(xml, 'text/xml');
  }

  // Create the return object
  var obj = {};

  if (xml.nodeType == 1) {
    // element
    // do attributes
    if (xml.attributes.length > 0) {
      obj['@attributes'] = {};
      for (var j = 0; j < xml.attributes.length; j++) {
        var attribute = xml.attributes.item(j);
        obj['@attributes'][attribute.nodeName] = attribute.nodeValue;
      }
    }
  } else if (xml.nodeType == 3) {
    // text
    obj = xml.nodeValue;
  }

  // do children
  // If just one text node inside
  if (xml.hasChildNodes() && xml.childNodes.length === 1 && xml.childNodes[0].nodeType === 3) {
    obj = xml.childNodes[0].nodeValue;
  } else if (xml.hasChildNodes()) {
    for (var i = 0; i < xml.childNodes.length; i++) {
      var item = xml.childNodes.item(i);
      var nodeName = item.nodeName;
      // camelCase
      nodeName = nodeName.charAt(0).toLowerCase() + nodeName.slice(1);
      if (typeof obj[nodeName] == 'undefined') {
        obj[nodeName] = xmlToJson(item);
      } else {
        if (typeof obj[nodeName].push == 'undefined') {
          var old = obj[nodeName];
          obj[nodeName] = [];
          obj[nodeName].push(old);
        }
        obj[nodeName].push(xmlToJson(item));
      }
    }
  }
  return obj;
}

function getIndexUrl(bucket, region, prefix) {
  // http://yourbucketname.s3.amazonaws.com/?delimiter=/&prefix=downloads/' (only http)
  // https://s3.ap-south-1.amazonaws.com/yourbucketname/?delimiter=/&prefix=downloads/
  return 'https://s3.' + region + '.amazonaws.com/' + bucket + '/?delimiter=/&prefix=' + prefix;
}

function getIndexJson(xml) {
  var json = xmlToJson(xml);
  var list = [];
  if (json.listBucketResult.commonPrefixes)
    list = list.concat(json.listBucketResult.commonPrefixes);
  if (json.listBucketResult.contents)
    list = list.concat(json.listBucketResult.contents);

  return list;
}

// /* description */

// getIndexUrl(bucket, region, prefix) - gives the url for directory index api call
// getIndexJson(xml) - accepts directory index xml data and gives required json 
// [ { prefix }, { eTag, key, lastModified, size, storageClass } ]

// /* example usage */

// var bucket = 'yourbucketname';
// var region = 'ap-south-1';
// var prefix = 'downloads/'; // must have trailing slash or can be empty string

// fetch(getIndexUrl(bucket, region, prefix))
//   .then(res => res.text())
//   .then(getIndexJson)
//   .then(j => console.log(j));