piobyte/flamingo

import Errors = require("flamingo/src/util/errors");
import { ReaderResult } from "flamingo/src/types/ReaderResult";
import { S3 } from "aws-sdk";

const { InvalidInputError } = Errors;

const type = "s3";
/**
 * S3 reader module
 * @module flamingo-s3/src/reader
 */

/**
 * Result of input reading
 * @typedef {{stream: function, type: string}} ReadResult
 * @property {string} type reader result type
 * @property {function} stream function that returns a readable image stream
 */

/**
 * Reader that creates a stream for a given http/https resource
 * @param {string} bucket bucket name
 * @param {string} key bucket key
 * @param {AWS} s3Client AWS s3 client
 * @return {Promise.<ReadResult>} promise that resolves a reader result
 */
function s3Reader(
  bucket: string,
  key: string,
  s3Client: S3
): Promise<ReaderResult> {
  const params = {
    Bucket: bucket,
    Key: key,
  };

  return s3Client
    .headObject(params)
    .promise()
    .then(() => ({
      stream: () =>
        Promise.resolve(s3Client.getObject(params).createReadStream()),
      type,
    }))
    .catch((error: Error) => {
      throw new InvalidInputError("Error trying to get object metadata", error);
    });
}

export = s3Reader;