Implement an S3 url parser

[alexburley]

I've seen this re-used a few times IE:

// for matching https://s3.eu-west-2.amazonaws.com/tray-csv-file-imports-dev/tests/test_csv.csv
const S3_URL_MATCH = /http(?:s)*:\/\/(?:s3\.(.+)\.)*s3\.([^\.]+)\.amazonaws\.com\/([^\?]*)/;

// for matching https://workflow-file-uploads.s3.us-west-2.amazonaws.com/aaaa or https://workflow-file-uploads.s3-us-west-2.amazonaws.com/aaaa
const S3_URL_MATCH_ALT = /http(?:s)*:\/\/(?:(.+)\.)*s3(?:[-|.](.*))*\.amazonaws\.com\/([^\?]*)/;

// matches one of the URL formats above and return bucket and key
module.exports = url => {
	const s3MatchRes = S3_URL_MATCH.exec(url);
	const s3MatchResAlt = S3_URL_MATCH_ALT.exec(url);

	if (s3MatchRes) {
		const bucketAndKey = s3MatchRes[3];
		const parts = bucketAndKey.split('/');
		const bucket = parts[0];
		parts.shift();
		const key = _.join(parts, '/');

		return {
			region: s3MatchRes[2] ? s3MatchRes[2] : undefined,
			bucket: bucket,
			key: decodeURIComponent(key),
		};
	} else if (s3MatchResAlt) {
		const match = s3MatchResAlt;
		if (!match[1]) {
			return undefined;
		}
		return {
			region: match[2] ? match[2] : undefined,
			bucket: match[1],
			key: decodeURIComponent(match[3]),
		};
	} else {
                
		return error; 
	}
};