hsuh/AWS validate key and secret access key

## AWS validate key and secret access key
url - https://forums.aws.amazon.com/message.jspa?messageID=671934
You could verify that they match a regular expression that describes every access key and every secret key (the AWS Security Blog has regexes you could use), but there's no way for the SDK to check if your credentials are valid without sending a request to a service. (Otherwise, the SDK would need to ship with everyone's access keys embedded in its source.)

If you do make a call to a service, though, the remote service will be able to validate your credentials and respond accordingly. If you call $s3Client->listBuckets() before calling $s3Client->registerStreamWrapper(), the client will call the service and convert the error to an exception if your credentials are invalid.
	url - https://forums.aws.amazon.com/message.jspa?messageID=671934
	You could verify that they match a regular expression that describes every access key and every secret key (the AWS Security Blog has regexes you could use), but there's no way for the SDK to check if your credentials are valid without sending a request to a service. (Otherwise, the SDK would need to ship with everyone's access keys embedded in its source.)

	If you do make a call to a service, though, the remote service will be able to validate your credentials and respond accordingly. If you call $s3Client->listBuckets() before calling $s3Client->registerStreamWrapper(), the client will call the service and convert the error to an exception if your credentials are invalid.