Prefix

Restricts the response to only contain results that begin with the specified prefix. If you omit this optional argument, the value of Prefix for your query will be the empty string. In other words, the results will be not be restricted by prefix.

Marker

This optional parameter enables pagination of large result sets. Marker specifies where in the result set to resume listing. It restricts the response to only contain results that occur alphabetically after the value of marker. To retrieve the next page of results, use the last key from the current page of results as the marker in your next request. For more information, see the NextMarker response element. If Marker is omitted, the first page of results is returned.

Delimiter

If this optional, Unicode string parameter is included with your request, then keys that contain the same string between the prefix and the first occurrence of the delimiter will be rolled up into a single result element in the CommonPrefixes collection. These rolled-up keys are not returned elsewhere in the response.

For example, with Prefix="USA/" and Delimiter="/", the matching keys "USA/Oregon/Salem" and "USA/Oregon/Portland" would be summarized in the response as a single "USA/Oregon" element in the CommonPrefixes collection. If an otherwise matching key does not contain the delimiter after the prefix, it appears in the Contents collection.

Each element in the CommonPrefixes collection counts as one against the MaxKeys limit. The rolled-up keys represented by each CommonPrefixes element do not.

If the Delimiter parameter is not present in your request, keys in the result set will not be rolled-up and neither the CommonPrefixes collection nor the NextMarker element will be present in the response.

MaxKeys

This optional argument limits the number of results returned in response to your query. Amazon S3 will return no more than this number of results, but possibly less. Even if MaxKeys is not specified, Amazon S3 will limit the number of results in the response. Check the IsTruncated flag to see if your results are incomplete. If so, use the Marker parameter to request the next page of results.

For the purpose of counting MaxKeys, a 'result' is either a key in the 'Contents' collection, or a delimited prefix in the 'CommonPrefixes' collection. So for delimiter requests, MaxKeys limits the total number of list results, not just the number of keys.