[REEF-1827] new Uri(path) in REEF.NET IO Returns Lowercase String

[shouhengyi-microsoft]

This corresponds to REEF-1827. In the Org.Apache.REEF.IO.FileSystem.IFileSystem, we have many methods that are based on C#'s Uri. For example:

void CopyToLocal(Uri remoteFileUri, string localName);
void CreateDirectory(Uri directoryUri);

From the logging and my experiments, this converts path to lowercase characters. For example:

new Uri("hdfs://XYZ123/mypath/data.txt") // Returns "hdfs://xyz123/mypath/data.txt"

If we are interacting with hdfs, in the subsequent dfs command in Org.Apache.REEF.IO.FileSystem.Hadoop:

public void CopyToLocal(Uri remoteFileUri, string localName)
{
    _commandRunner.Run("dfs -get " + remoteFileUri + " " + localName);
}

this will fail, since hdfs is case-sensitive.

JIRA:
REEF-1827

Pull request:
#1329

[motus]

LGTM, I can merge it. Do we have unit tests that reveal that problem, by the way?

[motus]

Also, could you please edit the PR title and prepend a JIRA id to it?

[jwang98052]

Do you mean even URI object converted the path into lower case, but uri.AbsolutePath will return case sensitive path, right?