[jira] [Created] (NET-721) FTPClient::retrieveFileStream returns empty stream for binary files when running on remote Linux

["Dmytro Sylaiev (Jira)" <ji...@apache.org>]

Dmytro Sylaiev created NET-721:
----------------------------------

             Summary: FTPClient::retrieveFileStream returns empty stream for binary files when running on remote Linux
                 Key: NET-721
                 URL: https://issues.apache.org/jira/browse/NET-721
             Project: Commons Net
          Issue Type: Bug
    Affects Versions: 3.9.0
            Reporter: Dmytro Sylaiev


I have next code works differently running on my local Windows machine and on linux docker container when args[0] is the binary file:

 

 
{noformat}
public class Main {
    public static void main(String[] args) throws IOException {
        String fileName = args[0];
        
        System.out.println("Print " + fileName + ":");
        printFile(fileName);

    }
    private static void printFile(String fileName) throws IOException {
    FTPClient client = new FTPClient();
    try {
        client.connect(host, port);

        client.login(user, pass);
        client.enterLocalPassiveMode();
        client.setFileType(FTP.BINARY_FILE_TYPE);
        try (InputStream is = client.retrieveFileStream(fileName)) {
            client.completePendingCommand();
            while (is.available() > 0) {
                int i = is.read();
                System.out.print((char) i);
            }

            System.out.println();
        }
    } finally {
        if (client.isConnected()) {
            client.disconnect();
        }
    }
    }
}{noformat}
 

 

When running it locally I have file content printed, but also I tried with jetty:11.0.15-jdk11 container, I executed same jar there and got empty stream in result:

 

 
{noformat}
docker cp ~\codecTest\. <containerName>:/codecTest
docker exec -it <containerName> /bin/bash
root@999c8e3413cc:/codecTest/target# java -jar codecTest-1.0-SNAPSHOT.jar output.zip
Print output.zip:


root@999c8e3413cc:/codecTest/target#{noformat}
When I put some debug log.info line I have found that is.available() is 0 when executing on linux, despite I have called client.setFileType(FTP.BINARY_FILE_TYPE); and client.completePendingCommand();

 

 

When execute same code in the remote debug and give the jvm some time to fetch the stream, it works correctly. Also no problem when retieveStream for ASCII files (even big one)

 

FileZilla log is also OK:

 
{noformat}
(000066)11.06.2023 15:58:08 - (not logged in) (ip)> Connected on port 9021, sending welcome message...
(000066)11.06.2023 15:58:08 - (not logged in) (ip)> 220-FileZilla Server 0.9.60 beta
(000066)11.06.2023 15:58:08 - (not logged in) (ip)> 220-written by Tim Kosse (tim.kosse@filezilla-project.org)
(000066)11.06.2023 15:58:08 - (not logged in) (ip)> 220 Please visit https://filezilla-project.org/
(000066)11.06.2023 15:58:08 - (not logged in) (ip)> USER <user>
(000066)11.06.2023 15:58:08 - (not logged in) (ip)> 331 Password required for lserver
(000066)11.06.2023 15:58:08 - (not logged in) (ip)> PASS <pass>
(000066)11.06.2023 15:58:08 - lserver (ip)> 230 Logged on
(000066)11.06.2023 15:58:08 - lserver (ip> TYPE I
(000066)11.06.2023 15:58:08 - lserver (ip)> 200 Type set to I
(000066)11.06.2023 15:58:08 - lserver (ip)> PASV
(000066)11.06.2023 15:58:08 - lserver (ip)> 227 Entering Passive Mode (95,67,26,232,60,72)
(000066)11.06.2023 15:58:08 - lserver (ip)> RETR output.zip
(000066)11.06.2023 15:58:08 - lserver (ip)> 150 Opening data channel for file download from server of "/output.zip"
(000066)11.06.2023 15:58:08 - lserver (ip)> 226 Successfully transferred "/output.zip"
(000066)11.06.2023 15:58:08 - lserver (ip)> disconnected{noformat}
 

 



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