Agent Vinod created NET-460:
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Summary: _retrieveFile() blocks calling thread, on FTP I/O till the time file
transfer is complete
Key: NET-460
URL: https://issues.apache.org/jira/browse/NET-460
Project: Commons Net
Issue Type: Wish
Components: FTP
Affects Versions: 3.1
Environment: linux/windows
Reporter: Agent Vinod
The Function _retrieveFile in file: FTPClient.java , does not respond to interrupts from calling
thread.
For Example:
A Basic FTP Client Application has 1 Main (Parent) Thread and 1 Child Thread.
Main (Parent) thread handles all functions except the FtpClient download/upload.
Child Thread handles only FtpClient related functions mainly (_retrieveFile()) etc.
Steps to reproduce:
1) Main Thread has initiated child Thread .
2) Child thread is presently downloading a file using _retrieveFile(String command, String
remote, OutputStream local) .
3) After some time, Main Thread fires Interrupt on child Thread to stop( Abort) download.
Expected behavior:
Child Thread immediately aborts download and dies.
Observed behavior:
Child Thread blocks on retrieveFile(String command, String remote, OutputStream local) till
the file finishes download.
Only after this ,does the Child thread respond to any interrupt from Parent Thread.
My Workaround:
file: FTPClient.java
Class: FTPClient
Step 1: declare private Socket mySocket;
Step 2: In the function : protected boolean _retrieveFile(String command, String remote, OutputStream
local) throws IOException{}
Comment out: Socket socket;
and instead use: mySocket ( declared as global in step1)
Step 3: In the function : public boolean abort() throws IOException
Add a statement: Util.closeQuietly(mySocket);
before the statement: return FTPReply.isPositiveCompletion(abor());
This way, every time the Main Thread calls abort(), the download active and blocked on mySocket
in _retrieveFile() is immediately interrupted and stopped.
raising an immediate Exception and thus stopping the Child thread (of course one needs to
catch this exception properly).
I am not sure if this is the right way of doing it and am afraid if this breaks something
else.
Requesting the core developers to look into a better solution to this workaround.
thank
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