[EMAIL PROTECTED] wrote: >hi all > >am trying to write some information into the file, which is located in >ftp, and this file can be updated by number of people, but if at all i >download a file from the ftp to my local machine, update it and then >upload it back to ftp, and at the same time if some one else downloads >the same file for the modification, then the data will be overwritten. > >so is there a way in Python script where i can lock the file, so that >no one updates it until i release the lock. > >Or is there a way where i can directly update the file from the ftp >itself, i mean without downloading it to my local machine. > >Thanks in advance for the help > >regards >yogi > > > I've come across this problem - instead of uploading the file to it's
intended directory, upload it to a temp directory, with a unique name (say uuuuuyyyymmddhhmmss where uuuuu is username and the rest are obvious) and then *rename* it to it's correct name in the real destination directory. Do the move in a try... except block and if it fails, take evasive action. In FTP a rename (i.e. move) is usually an atomic action but an upload is not. You have an unavoidable race condition here trying to lock a file (even if ftp allowed it) but with the method described above, you can avoid it, but get the same effect. Hope that helps! -andyj -- http://mail.python.org/mailman/listinfo/python-list
