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PyQt and a SSH upload droplet

Modern GUIs need Drag and Drop

The following is an example for a drag & drop action with PyQt4. It uses paramiko for SSH interactions. I'm well aware that it won't work on Windows that way. But that's a Windows problem. I'm also well aware that there's a password in this file. Give it a try.
The source is at GitHub. The indention seems to be broken there. But that's a GitHub problem. It seems to be broken here, too. But that's a Drupal problem. ;). Actually it isn't even a problem.

Just the imports. The os module is necessary if you want paramiko to use your private ssh-key. The sys module is needed due argv:

  1. import sys
  2. import paramiko # for ssh
  3. import os  
  4. from PyQt4 import QtGui, QtCore
  5. from mainwindow import Ui_MainWindow

I pretty much guess that's self-explaining now. That's the standard header to initiate the form:

  1. class gui_does(QtGui.QMainWindow):
  2.    def __init__(self):
  3.       QtGui.QMainWindow.__init__(self)
  4.       self.ui = Ui_MainWindow()
  5.       self.ui.setupUi(self)
  6.  
  7.   self.setWindowTitle('To-SSH Droplet')
  8.   # to accept drops
  9.         self.setAcceptDrops(True)
  10.         self.ui.lineEdit.setText("/home/wishi/")
  11.         self.statusBar().showMessage('Ready')

To make an application accept drop-acrions simply define this in an __init__. Compared to Cocoa e. g. this is really trivial.

  1.         def dragEnterEvent(self, event):
  2.                 if event.mimeData().hasUrls():
  3.                 event.acceptProposedAction()
  4.    
  5.     """ the initial drop action is scp """
  6. def dropEvent(self, event):
  7.         filelist = ('\r\n'.join([str(url.toString()) for url in event.mimeData().urls()]))
  8.         self.ui.textEdit.setText(filelist)
  9.         splitted_filelist = filelist.split("\r\n")
  10.         destination_path = self.ui.lineEdit.text()

- That's it to define the event-actions. If a user drops a file, handle it:

  1.         #privatekeyfile = os.path.expanduser('~/.ssh/id_rsa')
  2.         #mykey = paramiko.RSAKey.from_private_key_file(privatekeyfile)
  3.         username = 'wishi'
  4.         password = 'bmljZSB0cnkgaWRpb3Q='
  5.         host = 'crazylazy.info'
  6.         port = 22
  7.         error = False

So... paramiko is able to use your private key, as stated in the comment. It also supports passwords. Surely you know, that Base64 isn't used in SSH ;). However in this case it makes sense.

  1.         try:
  2.                 self.statusBar().showMessage("Uploading")
  3.                 ssh = paramiko.SSHClient()
  4.                 ssh.load_system_host_keys()
  5.                 ssh.connect(host, username = username, password = password)
  6.                 sftp = ssh.open_sftp()
  7.                
  8.                 for file in splitted_filelist:
  9.                         file = file[7:]
  10.                         patharray = file.split("/")
  11.                         destination_path = destination_path + patharray[len(patharray)-1]
  12.                         sftp.put(file, str(destination_path))
  13.            
  14.                 sftp.close()
  15.                 ssh.close()
  16.            
  17.         except:
  18.                 error = True
  19.        
  20.         if (error):    
  21.                 self.statusBar().showMessage("Error")
  22.         else:
  23.                 self.statusBar().showMessage("Ready")
  24.    
  25. if __name__=="__main__":
  26.         app = QtGui.QApplication(sys.argv)
  27.         window = gui_does()
  28.         window.show()
  29.         sys.exit(app.exec_())

The interesting point here are the text conversions, which are necessary. You see that str(destionation_path) converts self.ui.lineEdit.text(). That's confusing at the beginning, but Qt handles text as unicode. Most Python installation don't.
Paramiko wants an ASCII string. So you convert this into a standard Python string-type. Furthermore you see that the string-operations introduced in nearly every Python tutorial I ever read are more than essential. Even in GUI programming they're central.

If you take a look at the for-loop: destination_path = destination_path + patharray[len(patharray)-1] -> makes sftp.put keep the filename and put it into the destination_path. You need the last element, which is len(element)-1.
The URI string normally starts with "file://". You don't want to pass these identifier-string to sftp.put. So you start at th 7th (file = file[7:]) position. That converts the URI into a general Unix path.

The rest of the app is trivial. Starting Qt Designer, clicking: the GUI just needs a lineEdit and a textEdit. The whole project including the QT Designer files are at GitHub. Surely you can enhance it with a progress bar, a menu-bar, preferences and extend it into a full featured sftp client.

This is just a general snippet on how to implement Drag and Drop actions with Qt and Python. If you want to dive into it, enhance it and:

Have fun,
wishi

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