Allow to read from stdin

So it is possible to use functions like scanf.

Thanks to @ryukinix for letting me know about this enhancement.

[spoorcc]

I’m trying to implement this, but I’m a little stuck: My idea is to override all fgets calls with my_fgets using a macro. This my_fgets in master.c notifies its parent (subprocess.Popen in kernel.py) somehow to send an input_request through stdin_socket. When input_reply is received from the frontend the data is piped to the stdin of subprocess.

I managed to request and receive input from the frontend as such, which works just fine:

 def _raw_input(self, prompt, ident, parent):
          # Flush output before making the request.
          sys.stderr.flush()
          sys.stdout.flush()

          # Send the input request.
          content = dict(prompt=prompt)
          msg = self.session.send(self.stdin_socket, u'input_request', content, parent, ident=ident)

          # Await a response.
          ident,reply = self.session.recv(self.stdin_socket, 0)
          try:
              value = reply['content']['value']
          except:
              self.log.error("Got bad raw_input reply: %s"%Message(parent))
              value = ''
          return value

    def execute_request(self, stream, ident, parent):
        ''' Wrap execture_request function to force input call '''
        value = self._raw_input('Some info:', ident, parent)
        self.log.warn('Value: {}'.format(value))
        super(CKernel, self).execute_request(stream, ident, parent)

Questions

I cannot find or decide on a mechanism to notify from master.c to Python subprocess instance that input is requested:

• Is there anybody with an opinion or a better suggestion than:
  • Using zmq sockets directly from master.c?
  • Introducing new messaging system between master.c and kernel.py?
  • Piping some predefined message through stderr/stdout?
• I looked into raising signals SIGTTIN and SIGTTOU (good blog), but they appear to be used from parent-to-child and I want from child to parent.

[sdd3]

Ah, ok. I misunderstood the first post in this thread. Thanks for clearing that up. Any idea when an input function might be incorporated?