Write notebook server info file in security directory

IPython/html/notebookapp.py

@@ -19,6 +19,8 b' from __future__ import print_function'
 
 # stdlib
 import errno
+import io
+import json
 import logging
 import os
 import random
@@ -72,6 +74,7 b' from .base.handlers import AuthenticatedFileHandler, FileFindHandler'
 
 from IPython.config.application import catch_config_error, boolean_flag
 from IPython.core.application import BaseIPythonApplication
+from IPython.core.profiledir import ProfileDir
 from IPython.consoleapp import IPythonConsoleApp
 from IPython.kernel import swallow_argv
 from IPython.kernel.zmq.session import default_secure
@@ -499,6 +502,12 b' class NotebookApp(BaseIPythonApplication):'
               "sent by the upstream reverse proxy. Neccesary if the proxy handles SSL")
     )
     
+    info_file = Unicode()
+
+    def _info_file_default(self):
+        info_file = "nbserver-%s.json"%os.getpid()
+        return os.path.join(self.profile_dir.security_dir, info_file)
+
     def parse_command_line(self, argv=None):
         super(NotebookApp, self).parse_command_line(argv)
         
@@ -594,6 +603,20 b' class NotebookApp(BaseIPythonApplication):'
                               'no available port could be found.')
             self.exit(1)
     
+    @property
+    def display_url(self):
+        ip = self.ip if self.ip else '[all ip addresses on your system]'
+        return self._url(ip)
+
+    @property
+    def connection_url(self):
+        ip = self.ip if self.ip else localhost()
+        return self._url(ip)
+
+    def _url(self, ip):
+        proto = 'https' if self.certfile else 'http'
+        return "%s://%s:%i%s" % (proto, ip, self.port, self.base_project_url)
+
     def init_signal(self):
         if not sys.platform.startswith('win'):
             signal.signal(signal.SIGINT, self._handle_sigint)
@@ -666,7 +689,6 b' class NotebookApp(BaseIPythonApplication):'
         elif status == 'unclean':
             self.log.warn("components submodule unclean, you may see 404s on static/components")
             self.log.warn("run `setup.py submodule` or `git submodule update` to update")
-            
     
     @catch_config_error
     def initialize(self, argv=None):
@@ -691,33 +713,56 b' class NotebookApp(BaseIPythonApplication):'
         "Return the current working directory and the server url information"
         info = self.notebook_manager.info_string() + "\n"
         info += "%d active kernels \n" % len(self.kernel_manager._kernels)
-        return info + "The IPython Notebook is running at: %s" % self._url
+        return info + "The IPython Notebook is running at: %s" % self.display_url
+
+    def server_info(self):
+        """Return a JSONable dict of information about this server."""
+        return {'url': self.connection_url,
+                'hostname': self.ip if self.ip else 'localhost',
+                'port': self.port,
+                'secure': bool(self.certfile),
+                'baseurlpath': self.base_project_url,
+                'notebookdir': os.path.abspath(self.notebook_manager.notebook_dir),
+               }
+
+    def write_server_info_file(self):
+        """Write the result of server_info() to the JSON file info_file."""
+        with io.open(self.info_file, 'w', encoding='utf-8') as f:
+            json.dump(self.server_info(), f)
+
+    def remove_server_info_file(self):
+        """Remove the nbserver-<pid>.json file created for this server.
+        
+        Ignores the error raised when the file has already been removed.
+        """
+        try:
+            os.unlink(self.info_file)
+        except OSError as e:
+            if e.errno != errno.ENOENT:
+                raise
 
     def start(self):
         """ Start the IPython Notebook server app, after initialization
         
         This method takes no arguments so all configuration and initialization
         must be done prior to calling this method."""
-        ip = self.ip if self.ip else '[all ip addresses on your system]'
-        proto = 'https' if self.certfile else 'http'
         info = self.log.info
-        self._url = "%s://%s:%i%s" % (proto, ip, self.port,
-                                      self.base_project_url)
         for line in self.notebook_info().split("\n"):
             info(line)
         info("Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).")
 
+        self.write_server_info_file()
+
         if self.open_browser or self.file_to_run:
-            ip = self.ip or localhost()
             try:
                 browser = webbrowser.get(self.browser or None)
             except webbrowser.Error as e:
                 self.log.warn('No web browser found: %s.' % e)
                 browser = None
             
-            nbdir = os.path.abspath(self.notebook_manager.notebook_dir)
             f = self.file_to_run
             if f:
+                nbdir = os.path.abspath(self.notebook_manager.notebook_dir)
                 if f.startswith(nbdir):
                     f = f[len(nbdir):]
                 else:
@@ -732,8 +777,8 b' class NotebookApp(BaseIPythonApplication):'
             else:
                 url = url_path_join('tree', f)
             if browser:
-                b = lambda : browser.open("%s://%s:%i%s%s" % (proto, ip,
-                    self.port, self.base_project_url, url), new=2)
+                b = lambda : browser.open("%s%s" % (self.connection_url, url),
+                                          new=2)
                 threading.Thread(target=b).start()
         try:
             ioloop.IOLoop.instance().start()
@@ -741,7 +786,21 b' class NotebookApp(BaseIPythonApplication):'
             info("Interrupted...")
         finally:
             self.cleanup_kernels()
+            self.remove_server_info_file()
+
+
+def discover_running_servers(profile='default'):
+    """Iterate over the server info files of running notebook servers.
     
+    Given a profile name, find nbserver-* files in the security directory of
+    that profile, and yield dicts of their information, each one pertaining to
+    a currently running notebook server instance.
+    """
+    pd = ProfileDir.find_profile_dir_by_name(get_ipython_dir(), name=profile)
+    for file in os.listdir(pd.security_dir):
+        if file.startswith('nbserver-'):
+            with io.open(os.path.join(pd.security_dir, file), encoding='utf-8') as f:
+                yield json.load(f)
 
 #-----------------------------------------------------------------------------
 # Main entry point