"""Base Tornado handlers for the notebook.""" # Copyright (c) IPython Development Team. # Distributed under the terms of the Modified BSD License. import functools import json import logging import os import re import sys import traceback try: # py3 from http.client import responses except ImportError: from httplib import responses from jinja2 import TemplateNotFound from tornado import web try: from tornado.log import app_log except ImportError: app_log = logging.getLogger() from IPython.config import Application from IPython.utils.path import filefind from IPython.utils.py3compat import string_types from IPython.html.utils import is_hidden #----------------------------------------------------------------------------- # Top-level handlers #----------------------------------------------------------------------------- non_alphanum = re.compile(r'[^A-Za-z0-9]') class AuthenticatedHandler(web.RequestHandler): """A RequestHandler with an authenticated user.""" def set_default_headers(self): headers = self.settings.get('headers', {}) for header_name,value in headers.items() : try: self.set_header(header_name, value) except Exception: # tornado raise Exception (not a subclass) # if method is unsupported (websocket and Access-Control-Allow-Origin # for example, so just ignore) pass def clear_login_cookie(self): self.clear_cookie(self.cookie_name) def get_current_user(self): user_id = self.get_secure_cookie(self.cookie_name) # For now the user_id should not return empty, but it could eventually if user_id == '': user_id = 'anonymous' if user_id is None: # prevent extra Invalid cookie sig warnings: self.clear_login_cookie() if not self.login_available: user_id = 'anonymous' return user_id @property def cookie_name(self): default_cookie_name = non_alphanum.sub('-', 'username-{}'.format( self.request.host )) return self.settings.get('cookie_name', default_cookie_name) @property def password(self): """our password""" return self.settings.get('password', '') @property def logged_in(self): """Is a user currently logged in? """ user = self.get_current_user() return (user and not user == 'anonymous') @property def login_available(self): """May a user proceed to log in? This returns True if login capability is available, irrespective of whether the user is already logged in or not. """ return bool(self.settings.get('password', '')) class IPythonHandler(AuthenticatedHandler): """IPython-specific extensions to authenticated handling Mostly property shortcuts to IPython-specific settings. """ @property def config(self): return self.settings.get('config', None) @property def log(self): """use the IPython log by default, falling back on tornado's logger""" if Application.initialized(): return Application.instance().log else: return app_log #--------------------------------------------------------------- # URLs #--------------------------------------------------------------- @property def mathjax_url(self): return self.settings.get('mathjax_url', '') @property def base_url(self): return self.settings.get('base_url', '/') #--------------------------------------------------------------- # Manager objects #--------------------------------------------------------------- @property def kernel_manager(self): return self.settings['kernel_manager'] @property def notebook_manager(self): return self.settings['notebook_manager'] @property def cluster_manager(self): return self.settings['cluster_manager'] @property def session_manager(self): return self.settings['session_manager'] @property def kernel_spec_manager(self): return self.settings['kernel_spec_manager'] @property def project_dir(self): return self.notebook_manager.notebook_dir #--------------------------------------------------------------- # CORS #--------------------------------------------------------------- @property def cors_origin(self): """Normal Access-Control-Allow-Origin""" return self.settings.get('cors_origin', '') @property def cors_origin_pat(self): """Regular expression version of cors_origin""" return self.settings.get('cors_origin_pat', None) @property def cors_credentials(self): """Whether to set Access-Control-Allow-Credentials""" return self.settings.get('cors_credentials', False) def set_default_headers(self): """Add CORS headers, if defined""" super(IPythonHandler, self).set_default_headers() if self.cors_origin: self.set_header("Access-Control-Allow-Origin", self.cors_origin) elif self.cors_origin_pat: origin = self.get_origin() if origin and self.cors_origin_pat.match(origin): self.set_header("Access-Control-Allow-Origin", origin) if self.cors_credentials: self.set_header("Access-Control-Allow-Credentials", 'true') def get_origin(self): # Handle WebSocket Origin naming convention differences # The difference between version 8 and 13 is that in 8 the # client sends a "Sec-Websocket-Origin" header and in 13 it's # simply "Origin". if "Origin" in self.request.headers: origin = self.request.headers.get("Origin") else: origin = self.request.headers.get("Sec-Websocket-Origin", None) return origin #--------------------------------------------------------------- # template rendering #--------------------------------------------------------------- def get_template(self, name): """Return the jinja template object for a given name""" return self.settings['jinja2_env'].get_template(name) def render_template(self, name, **ns): ns.update(self.template_namespace) template = self.get_template(name) return template.render(**ns) @property def template_namespace(self): return dict( base_url=self.base_url, logged_in=self.logged_in, login_available=self.login_available, static_url=self.static_url, ) def get_json_body(self): """Return the body of the request as JSON data.""" if not self.request.body: return None # Do we need to call body.decode('utf-8') here? body = self.request.body.strip().decode(u'utf-8') try: model = json.loads(body) except Exception: self.log.debug("Bad JSON: %r", body) self.log.error("Couldn't parse JSON", exc_info=True) raise web.HTTPError(400, u'Invalid JSON in body of request') return model def get_error_html(self, status_code, **kwargs): """render custom error pages""" exception = kwargs.get('exception') message = '' status_message = responses.get(status_code, 'Unknown HTTP Error') if exception: # get the custom message, if defined try: message = exception.log_message % exception.args except Exception: pass # construct the custom reason, if defined reason = getattr(exception, 'reason', '') if reason: status_message = reason # build template namespace ns = dict( status_code=status_code, status_message=status_message, message=message, exception=exception, ) # render the template try: html = self.render_template('%s.html' % status_code, **ns) except TemplateNotFound: self.log.debug("No template for %d", status_code) html = self.render_template('error.html', **ns) return html class Template404(IPythonHandler): """Render our 404 template""" def prepare(self): raise web.HTTPError(404) class AuthenticatedFileHandler(IPythonHandler, web.StaticFileHandler): """static files should only be accessible when logged in""" @web.authenticated def get(self, path): if os.path.splitext(path)[1] == '.ipynb': name = os.path.basename(path) self.set_header('Content-Type', 'application/json') self.set_header('Content-Disposition','attachment; filename="%s"' % name) return web.StaticFileHandler.get(self, path) def compute_etag(self): return None def validate_absolute_path(self, root, absolute_path): """Validate and return the absolute path. Requires tornado 3.1 Adding to tornado's own handling, forbids the serving of hidden files. """ abs_path = super(AuthenticatedFileHandler, self).validate_absolute_path(root, absolute_path) abs_root = os.path.abspath(root) if is_hidden(abs_path, abs_root): self.log.info("Refusing to serve hidden file, via 404 Error") raise web.HTTPError(404) return abs_path def json_errors(method): """Decorate methods with this to return GitHub style JSON errors. This should be used on any JSON API on any handler method that can raise HTTPErrors. This will grab the latest HTTPError exception using sys.exc_info and then: 1. Set the HTTP status code based on the HTTPError 2. Create and return a JSON body with a message field describing the error in a human readable form. """ @functools.wraps(method) def wrapper(self, *args, **kwargs): try: result = method(self, *args, **kwargs) except web.HTTPError as e: status = e.status_code message = e.log_message self.log.warn(message) self.set_status(e.status_code) self.finish(json.dumps(dict(message=message))) except Exception: self.log.error("Unhandled error in API request", exc_info=True) status = 500 message = "Unknown server error" t, value, tb = sys.exc_info() self.set_status(status) tb_text = ''.join(traceback.format_exception(t, value, tb)) reply = dict(message=message, traceback=tb_text) self.finish(json.dumps(reply)) else: return result return wrapper #----------------------------------------------------------------------------- # File handler #----------------------------------------------------------------------------- # to minimize subclass changes: HTTPError = web.HTTPError class FileFindHandler(web.StaticFileHandler): """subclass of StaticFileHandler for serving files from a search path""" # cache search results, don't search for files more than once _static_paths = {} def initialize(self, path, default_filename=None): if isinstance(path, string_types): path = [path] self.root = tuple( os.path.abspath(os.path.expanduser(p)) + os.sep for p in path ) self.default_filename = default_filename def compute_etag(self): return None @classmethod def get_absolute_path(cls, roots, path): """locate a file to serve on our static file search path""" with cls._lock: if path in cls._static_paths: return cls._static_paths[path] try: abspath = os.path.abspath(filefind(path, roots)) except IOError: # IOError means not found return '' cls._static_paths[path] = abspath return abspath def validate_absolute_path(self, root, absolute_path): """check if the file should be served (raises 404, 403, etc.)""" if absolute_path == '': raise web.HTTPError(404) for root in self.root: if (absolute_path + os.sep).startswith(root): break return super(FileFindHandler, self).validate_absolute_path(root, absolute_path) class TrailingSlashHandler(web.RequestHandler): """Simple redirect handler that strips trailing slashes This should be the first, highest priority handler. """ SUPPORTED_METHODS = ['GET'] def get(self): self.redirect(self.request.uri.rstrip('/')) #----------------------------------------------------------------------------- # URL pattern fragments for re-use #----------------------------------------------------------------------------- path_regex = r"(?P(?:/.*)*)" notebook_name_regex = r"(?P[^/]+\.ipynb)" notebook_path_regex = "%s/%s" % (path_regex, notebook_name_regex) #----------------------------------------------------------------------------- # URL to handler mappings #----------------------------------------------------------------------------- default_handlers = [ (r".*/", TrailingSlashHandler) ]