"""Base Tornado handlers for the notebook server.""" # 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() import IPython from IPython.utils.sysinfo import get_sys_info 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, url_path_join, url_escape from IPython.html.services.security import csp_report_uri #----------------------------------------------------------------------------- # Top-level handlers #----------------------------------------------------------------------------- non_alphanum = re.compile(r'[^A-Za-z0-9]') sys_info = json.dumps(get_sys_info()) class AuthenticatedHandler(web.RequestHandler): """A RequestHandler with an authenticated user.""" def set_default_headers(self): headers = self.settings.get('headers', {}) if "Content-Security-Policy" not in headers: headers["Content-Security-Policy"] = ( "frame-ancestors 'self'; " # Make sure the report-uri is relative to the base_url "report-uri " + url_path_join(self.base_url, csp_report_uri) + ";" ) # Allow for overriding headers for header_name,value in headers.items() : try: self.set_header(header_name, value) except Exception as e: # tornado raise Exception (not a subclass) # if method is unsupported (websocket and Access-Control-Allow-Origin # for example, so just ignore) self.log.debug(e) def clear_login_cookie(self): self.clear_cookie(self.cookie_name) def get_current_user(self): if self.login_handler is None: return 'anonymous' return self.login_handler.get_user(self) @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 logged_in(self): """Is a user currently logged in?""" user = self.get_current_user() return (user and not user == 'anonymous') @property def login_handler(self): """Return the login handler for this application, if any.""" return self.settings.get('login_handler_class', None) @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. """ if self.login_handler is None: return False return bool(self.login_handler.login_available(self.settings)) 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 version_hash(self): """The version hash to use for cache hints for static files""" return self.settings.get('version_hash', '') @property def mathjax_url(self): return self.settings.get('mathjax_url', '') @property def base_url(self): return self.settings.get('base_url', '/') @property def ws_url(self): return self.settings.get('websocket_url', '') @property def contents_js_source(self): self.log.debug("Using contents: %s", self.settings.get('contents_js_source', 'services/contents')) return self.settings.get('contents_js_source', 'services/contents') #--------------------------------------------------------------- # Manager objects #--------------------------------------------------------------- @property def kernel_manager(self): return self.settings['kernel_manager'] @property def contents_manager(self): return self.settings['contents_manager'] @property def cluster_manager(self): return self.settings['cluster_manager'] @property def session_manager(self): return self.settings['session_manager'] @property def terminal_manager(self): return self.settings['terminal_manager'] @property def kernel_spec_manager(self): return self.settings['kernel_spec_manager'] @property def config_manager(self): return self.settings['config_manager'] #--------------------------------------------------------------- # CORS #--------------------------------------------------------------- @property def allow_origin(self): """Normal Access-Control-Allow-Origin""" return self.settings.get('allow_origin', '') @property def allow_origin_pat(self): """Regular expression version of allow_origin""" return self.settings.get('allow_origin_pat', None) @property def allow_credentials(self): """Whether to set Access-Control-Allow-Credentials""" return self.settings.get('allow_credentials', False) def set_default_headers(self): """Add CORS headers, if defined""" super(IPythonHandler, self).set_default_headers() if self.allow_origin: self.set_header("Access-Control-Allow-Origin", self.allow_origin) elif self.allow_origin_pat: origin = self.get_origin() if origin and self.allow_origin_pat.match(origin): self.set_header("Access-Control-Allow-Origin", origin) if self.allow_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, ws_url=self.ws_url, logged_in=self.logged_in, login_available=self.login_available, static_url=self.static_url, sys_info=sys_info, contents_js_source=self.contents_js_source, version_hash=self.version_hash, ) 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 write_error(self, status_code, **kwargs): """render custom error pages""" exc_info = kwargs.get('exc_info') message = '' status_message = responses.get(status_code, 'Unknown HTTP Error') if exc_info: exception = exc_info[1] # 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, ) self.set_header('Content-Type', 'text/html') # 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) self.write(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 = path.rsplit('/', 1)[-1] self.set_header('Content-Type', 'application/json') self.set_header('Content-Disposition','attachment; filename="%s"' % name) return web.StaticFileHandler.get(self, path) def set_headers(self): super(AuthenticatedFileHandler, self).set_headers() # disable browser caching, rely on 304 replies for savings if "v" not in self.request.arguments: self.add_header("Cache-Control", "no-cache") 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 set_headers(self): super(FileFindHandler, self).set_headers() # disable browser caching, rely on 304 replies for savings if "v" not in self.request.arguments or \ any(self.request.path.startswith(path) for path in self.no_cache_paths): self.add_header("Cache-Control", "no-cache") def initialize(self, path, default_filename=None, no_cache_paths=None): self.no_cache_paths = no_cache_paths or [] 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 ApiVersionHandler(IPythonHandler): @json_errors def get(self): # not authenticated, so give as few info as possible self.finish(json.dumps({"version":IPython.__version__})) class TrailingSlashHandler(web.RequestHandler): """Simple redirect handler that strips trailing slashes This should be the first, highest priority handler. """ def get(self): self.redirect(self.request.uri.rstrip('/')) post = put = get class FilesRedirectHandler(IPythonHandler): """Handler for redirecting relative URLs to the /files/ handler""" def get(self, path=''): cm = self.contents_manager if cm.dir_exists(path): # it's a *directory*, redirect to /tree url = url_path_join(self.base_url, 'tree', path) else: orig_path = path # otherwise, redirect to /files parts = path.split('/') if not cm.file_exists(path=path) and 'files' in parts: # redirect without files/ iff it would 404 # this preserves pre-2.0-style 'files/' links self.log.warn("Deprecated files/ URL: %s", orig_path) parts.remove('files') path = '/'.join(parts) if not cm.file_exists(path=path): raise web.HTTPError(404) url = url_path_join(self.base_url, 'files', path) url = url_escape(url) self.log.debug("Redirecting %s to %s", self.request.path, url) self.redirect(url) #----------------------------------------------------------------------------- # URL pattern fragments for re-use #----------------------------------------------------------------------------- # path matches any number of `/foo[/bar...]` or just `/` or '' path_regex = r"(?P(?:(?:/[^/]+)+|/?))" notebook_path_regex = r"(?P(?:/[^/]+)+\.ipynb)" #----------------------------------------------------------------------------- # URL to handler mappings #----------------------------------------------------------------------------- default_handlers = [ (r".*/", TrailingSlashHandler), (r"api", ApiVersionHandler) ]