add FileFindHandler for serving static files from a search path

IPython/frontend/html/notebook/handlers.py

@@ -16,8 +16,14 @@ Authors:
 # Imports
 #-----------------------------------------------------------------------------
 
-import logging
 import Cookie
+import datetime
+import email.utils
+import hashlib
+import logging
+import mimetypes
+import os
+import stat
 import time
 import uuid
 
@@ -31,6 +37,7 @@ from IPython.external.decorator import decorator
 from IPython.zmq.session import Session
 from IPython.lib.security import passwd_check
 from IPython.utils.jsonutil import date_default
+from IPython.utils.path import filefind
 
 try:
     from docutils.core import publish_string
@@ -736,3 +743,138 @@ class RSTHandler(AuthenticatedHandler):
         self.finish(html)
 
 
+class FileFindHandler(web.StaticFileHandler):
+    """subclass of StaticFileHandler for serving files from a search path"""
+    
+    _static_paths = {}
+    
+    def initialize(self, path, default_filename=None):
+        self.roots = tuple(
+            os.path.abspath(os.path.expanduser(p)) + os.path.sep for p in path
+        )
+        self.default_filename = default_filename
+    
+    @classmethod
+    def locate_file(cls, path, roots):
+        """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:
+                # empty string should always give exists=False
+                return ''
+        
+            # os.path.abspath strips a trailing /
+            # it needs to be temporarily added back for requests to root/
+            if not (abspath + os.path.sep).startswith(roots):
+                raise web.HTTPError(403, "%s is not in root static directory", path)
+        
+            cls._static_paths[path] = abspath
+            return abspath
+    
+    def get(self, path, include_body=True):
+        path = self.parse_url_path(path)
+        abspath = self.locate_file(path, self.roots)
+        
+        # from here on, this method is unchanged from the parent:
+        # other than using web.HTTPError instead of just HTTPError
+        
+        if os.path.isdir(abspath) and self.default_filename is not None:
+            # need to look at the request.path here for when path is empty
+            # but there is some prefix to the path that was already
+            # trimmed by the routing
+            if not self.request.path.endswith("/"):
+                self.redirect(self.request.path + "/")
+                return
+            abspath = os.path.join(abspath, self.default_filename)
+        if not os.path.exists(abspath):
+            raise web.HTTPError(404)
+        if not os.path.isfile(abspath):
+            raise web.HTTPError(403, "%s is not a file", path)
+
+        stat_result = os.stat(abspath)
+        modified = datetime.datetime.fromtimestamp(stat_result[stat.ST_MTIME])
+
+        self.set_header("Last-Modified", modified)
+
+        mime_type, encoding = mimetypes.guess_type(abspath)
+        if mime_type:
+            self.set_header("Content-Type", mime_type)
+
+        cache_time = self.get_cache_time(path, modified, mime_type)
+
+        if cache_time > 0:
+            self.set_header("Expires", datetime.datetime.utcnow() + \
+                                       datetime.timedelta(seconds=cache_time))
+            self.set_header("Cache-Control", "max-age=" + str(cache_time))
+        else:
+            self.set_header("Cache-Control", "public")
+
+        self.set_extra_headers(path)
+
+        # Check the If-Modified-Since, and don't send the result if the
+        # content has not been modified
+        ims_value = self.request.headers.get("If-Modified-Since")
+        if ims_value is not None:
+            date_tuple = email.utils.parsedate(ims_value)
+            if_since = datetime.datetime.fromtimestamp(time.mktime(date_tuple))
+            if if_since >= modified:
+                self.set_status(304)
+                return
+
+        with open(abspath, "rb") as file:
+            data = file.read()
+            hasher = hashlib.sha1()
+            hasher.update(data)
+            self.set_header("Etag", '"%s"' % hasher.hexdigest())
+            if include_body:
+                self.write(data)
+            else:
+                assert self.request.method == "HEAD"
+                self.set_header("Content-Length", len(data))
+
+    @classmethod
+    def get_version(cls, settings, path):
+        """Generate the version string to be used in static URLs.
+
+        This method may be overridden in subclasses (but note that it
+        is a class method rather than a static method).  The default
+        implementation uses a hash of the file's contents.
+
+        ``settings`` is the `Application.settings` dictionary and ``path``
+        is the relative location of the requested asset on the filesystem.
+        The returned value should be a string, or ``None`` if no version
+        could be determined.
+        """
+        # begin subclass override:
+        static_path = settings['static_path']
+        roots = tuple(
+            os.path.abspath(os.path.expanduser(p)) + os.path.sep for p in static_path
+        )
+
+        try:
+            abs_path = filefind(path, roots)
+        except Exception:
+            logging.error("Could not find static file %r", path)
+            return None
+        
+        # end subclass override
+        
+        with cls._lock:
+            hashes = cls._static_hashes
+            if abs_path not in hashes:
+                try:
+                    f = open(abs_path, "rb")
+                    hashes[abs_path] = hashlib.md5(f.read()).hexdigest()
+                    f.close()
+                except Exception:
+                    logging.error("Could not open static file %r", path)
+                    hashes[abs_path] = None
+            hsh = hashes.get(abs_path)
+            if hsh:
+                return hsh[:5]
+        return None
+
+