URL escape # in notebook content paths

This avoids issues when trying to deal with Emacs auto-save files in
notebook directories, paths like #bookmarks.org#.  The notebook server
believes the hash to be the start of the fragment component of a URL.

* jupyter-rest-api.el (jupyter-api--sanitize-path): New function.
(jupyter-api--strip-slashes): Remove.
(jupyter-api-content-path): Use new function.

Author: nnicandro

jupyter-rest-api.el

@@ -894,24 +894,25 @@ available via CLIENT."
 
 ;;; Contents API
 
-;; TODO: Actually consider encoding/decoding
-;; https://jupyter-notebook.readthedocs.io/en/stable/extending/contents.html#filesystem-entities
+(autoload 'tramp-drop-volume-letter "tramp")
 
-(defun jupyter-api--strip-slashes (path)
-  (thread-last path
+(defun jupyter-api--sanitize-path (path)
+  (thread-last
+    path
+    (tramp-drop-volume-letter)
+    ;; Strip slashes
     (replace-regexp-in-string "^/+" "")
-    (replace-regexp-in-string "/+$" "")))
-
-(autoload 'tramp-drop-volume-letter "tramp")
+    (replace-regexp-in-string "/+$" "")
+    ;; Handle #
+    (string-replace "#" "%23")))
 
-;; See https://jupyter-notebook.readthedocs.io/en/stable/extending/contents.html#api-paths
+;; See https://jupyter-server.readthedocs.io/en/latest/developers/contents.html#api-paths
 (defsubst jupyter-api-content-path (file)
   "Return a sanitized path for locating FILE on a Jupyter REST server.
 Note, if FILE is not an absolute file name, it is expanded into
 one as if the `default-directory' where /."
-  (jupyter-api--strip-slashes
-   (tramp-drop-volume-letter
-    (expand-file-name (file-local-name file) "/"))))
+  (jupyter-api--sanitize-path
+   (expand-file-name (file-local-name file) "/")))
 
 (defun jupyter-api-get-file-model (client file &optional no-content type)
   "Send a request using CLIENT to get a model of FILE.