add the ability to redirect a file-looking request to a dir

if the client has requested /foo, and foo is actually a directory,
this redirects the client to /foo/

incorporealcms/pages.py

@@ -6,7 +6,7 @@ import os
 import markdown
 from flask import Blueprint, Markup, abort
 from flask import current_app as app
-from flask import render_template
+from flask import redirect, render_template
 from tzlocal import get_localzone
 
 logger = logging.getLogger(__name__)
@@ -19,6 +19,9 @@ md = markdown.Markdown(extensions=['meta', 'tables'])
 @bp.route('/<path:path>')
 def display_page(path):
     """Get the file contents of the requested path and render the file."""
+    if is_file_path_actually_dir_path(path):
+        return redirect(f'{path}/', code=301)
+
     resolved_path = resolve_page_file(path)
     logger.debug("received request for path '%s', resolved to '%s'", path, resolved_path)
     try:
@@ -52,6 +55,22 @@ def resolve_page_file(path):
     return path
 
 
+def is_file_path_actually_dir_path(path):
+    """Check if requested path which looks like a file is actually a directory.
+
+    If, for example, /foo used to be a file (foo.md) which later became a directory,
+    foo/, this returns True. Useful for when I make my structure more complicated
+    than it originally was, or if users are just weird.
+    """
+    if not path.endswith('/'):
+        logger.debug("requested path '%s' looks like a file", path)
+        if os.path.isdir(f'{app.instance_path}/pages/{path}'):
+            logger.debug("...and it's actually a dir")
+            return True
+
+    return False
+
+
 def generate_parent_navs(path):
     """Create a series of paths/links to navigate up from the given path."""
     # derive additional path/location stuff based on path