requiremnets bump

unnecessarily duplicated now that I have div.header, and also useful for
when I start the error handling pages

incorporealcms/__init__.py

@@ -45,7 +45,10 @@ def create_app(instance_path=None, test_config=None):
         return send_from_directory(os.path.join(app.instance_path, app.config['MEDIA_DIR']),
                                    filename)
 
-    from . import pages
+    from . import error_pages, pages
     app.register_blueprint(pages.bp)
+    app.register_error_handler(400, error_pages.bad_request)
+    app.register_error_handler(404, error_pages.page_not_found)
+    app.register_error_handler(500, error_pages.internal_server_error)
 
     return app

incorporealcms/error_pages.py

@@ -0,0 +1,17 @@
+"""Error page views for 400, 404, etc."""
+from incorporealcms.lib import render
+
+
+def bad_request(error):
+    """Display 400 error messaging."""
+    return render('400.html'), 400
+
+
+def internal_server_error(error):
+    """Display 500 error messaging."""
+    return render('500.html'), 500
+
+
+def page_not_found(error):
+    """Display 404 error messaging."""
+    return render('404.html'), 404

incorporealcms/lib.py

@@ -1,6 +1,11 @@
 """Miscellaneous helper functions and whatnot."""
+import logging
+
 import markdown
 from flask import current_app as app
+from flask import make_response, render_template, request
+
+logger = logging.getLogger(__name__)
 
 
 def get_meta_str(md, key):
@@ -19,3 +24,27 @@ def init_md():
     # extensions our app depends on, like the meta extension
     return markdown.Markdown(extensions=app.config['MARKDOWN_EXTENSIONS'] + ['meta'],
                              extension_configs=app.config['MARKDOWN_EXTENSION_CONFIGS'])
+
+
+def render(template_name_or_list, **context):
+    """Wrap Flask's render_template.
+
+    * Determine the proper site theme to use in the template and provide it.
+    """
+    PAGE_STYLES = {
+        'dark': 'css/dark.css',
+        'light': 'css/light.css',
+    }
+
+    selected_style = request.args.get('style', None)
+    if selected_style:
+        user_style = selected_style
+    else:
+        user_style = request.cookies.get('user-style')
+        logger.debug("user style cookie: %s", user_style)
+    context['user_style'] = PAGE_STYLES.get(user_style, PAGE_STYLES.get(app.config['DEFAULT_PAGE_STYLE']))
+
+    resp = make_response(render_template(template_name_or_list, **context))
+    if selected_style:
+        resp.set_cookie('user-style', selected_style)
+    return resp

incorporealcms/pages.py

@@ -2,13 +2,14 @@
 import datetime
 import logging
 import os
+import re
 
 from flask import Blueprint, Markup, abort
 from flask import current_app as app
-from flask import make_response, redirect, render_template, request
+from flask import redirect, request
 from tzlocal import get_localzone
 
-from incorporealcms.lib import get_meta_str, init_md
+from incorporealcms.lib import get_meta_str, init_md, render
 
 logger = logging.getLogger(__name__)
 
@@ -19,101 +20,115 @@ bp = Blueprint('pages', __name__, url_prefix='/')
 @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)
+    try:
+        resolved_path = request_path_to_instance_resource_path(path)
         logger.debug("received request for path '%s', resolved to '%s'", path, resolved_path)
+    except PermissionError:
+        abort(400)
+    except IsADirectoryError:
+        return redirect(f'{path}/', code=301)
+    except FileNotFoundError:
+        abort(404)
+
     try:
         with app.open_instance_resource(resolved_path, 'r') as entry_file:
-            logger.debug("file '%s' found", resolved_path)
-            parent_navs = generate_parent_navs(path)
             mtime = datetime.datetime.fromtimestamp(os.path.getmtime(entry_file.name), get_localzone())
             entry = entry_file.read()
-    except FileNotFoundError:
-        logger.warning("requested path '%s' (resolved path '%s') not found!", path, resolved_path)
-        abort(404)
+    except OSError:
+        logger.exception("resolved path '%s' could not be opened!", resolved_path)
+        abort(500)
     else:
         md = init_md()
         content = Markup(md.convert(entry))
         logger.debug("file metadata: %s", md.Meta)
 
-        return render('base.html', title=get_meta_str(md, 'title'), description=get_meta_str(md, 'description'),
+        parent_navs = generate_parent_navs(resolved_path)
+
+        page_name = (get_meta_str(md, 'title') if md.Meta.get('title') else
+                     f'/{instance_resource_path_to_request_path(resolved_path)}')
+        page_title = f'{page_name} - {app.config["TITLE_SUFFIX"]}' if page_name else app.config['TITLE_SUFFIX']
+        logger.debug("title (potentially derived): %s", page_title)
+
+        return render('base.html', title=page_title, description=get_meta_str(md, 'description'),
                       image=get_meta_str(md, 'image'), base_url=request.base_url, content=content, navs=parent_navs,
                       mtime=mtime.strftime('%Y-%m-%d %H:%M:%S %Z'))
 
 
-def render(template_name_or_list, **context):
-    """Wrap Flask's render_template.
+def request_path_to_instance_resource_path(path):
+    """Turn a request URL path to the full page path.
 
-    * Determine the proper site theme to use in the template and provide it.
+    flask.Flask.open_instance_resource will open a file like /etc/hosts if you tell it to,
+    which sucks, so we do a lot of work here to make sure we have a valid request to
+    something inside the pages dir.
     """
-    PAGE_STYLES = {
-        'dark': 'css/dark.css',
-        'light': 'css/light.css',
-    }
+    # check if the path is allowed
+    base_dir = os.path.realpath(f'{app.instance_path}/pages/')
+    resolved_path = os.path.realpath(os.path.join(base_dir, path))
+    logger.debug("base_dir: %s, constructed resolved_path: %s", base_dir, resolved_path)
 
-    selected_style = request.args.get('style', None)
-    if selected_style:
-        user_style = selected_style
+    # bail if the requested real path isn't inside the base directory
+    if base_dir != os.path.commonpath((base_dir, resolved_path)):
+        logger.warning("client tried to request a path '%s' outside of the base_dir!", path)
+        raise PermissionError
+
+    # if this is a file-like requset but actually a directory, redirect the user
+    if os.path.isdir(resolved_path) and not path.endswith('/'):
+        logger.info("client requested a path '%s' that is actually a directory", path)
+        raise IsADirectoryError
+
+    # derive the proper markdown file depending on if this is a dir or file
+    if os.path.isdir(resolved_path):
+        absolute_resource = os.path.join(resolved_path, 'index.md')
     else:
-        user_style = request.cookies.get('user-style')
-        logger.debug("user style cookie: %s", user_style)
-    context['user_style'] = PAGE_STYLES.get(user_style, PAGE_STYLES.get(app.config['DEFAULT_PAGE_STYLE']))
+        absolute_resource = f'{resolved_path}.md'
 
-    resp = make_response(render_template(template_name_or_list, **context))
-    if selected_style:
-        resp.set_cookie('user-style', selected_style)
-    return resp
+    logger.info("final path = '%s' for request '%s'", absolute_resource, path)
+
+    # does the final file actually exist?
+    if not os.path.exists(absolute_resource):
+        logger.warning("requested final path '%s' does not exist!", absolute_resource)
+        raise FileNotFoundError
+
+    # we checked that the file exists via absolute path, but now we need to give the path relative to instance dir
+    return absolute_resource.replace(f'{app.instance_path}{os.path.sep}', '')
 
 
-def resolve_page_file(path):
-    """Manipulate the request path to find appropriate page file.
+def instance_resource_path_to_request_path(path):
+    """Reverse a (presumed to exist) disk path to the canonical path that would show up in a Flask route.
 
-    * convert dir requests to index files
-
-    Worth noting, Flask already does stuff like convert '/foo/../../../bar' to
-    '/bar', so we don't need to take care around file access here.
+    This does not include the leading /, so aside from the root index case, this should be
+    bidirectional.
     """
-    if path.endswith('/'):
-        path = f'{path}index'
-    path = f'pages/{path}.md'
-    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
+    return re.sub(r'^pages/', '', re.sub(r'.md$', '', re.sub(r'index.md$', '', path)))
 
 
 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
-    resolved_path = resolve_page_file(path)
-    parent_dir = os.path.dirname(resolved_path)
-    parent_path = '/'.join(path[:-1].split('/')[:-1]) + '/'
-
-    logger.debug("path: '%s'; parent path: '%s'; resolved path: '%s'; parent dir: '%s'",
-                 path, parent_path, resolved_path, parent_dir)
-
-    if path in ('index', '/'):
+    """Create a series of paths/links to navigate up from the given resource path."""
+    if path == 'pages/index.md':
+        # bail and return the title suffix (generally the domain name) as a terminal case
         return [(app.config['TITLE_SUFFIX'], '/')]
     else:
-        with app.open_instance_resource(resolved_path, 'r') as entry_file:
-            entry = entry_file.read()
+        if path.endswith('index.md'):
+            # index case: one dirname for foo/bar/index.md -> foo/bar, one for foo/bar -> foo
+            parent_resource_dir = os.path.dirname(os.path.dirname(path))
+        else:
+            # usual case: foo/buh.md -> foo
+            parent_resource_dir = os.path.dirname(path)
+
+        # generate the request path (i.e. what the link will be) for this path, and
+        # also the resource path of this parent (which is always a dir, so always index.md)
+        request_path = f'/{instance_resource_path_to_request_path(path)}'
+        parent_resource_path = os.path.join(parent_resource_dir, 'index.md')
+
+        logger.debug("resource path: '%s'; request path: '%s'; parent resource path: '%s'", path,
+                     request_path, parent_resource_path)
+
         # for issues regarding parser reuse (see lib.init_md) we reinitialize the parser here
         md = init_md()
+
+        # read the resource
+        with app.open_instance_resource(path, 'r') as entry_file:
+            entry = entry_file.read()
         _ = Markup(md.convert(entry))
-        page_name = " ".join(md.Meta.get('title')) if md.Meta.get('title') else f'/{path}'
-        return generate_parent_navs(parent_path) + [(page_name, f'/{path}')]
+        page_name = " ".join(md.Meta.get('title')) if md.Meta.get('title') else request_path
+        return generate_parent_navs(parent_resource_path) + [(page_name, request_path)]

incorporealcms/static/css/dark.css

@@ -35,13 +35,10 @@ a:hover, a:active {
 div.header {
     background: #222;
     border-bottom: 1px solid #222;
-}
-
-div.nav, div.styles {
     color: #BBB;
 }
 
-div.nav a, div.styles a {
+div.header a {
     color: #BBB;
 }
 

incorporealcms/static/css/light.css

@@ -35,13 +35,10 @@ a:hover, a:active {
 div.header {
     background: #EEE;
     border-bottom: 1px solid #CCC;
-}
-
-div.nav, div.styles {
     color: #666;
 }
 
-div.nav a, div.styles a {
+div.header a {
     color: #666;
 }
 

incorporealcms/static/css/style.css

@@ -66,14 +66,11 @@ a:active {
 div.header {
     display: flex;
     justify-content: space-between;
-}
-
-div.nav, div.styles {
     font-size: 0.75em;
     padding: 0.25em 0.5em;
 }
 
-div.nav a, div.styles a {
+div.header a {
     border-bottom: none;
 }
 

incorporealcms/templates/400.html

@@ -0,0 +1,14 @@
+{% extends "base.html" %}
+
+{% block header %}
+<div class="header">
+    <a href="/">{{ config.TITLE_SUFFIX }}</a>
+</div>
+{% endblock %}
+
+{% block body %}
+<div class="content">
+    <h1>BAD REQUEST</h1>
+    <p>You're doing something you're not supposed to. Stop it?</p>
+</div>
+{% endblock %}

incorporealcms/templates/404.html

@@ -0,0 +1,19 @@
+{% extends "base.html" %}
+
+{% block header %}
+<div class="header">
+    <a href="/">{{ config.TITLE_SUFFIX }}</a>
+</div>
+{% endblock %}
+
+{% block body %}
+<div class="content">
+    <h1>NOT FOUND</h1>
+    <p>Sorry, <b><tt>{{ request.path }}</tt></b> does not seem to exist, at least not anymore.</p>
+    <p>It's possible you followed a dead link on this site, in which case I would appreciate it if you could email me via:
+    bss @ &lt;this domain&gt; and I can take a look. I make an effort to symlink old content to its new location,
+    so old links and URLs should, generally speaking, work.</p>
+    <p>Otherwise, I suggest you go <a href="/">to the index</a> and navigate your way (hopefully) to what
+    you're looking for.</p>
+</div>
+{% endblock %}

incorporealcms/templates/500.html

@@ -0,0 +1,14 @@
+{% extends "base.html" %}
+
+{% block header %}
+<div class="header">
+    <a href="/">{{ config.TITLE_SUFFIX }}</a>
+</div>
+{% endblock %}
+
+{% block body %}
+<div class="content">
+    <h1>INTERNAL SERVER ERROR</h1>
+    <p>Something bad happened! Please email me at bss @ &lt;this domain&gt; and tell me what happened.</p>
+</div>
+{% endblock %}

incorporealcms/templates/base.html

@@ -1,6 +1,6 @@
 <!doctype html>
 <html lang="en">
-<title>{{ title }}{% if title %} - {% endif %}{{ config.TITLE_SUFFIX }}</title>
+<title>{{ title }}</title>
 {% if title %}<meta property="og:title" content="{{ title }}">{% endif %}
 {% if description %}<meta property="og:description" content="{{ description }}">{% endif %}
 {% if image %}<meta property="og:image" content="{{ image }}">{% endif %}
@@ -12,6 +12,7 @@
 <link rel="icon" href="{{ url_for('static', filename='img/favicon.png') }}">
 
 <div class="site-wrap">
+    {% block header %}
     <div class="header">
         <div class="nav">
             {% for nav in navs %}
@@ -24,11 +25,14 @@
             <a href="?style=light">[light]</a>
         </div>
     </div>
+    {% endblock %}
+    {% block body %}
     <div class="content">
         {{ content }}
     </div>
     <footer>
         <i>Last modified: {{ mtime }}</i>
     </footer>
+    {% endblock %}
 </div>
 </html>

requirements/requirements-dev.txt

@@ -10,13 +10,13 @@ attrs==20.3.0
     # via pytest
 bandit==1.6.2
     # via -r requirements/requirements-dev.in
-bleach==3.2.2
+bleach==3.3.0
     # via mdx-linkify
 click==7.1.2
     # via
     #   flask
     #   pip-tools
-coverage==5.3.1
+coverage==5.4
     # via pytest-cov
 distlib==0.3.1
     # via virtualenv
@@ -55,7 +55,7 @@ flask==1.1.2
     # via -r requirements/requirements.in
 gitdb==4.0.5
     # via gitpython
-gitpython==3.1.12
+gitpython==3.1.13
     # via bandit
 iniconfig==1.1.1
     # via pytest
@@ -63,7 +63,7 @@ isort==5.7.0
     # via flake8-isort
 itsdangerous==1.1.0
     # via flask
-jinja2==2.11.2
+jinja2==2.11.3
     # via flask
 markdown==3.3.3
     # via
@@ -75,7 +75,7 @@ mccabe==0.6.1
     # via flake8
 mdx-linkify==2.1
     # via -r requirements/requirements.in
-packaging==20.8
+packaging==20.9
     # via
     #   bleach
     #   pytest
@@ -102,11 +102,11 @@ pyparsing==2.4.7
     # via packaging
 pytest-cov==2.11.1
     # via -r requirements/requirements-dev.in
-pytest==6.2.1
+pytest==6.2.2
     # via
     #   -r requirements/requirements-dev.in
     #   pytest-cov
-pytz==2020.5
+pytz==2021.1
     # via tzlocal
 pyyaml==5.4.1
     # via bandit
@@ -116,7 +116,7 @@ six==1.15.0
     #   bleach
     #   tox
     #   virtualenv
-smmap==3.0.4
+smmap==3.0.5
     # via gitdb
 snowballstemmer==2.1.0
     # via pydocstyle
@@ -130,7 +130,7 @@ toml==0.10.2
     #   tox
 tox-wheel==0.6.0
     # via -r requirements/requirements-dev.in
-tox==3.21.2
+tox==3.22.0
     # via
     #   -r requirements/requirements-dev.in
     #   tox-wheel
@@ -138,7 +138,7 @@ tzlocal==2.1
     # via -r requirements/requirements.in
 versioneer==0.19
     # via -r requirements/requirements-dev.in
-virtualenv==20.4.0
+virtualenv==20.4.2
     # via tox
 webencodings==0.5.1
     # via bleach

requirements/requirements.txt

@@ -4,7 +4,7 @@
 #
 #    pip-compile --output-file=requirements/requirements.txt requirements/requirements.in
 #
-bleach==3.2.2
+bleach==3.3.0
     # via mdx-linkify
 click==7.1.2
     # via flask
@@ -12,7 +12,7 @@ flask==1.1.2
     # via -r requirements/requirements.in
 itsdangerous==1.1.0
     # via flask
-jinja2==2.11.2
+jinja2==2.11.3
     # via flask
 markdown==3.3.3
     # via
@@ -22,11 +22,11 @@ markupsafe==1.1.1
     # via jinja2
 mdx-linkify==2.1
     # via -r requirements/requirements.in
-packaging==20.8
+packaging==20.9
     # via bleach
 pyparsing==2.4.7
     # via packaging
-pytz==2020.5
+pytz==2021.1
     # via tzlocal
 six==1.15.0
     # via bleach

tests/functional_tests.py

@@ -10,9 +10,30 @@ def test_page_that_exists(client):
 
 
 def test_page_that_doesnt_exist(client):
-    """Test that the app returns 404 for nonsense requests."""
+    """Test that the app returns 404 for nonsense requests and they use my error page."""
     response = client.get('/ohuesthaoeusth')
     assert response.status_code == 404
+    assert b'<b><tt>/ohuesthaoeusth</tt></b> does not seem to exist' in response.data
+
+
+def test_files_outside_pages_do_not_get_served(client):
+    """Test that page pathing doesn't break out of the instance/pages/ dir, and the error uses my error page."""
+    response = client.get('/../unreachable')
+    assert response.status_code == 400
+    assert b'You\'re doing something you\'re not supposed to. Stop it?' in response.data
+
+
+def test_internal_server_error_serves_error_page(client):
+    """Test that various exceptions serve up the 500 page."""
+    response = client.get('/actually-a-png')
+    assert response.status_code == 500
+    assert b'INTERNAL SERVER ERROR' in response.data
+
+
+def test_weird_paths_do_not_get_served(client):
+    """Test that we clean up requests as desired."""
+    response = client.get('/../../')
+    assert response.status_code == 400
 
 
 def test_page_with_title_metadata(client):
@@ -26,19 +47,41 @@ def test_page_without_title_metadata(client):
     """Test that a page without title metadata gets the default title."""
     response = client.get('/no-title')
     assert response.status_code == 200
-    assert b'<title>incorporeal.org</title>' in response.data
-    assert b'<h1>this page doesn\'t have a title!</h1>' in response.data
+    assert b'<title>/no-title - incorporeal.org</title>' in response.data
+
+
+def test_page_in_subdir_without_title_metadata(client):
+    """Test that the title-less page display is as expected."""
+    response = client.get('/subdir//page-no-title')
+    assert response.status_code == 200
+    assert b'<title>/subdir/page-no-title - incorporeal.org</title>' in response.data
 
 
 def test_page_with_card_metadata(client):
     """Test that a page with opengraph metadata."""
     response = client.get('/more-metadata')
     assert response.status_code == 200
-    assert b'<meta property="og:title" content="title for the page">' in response.data
+    assert b'<meta property="og:title" content="title for the page - incorporeal.org">' in response.data
     assert b'<meta property="og:description" content="description of this page made even longer">' in response.data
     assert b'<meta property="og:image" content="http://buh.com/test.img">' in response.data
 
 
+def test_page_with_card_title_even_when_no_metadata(client):
+    """Test that a page without metadata still has a card with the derived title."""
+    response = client.get('/no-title')
+    assert response.status_code == 200
+    assert b'<meta property="og:title" content="/no-title - incorporeal.org">' in response.data
+    assert b'<meta property="og:description"' not in response.data
+    assert b'<meta property="og:image"' not in response.data
+
+
+def test_page_with_forced_empty_title_just_shows_suffix(client):
+    """Test that if a page specifies a blank Title meta tag explicitly, only the suffix is used in the title."""
+    response = client.get('/forced-no-title')
+    assert response.status_code == 200
+    assert b'<title>incorporeal.org</title>' in response.data
+
+
 def test_page_has_modified_timestamp(client):
     """Test that pages have modified timestamps in them."""
     response = client.get('/')

tests/instance/pages/forced-no-title.md

@@ -0,0 +1,3 @@
+Title:
+
+some words are here

tests/instance/pages/subdir/page-no-title.md

@@ -0,0 +1 @@
+this is just a page

tests/instance/unreachable.md

@@ -0,0 +1 @@
+this file exists but the app should not serve it.

tests/test_factory.py

@@ -50,7 +50,7 @@ def test_title_override():
     client = app.test_client()
     response = client.get('/no-title')
     assert response.status_code == 200
-    assert b'<title>suou.net</title>' in response.data
+    assert b'<title>/no-title - suou.net</title>' in response.data
 
 
 def test_media_file_access(client):

tests/test_pages.py

@@ -1,83 +1,40 @@
 """Unit test helper methods."""
+import pytest
 from werkzeug.http import dump_cookie
 
-from incorporealcms.pages import generate_parent_navs, is_file_path_actually_dir_path, render, resolve_page_file
-
-
-def test_resolve_page_file_dir_to_index():
-    """Test that a request to a directory path results in the dir's index.md."""
-    assert resolve_page_file('foo/') == 'pages/foo/index.md'
-
-
-def test_resolve_page_file_subdir_to_index():
-    """Test that a request to a dir's subdir path results in the subdir's index.md."""
-    assert resolve_page_file('foo/bar/') == 'pages/foo/bar/index.md'
-
-
-def test_resolve_page_file_other_requests_fine():
-    """Test that a request to non-dir path results in a Markdown file."""
-    assert resolve_page_file('foo/baz') == 'pages/foo/baz.md'
+from incorporealcms.pages import (generate_parent_navs, instance_resource_path_to_request_path, render,
+                                  request_path_to_instance_resource_path)
 
 
 def test_generate_page_navs_index(app):
     """Test that the index page has navs to the root (itself)."""
     with app.app_context():
-        assert generate_parent_navs('/') == [('incorporeal.org', '/')]
-
-
-def test_generate_page_navs_alternate_index(app):
-    """Test that the index page (as a page, not a path) also has navs only to the root (by path)."""
-    with app.app_context():
-        assert generate_parent_navs('index') == [('incorporeal.org', '/')]
+        assert generate_parent_navs('pages/index.md') == [('incorporeal.org', '/')]
 
 
 def test_generate_page_navs_subdir_index(app):
     """Test that dir pages have navs to the root and themselves."""
     with app.app_context():
-        assert generate_parent_navs('subdir/') == [('incorporeal.org', '/'), ('/subdir/', '/subdir/')]
+        assert generate_parent_navs('pages/subdir/index.md') == [('incorporeal.org', '/'), ('/subdir/', '/subdir/')]
 
 
 def test_generate_page_navs_subdir_real_page(app):
     """Test that real pages have navs to the root, their parent, and themselves."""
     with app.app_context():
-        assert generate_parent_navs('subdir/page') == [('incorporeal.org', '/'), ('/subdir/', '/subdir/'),
+        assert generate_parent_navs('pages/subdir/page.md') == [('incorporeal.org', '/'), ('/subdir/', '/subdir/'),
                                                                 ('Page', '/subdir/page')]
 
 
 def test_generate_page_navs_subdir_with_title_parsing_real_page(app):
     """Test that title metadata is used in the nav text."""
     with app.app_context():
-        assert generate_parent_navs('subdir-with-title/page') == [
+        assert generate_parent_navs('pages/subdir-with-title/page.md') == [
             ('incorporeal.org', '/'),
             ('SUB!', '/subdir-with-title/'),
             ('/subdir-with-title/page', '/subdir-with-title/page')
         ]
 
 
-def test_is_file_path_actually_dir_path_valid_file_is_yes(app):
-    """Test that a file request for what's actually a directory is detected as such."""
-    with app.app_context():
-        assert is_file_path_actually_dir_path('/subdir')
-
-
-def test_is_file_path_actually_dir_path_valid_dir_is_no(app):
-    """Test that a directory request is still a directory request."""
-    with app.app_context():
-        assert not is_file_path_actually_dir_path('/subdir/')
-
-
-def test_is_file_path_actually_dir_path_nonsense_file_is_no(app):
-    """Test that requests to nonsense file-looking paths aren't treated as dirs."""
-    with app.app_context():
-        assert not is_file_path_actually_dir_path('/antphnathpnthapnthsnthax')
-
-
-def test_is_file_path_actually_dir_path_nonsense_dir_is_no(app):
-    """Test that a directory request is a directory request even if the dir doesn't exist."""
-    with app.app_context():
-        assert not is_file_path_actually_dir_path('/antphnathpnthapnthsnthax/')
-
-
 def test_render_with_user_dark_theme(app):
     """Test that a request with the dark theme selected renders the dark theme."""
     cookie = dump_cookie("user-style", 'dark')
@@ -98,3 +55,110 @@ def test_render_with_no_user_theme(app):
     with app.test_request_context():
         assert b'light.css' in render('base.html').data
         assert b'dark.css' not in render('base.html').data
+
+
+def test_request_path_to_instance_resource_path(app):
+    """Test a normal URL request is transformed into the file path."""
+    with app.test_request_context():
+        assert request_path_to_instance_resource_path('index') == 'pages/index.md'
+
+
+def test_request_path_to_instance_resource_path_direct_file(app):
+    """Test a normal URL request is transformed into the file path."""
+    with app.test_request_context():
+        assert request_path_to_instance_resource_path('no-title') == 'pages/no-title.md'
+
+
+def test_request_path_to_instance_resource_path_in_subdir(app):
+    """Test a normal URL request is transformed into the file path."""
+    with app.test_request_context():
+        assert request_path_to_instance_resource_path('subdir/page') == 'pages/subdir/page.md'
+
+
+def test_request_path_to_instance_resource_path_subdir_index(app):
+    """Test a normal URL request is transformed into the file path."""
+    with app.test_request_context():
+        assert request_path_to_instance_resource_path('subdir/') == 'pages/subdir/index.md'
+
+
+def test_request_path_to_instance_resource_path_relatives_walked(app):
+    """Test a normal URL request is transformed into the file path."""
+    with app.test_request_context():
+        assert (request_path_to_instance_resource_path('subdir/more-subdir/../../more-metadata') ==
+                'pages/more-metadata.md')
+
+
+def test_request_path_to_instance_resource_path_relatives_walked_indexes_work_too(app):
+    """Test a normal URL request is transformed into the file path."""
+    with app.test_request_context():
+        assert request_path_to_instance_resource_path('subdir/more-subdir/../../') == 'pages/index.md'
+
+
+def test_request_path_to_instance_resource_path_relatives_walked_into_subdirs_also_fine(app):
+    """Test a normal URL request is transformed into the file path."""
+    with app.test_request_context():
+        assert request_path_to_instance_resource_path('subdir/more-subdir/../../subdir/page') == 'pages/subdir/page.md'
+
+
+def test_request_path_to_instance_resource_path_permission_error_on_ref_above_pages(app):
+    """Test that attempts to get above the base dir ("/../../foo") fail."""
+    with app.test_request_context():
+        with pytest.raises(PermissionError):
+            assert request_path_to_instance_resource_path('../unreachable')
+
+
+def test_request_path_to_instance_resource_path_isadirectory_on_file_like_req_for_dir(app):
+    """Test that a request for e.g. '/foo' when foo is a dir indicate to redirect."""
+    with app.test_request_context():
+        with pytest.raises(IsADirectoryError):
+            assert request_path_to_instance_resource_path('subdir')
+
+
+def test_request_path_to_instance_resource_path_nonexistant_file_errors(app):
+    """Test that a request for something not on disk errors."""
+    with app.test_request_context():
+        with pytest.raises(FileNotFoundError):
+            assert request_path_to_instance_resource_path('nthanpthpnh')
+
+
+def test_request_path_to_instance_resource_path_absolute_file_errors(app):
+    """Test that a request for something not on disk errors."""
+    with app.test_request_context():
+        with pytest.raises(PermissionError):
+            assert request_path_to_instance_resource_path('/etc/hosts')
+
+
+def test_instance_resource_path_to_request_path_on_index(app):
+    """Test index.md -> /."""
+    with app.test_request_context():
+        assert instance_resource_path_to_request_path('index.md') == ''
+
+
+def test_instance_resource_path_to_request_path_on_page(app):
+    """Test no-title.md -> no-title."""
+    with app.test_request_context():
+        assert instance_resource_path_to_request_path('no-title.md') == 'no-title'
+
+
+def test_instance_resource_path_to_request_path_on_subdir(app):
+    """Test subdir/index.md -> subdir/."""
+    with app.test_request_context():
+        assert instance_resource_path_to_request_path('subdir/index.md') == 'subdir/'
+
+
+def test_instance_resource_path_to_request_path_on_subdir_and_page(app):
+    """Test subdir/page.md -> subdir/page."""
+    with app.test_request_context():
+        assert instance_resource_path_to_request_path('subdir/page.md') == 'subdir/page'
+
+
+def test_request_resource_request_root(app):
+    """Test that a request can resolve to a resource and back to a request."""
+    with app.test_request_context():
+        instance_resource_path_to_request_path(request_path_to_instance_resource_path('index')) == ''
+
+
+def test_request_resource_request_page(app):
+    """Test that a request can resolve to a resource and back to a request."""
+    with app.test_request_context():
+        instance_resource_path_to_request_path(request_path_to_instance_resource_path('no-title')) == 'no-title'