Resolve media and template files relative to component class dir (#395), thanks @JuroOravec

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Emil Stenström <emil@emilstenstrom.se>

django_components/template_loader.py

@@ -2,34 +2,84 @@
 Template loader that loads templates from each Django app's "components" directory.
 """
 
+import os
 from pathlib import Path
+from typing import Set
 
+from django.apps import apps
 from django.conf import settings
 from django.template.loaders.filesystem import Loader as FilesystemLoader
-from django.template.utils import get_app_template_dirs
+
+from django_components.logger import logger
+
+
+# Same as `Path.is_relative_to`, defined as standalone function because `Path.is_relative_to`
+# is marked for deprecation.
+def path_is_relative_to(child_path: str, parent_path: str):
+    # If the relative path doesn't start with `..`, then child is descendant of parent
+    # See https://stackoverflow.com/a/7288073/9788634
+    rel_path = os.path.relpath(child_path, parent_path)
+    return not rel_path.startswith("..")
 
 
 class Loader(FilesystemLoader):
     def get_dirs(self):
-        component_dir = "components"
-        directories = set(get_app_template_dirs(component_dir))
+        # Allow to configure from settings which dirs should be checked for components
+        if hasattr(settings, "STATICFILES_DIRS") and len(settings.STATICFILES_DIRS):
+            component_dirs = settings.STATICFILES_DIRS
+        else:
+            component_dirs = ["components"]
 
-        if hasattr(settings, "BASE_DIR"):
-            path = (Path(settings.BASE_DIR) / component_dir).resolve()
-            if path.is_dir():
-                directories.add(path)
+        logger.debug(
+            "Template loader will search for valid template dirs from following options:\n"
+            + "\n".join([f" - {str(d)}" for d in component_dirs])
+        )
 
-        if settings.SETTINGS_MODULE:
-            module_parts = settings.SETTINGS_MODULE.split(".")
-            module_path = Path(*module_parts)
+        directories: Set[Path] = set()
+        for component_dir in component_dirs:
+            curr_directories: Set[Path] = set()
 
-            if len(module_parts) > 2:
-                module_path = Path(*module_parts[:-1])
+            # For each dir in `settings.STATICFILES_DIRS`, we go over all Django apps
+            # and, for each app, check if the STATICFILES_DIRS dir is within that app dir.
+            # If so, we add the dir as a valid source.
+            # The for loop is based on Django's `get_app_template_dirs`.
+            for app_config in apps.get_app_configs():
+                if not app_config.path:
+                    continue
+                if not Path(component_dir).is_dir():
+                    continue
 
-            # Use list() for < Python 3.9
-            for parent in list(module_path.parents)[:2]:
-                path = (parent / component_dir).resolve()
+                if path_is_relative_to(component_dir, app_config.path):
+                    curr_directories.add(Path(component_dir).resolve())
+
+            if hasattr(settings, "BASE_DIR"):
+                path = (Path(settings.BASE_DIR) / component_dir).resolve()
                 if path.is_dir():
-                    directories.add(path)
+                    curr_directories.add(path)
 
+            # Add the directory that holds the settings file
+            if settings.SETTINGS_MODULE:
+                module_parts = settings.SETTINGS_MODULE.split(".")
+                module_path = Path(*module_parts)
+
+                # - If len() == 2, then path to settings file is <app_name>/<settings_file>.py
+                # - If len() > 2, then we assume that settings file is in a settings directory,
+                #   e.g. <app_name>/settings/<settings_file>.py
+                if len(module_parts) > 2:
+                    module_path = Path(*module_parts[:-1])
+
+                # Get the paths for the nested settings dir like `<app_name>/settings`,
+                # or for non-nested dir like `<app_name>`
+                #
+                # NOTE: Use list() for < Python 3.9
+                for parent in list(module_path.parents)[:2]:
+                    path = (parent / component_dir).resolve()
+                    if path.is_dir():
+                        curr_directories.add(path)
+
+            directories.update(curr_directories)
+
+        logger.debug(
+            "Template loader matched following template dirs:\n" + "\n".join([f" - {str(d)}" for d in directories])
+        )
         return list(directories)