"""
Custom template loaders for Duck.
"""
import os
from functools import lru_cache
from typing import (
List,
Optional,
Tuple,
Generator,
Callable,
)
from jinja2.loaders import BaseLoader as Jinja2BaseLoader
from django.template.loaders.base import Loader as DjangoBaseLoader
from duck.routes import (
Blueprint,
BlueprintJoinPathError,
BlueprintJoinPathNameNoMatch,
blueprint_joinpath,
)
from duck.settings import SETTINGS
from duck.utils.path import joinpaths
[docs]
class BaseLoader:
"""
Base Loader class.
"""
[docs]
def blueprint_template_dirs(self) -> Generator[Tuple[Blueprint, str], None, None]:
"""
Returns a generator for the template directories for all blueprints.
"""
from duck.settings.loaded import SettingsLoaded
for blueprint in SettingsLoaded.BLUEPRINTS:
if blueprint.enable_template_dir:
template_dir = joinpaths(blueprint.root_directory, blueprint.template_dir)
yield (blueprint, template_dir)
[docs]
def global_template_dirs(self) -> List[str]:
"""
Returns the global template directories for entire app scope.
"""
template_dirs = SETTINGS["TEMPLATE_DIRS"] or []
return template_dirs
[docs]
class Jinja2FileSystemLoader(BaseLoader, Jinja2BaseLoader):
"""
Custom File System Loader for Jinja2.
"""
[docs]
def get_source(self, environment, template: str) -> Tuple[str, str, Callable]:
# This is needed by jinja2
from jinja2 import TemplateNotFound
def template_found(template_path: str) -> Tuple[str, str, Callable]:
"""
Returns the appropriate data when a template is found.
"""
mtime = os.path.getmtime(template_path)
source = None
try:
with open(template_path, "r") as fd:
source = fd.read()
except FileNotFoundError:
# Template not found anymore, maybe deleted
raise TemplateNotFound(f"Template `{template}` doesn't exist anymore.")
return (source, template_path, lambda: mtime == os.path.getmtime(template_path))
# First lookup for template in global_template_dirs
global_template_dirs = self.global_template_dirs()
for template_dir in global_template_dirs:
template_path = joinpaths(template_dir, template)
if os.path.isfile(template_path):
# Template found
return template_found(template_path)
# Template not found, lookup in blueprint template dirs
original_template_name = template
for blueprint, template_dir in self.blueprint_template_dirs():
try:
template_path = blueprint_joinpath(template_dir, original_template_name, blueprint)
except (BlueprintJoinPathError, BlueprintJoinPathNameNoMatch, ValueError):
# Raised if maybe template could not be resolved.
continue
if os.path.isfile(template_path):
return template_found(template_path)
# Template not found anywhere
raise TemplateNotFound(f"Template `{template}` not found anywhere in global template dirs or blueprint template dirs.")
[docs]
class DjangoFileSystemLoader(BaseLoader, DjangoBaseLoader):
"""
Custom File System Loader for Django.
"""
[docs]
def get_contents(self, origin):
from django.template import TemplateDoesNotExist
if os.path.isfile(origin.name):
try:
with open(origin.name, encoding=self.engine.file_charset) as fd:
contents = fd.read()
return contents
except FileNotFoundError:
# File not found anymore, may be deleted.
raise TemplateDoesNotExist(f"Template `{origin.name}` doesn't exist anymore.")
# Source not found
raise TemplateDoesNotExist(f"Source template `{origin.name}` does not exist.")
[docs]
def get_template_sources(self, template_name: str) -> Generator["Origin", None, None]:
# Must be implemented for django
# Provide all possible sources.
from django.template import Origin
# First iter in global_template_dirs
global_template_dirs = self.global_template_dirs()
for template_dir in global_template_dirs:
template_path = joinpaths(template_dir, template_name)
# Yield source
yield Origin(
name=template_path,
template_name=template_name,
loader=self,
)
# Also yield blueprint template sources
original_template_name = template_name
for blueprint, template_dir in self.blueprint_template_dirs():
try:
template_path = blueprint_joinpath(template_dir, original_template_name, blueprint)
except (BlueprintJoinPathError, BlueprintJoinPathNameNoMatch, ValueError):
# Raised if maybe template could not be resolved.
continue
# Yield source
yield Origin(
name=template_path,
template_name=template_name,
loader=self,
)
