668 lines
23 KiB
Python
668 lines
23 KiB
Python
"""API and implementations for loading templates from different data
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sources.
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"""
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import importlib.util
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import os
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import posixpath
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import sys
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import typing as t
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import weakref
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import zipimport
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from collections import abc
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from hashlib import sha1
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from importlib import import_module
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from types import ModuleType
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from .exceptions import TemplateNotFound
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from .utils import internalcode
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if t.TYPE_CHECKING:
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from .environment import Environment
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from .environment import Template
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def split_template_path(template: str) -> t.List[str]:
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"""Split a path into segments and perform a sanity check. If it detects
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'..' in the path it will raise a `TemplateNotFound` error.
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"""
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pieces = []
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for piece in template.split("/"):
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if (
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os.path.sep in piece
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or (os.path.altsep and os.path.altsep in piece)
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or piece == os.path.pardir
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):
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raise TemplateNotFound(template)
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elif piece and piece != ".":
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pieces.append(piece)
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return pieces
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class BaseLoader:
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"""Baseclass for all loaders. Subclass this and override `get_source` to
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implement a custom loading mechanism. The environment provides a
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`get_template` method that calls the loader's `load` method to get the
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:class:`Template` object.
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A very basic example for a loader that looks up templates on the file
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system could look like this::
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from jinja2 import BaseLoader, TemplateNotFound
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from os.path import join, exists, getmtime
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class MyLoader(BaseLoader):
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def __init__(self, path):
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self.path = path
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def get_source(self, environment, template):
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path = join(self.path, template)
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if not exists(path):
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raise TemplateNotFound(template)
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mtime = getmtime(path)
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with open(path) as f:
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source = f.read()
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return source, path, lambda: mtime == getmtime(path)
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"""
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#: if set to `False` it indicates that the loader cannot provide access
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#: to the source of templates.
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#:
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#: .. versionadded:: 2.4
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has_source_access = True
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def get_source(
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self, environment: "Environment", template: str
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) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]:
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"""Get the template source, filename and reload helper for a template.
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It's passed the environment and template name and has to return a
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tuple in the form ``(source, filename, uptodate)`` or raise a
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`TemplateNotFound` error if it can't locate the template.
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The source part of the returned tuple must be the source of the
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template as a string. The filename should be the name of the
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file on the filesystem if it was loaded from there, otherwise
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``None``. The filename is used by Python for the tracebacks
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if no loader extension is used.
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The last item in the tuple is the `uptodate` function. If auto
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reloading is enabled it's always called to check if the template
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changed. No arguments are passed so the function must store the
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old state somewhere (for example in a closure). If it returns `False`
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the template will be reloaded.
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"""
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if not self.has_source_access:
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raise RuntimeError(
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f"{type(self).__name__} cannot provide access to the source"
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)
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raise TemplateNotFound(template)
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def list_templates(self) -> t.List[str]:
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"""Iterates over all templates. If the loader does not support that
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it should raise a :exc:`TypeError` which is the default behavior.
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"""
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raise TypeError("this loader cannot iterate over all templates")
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@internalcode
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def load(
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self,
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environment: "Environment",
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name: str,
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globals: t.Optional[t.MutableMapping[str, t.Any]] = None,
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) -> "Template":
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"""Loads a template. This method looks up the template in the cache
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or loads one by calling :meth:`get_source`. Subclasses should not
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override this method as loaders working on collections of other
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loaders (such as :class:`PrefixLoader` or :class:`ChoiceLoader`)
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will not call this method but `get_source` directly.
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"""
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code = None
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if globals is None:
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globals = {}
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# first we try to get the source for this template together
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# with the filename and the uptodate function.
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source, filename, uptodate = self.get_source(environment, name)
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# try to load the code from the bytecode cache if there is a
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# bytecode cache configured.
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bcc = environment.bytecode_cache
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if bcc is not None:
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bucket = bcc.get_bucket(environment, name, filename, source)
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code = bucket.code
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# if we don't have code so far (not cached, no longer up to
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# date) etc. we compile the template
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if code is None:
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code = environment.compile(source, name, filename)
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# if the bytecode cache is available and the bucket doesn't
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# have a code so far, we give the bucket the new code and put
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# it back to the bytecode cache.
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if bcc is not None and bucket.code is None:
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bucket.code = code
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bcc.set_bucket(bucket)
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return environment.template_class.from_code(
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environment, code, globals, uptodate
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)
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class FileSystemLoader(BaseLoader):
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"""Load templates from a directory in the file system.
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The path can be relative or absolute. Relative paths are relative to
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the current working directory.
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.. code-block:: python
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loader = FileSystemLoader("templates")
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A list of paths can be given. The directories will be searched in
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order, stopping at the first matching template.
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.. code-block:: python
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loader = FileSystemLoader(["/override/templates", "/default/templates"])
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:param searchpath: A path, or list of paths, to the directory that
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contains the templates.
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:param encoding: Use this encoding to read the text from template
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files.
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:param followlinks: Follow symbolic links in the path.
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.. versionchanged:: 2.8
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Added the ``followlinks`` parameter.
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"""
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def __init__(
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self,
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searchpath: t.Union[
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str, "os.PathLike[str]", t.Sequence[t.Union[str, "os.PathLike[str]"]]
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],
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encoding: str = "utf-8",
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followlinks: bool = False,
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) -> None:
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if not isinstance(searchpath, abc.Iterable) or isinstance(searchpath, str):
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searchpath = [searchpath]
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self.searchpath = [os.fspath(p) for p in searchpath]
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self.encoding = encoding
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self.followlinks = followlinks
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def get_source(
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self, environment: "Environment", template: str
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) -> t.Tuple[str, str, t.Callable[[], bool]]:
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pieces = split_template_path(template)
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for searchpath in self.searchpath:
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# Use posixpath even on Windows to avoid "drive:" or UNC
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# segments breaking out of the search directory.
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filename = posixpath.join(searchpath, *pieces)
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if os.path.isfile(filename):
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break
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else:
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raise TemplateNotFound(template)
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with open(filename, encoding=self.encoding) as f:
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contents = f.read()
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mtime = os.path.getmtime(filename)
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def uptodate() -> bool:
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try:
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return os.path.getmtime(filename) == mtime
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except OSError:
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return False
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# Use normpath to convert Windows altsep to sep.
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return contents, os.path.normpath(filename), uptodate
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def list_templates(self) -> t.List[str]:
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found = set()
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for searchpath in self.searchpath:
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walk_dir = os.walk(searchpath, followlinks=self.followlinks)
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for dirpath, _, filenames in walk_dir:
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for filename in filenames:
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template = (
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os.path.join(dirpath, filename)[len(searchpath) :]
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.strip(os.path.sep)
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.replace(os.path.sep, "/")
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)
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if template[:2] == "./":
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template = template[2:]
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if template not in found:
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found.add(template)
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return sorted(found)
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class PackageLoader(BaseLoader):
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"""Load templates from a directory in a Python package.
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:param package_name: Import name of the package that contains the
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template directory.
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:param package_path: Directory within the imported package that
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contains the templates.
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:param encoding: Encoding of template files.
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The following example looks up templates in the ``pages`` directory
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within the ``project.ui`` package.
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.. code-block:: python
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loader = PackageLoader("project.ui", "pages")
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Only packages installed as directories (standard pip behavior) or
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zip/egg files (less common) are supported. The Python API for
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introspecting data in packages is too limited to support other
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installation methods the way this loader requires.
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There is limited support for :pep:`420` namespace packages. The
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template directory is assumed to only be in one namespace
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contributor. Zip files contributing to a namespace are not
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supported.
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.. versionchanged:: 3.0
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No longer uses ``setuptools`` as a dependency.
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.. versionchanged:: 3.0
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Limited PEP 420 namespace package support.
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"""
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def __init__(
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self,
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package_name: str,
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package_path: "str" = "templates",
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encoding: str = "utf-8",
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) -> None:
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package_path = os.path.normpath(package_path).rstrip(os.path.sep)
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# normpath preserves ".", which isn't valid in zip paths.
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if package_path == os.path.curdir:
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package_path = ""
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elif package_path[:2] == os.path.curdir + os.path.sep:
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package_path = package_path[2:]
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self.package_path = package_path
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self.package_name = package_name
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self.encoding = encoding
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# Make sure the package exists. This also makes namespace
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# packages work, otherwise get_loader returns None.
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import_module(package_name)
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spec = importlib.util.find_spec(package_name)
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assert spec is not None, "An import spec was not found for the package."
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loader = spec.loader
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assert loader is not None, "A loader was not found for the package."
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self._loader = loader
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self._archive = None
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template_root = None
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if isinstance(loader, zipimport.zipimporter):
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self._archive = loader.archive
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pkgdir = next(iter(spec.submodule_search_locations)) # type: ignore
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template_root = os.path.join(pkgdir, package_path).rstrip(os.path.sep)
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else:
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roots: t.List[str] = []
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# One element for regular packages, multiple for namespace
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# packages, or None for single module file.
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if spec.submodule_search_locations:
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roots.extend(spec.submodule_search_locations)
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# A single module file, use the parent directory instead.
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elif spec.origin is not None:
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roots.append(os.path.dirname(spec.origin))
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for root in roots:
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root = os.path.join(root, package_path)
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if os.path.isdir(root):
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template_root = root
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break
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if template_root is None:
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raise ValueError(
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f"The {package_name!r} package was not installed in a"
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" way that PackageLoader understands."
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)
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self._template_root = template_root
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def get_source(
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self, environment: "Environment", template: str
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) -> t.Tuple[str, str, t.Optional[t.Callable[[], bool]]]:
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# Use posixpath even on Windows to avoid "drive:" or UNC
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# segments breaking out of the search directory. Use normpath to
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# convert Windows altsep to sep.
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p = os.path.normpath(
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posixpath.join(self._template_root, *split_template_path(template))
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)
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up_to_date: t.Optional[t.Callable[[], bool]]
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if self._archive is None:
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# Package is a directory.
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if not os.path.isfile(p):
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raise TemplateNotFound(template)
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with open(p, "rb") as f:
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source = f.read()
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mtime = os.path.getmtime(p)
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def up_to_date() -> bool:
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return os.path.isfile(p) and os.path.getmtime(p) == mtime
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else:
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# Package is a zip file.
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try:
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source = self._loader.get_data(p) # type: ignore
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except OSError as e:
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raise TemplateNotFound(template) from e
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# Could use the zip's mtime for all template mtimes, but
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# would need to safely reload the module if it's out of
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# date, so just report it as always current.
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up_to_date = None
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return source.decode(self.encoding), p, up_to_date
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def list_templates(self) -> t.List[str]:
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results: t.List[str] = []
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if self._archive is None:
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# Package is a directory.
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offset = len(self._template_root)
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for dirpath, _, filenames in os.walk(self._template_root):
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dirpath = dirpath[offset:].lstrip(os.path.sep)
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results.extend(
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os.path.join(dirpath, name).replace(os.path.sep, "/")
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for name in filenames
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)
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else:
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if not hasattr(self._loader, "_files"):
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raise TypeError(
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"This zip import does not have the required"
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" metadata to list templates."
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)
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# Package is a zip file.
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prefix = (
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self._template_root[len(self._archive) :].lstrip(os.path.sep)
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+ os.path.sep
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)
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offset = len(prefix)
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for name in self._loader._files.keys():
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# Find names under the templates directory that aren't directories.
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if name.startswith(prefix) and name[-1] != os.path.sep:
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results.append(name[offset:].replace(os.path.sep, "/"))
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results.sort()
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return results
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class DictLoader(BaseLoader):
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"""Loads a template from a Python dict mapping template names to
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template source. This loader is useful for unittesting:
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>>> loader = DictLoader({'index.html': 'source here'})
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Because auto reloading is rarely useful this is disabled per default.
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"""
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def __init__(self, mapping: t.Mapping[str, str]) -> None:
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self.mapping = mapping
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def get_source(
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self, environment: "Environment", template: str
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) -> t.Tuple[str, None, t.Callable[[], bool]]:
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if template in self.mapping:
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source = self.mapping[template]
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return source, None, lambda: source == self.mapping.get(template)
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raise TemplateNotFound(template)
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def list_templates(self) -> t.List[str]:
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return sorted(self.mapping)
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class FunctionLoader(BaseLoader):
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"""A loader that is passed a function which does the loading. The
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function receives the name of the template and has to return either
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a string with the template source, a tuple in the form ``(source,
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filename, uptodatefunc)`` or `None` if the template does not exist.
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>>> def load_template(name):
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... if name == 'index.html':
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... return '...'
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...
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>>> loader = FunctionLoader(load_template)
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The `uptodatefunc` is a function that is called if autoreload is enabled
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and has to return `True` if the template is still up to date. For more
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details have a look at :meth:`BaseLoader.get_source` which has the same
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return value.
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"""
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def __init__(
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self,
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load_func: t.Callable[
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[str],
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t.Optional[
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t.Union[
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str, t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]
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]
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],
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],
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) -> None:
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self.load_func = load_func
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def get_source(
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self, environment: "Environment", template: str
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) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]:
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rv = self.load_func(template)
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if rv is None:
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raise TemplateNotFound(template)
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if isinstance(rv, str):
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return rv, None, None
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return rv
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class PrefixLoader(BaseLoader):
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"""A loader that is passed a dict of loaders where each loader is bound
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to a prefix. The prefix is delimited from the template by a slash per
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default, which can be changed by setting the `delimiter` argument to
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something else::
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loader = PrefixLoader({
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'app1': PackageLoader('mypackage.app1'),
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'app2': PackageLoader('mypackage.app2')
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})
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By loading ``'app1/index.html'`` the file from the app1 package is loaded,
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by loading ``'app2/index.html'`` the file from the second.
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"""
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def __init__(
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self, mapping: t.Mapping[str, BaseLoader], delimiter: str = "/"
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) -> None:
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self.mapping = mapping
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self.delimiter = delimiter
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def get_loader(self, template: str) -> t.Tuple[BaseLoader, str]:
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try:
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prefix, name = template.split(self.delimiter, 1)
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loader = self.mapping[prefix]
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except (ValueError, KeyError) as e:
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raise TemplateNotFound(template) from e
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return loader, name
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def get_source(
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self, environment: "Environment", template: str
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) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]:
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loader, name = self.get_loader(template)
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try:
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return loader.get_source(environment, name)
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except TemplateNotFound as e:
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# re-raise the exception with the correct filename here.
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# (the one that includes the prefix)
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raise TemplateNotFound(template) from e
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@internalcode
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def load(
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self,
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environment: "Environment",
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name: str,
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globals: t.Optional[t.MutableMapping[str, t.Any]] = None,
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) -> "Template":
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loader, local_name = self.get_loader(name)
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try:
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return loader.load(environment, local_name, globals)
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except TemplateNotFound as e:
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# re-raise the exception with the correct filename here.
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# (the one that includes the prefix)
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raise TemplateNotFound(name) from e
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def list_templates(self) -> t.List[str]:
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result = []
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for prefix, loader in self.mapping.items():
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for template in loader.list_templates():
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result.append(prefix + self.delimiter + template)
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return result
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class ChoiceLoader(BaseLoader):
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"""This loader works like the `PrefixLoader` just that no prefix is
|
|
specified. If a template could not be found by one loader the next one
|
|
is tried.
|
|
|
|
>>> loader = ChoiceLoader([
|
|
... FileSystemLoader('/path/to/user/templates'),
|
|
... FileSystemLoader('/path/to/system/templates')
|
|
... ])
|
|
|
|
This is useful if you want to allow users to override builtin templates
|
|
from a different location.
|
|
"""
|
|
|
|
def __init__(self, loaders: t.Sequence[BaseLoader]) -> None:
|
|
self.loaders = loaders
|
|
|
|
def get_source(
|
|
self, environment: "Environment", template: str
|
|
) -> t.Tuple[str, t.Optional[str], t.Optional[t.Callable[[], bool]]]:
|
|
for loader in self.loaders:
|
|
try:
|
|
return loader.get_source(environment, template)
|
|
except TemplateNotFound:
|
|
pass
|
|
raise TemplateNotFound(template)
|
|
|
|
@internalcode
|
|
def load(
|
|
self,
|
|
environment: "Environment",
|
|
name: str,
|
|
globals: t.Optional[t.MutableMapping[str, t.Any]] = None,
|
|
) -> "Template":
|
|
for loader in self.loaders:
|
|
try:
|
|
return loader.load(environment, name, globals)
|
|
except TemplateNotFound:
|
|
pass
|
|
raise TemplateNotFound(name)
|
|
|
|
def list_templates(self) -> t.List[str]:
|
|
found = set()
|
|
for loader in self.loaders:
|
|
found.update(loader.list_templates())
|
|
return sorted(found)
|
|
|
|
|
|
class _TemplateModule(ModuleType):
|
|
"""Like a normal module but with support for weak references"""
|
|
|
|
|
|
class ModuleLoader(BaseLoader):
|
|
"""This loader loads templates from precompiled templates.
|
|
|
|
Example usage:
|
|
|
|
>>> loader = ChoiceLoader([
|
|
... ModuleLoader('/path/to/compiled/templates'),
|
|
... FileSystemLoader('/path/to/templates')
|
|
... ])
|
|
|
|
Templates can be precompiled with :meth:`Environment.compile_templates`.
|
|
"""
|
|
|
|
has_source_access = False
|
|
|
|
def __init__(
|
|
self,
|
|
path: t.Union[
|
|
str, "os.PathLike[str]", t.Sequence[t.Union[str, "os.PathLike[str]"]]
|
|
],
|
|
) -> None:
|
|
package_name = f"_jinja2_module_templates_{id(self):x}"
|
|
|
|
# create a fake module that looks for the templates in the
|
|
# path given.
|
|
mod = _TemplateModule(package_name)
|
|
|
|
if not isinstance(path, abc.Iterable) or isinstance(path, str):
|
|
path = [path]
|
|
|
|
mod.__path__ = [os.fspath(p) for p in path]
|
|
|
|
sys.modules[package_name] = weakref.proxy(
|
|
mod, lambda x: sys.modules.pop(package_name, None)
|
|
)
|
|
|
|
# the only strong reference, the sys.modules entry is weak
|
|
# so that the garbage collector can remove it once the
|
|
# loader that created it goes out of business.
|
|
self.module = mod
|
|
self.package_name = package_name
|
|
|
|
@staticmethod
|
|
def get_template_key(name: str) -> str:
|
|
return "tmpl_" + sha1(name.encode("utf-8")).hexdigest()
|
|
|
|
@staticmethod
|
|
def get_module_filename(name: str) -> str:
|
|
return ModuleLoader.get_template_key(name) + ".py"
|
|
|
|
@internalcode
|
|
def load(
|
|
self,
|
|
environment: "Environment",
|
|
name: str,
|
|
globals: t.Optional[t.MutableMapping[str, t.Any]] = None,
|
|
) -> "Template":
|
|
key = self.get_template_key(name)
|
|
module = f"{self.package_name}.{key}"
|
|
mod = getattr(self.module, module, None)
|
|
|
|
if mod is None:
|
|
try:
|
|
mod = __import__(module, None, None, ["root"])
|
|
except ImportError as e:
|
|
raise TemplateNotFound(name) from e
|
|
|
|
# remove the entry from sys.modules, we only want the attribute
|
|
# on the module object we have stored on the loader.
|
|
sys.modules.pop(module, None)
|
|
|
|
if globals is None:
|
|
globals = {}
|
|
|
|
return environment.template_class.from_module_dict(
|
|
environment, mod.__dict__, globals
|
|
)
|