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"""Flatpages extension."""
import operator
import os
from itertools import takewhile
import six
from flask import abort
from werkzeug.utils import cached_property, import_string
from yaml import (
BlockMappingStartToken,
BlockSequenceStartToken,
DocumentEndToken,
DocumentStartToken,
FlowMappingStartToken,
FlowSequenceStartToken,
KeyToken,
SafeLoader,
ScalarToken
)
from .page import Page
from .utils import force_unicode, pygmented_markdown
if six.PY3:
from inspect import getfullargspec
from io import StringIO
else:
from inspect import getargspec as getfullargspec
from StringIO import StringIO
START_TOKENS = (BlockMappingStartToken, BlockSequenceStartToken,
DocumentStartToken, FlowMappingStartToken,
FlowSequenceStartToken, KeyToken)
def _check_newline_token(token):
return (
isinstance(token, ScalarToken) and
token.style is None and
'\n' in token.value
)
def _check_continue_parsing_tokens(token):
return not (
isinstance(
token,
(DocumentStartToken, DocumentEndToken)
) or token is None
)
class FlatPages(object):
"""A collection of :class:`Page` objects."""
#: Default configuration for FlatPages extension
default_config = (
('root', 'pages'),
('extension', '.html'),
('encoding', 'utf-8'),
('html_renderer', pygmented_markdown),
('markdown_extensions', ['codehilite']),
('extension_configs', {}),
('auto_reload', 'if debug'),
('case_insensitive', False),
('instance_relative', False),
('legacy_meta_parser', False),
)
def __init__(self, app=None, name=None):
"""Initialize FlatPages extension.
:param app: Your application. Can be omitted if you call
:meth:`init_app` later.
:type app: A :class:`~flask.Flask` instance
:param name: The name for this FlatPages instance. Used for looking
up config values using
'FLATPAGES_%s_%s' % (name.upper(), key)
By default, no name is used, so configuration is
done by specifying config values using
'FLATPAGES_%s' % (key)
Typically, you only need to set this parameter if you
want to use multiple :class:`FlatPages instances within the
same Flask application.
:type name: string
.. versionchanged:: 0.6
New parameter `name` to support multiple FlatPages instances.
"""
self.name = name
if name is None:
self.config_prefix = 'FLATPAGES'
else:
self.config_prefix = '_'.join(('FLATPAGES', name.upper()))
#: dict of filename: (page object, mtime when loaded)
self._file_cache = {}
if app:
self.init_app(app)
def __iter__(self):
"""Iterate on all :class:`Page` objects."""
return six.itervalues(self._pages)
def config(self, key):
"""Read actual configuration from Flask application config.
:param key: Lowercase config key from :attr:`default_config` tuple
"""
return self.app.config['_'.join((self.config_prefix, key.upper()))]
def get(self, path, default=None):
"""
Return the :class:`Page` object at ``path``.
Returns ``default`` if there is no such page.
"""
# This may trigger the property. Do it outside of the try block.
pages = self._pages
try:
return pages[path]
except KeyError:
return default
def get_or_404(self, path):
"""
Return the :class:`Page` object at ``path``.
Raise Flask's 404 error if there is no such page.
"""
page = self.get(path)
if not page:
abort(404)
return page
def init_app(self, app):
"""
Use to initialize an application.
Ueful for passing an app later and app factory patterns.
:param app: your application
:type app: a :class:`~flask.Flask` instance
"""
# Store default config to application
for key, value in self.default_config:
config_key = '_'.join((self.config_prefix, key.upper()))
app.config.setdefault(config_key, value)
# Register function to forget all pages if necessary
app.before_request(self._conditional_auto_reset)
# And finally store application to current instance and current
# instance to application
if 'flatpages' not in app.extensions:
app.extensions['flatpages'] = {}
app.extensions['flatpages'][self.name] = self
self.app = app
def reload(self):
"""Forget all pages.
All pages will be reloaded next time they're accessed.
"""
try:
# This will "unshadow" the cached_property.
# The property will be re-executed on next access.
del self.__dict__['_pages']
except KeyError:
pass
@property
def root(self):
"""Full path to the directory where pages are looked for.
This corresponds to the `FLATPAGES_%(name)s_ROOT` config value,
interpreted as relative to the app's root directory, or as relative
to the app's instance folder if `FLATPAGES_%(name)s_INSTANCE_RELATIVE`
is set to `True`.
"""
if self.config('instance_relative'):
root_dir = os.path.join(self.app.instance_path,
self.config('root'))
else:
root_dir = os.path.join(self.app.root_path, self.config('root'))
return force_unicode(root_dir)
def _conditional_auto_reset(self):
"""Reset if configured to do so on new requests."""
auto = self.config('auto_reload')
if auto == 'if debug':
auto = self.app.debug
if auto:
self.reload()
def _load_file(self, path, filename, rel_path):
"""
Load file from file system and cache it.
We store the result as a tuple of :class:`Path` and the file `mtime`.
"""
mtime = os.path.getmtime(filename)
cached = self._file_cache.get(filename)
if cached and cached[1] == mtime:
page = cached[0]
else:
encoding = self.config('encoding')
if six.PY3:
with open(filename, encoding=encoding) as handler:
content = handler.read()
else:
with open(filename) as handler:
content = handler.read().decode(encoding)
page = self._parse(content, path, rel_path)
self._file_cache[filename] = (page, mtime)
return page
@cached_property
def _pages(self):
"""
Walk the page root directory and return a dict of pages.
Returns a dictionary of pages keyed by their path.
"""
def _walker():
"""
Walk over directory and find all possible flatpages.
Returns files which end with the string or sequence given by
``FLATPAGES_%(name)s_EXTENSION``.
"""
for cur_path, _, filenames in os.walk(self.root):
rel_path = cur_path.replace(self.root, '').lstrip(os.sep)
path_prefix = tuple(rel_path.split(os.sep)) if rel_path else ()
for name in filenames:
if not name.endswith(extension):
continue
full_name = os.path.join(cur_path, name)
name_without_extension = [name[:-len(item)]
for item in extension
if name.endswith(item)][0]
path = u'/'.join(path_prefix + (name_without_extension, ))
if self.config('case_insensitive'):
path = path.lower()
yield (path, full_name, rel_path)
# Read extension from config
extension = self.config('extension')
# Support for multiple extensions
if isinstance(extension, six.string_types):
if ',' in extension:
extension = tuple(extension.split(','))
else:
extension = (extension, )
elif isinstance(extension, (list, set)):
extension = tuple(extension)
# FlatPage extension should be a string or a sequence
if not isinstance(extension, tuple):
raise ValueError(
'Invalid value for FlatPages extension. Should be a string or '
'a sequence, got {0} instead: {1}'.
format(type(extension).__name__, extension)
)
pages = {}
for path, full_name, rel_path in _walker():
if path in pages:
raise ValueError(
'Multiple pages found which correspond to the same path. '
'This error can arise when using multiple extensions.')
pages[path] = self._load_file(path, full_name, rel_path)
return pages
def _libyaml_parser(self, content):
if not six.PY3:
content = force_unicode(content)
yaml_loader = SafeLoader(StringIO(content))
yaml_loader.get_token() # Get stream start token
token = yaml_loader.get_token()
if not isinstance(token, START_TOKENS):
meta = ''
content = content.lstrip('\n')
else:
lines = content.split('\n')
if isinstance(token, DocumentStartToken):
token = yaml_loader.get_token()
newline_token = None
while _check_continue_parsing_tokens(token):
try:
token = yaml_loader.get_token()
if (
_check_newline_token(token) and
newline_token is None
):
newline_token = token
except Exception:
break
if token is None and newline_token is None:
meta = content
content = ''
else:
if token is not None:
meta_end_line = token.end_mark.line + 1
else:
meta_end_line = newline_token.start_mark.line
meta_end_line += lines[meta_end_line:].index('')
meta = '\n'.join(lines[:meta_end_line])
content = '\n'.join(lines[meta_end_line:]).lstrip('\n')
if not six.PY3:
return force_unicode(meta), force_unicode(content)
return meta, content
def _legacy_parser(self, content):
lines = iter(content.split('\n'))
# Read lines until an empty line is encountered.
meta = '\n'.join(takewhile(operator.methodcaller('strip'), lines))
# The rest is the content. `lines` is an iterator so it continues
# where `itertools.takewhile` left it.
content = '\n'.join(lines)
return meta, content
def _parse(self, content, path, rel_path):
"""Parse a flatpage file, i.e. read and parse its meta data and body.
:return: initialized :class:`Page` instance.
"""
if self.config('legacy_meta_parser'):
meta, content = self._legacy_parser(content)
else:
meta, content = self._libyaml_parser(content)
# Now we ready to get HTML renderer function
html_renderer = self.config('html_renderer')
# If function is not callable yet, import it
if not callable(html_renderer):
html_renderer = import_string(html_renderer)
# Make able to pass custom arguments to renderer function
html_renderer = self._smart_html_renderer(html_renderer)
# Assign the relative path (to root) for use in the page object
folder = rel_path
# Initialize and return Page instance
return Page(path, meta, content, html_renderer, folder)
def _smart_html_renderer(self, html_renderer):
"""
Wrappper to enable rendering functions with differing signatures.
We stay backwards compatible by using reflection, i.e. we inspect the
given rendering function's signature in order to find out how many
arguments the function takes.
.. versionchanged:: 0.6
Support for HTML renderer functions with signature
``f(body, flatpages, page)``, where ``page`` is an instance of
:class:`Page`.
.. versionchanged:: 0.5
Support for HTML renderer functions with signature
``f(body, flatpages)``, where ``flatpages`` is an instance of
:class:`FlatPages`.
"""
def wrapper(page):
"""Wrap HTML renderer function.
Pass arguments to the renderer based on the number of arguments.
* 1 argument -> page body
* 2 arguments -> page body, flatpages instance
* 3 arguments -> page body, flatpages instance, page instance
"""
body = page.body
try:
args_length = len(getfullargspec(html_renderer).args)
except TypeError:
return html_renderer(body)
if args_length == 1:
return html_renderer(body)
elif args_length == 2:
return html_renderer(body, self)
elif args_length == 3:
return html_renderer(body, self, page)
raise ValueError(
'HTML renderer function {0!r} not supported by '
'Flask-FlatPages, wrong number of arguments: {1}.'.
format(html_renderer, args_length)
)
return wrapper