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Diffstat (limited to 'python/flask/helpers.py')
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diff --git a/python/flask/helpers.py b/python/flask/helpers.py new file mode 100644 index 0000000..158edc5 --- /dev/null +++ b/python/flask/helpers.py @@ -0,0 +1,1051 @@ +# -*- coding: utf-8 -*- +""" + flask.helpers + ~~~~~~~~~~~~~ + + Implements various helpers. + + :copyright: © 2010 by the Pallets team. + :license: BSD, see LICENSE for more details. +""" + +import os +import socket +import sys +import pkgutil +import posixpath +import mimetypes +from time import time +from zlib import adler32 +from threading import RLock +import unicodedata +from werkzeug.routing import BuildError +from functools import update_wrapper + +from werkzeug.urls import url_quote +from werkzeug.datastructures import Headers, Range +from werkzeug.exceptions import BadRequest, NotFound, \ + RequestedRangeNotSatisfiable + +from werkzeug.wsgi import wrap_file +from jinja2 import FileSystemLoader + +from .signals import message_flashed +from .globals import session, _request_ctx_stack, _app_ctx_stack, \ + current_app, request +from ._compat import string_types, text_type, PY2 + +# sentinel +_missing = object() + + +# what separators does this operating system provide that are not a slash? +# this is used by the send_from_directory function to ensure that nobody is +# able to access files from outside the filesystem. +_os_alt_seps = list(sep for sep in [os.path.sep, os.path.altsep] + if sep not in (None, '/')) + + +def get_env(): + """Get the environment the app is running in, indicated by the + :envvar:`FLASK_ENV` environment variable. The default is + ``'production'``. + """ + return os.environ.get('FLASK_ENV') or 'production' + + +def get_debug_flag(): + """Get whether debug mode should be enabled for the app, indicated + by the :envvar:`FLASK_DEBUG` environment variable. The default is + ``True`` if :func:`.get_env` returns ``'development'``, or ``False`` + otherwise. + """ + val = os.environ.get('FLASK_DEBUG') + + if not val: + return get_env() == 'development' + + return val.lower() not in ('0', 'false', 'no') + + +def get_load_dotenv(default=True): + """Get whether the user has disabled loading dotenv files by setting + :envvar:`FLASK_SKIP_DOTENV`. The default is ``True``, load the + files. + + :param default: What to return if the env var isn't set. + """ + val = os.environ.get('FLASK_SKIP_DOTENV') + + if not val: + return default + + return val.lower() in ('0', 'false', 'no') + + +def _endpoint_from_view_func(view_func): + """Internal helper that returns the default endpoint for a given + function. This always is the function name. + """ + assert view_func is not None, 'expected view func if endpoint ' \ + 'is not provided.' + return view_func.__name__ + + +def stream_with_context(generator_or_function): + """Request contexts disappear when the response is started on the server. + This is done for efficiency reasons and to make it less likely to encounter + memory leaks with badly written WSGI middlewares. The downside is that if + you are using streamed responses, the generator cannot access request bound + information any more. + + This function however can help you keep the context around for longer:: + + from flask import stream_with_context, request, Response + + @app.route('/stream') + def streamed_response(): + @stream_with_context + def generate(): + yield 'Hello ' + yield request.args['name'] + yield '!' + return Response(generate()) + + Alternatively it can also be used around a specific generator:: + + from flask import stream_with_context, request, Response + + @app.route('/stream') + def streamed_response(): + def generate(): + yield 'Hello ' + yield request.args['name'] + yield '!' + return Response(stream_with_context(generate())) + + .. versionadded:: 0.9 + """ + try: + gen = iter(generator_or_function) + except TypeError: + def decorator(*args, **kwargs): + gen = generator_or_function(*args, **kwargs) + return stream_with_context(gen) + return update_wrapper(decorator, generator_or_function) + + def generator(): + ctx = _request_ctx_stack.top + if ctx is None: + raise RuntimeError('Attempted to stream with context but ' + 'there was no context in the first place to keep around.') + with ctx: + # Dummy sentinel. Has to be inside the context block or we're + # not actually keeping the context around. + yield None + + # The try/finally is here so that if someone passes a WSGI level + # iterator in we're still running the cleanup logic. Generators + # don't need that because they are closed on their destruction + # automatically. + try: + for item in gen: + yield item + finally: + if hasattr(gen, 'close'): + gen.close() + + # The trick is to start the generator. Then the code execution runs until + # the first dummy None is yielded at which point the context was already + # pushed. This item is discarded. Then when the iteration continues the + # real generator is executed. + wrapped_g = generator() + next(wrapped_g) + return wrapped_g + + +def make_response(*args): + """Sometimes it is necessary to set additional headers in a view. Because + views do not have to return response objects but can return a value that + is converted into a response object by Flask itself, it becomes tricky to + add headers to it. This function can be called instead of using a return + and you will get a response object which you can use to attach headers. + + If view looked like this and you want to add a new header:: + + def index(): + return render_template('index.html', foo=42) + + You can now do something like this:: + + def index(): + response = make_response(render_template('index.html', foo=42)) + response.headers['X-Parachutes'] = 'parachutes are cool' + return response + + This function accepts the very same arguments you can return from a + view function. This for example creates a response with a 404 error + code:: + + response = make_response(render_template('not_found.html'), 404) + + The other use case of this function is to force the return value of a + view function into a response which is helpful with view + decorators:: + + response = make_response(view_function()) + response.headers['X-Parachutes'] = 'parachutes are cool' + + Internally this function does the following things: + + - if no arguments are passed, it creates a new response argument + - if one argument is passed, :meth:`flask.Flask.make_response` + is invoked with it. + - if more than one argument is passed, the arguments are passed + to the :meth:`flask.Flask.make_response` function as tuple. + + .. versionadded:: 0.6 + """ + if not args: + return current_app.response_class() + if len(args) == 1: + args = args[0] + return current_app.make_response(args) + + +def url_for(endpoint, **values): + """Generates a URL to the given endpoint with the method provided. + + Variable arguments that are unknown to the target endpoint are appended + to the generated URL as query arguments. If the value of a query argument + is ``None``, the whole pair is skipped. In case blueprints are active + you can shortcut references to the same blueprint by prefixing the + local endpoint with a dot (``.``). + + This will reference the index function local to the current blueprint:: + + url_for('.index') + + For more information, head over to the :ref:`Quickstart <url-building>`. + + To integrate applications, :class:`Flask` has a hook to intercept URL build + errors through :attr:`Flask.url_build_error_handlers`. The `url_for` + function results in a :exc:`~werkzeug.routing.BuildError` when the current + app does not have a URL for the given endpoint and values. When it does, the + :data:`~flask.current_app` calls its :attr:`~Flask.url_build_error_handlers` if + it is not ``None``, which can return a string to use as the result of + `url_for` (instead of `url_for`'s default to raise the + :exc:`~werkzeug.routing.BuildError` exception) or re-raise the exception. + An example:: + + def external_url_handler(error, endpoint, values): + "Looks up an external URL when `url_for` cannot build a URL." + # This is an example of hooking the build_error_handler. + # Here, lookup_url is some utility function you've built + # which looks up the endpoint in some external URL registry. + url = lookup_url(endpoint, **values) + if url is None: + # External lookup did not have a URL. + # Re-raise the BuildError, in context of original traceback. + exc_type, exc_value, tb = sys.exc_info() + if exc_value is error: + raise exc_type, exc_value, tb + else: + raise error + # url_for will use this result, instead of raising BuildError. + return url + + app.url_build_error_handlers.append(external_url_handler) + + Here, `error` is the instance of :exc:`~werkzeug.routing.BuildError`, and + `endpoint` and `values` are the arguments passed into `url_for`. Note + that this is for building URLs outside the current application, and not for + handling 404 NotFound errors. + + .. versionadded:: 0.10 + The `_scheme` parameter was added. + + .. versionadded:: 0.9 + The `_anchor` and `_method` parameters were added. + + .. versionadded:: 0.9 + Calls :meth:`Flask.handle_build_error` on + :exc:`~werkzeug.routing.BuildError`. + + :param endpoint: the endpoint of the URL (name of the function) + :param values: the variable arguments of the URL rule + :param _external: if set to ``True``, an absolute URL is generated. Server + address can be changed via ``SERVER_NAME`` configuration variable which + falls back to the `Host` header, then to the IP and port of the request. + :param _scheme: a string specifying the desired URL scheme. The `_external` + parameter must be set to ``True`` or a :exc:`ValueError` is raised. The default + behavior uses the same scheme as the current request, or + ``PREFERRED_URL_SCHEME`` from the :ref:`app configuration <config>` if no + request context is available. As of Werkzeug 0.10, this also can be set + to an empty string to build protocol-relative URLs. + :param _anchor: if provided this is added as anchor to the URL. + :param _method: if provided this explicitly specifies an HTTP method. + """ + appctx = _app_ctx_stack.top + reqctx = _request_ctx_stack.top + + if appctx is None: + raise RuntimeError( + 'Attempted to generate a URL without the application context being' + ' pushed. This has to be executed when application context is' + ' available.' + ) + + # If request specific information is available we have some extra + # features that support "relative" URLs. + if reqctx is not None: + url_adapter = reqctx.url_adapter + blueprint_name = request.blueprint + + if endpoint[:1] == '.': + if blueprint_name is not None: + endpoint = blueprint_name + endpoint + else: + endpoint = endpoint[1:] + + external = values.pop('_external', False) + + # Otherwise go with the url adapter from the appctx and make + # the URLs external by default. + else: + url_adapter = appctx.url_adapter + + if url_adapter is None: + raise RuntimeError( + 'Application was not able to create a URL adapter for request' + ' independent URL generation. You might be able to fix this by' + ' setting the SERVER_NAME config variable.' + ) + + external = values.pop('_external', True) + + anchor = values.pop('_anchor', None) + method = values.pop('_method', None) + scheme = values.pop('_scheme', None) + appctx.app.inject_url_defaults(endpoint, values) + + # This is not the best way to deal with this but currently the + # underlying Werkzeug router does not support overriding the scheme on + # a per build call basis. + old_scheme = None + if scheme is not None: + if not external: + raise ValueError('When specifying _scheme, _external must be True') + old_scheme = url_adapter.url_scheme + url_adapter.url_scheme = scheme + + try: + try: + rv = url_adapter.build(endpoint, values, method=method, + force_external=external) + finally: + if old_scheme is not None: + url_adapter.url_scheme = old_scheme + except BuildError as error: + # We need to inject the values again so that the app callback can + # deal with that sort of stuff. + values['_external'] = external + values['_anchor'] = anchor + values['_method'] = method + values['_scheme'] = scheme + return appctx.app.handle_url_build_error(error, endpoint, values) + + if anchor is not None: + rv += '#' + url_quote(anchor) + return rv + + +def get_template_attribute(template_name, attribute): + """Loads a macro (or variable) a template exports. This can be used to + invoke a macro from within Python code. If you for example have a + template named :file:`_cider.html` with the following contents: + + .. sourcecode:: html+jinja + + {% macro hello(name) %}Hello {{ name }}!{% endmacro %} + + You can access this from Python code like this:: + + hello = get_template_attribute('_cider.html', 'hello') + return hello('World') + + .. versionadded:: 0.2 + + :param template_name: the name of the template + :param attribute: the name of the variable of macro to access + """ + return getattr(current_app.jinja_env.get_template(template_name).module, + attribute) + + +def flash(message, category='message'): + """Flashes a message to the next request. In order to remove the + flashed message from the session and to display it to the user, + the template has to call :func:`get_flashed_messages`. + + .. versionchanged:: 0.3 + `category` parameter added. + + :param message: the message to be flashed. + :param category: the category for the message. The following values + are recommended: ``'message'`` for any kind of message, + ``'error'`` for errors, ``'info'`` for information + messages and ``'warning'`` for warnings. However any + kind of string can be used as category. + """ + # Original implementation: + # + # session.setdefault('_flashes', []).append((category, message)) + # + # This assumed that changes made to mutable structures in the session are + # always in sync with the session object, which is not true for session + # implementations that use external storage for keeping their keys/values. + flashes = session.get('_flashes', []) + flashes.append((category, message)) + session['_flashes'] = flashes + message_flashed.send(current_app._get_current_object(), + message=message, category=category) + + +def get_flashed_messages(with_categories=False, category_filter=[]): + """Pulls all flashed messages from the session and returns them. + Further calls in the same request to the function will return + the same messages. By default just the messages are returned, + but when `with_categories` is set to ``True``, the return value will + be a list of tuples in the form ``(category, message)`` instead. + + Filter the flashed messages to one or more categories by providing those + categories in `category_filter`. This allows rendering categories in + separate html blocks. The `with_categories` and `category_filter` + arguments are distinct: + + * `with_categories` controls whether categories are returned with message + text (``True`` gives a tuple, where ``False`` gives just the message text). + * `category_filter` filters the messages down to only those matching the + provided categories. + + See :ref:`message-flashing-pattern` for examples. + + .. versionchanged:: 0.3 + `with_categories` parameter added. + + .. versionchanged:: 0.9 + `category_filter` parameter added. + + :param with_categories: set to ``True`` to also receive categories. + :param category_filter: whitelist of categories to limit return values + """ + flashes = _request_ctx_stack.top.flashes + if flashes is None: + _request_ctx_stack.top.flashes = flashes = session.pop('_flashes') \ + if '_flashes' in session else [] + if category_filter: + flashes = list(filter(lambda f: f[0] in category_filter, flashes)) + if not with_categories: + return [x[1] for x in flashes] + return flashes + + +def send_file(filename_or_fp, mimetype=None, as_attachment=False, + attachment_filename=None, add_etags=True, + cache_timeout=None, conditional=False, last_modified=None): + """Sends the contents of a file to the client. This will use the + most efficient method available and configured. By default it will + try to use the WSGI server's file_wrapper support. Alternatively + you can set the application's :attr:`~Flask.use_x_sendfile` attribute + to ``True`` to directly emit an ``X-Sendfile`` header. This however + requires support of the underlying webserver for ``X-Sendfile``. + + By default it will try to guess the mimetype for you, but you can + also explicitly provide one. For extra security you probably want + to send certain files as attachment (HTML for instance). The mimetype + guessing requires a `filename` or an `attachment_filename` to be + provided. + + ETags will also be attached automatically if a `filename` is provided. You + can turn this off by setting `add_etags=False`. + + If `conditional=True` and `filename` is provided, this method will try to + upgrade the response stream to support range requests. This will allow + the request to be answered with partial content response. + + Please never pass filenames to this function from user sources; + you should use :func:`send_from_directory` instead. + + .. versionadded:: 0.2 + + .. versionadded:: 0.5 + The `add_etags`, `cache_timeout` and `conditional` parameters were + added. The default behavior is now to attach etags. + + .. versionchanged:: 0.7 + mimetype guessing and etag support for file objects was + deprecated because it was unreliable. Pass a filename if you are + able to, otherwise attach an etag yourself. This functionality + will be removed in Flask 1.0 + + .. versionchanged:: 0.9 + cache_timeout pulls its default from application config, when None. + + .. versionchanged:: 0.12 + The filename is no longer automatically inferred from file objects. If + you want to use automatic mimetype and etag support, pass a filepath via + `filename_or_fp` or `attachment_filename`. + + .. versionchanged:: 0.12 + The `attachment_filename` is preferred over `filename` for MIME-type + detection. + + .. versionchanged:: 1.0 + UTF-8 filenames, as specified in `RFC 2231`_, are supported. + + .. _RFC 2231: https://tools.ietf.org/html/rfc2231#section-4 + + .. versionchanged:: 1.0.3 + Filenames are encoded with ASCII instead of Latin-1 for broader + compatibility with WSGI servers. + + :param filename_or_fp: the filename of the file to send. + This is relative to the :attr:`~Flask.root_path` + if a relative path is specified. + Alternatively a file object might be provided in + which case ``X-Sendfile`` might not work and fall + back to the traditional method. Make sure that the + file pointer is positioned at the start of data to + send before calling :func:`send_file`. + :param mimetype: the mimetype of the file if provided. If a file path is + given, auto detection happens as fallback, otherwise an + error will be raised. + :param as_attachment: set to ``True`` if you want to send this file with + a ``Content-Disposition: attachment`` header. + :param attachment_filename: the filename for the attachment if it + differs from the file's filename. + :param add_etags: set to ``False`` to disable attaching of etags. + :param conditional: set to ``True`` to enable conditional responses. + + :param cache_timeout: the timeout in seconds for the headers. When ``None`` + (default), this value is set by + :meth:`~Flask.get_send_file_max_age` of + :data:`~flask.current_app`. + :param last_modified: set the ``Last-Modified`` header to this value, + a :class:`~datetime.datetime` or timestamp. + If a file was passed, this overrides its mtime. + """ + mtime = None + fsize = None + if isinstance(filename_or_fp, string_types): + filename = filename_or_fp + if not os.path.isabs(filename): + filename = os.path.join(current_app.root_path, filename) + file = None + if attachment_filename is None: + attachment_filename = os.path.basename(filename) + else: + file = filename_or_fp + filename = None + + if mimetype is None: + if attachment_filename is not None: + mimetype = mimetypes.guess_type(attachment_filename)[0] \ + or 'application/octet-stream' + + if mimetype is None: + raise ValueError( + 'Unable to infer MIME-type because no filename is available. ' + 'Please set either `attachment_filename`, pass a filepath to ' + '`filename_or_fp` or set your own MIME-type via `mimetype`.' + ) + + headers = Headers() + if as_attachment: + if attachment_filename is None: + raise TypeError('filename unavailable, required for ' + 'sending as attachment') + + if not isinstance(attachment_filename, text_type): + attachment_filename = attachment_filename.decode('utf-8') + + try: + attachment_filename = attachment_filename.encode('ascii') + except UnicodeEncodeError: + filenames = { + 'filename': unicodedata.normalize( + 'NFKD', attachment_filename).encode('ascii', 'ignore'), + 'filename*': "UTF-8''%s" % url_quote(attachment_filename), + } + else: + filenames = {'filename': attachment_filename} + + headers.add('Content-Disposition', 'attachment', **filenames) + + if current_app.use_x_sendfile and filename: + if file is not None: + file.close() + headers['X-Sendfile'] = filename + fsize = os.path.getsize(filename) + headers['Content-Length'] = fsize + data = None + else: + if file is None: + file = open(filename, 'rb') + mtime = os.path.getmtime(filename) + fsize = os.path.getsize(filename) + headers['Content-Length'] = fsize + data = wrap_file(request.environ, file) + + rv = current_app.response_class(data, mimetype=mimetype, headers=headers, + direct_passthrough=True) + + if last_modified is not None: + rv.last_modified = last_modified + elif mtime is not None: + rv.last_modified = mtime + + rv.cache_control.public = True + if cache_timeout is None: + cache_timeout = current_app.get_send_file_max_age(filename) + if cache_timeout is not None: + rv.cache_control.max_age = cache_timeout + rv.expires = int(time() + cache_timeout) + + if add_etags and filename is not None: + from warnings import warn + + try: + rv.set_etag('%s-%s-%s' % ( + os.path.getmtime(filename), + os.path.getsize(filename), + adler32( + filename.encode('utf-8') if isinstance(filename, text_type) + else filename + ) & 0xffffffff + )) + except OSError: + warn('Access %s failed, maybe it does not exist, so ignore etags in ' + 'headers' % filename, stacklevel=2) + + if conditional: + try: + rv = rv.make_conditional(request, accept_ranges=True, + complete_length=fsize) + except RequestedRangeNotSatisfiable: + if file is not None: + file.close() + raise + # make sure we don't send x-sendfile for servers that + # ignore the 304 status code for x-sendfile. + if rv.status_code == 304: + rv.headers.pop('x-sendfile', None) + return rv + + +def safe_join(directory, *pathnames): + """Safely join `directory` and zero or more untrusted `pathnames` + components. + + Example usage:: + + @app.route('/wiki/<path:filename>') + def wiki_page(filename): + filename = safe_join(app.config['WIKI_FOLDER'], filename) + with open(filename, 'rb') as fd: + content = fd.read() # Read and process the file content... + + :param directory: the trusted base directory. + :param pathnames: the untrusted pathnames relative to that directory. + :raises: :class:`~werkzeug.exceptions.NotFound` if one or more passed + paths fall out of its boundaries. + """ + + parts = [directory] + + for filename in pathnames: + if filename != '': + filename = posixpath.normpath(filename) + + if ( + any(sep in filename for sep in _os_alt_seps) + or os.path.isabs(filename) + or filename == '..' + or filename.startswith('../') + ): + raise NotFound() + + parts.append(filename) + + return posixpath.join(*parts) + + +def send_from_directory(directory, filename, **options): + """Send a file from a given directory with :func:`send_file`. This + is a secure way to quickly expose static files from an upload folder + or something similar. + + Example usage:: + + @app.route('/uploads/<path:filename>') + def download_file(filename): + return send_from_directory(app.config['UPLOAD_FOLDER'], + filename, as_attachment=True) + + .. admonition:: Sending files and Performance + + It is strongly recommended to activate either ``X-Sendfile`` support in + your webserver or (if no authentication happens) to tell the webserver + to serve files for the given path on its own without calling into the + web application for improved performance. + + .. versionadded:: 0.5 + + :param directory: the directory where all the files are stored. + :param filename: the filename relative to that directory to + download. + :param options: optional keyword arguments that are directly + forwarded to :func:`send_file`. + """ + filename = safe_join(directory, filename) + if not os.path.isabs(filename): + filename = os.path.join(current_app.root_path, filename) + try: + if not os.path.isfile(filename): + raise NotFound() + except (TypeError, ValueError): + raise BadRequest() + options.setdefault('conditional', True) + return send_file(filename, **options) + + +def get_root_path(import_name): + """Returns the path to a package or cwd if that cannot be found. This + returns the path of a package or the folder that contains a module. + + Not to be confused with the package path returned by :func:`find_package`. + """ + # Module already imported and has a file attribute. Use that first. + mod = sys.modules.get(import_name) + if mod is not None and hasattr(mod, '__file__'): + return os.path.dirname(os.path.abspath(mod.__file__)) + + # Next attempt: check the loader. + loader = pkgutil.get_loader(import_name) + + # Loader does not exist or we're referring to an unloaded main module + # or a main module without path (interactive sessions), go with the + # current working directory. + if loader is None or import_name == '__main__': + return os.getcwd() + + # For .egg, zipimporter does not have get_filename until Python 2.7. + # Some other loaders might exhibit the same behavior. + if hasattr(loader, 'get_filename'): + filepath = loader.get_filename(import_name) + else: + # Fall back to imports. + __import__(import_name) + mod = sys.modules[import_name] + filepath = getattr(mod, '__file__', None) + + # If we don't have a filepath it might be because we are a + # namespace package. In this case we pick the root path from the + # first module that is contained in our package. + if filepath is None: + raise RuntimeError('No root path can be found for the provided ' + 'module "%s". This can happen because the ' + 'module came from an import hook that does ' + 'not provide file name information or because ' + 'it\'s a namespace package. In this case ' + 'the root path needs to be explicitly ' + 'provided.' % import_name) + + # filepath is import_name.py for a module, or __init__.py for a package. + return os.path.dirname(os.path.abspath(filepath)) + + +def _matching_loader_thinks_module_is_package(loader, mod_name): + """Given the loader that loaded a module and the module this function + attempts to figure out if the given module is actually a package. + """ + # If the loader can tell us if something is a package, we can + # directly ask the loader. + if hasattr(loader, 'is_package'): + return loader.is_package(mod_name) + # importlib's namespace loaders do not have this functionality but + # all the modules it loads are packages, so we can take advantage of + # this information. + elif (loader.__class__.__module__ == '_frozen_importlib' and + loader.__class__.__name__ == 'NamespaceLoader'): + return True + # Otherwise we need to fail with an error that explains what went + # wrong. + raise AttributeError( + ('%s.is_package() method is missing but is required by Flask of ' + 'PEP 302 import hooks. If you do not use import hooks and ' + 'you encounter this error please file a bug against Flask.') % + loader.__class__.__name__) + + +def find_package(import_name): + """Finds a package and returns the prefix (or None if the package is + not installed) as well as the folder that contains the package or + module as a tuple. The package path returned is the module that would + have to be added to the pythonpath in order to make it possible to + import the module. The prefix is the path below which a UNIX like + folder structure exists (lib, share etc.). + """ + root_mod_name = import_name.split('.')[0] + loader = pkgutil.get_loader(root_mod_name) + if loader is None or import_name == '__main__': + # import name is not found, or interactive/main module + package_path = os.getcwd() + else: + # For .egg, zipimporter does not have get_filename until Python 2.7. + if hasattr(loader, 'get_filename'): + filename = loader.get_filename(root_mod_name) + elif hasattr(loader, 'archive'): + # zipimporter's loader.archive points to the .egg or .zip + # archive filename is dropped in call to dirname below. + filename = loader.archive + else: + # At least one loader is missing both get_filename and archive: + # Google App Engine's HardenedModulesHook + # + # Fall back to imports. + __import__(import_name) + filename = sys.modules[import_name].__file__ + package_path = os.path.abspath(os.path.dirname(filename)) + + # In case the root module is a package we need to chop of the + # rightmost part. This needs to go through a helper function + # because of python 3.3 namespace packages. + if _matching_loader_thinks_module_is_package( + loader, root_mod_name): + package_path = os.path.dirname(package_path) + + site_parent, site_folder = os.path.split(package_path) + py_prefix = os.path.abspath(sys.prefix) + if package_path.startswith(py_prefix): + return py_prefix, package_path + elif site_folder.lower() == 'site-packages': + parent, folder = os.path.split(site_parent) + # Windows like installations + if folder.lower() == 'lib': + base_dir = parent + # UNIX like installations + elif os.path.basename(parent).lower() == 'lib': + base_dir = os.path.dirname(parent) + else: + base_dir = site_parent + return base_dir, package_path + return None, package_path + + +class locked_cached_property(object): + """A decorator that converts a function into a lazy property. The + function wrapped is called the first time to retrieve the result + and then that calculated result is used the next time you access + the value. Works like the one in Werkzeug but has a lock for + thread safety. + """ + + def __init__(self, func, name=None, doc=None): + self.__name__ = name or func.__name__ + self.__module__ = func.__module__ + self.__doc__ = doc or func.__doc__ + self.func = func + self.lock = RLock() + + def __get__(self, obj, type=None): + if obj is None: + return self + with self.lock: + value = obj.__dict__.get(self.__name__, _missing) + if value is _missing: + value = self.func(obj) + obj.__dict__[self.__name__] = value + return value + + +class _PackageBoundObject(object): + #: The name of the package or module that this app belongs to. Do not + #: change this once it is set by the constructor. + import_name = None + + #: Location of the template files to be added to the template lookup. + #: ``None`` if templates should not be added. + template_folder = None + + #: Absolute path to the package on the filesystem. Used to look up + #: resources contained in the package. + root_path = None + + def __init__(self, import_name, template_folder=None, root_path=None): + self.import_name = import_name + self.template_folder = template_folder + + if root_path is None: + root_path = get_root_path(self.import_name) + + self.root_path = root_path + self._static_folder = None + self._static_url_path = None + + def _get_static_folder(self): + if self._static_folder is not None: + return os.path.join(self.root_path, self._static_folder) + + def _set_static_folder(self, value): + self._static_folder = value + + static_folder = property( + _get_static_folder, _set_static_folder, + doc='The absolute path to the configured static folder.' + ) + del _get_static_folder, _set_static_folder + + def _get_static_url_path(self): + if self._static_url_path is not None: + return self._static_url_path + + if self.static_folder is not None: + return '/' + os.path.basename(self.static_folder) + + def _set_static_url_path(self, value): + self._static_url_path = value + + static_url_path = property( + _get_static_url_path, _set_static_url_path, + doc='The URL prefix that the static route will be registered for.' + ) + del _get_static_url_path, _set_static_url_path + + @property + def has_static_folder(self): + """This is ``True`` if the package bound object's container has a + folder for static files. + + .. versionadded:: 0.5 + """ + return self.static_folder is not None + + @locked_cached_property + def jinja_loader(self): + """The Jinja loader for this package bound object. + + .. versionadded:: 0.5 + """ + if self.template_folder is not None: + return FileSystemLoader(os.path.join(self.root_path, + self.template_folder)) + + def get_send_file_max_age(self, filename): + """Provides default cache_timeout for the :func:`send_file` functions. + + By default, this function returns ``SEND_FILE_MAX_AGE_DEFAULT`` from + the configuration of :data:`~flask.current_app`. + + Static file functions such as :func:`send_from_directory` use this + function, and :func:`send_file` calls this function on + :data:`~flask.current_app` when the given cache_timeout is ``None``. If a + cache_timeout is given in :func:`send_file`, that timeout is used; + otherwise, this method is called. + + This allows subclasses to change the behavior when sending files based + on the filename. For example, to set the cache timeout for .js files + to 60 seconds:: + + class MyFlask(flask.Flask): + def get_send_file_max_age(self, name): + if name.lower().endswith('.js'): + return 60 + return flask.Flask.get_send_file_max_age(self, name) + + .. versionadded:: 0.9 + """ + return total_seconds(current_app.send_file_max_age_default) + + def send_static_file(self, filename): + """Function used internally to send static files from the static + folder to the browser. + + .. versionadded:: 0.5 + """ + if not self.has_static_folder: + raise RuntimeError('No static folder for this object') + # Ensure get_send_file_max_age is called in all cases. + # Here, we ensure get_send_file_max_age is called for Blueprints. + cache_timeout = self.get_send_file_max_age(filename) + return send_from_directory(self.static_folder, filename, + cache_timeout=cache_timeout) + + def open_resource(self, resource, mode='rb'): + """Opens a resource from the application's resource folder. To see + how this works, consider the following folder structure:: + + /myapplication.py + /schema.sql + /static + /style.css + /templates + /layout.html + /index.html + + If you want to open the :file:`schema.sql` file you would do the + following:: + + with app.open_resource('schema.sql') as f: + contents = f.read() + do_something_with(contents) + + :param resource: the name of the resource. To access resources within + subfolders use forward slashes as separator. + :param mode: resource file opening mode, default is 'rb'. + """ + if mode not in ('r', 'rb'): + raise ValueError('Resources can only be opened for reading') + return open(os.path.join(self.root_path, resource), mode) + + +def total_seconds(td): + """Returns the total seconds from a timedelta object. + + :param timedelta td: the timedelta to be converted in seconds + + :returns: number of seconds + :rtype: int + """ + return td.days * 60 * 60 * 24 + td.seconds + + +def is_ip(value): + """Determine if the given string is an IP address. + + Python 2 on Windows doesn't provide ``inet_pton``, so this only + checks IPv4 addresses in that environment. + + :param value: value to check + :type value: str + + :return: True if string is an IP address + :rtype: bool + """ + if PY2 and os.name == 'nt': + try: + socket.inet_aton(value) + return True + except socket.error: + return False + + for family in (socket.AF_INET, socket.AF_INET6): + try: + socket.inet_pton(family, value) + except socket.error: + pass + else: + return True + + return False |