Skip to content
This repository
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 374 lines (319 sloc) 15.269 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373
# -*- coding: utf-8 -*-
"""
flask.blueprints
~~~~~~~~~~~~~~~~

Blueprints are the recommended way to implement larger or more
pluggable applications in Flask 0.7 and later.

:copyright: (c) 2011 by Armin Ronacher.
:license: BSD, see LICENSE for more details.
"""
from functools import update_wrapper

from .helpers import _PackageBoundObject, _endpoint_from_view_func


class BlueprintSetupState(object):
    """Temporary holder object for registering a blueprint with the
application. An instance of this class is created by the
:meth:`~flask.Blueprint.make_setup_state` method and later passed
to all register callback functions.
"""

    def __init__(self, blueprint, app, options, first_registration):
        #: a reference to the current application
        self.app = app

        #: a reference to the blueprint that created this setup state.
        self.blueprint = blueprint

        #: a dictionary with all options that were passed to the
        #: :meth:`~flask.Flask.register_blueprint` method.
        self.options = options

        #: as blueprints can be registered multiple times with the
        #: application and not everything wants to be registered
        #: multiple times on it, this attribute can be used to figure
        #: out if the blueprint was registered in the past already.
        self.first_registration = first_registration

        subdomain = self.options.get('subdomain')
        if subdomain is None:
            subdomain = self.blueprint.subdomain

        #: The subdomain that the blueprint should be active for, `None`
        #: otherwise.
        self.subdomain = subdomain

        url_prefix = self.options.get('url_prefix')
        if url_prefix is None:
            url_prefix = self.blueprint.url_prefix

        #: The prefix that should be used for all URLs defined on the
        #: blueprint.
        self.url_prefix = url_prefix

        #: A dictionary with URL defaults that is added to each and every
        #: URL that was defined with the blueprint.
        self.url_defaults = dict(self.blueprint.url_values_defaults)
        self.url_defaults.update(self.options.get('url_defaults', ()))

    def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
        """A helper method to register a rule (and optionally a view function)
to the application. The endpoint is automatically prefixed with the
blueprint's name.
"""
        if self.url_prefix:
            rule = self.url_prefix + rule
        options.setdefault('subdomain', self.subdomain)
        if endpoint is None:
            endpoint = _endpoint_from_view_func(view_func)
        defaults = self.url_defaults
        if 'defaults' in options:
            defaults = dict(defaults, **options.pop('defaults'))
        self.app.add_url_rule(rule, '%s.%s' % (self.blueprint.name, endpoint),
                              view_func, defaults=defaults, **options)


class Blueprint(_PackageBoundObject):
    """Represents a blueprint. A blueprint is an object that records
functions that will be called with the
:class:`~flask.blueprint.BlueprintSetupState` later to register functions
or other things on the main application. See :ref:`blueprints` for more
information.

.. versionadded:: 0.7
"""

    warn_on_modifications = False
    _got_registered_once = False

    def __init__(self, name, import_name, static_folder=None,
                 static_url_path=None, template_folder=None,
                 url_prefix=None, subdomain=None, url_defaults=None):
        _PackageBoundObject.__init__(self, import_name, template_folder)
        self.name = name
        self.url_prefix = url_prefix
        self.subdomain = subdomain
        self.static_folder = static_folder
        self.static_url_path = static_url_path
        self.deferred_functions = []
        self.view_functions = {}
        if url_defaults is None:
            url_defaults = {}
        self.url_values_defaults = url_defaults

    def record(self, func):
        """Registers a function that is called when the blueprint is
registered on the application. This function is called with the
state as argument as returned by the :meth:`make_setup_state`
method.
"""
        if self._got_registered_once and self.warn_on_modifications:
            from warnings import warn
            warn(Warning('The blueprint was already registered once '
                         'but is getting modified now. These changes '
                         'will not show up.'))
        self.deferred_functions.append(func)

    def record_once(self, func):
        """Works like :meth:`record` but wraps the function in another
function that will ensure the function is only called once. If the
blueprint is registered a second time on the application, the
function passed is not called.
"""
        def wrapper(state):
            if state.first_registration:
                func(state)
        return self.record(update_wrapper(wrapper, func))

    def make_setup_state(self, app, options, first_registration=False):
        """Creates an instance of :meth:`~flask.blueprints.BlueprintSetupState`
object that is later passed to the register callback functions.
Subclasses can override this to return a subclass of the setup state.
"""
        return BlueprintSetupState(self, app, options, first_registration)

    def register(self, app, options, first_registration=False):
        """Called by :meth:`Flask.register_blueprint` to register a blueprint
on the application. This can be overridden to customize the register
behavior. Keyword arguments from
:func:`~flask.Flask.register_blueprint` are directly forwarded to this
method in the `options` dictionary.
"""
        self._got_registered_once = True
        state = self.make_setup_state(app, options, first_registration)
        if self.has_static_folder:
            state.add_url_rule(self.static_url_path + '/<path:filename>',
                               view_func=self.send_static_file,
                               endpoint='static')

        for deferred in self.deferred_functions:
            deferred(state)

    def route(self, rule, **options):
        """Like :meth:`Flask.route` but for a blueprint. The endpoint for the
:func:`url_for` function is prefixed with the name of the blueprint.
"""
        def decorator(f):
            endpoint = options.pop("endpoint", f.__name__)
            self.add_url_rule(rule, endpoint, f, **options)
            return f
        return decorator

    def add_url_rule(self, rule, endpoint=None, view_func=None, **options):
        """Like :meth:`Flask.add_url_rule` but for a blueprint. The endpoint for
the :func:`url_for` function is prefixed with the name of the blueprint.
"""
        if endpoint:
            assert '.' not in endpoint, "Blueprint endpoint's should not contain dot's"
        self.record(lambda s:
            s.add_url_rule(rule, endpoint, view_func, **options))

    def endpoint(self, endpoint):
        """Like :meth:`Flask.endpoint` but for a blueprint. This does not
prefix the endpoint with the blueprint name, this has to be done
explicitly by the user of this method. If the endpoint is prefixed
with a `.` it will be registered to the current blueprint, otherwise
it's an application independent endpoint.
"""
        def decorator(f):
            def register_endpoint(state):
                state.app.view_functions[endpoint] = f
            self.record_once(register_endpoint)
            return f
        return decorator

    def app_template_filter(self, name=None):
        """Register a custom template filter, available application wide. Like
:meth:`Flask.template_filter` but for a blueprint.

:param name: the optional name of the filter, otherwise the
function name will be used.
"""
        def decorator(f):
            self.add_app_template_filter(f, name=name)
            return f
        return decorator

    def add_app_template_filter(self, f, name=None):
        """Register a custom template filter, available application wide. Like
:meth:`Flask.add_template_filter` but for a blueprint. Works exactly
like the :meth:`app_template_filter` decorator.

:param name: the optional name of the filter, otherwise the
function name will be used.
"""
        def register_template(state):
            state.app.jinja_env.filters[name or f.__name__] = f
        self.record_once(register_template)

    def app_template_test(self, name=None):
        """Register a custom template test, available application wide. Like
:meth:`Flask.template_test` but for a blueprint.

.. versionadded:: 0.10

:param name: the optional name of the test, otherwise the
function name will be used.
"""
        def decorator(f):
            self.add_app_template_test(f, name=name)
            return f
        return decorator

    def add_app_template_test(self, f, name=None):
        """Register a custom template test, available application wide. Like
:meth:`Flask.add_template_test` but for a blueprint. Works exactly
like the :meth:`app_template_test` decorator.

.. versionadded:: 0.10

:param name: the optional name of the test, otherwise the
function name will be used.
"""
        def register_template(state):
            state.app.jinja_env.tests[name or f.__name__] = f
        self.record_once(register_template)

    def before_request(self, f):
        """Like :meth:`Flask.before_request` but for a blueprint. This function
is only executed before each request that is handled by a function of
that blueprint.
"""
        self.record_once(lambda s: s.app.before_request_funcs
            .setdefault(self.name, []).append(f))
        return f

    def before_app_request(self, f):
        """Like :meth:`Flask.before_request`. Such a function is executed
before each request, even if outside of a blueprint.
"""
        self.record_once(lambda s: s.app.before_request_funcs
            .setdefault(None, []).append(f))
        return f

    def before_app_first_request(self, f):
        """Like :meth:`Flask.before_first_request`. Such a function is
executed before the first request to the application.
"""
        self.record_once(lambda s: s.app.before_first_request_funcs.append(f))
        return f

    def after_request(self, f):
        """Like :meth:`Flask.after_request` but for a blueprint. This function
is only executed after each request that is handled by a function of
that blueprint.
"""
        self.record_once(lambda s: s.app.after_request_funcs
            .setdefault(self.name, []).append(f))
        return f

    def after_app_request(self, f):
        """Like :meth:`Flask.after_request` but for a blueprint. Such a function
is executed after each request, even if outside of the blueprint.
"""
        self.record_once(lambda s: s.app.after_request_funcs
            .setdefault(None, []).append(f))
        return f

    def teardown_request(self, f):
        """Like :meth:`Flask.teardown_request` but for a blueprint. This
function is only executed when tearing down requests handled by a
function of that blueprint. Teardown request functions are executed
when the request context is popped, even when no actual request was
performed.
"""
        self.record_once(lambda s: s.app.teardown_request_funcs
            .setdefault(self.name, []).append(f))
        return f

    def teardown_app_request(self, f):
        """Like :meth:`Flask.teardown_request` but for a blueprint. Such a
function is executed when tearing down each request, even if outside of
the blueprint.
"""
        self.record_once(lambda s: s.app.teardown_request_funcs
            .setdefault(None, []).append(f))
        return f

    def context_processor(self, f):
        """Like :meth:`Flask.context_processor` but for a blueprint. This
function is only executed for requests handled by a blueprint.
"""
        self.record_once(lambda s: s.app.template_context_processors
            .setdefault(self.name, []).append(f))
        return f

    def app_context_processor(self, f):
        """Like :meth:`Flask.context_processor` but for a blueprint. Such a
function is executed each request, even if outside of the blueprint.
"""
        self.record_once(lambda s: s.app.template_context_processors
            .setdefault(None, []).append(f))
        return f

    def app_errorhandler(self, code):
        """Like :meth:`Flask.errorhandler` but for a blueprint. This
handler is used for all requests, even if outside of the blueprint.
"""
        def decorator(f):
            self.record_once(lambda s: s.app.errorhandler(code)(f))
            return f
        return decorator

    def url_value_preprocessor(self, f):
        """Registers a function as URL value preprocessor for this
blueprint. It's called before the view functions are called and
can modify the url values provided.
"""
        self.record_once(lambda s: s.app.url_value_preprocessors
            .setdefault(self.name, []).append(f))
        return f

    def url_defaults(self, f):
        """Callback function for URL defaults for this blueprint. It's called
with the endpoint and values and should update the values passed
in place.
"""
        self.record_once(lambda s: s.app.url_default_functions
            .setdefault(self.name, []).append(f))
        return f

    def app_url_value_preprocessor(self, f):
        """Same as :meth:`url_value_preprocessor` but application wide.
"""
        self.record_once(lambda s: s.app.url_value_preprocessors
            .setdefault(None, []).append(f))
        return f

    def app_url_defaults(self, f):
        """Same as :meth:`url_defaults` but application wide.
"""
        self.record_once(lambda s: s.app.url_default_functions
            .setdefault(None, []).append(f))
        return f

    def errorhandler(self, code_or_exception):
        """Registers an error handler that becomes active for this blueprint
only. Please be aware that routing does not happen local to a
blueprint so an error handler for 404 usually is not handled by
a blueprint unless it is caused inside a view function. Another
special case is the 500 internal server error which is always looked
up from the application.

Otherwise works as the :meth:`~flask.Flask.errorhandler` decorator
of the :class:`~flask.Flask` object.
"""
        def decorator(f):
            self.record_once(lambda s: s.app._register_error_handler(
                self.name, code_or_exception, f))
            return f
        return decorator
Something went wrong with that request. Please try again.