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Source code for pyramid.renderers

import json
import os

from zope.interface import (
    implementer,
    providedBy,
    )
from zope.interface.registry import Components

from pyramid.interfaces import (
    IJSONAdapter,
    IRendererFactory,
    IResponseFactory,
    IRendererInfo,
    )

from pyramid.compat import (
    string_types,
    text_type,
    )

from pyramid.decorator import reify

from pyramid.events import BeforeRender

from pyramid.path import caller_package

from pyramid.response import Response
from pyramid.threadlocal import get_current_registry

# API

[docs]def render(renderer_name, value, request=None, package=None): """ Using the renderer ``renderer_name`` (a template or a static renderer), render the value (or set of values) present in ``value``. Return the result of the renderer's ``__call__`` method (usually a string or Unicode). If the ``renderer_name`` refers to a file on disk, such as when the renderer is a template, it's usually best to supply the name as an :term:`asset specification` (e.g. ``packagename:path/to/template.pt``). You may supply a relative asset spec as ``renderer_name``. If the ``package`` argument is supplied, a relative renderer path will be converted to an absolute asset specification by combining the package ``package`` with the relative asset specification ``renderer_name``. If ``package`` is ``None`` (the default), the package name of the *caller* of this function will be used as the package. The ``value`` provided will be supplied as the input to the renderer. Usually, for template renderings, this should be a dictionary. For other renderers, this will need to be whatever sort of value the renderer expects. The 'system' values supplied to the renderer will include a basic set of top-level system names, such as ``request``, ``context``, ``renderer_name``, and ``view``. See :ref:`renderer_system_values` for the full list. If :term:`renderer globals` have been specified, these will also be used to augment the value. Supply a ``request`` parameter in order to provide the renderer with the most correct 'system' values (``request`` and ``context`` in particular). """ try: registry = request.registry except AttributeError: registry = None if package is None: package = caller_package() helper = RendererHelper(name=renderer_name, package=package, registry=registry) saved_response = None # save the current response, preventing the renderer from affecting it attrs = request.__dict__ if request is not None else {} if 'response' in attrs: saved_response = attrs['response'] del attrs['response'] result = helper.render(value, None, request=request) # restore the original response, overwriting any changes if saved_response is not None: attrs['response'] = saved_response elif 'response' in attrs: del attrs['response'] return result
[docs]def render_to_response(renderer_name, value, request=None, package=None): """ Using the renderer ``renderer_name`` (a template or a static renderer), render the value (or set of values) using the result of the renderer's ``__call__`` method (usually a string or Unicode) as the response body. If the renderer name refers to a file on disk (such as when the renderer is a template), it's usually best to supply the name as a :term:`asset specification`. You may supply a relative asset spec as ``renderer_name``. If the ``package`` argument is supplied, a relative renderer name will be converted to an absolute asset specification by combining the package ``package`` with the relative asset specification ``renderer_name``. If you do not supply a ``package`` (or ``package`` is ``None``) the package name of the *caller* of this function will be used as the package. The ``value`` provided will be supplied as the input to the renderer. Usually, for template renderings, this should be a dictionary. For other renderers, this will need to be whatever sort of value the renderer expects. The 'system' values supplied to the renderer will include a basic set of top-level system names, such as ``request``, ``context``, ``renderer_name``, and ``view``. See :ref:`renderer_system_values` for the full list. If :term:`renderer globals` have been specified, these will also be used to argument the value. Supply a ``request`` parameter in order to provide the renderer with the most correct 'system' values (``request`` and ``context`` in particular). Keep in mind that if the ``request`` parameter is not passed in, any changes to ``request.response`` attributes made before calling this function will be ignored. """ try: registry = request.registry except AttributeError: registry = None if package is None: package = caller_package() helper = RendererHelper(name=renderer_name, package=package, registry=registry) return helper.render_to_response(value, None, request=request)
[docs]def get_renderer(renderer_name, package=None): """ Return the renderer object for the renderer ``renderer_name``. You may supply a relative asset spec as ``renderer_name``. If the ``package`` argument is supplied, a relative renderer name will be converted to an absolute asset specification by combining the package ``package`` with the relative asset specification ``renderer_name``. If ``package`` is ``None`` (the default), the package name of the *caller* of this function will be used as the package. """ if package is None: package = caller_package() helper = RendererHelper(name=renderer_name, package=package) return helper.renderer # concrete renderer factory implementations (also API)
def string_renderer_factory(info): def _render(value, system): if not isinstance(value, string_types): value = str(value) request = system.get('request') if request is not None: response = request.response ct = response.content_type if ct == response.default_content_type: response.content_type = 'text/plain' return value return _render _marker = object()
[docs]class JSON(object): """ Renderer that returns a JSON-encoded string. Configure a custom JSON renderer using the :meth:`~pyramid.config.Configurator.add_renderer` API at application startup time: .. code-block:: python from pyramid.config import Configurator config = Configurator() config.add_renderer('myjson', JSON(indent=4)) Once this renderer is registered as above, you can use ``myjson`` as the ``renderer=`` parameter to ``@view_config`` or :meth:`~pyramid.config.Configurator.add_view``: .. code-block:: python from pyramid.view import view_config @view_config(renderer='myjson') def myview(request): return {'greeting':'Hello world'} Custom objects can be serialized using the renderer by either implementing the ``__json__`` magic method, or by registering adapters with the renderer. See :ref:`json_serializing_custom_objects` for more information. .. note:: The default serializer uses ``json.JSONEncoder``. A different serializer can be specified via the ``serializer`` argument. Custom serializers should accept the object, a callback ``default``, and any extra ``kw`` keyword arguments passed during renderer construction. This feature isn't widely used but it can be used to replace the stock JSON serializer with, say, simplejson. If all you want to do, however, is serialize custom objects, you should use the method explained in :ref:`json_serializing_custom_objects` instead of replacing the serializer. .. versionadded:: 1.4 Prior to this version, there was no public API for supplying options to the underlying serializer without defining a custom renderer. """ def __init__(self, serializer=json.dumps, adapters=(), **kw): """ Any keyword arguments will be passed to the ``serializer`` function.""" self.serializer = serializer self.kw = kw self.components = Components() for type, adapter in adapters: self.add_adapter(type, adapter)
[docs] def add_adapter(self, type_or_iface, adapter): """ When an object of the type (or interface) ``type_or_iface`` fails to automatically encode using the serializer, the renderer will use the adapter ``adapter`` to convert it into a JSON-serializable object. The adapter must accept two arguments: the object and the currently active request. .. code-block:: python class Foo(object): x = 5 def foo_adapter(obj, request): return obj.x renderer = JSON(indent=4) renderer.add_adapter(Foo, foo_adapter) When you've done this, the JSON renderer will be able to serialize instances of the ``Foo`` class when they're encountered in your view results.""" self.components.registerAdapter(adapter, (type_or_iface,), IJSONAdapter)
def __call__(self, info): """ Returns a plain JSON-encoded string with content-type ``application/json``. The content-type may be overridden by setting ``request.response.content_type``.""" def _render(value, system): request = system.get('request') if request is not None: response = request.response ct = response.content_type if ct == response.default_content_type: response.content_type = 'application/json' default = self._make_default(request) return self.serializer(value, default=default, **self.kw) return _render def _make_default(self, request): def default(obj): if hasattr(obj, '__json__'): return obj.__json__(request) obj_iface = providedBy(obj) adapters = self.components.adapters result = adapters.lookup((obj_iface,), IJSONAdapter, default=_marker) if result is _marker: raise TypeError('%r is not JSON serializable' % (obj,)) return result(obj, request) return default
json_renderer_factory = JSON() # bw compat
[docs]class JSONP(JSON): """ `JSONP <http://en.wikipedia.org/wiki/JSONP>`_ renderer factory helper which implements a hybrid json/jsonp renderer. JSONP is useful for making cross-domain AJAX requests. Configure a JSONP renderer using the :meth:`pyramid.config.Configurator.add_renderer` API at application startup time: .. code-block:: python from pyramid.config import Configurator config = Configurator() config.add_renderer('jsonp', JSONP(param_name='callback')) The class' constructor also accepts arbitrary keyword arguments. All keyword arguments except ``param_name`` are passed to the ``json.dumps`` function as its keyword arguments. .. code-block:: python from pyramid.config import Configurator config = Configurator() config.add_renderer('jsonp', JSONP(param_name='callback', indent=4)) .. versionchanged:: 1.4 The ability of this class to accept a ``**kw`` in its constructor. The arguments passed to this class' constructor mean the same thing as the arguments passed to :class:`pyramid.renderers.JSON` (including ``serializer`` and ``adapters``). Once this renderer is registered via :meth:`~pyramid.config.Configurator.add_renderer` as above, you can use ``jsonp`` as the ``renderer=`` parameter to ``@view_config`` or :meth:`pyramid.config.Configurator.add_view``: .. code-block:: python from pyramid.view import view_config @view_config(renderer='jsonp') def myview(request): return {'greeting':'Hello world'} When a view is called that uses the JSONP renderer: - If there is a parameter in the request's HTTP query string that matches the ``param_name`` of the registered JSONP renderer (by default, ``callback``), the renderer will return a JSONP response. - If there is no callback parameter in the request's query string, the renderer will return a 'plain' JSON response. .. versionadded:: 1.1 .. seealso:: See also :ref:`jsonp_renderer`. """ def __init__(self, param_name='callback', **kw): self.param_name = param_name JSON.__init__(self, **kw) def __call__(self, info): """ Returns JSONP-encoded string with content-type ``application/javascript`` if query parameter matching ``self.param_name`` is present in request.GET; otherwise returns plain-JSON encoded string with content-type ``application/json``""" def _render(value, system): request = system['request'] default = self._make_default(request) val = self.serializer(value, default=default, **self.kw) callback = request.GET.get(self.param_name) if callback is None: ct = 'application/json' body = val else: ct = 'application/javascript' body = '%s(%s);' % (callback, val) response = request.response if response.content_type == response.default_content_type: response.content_type = ct return body return _render
@implementer(IRendererInfo) class RendererHelper(object): def __init__(self, name=None, package=None, registry=None): if name and '.' in name: rtype = os.path.splitext(name)[1] else: # important.. must be a string; cannot be None; see issue 249 rtype = name or '' if registry is None: registry = get_current_registry() self.name = name self.package = package self.type = rtype self.registry = registry @reify def settings(self): settings = self.registry.settings if settings is None: settings = {} return settings @reify def renderer(self): factory = self.registry.queryUtility(IRendererFactory, name=self.type) if factory is None: raise ValueError( 'No such renderer factory %s' % str(self.type)) return factory(self) def get_renderer(self): return self.renderer def render_view(self, request, response, view, context): system = {'view':view, 'renderer_name':self.name, # b/c 'renderer_info':self, 'context':context, 'request':request, 'req':request, } return self.render_to_response(response, system, request=request) def render(self, value, system_values, request=None): renderer = self.renderer if system_values is None: system_values = { 'view':None, 'renderer_name':self.name, # b/c 'renderer_info':self, 'context':getattr(request, 'context', None), 'request':request, 'req':request, } system_values = BeforeRender(system_values, value) registry = self.registry registry.notify(system_values) result = renderer(value, system_values) return result def render_to_response(self, value, system_values, request=None): result = self.render(value, system_values, request=request) return self._make_response(result, request) def _make_response(self, result, request): # broken out of render_to_response as a separate method for testing # purposes response = getattr(request, 'response', None) if response is None: # request is None or request is not a pyramid.response.Response registry = self.registry response_factory = registry.queryUtility(IResponseFactory, default=Response) response = response_factory() if result is not None: if isinstance(result, text_type): response.text = result else: response.body = result return response def clone(self, name=None, package=None, registry=None): if name is None: name = self.name if package is None: package = self.package if registry is None: registry = self.registry return self.__class__(name=name, package=package, registry=registry) class NullRendererHelper(RendererHelper): """ Special renderer helper that has render_* methods which simply return the value they are fed rather than converting them to response objects; useful for testing purposes and special case view configuration registrations that want to use the view configuration machinery but do not want actual rendering to happen .""" def __init__(self, name=None, package=None, registry=None): # we override the initializer to avoid calling get_current_registry # (it will return a reference to the global registry when this # thing is called at module scope; we don't want that). self.name = None self.package = None self.type = '' self.registry = None @property def settings(self): return get_current_registry().settings or {} def render_view(self, request, value, view, context): return value def render(self, value, system_values, request=None): return value def render_to_response(self, value, system_values, request=None): return value def clone(self, name=None, package=None, registry=None): return self null_renderer = NullRendererHelper()