|
| 1 | +from __future__ import unicode_literals |
| 2 | +import warnings |
| 3 | +from django.conf.urls import url, patterns, include |
| 4 | +from django.core.exceptions import ImproperlyConfigured |
| 5 | +from django.core.urlresolvers import reverse |
| 6 | +from django.http import HttpResponse, HttpResponseBadRequest |
| 7 | +from tastypie.exceptions import NotRegistered, BadRequest |
| 8 | +from tastypie.serializers import Serializer |
| 9 | +from tastypie.utils import trailing_slash, is_valid_jsonp_callback_value |
| 10 | +from tastypie.utils.mime import determine_format, build_content_type |
| 11 | + |
| 12 | +class Api(object): |
| 13 | + """ |
| 14 | + Implements a registry to tie together the various resources that make up |
| 15 | + an API. |
| 16 | +
|
| 17 | + Especially useful for navigation, HATEOAS and for providing multiple |
| 18 | + versions of your API. |
| 19 | +
|
| 20 | + Optionally supplying ``api_name`` allows you to name the API. Generally, |
| 21 | + this is done with version numbers (i.e. ``v1``, ``v2``, etc.) but can |
| 22 | + be named any string. |
| 23 | + """ |
| 24 | + def __init__(self, api_name="v1", serializer_class=Serializer): |
| 25 | + self.api_name = api_name |
| 26 | + self._registry = {} |
| 27 | + self._canonicals = {} |
| 28 | + self.serializer = serializer_class() |
| 29 | + |
| 30 | + def register(self, resource, canonical=True): |
| 31 | + """ |
| 32 | + Registers an instance of a ``Resource`` subclass with the API. |
| 33 | +
|
| 34 | + Optionally accept a ``canonical`` argument, which indicates that the |
| 35 | + resource being registered is the canonical variant. Defaults to |
| 36 | + ``True``. |
| 37 | + """ |
| 38 | + resource_name = getattr(resource._meta, 'resource_name', None) |
| 39 | + |
| 40 | + if resource_name is None: |
| 41 | + raise ImproperlyConfigured("Resource %r must define a 'resource_name'." % resource) |
| 42 | + |
| 43 | + self._registry[resource_name] = resource |
| 44 | + |
| 45 | + if canonical is True: |
| 46 | + if resource_name in self._canonicals: |
| 47 | + warnings.warn("A new resource '%r' is replacing the existing canonical URL for '%s'." % (resource, resource_name), Warning, stacklevel=2) |
| 48 | + |
| 49 | + self._canonicals[resource_name] = resource |
| 50 | + # TODO: This is messy, but makes URI resolution on FK/M2M fields |
| 51 | + # work consistently. |
| 52 | + resource._meta.api_name = self.api_name |
| 53 | + resource.__class__.Meta.api_name = self.api_name |
| 54 | + |
| 55 | + def unregister(self, resource_name): |
| 56 | + """ |
| 57 | + If present, unregisters a resource from the API. |
| 58 | + """ |
| 59 | + if resource_name in self._registry: |
| 60 | + del(self._registry[resource_name]) |
| 61 | + |
| 62 | + if resource_name in self._canonicals: |
| 63 | + del(self._canonicals[resource_name]) |
| 64 | + |
| 65 | + def canonical_resource_for(self, resource_name): |
| 66 | + """ |
| 67 | + Returns the canonical resource for a given ``resource_name``. |
| 68 | + """ |
| 69 | + if resource_name in self._canonicals: |
| 70 | + return self._canonicals[resource_name] |
| 71 | + |
| 72 | + raise NotRegistered("No resource was registered as canonical for '%s'." % resource_name) |
| 73 | + |
| 74 | + def wrap_view(self, view): |
| 75 | + def wrapper(request, *args, **kwargs): |
| 76 | + try: |
| 77 | + return getattr(self, view)(request, *args, **kwargs) |
| 78 | + except BadRequest: |
| 79 | + return HttpResponseBadRequest() |
| 80 | + return wrapper |
| 81 | + |
| 82 | + def override_urls(self): |
| 83 | + """ |
| 84 | + Deprecated. Will be removed by v1.0.0. Please use ``prepend_urls`` instead. |
| 85 | + """ |
| 86 | + return [] |
| 87 | + |
| 88 | + def prepend_urls(self): |
| 89 | + """ |
| 90 | + A hook for adding your own URLs or matching before the default URLs. |
| 91 | + """ |
| 92 | + return [] |
| 93 | + |
| 94 | + @property |
| 95 | + def urls(self): |
| 96 | + """ |
| 97 | + Provides URLconf details for the ``Api`` and all registered |
| 98 | + ``Resources`` beneath it. |
| 99 | + """ |
| 100 | + pattern_list = [ |
| 101 | + url(r"^(?P<api_name>%s)%s$" % (self.api_name, trailing_slash()), self.wrap_view('top_level'), name="api_%s_top_level" % self.api_name), |
| 102 | + ] |
| 103 | + |
| 104 | + for name in sorted(self._registry.keys()): |
| 105 | + self._registry[name].api_name = self.api_name |
| 106 | + pattern_list.append((r"^(?P<api_name>%s)/" % self.api_name, include(self._registry[name].urls))) |
| 107 | + |
| 108 | + urlpatterns = self.prepend_urls() |
| 109 | + |
| 110 | + overridden_urls = self.override_urls() |
| 111 | + if overridden_urls: |
| 112 | + warnings.warn("'override_urls' is a deprecated method & will be removed by v1.0.0. Please rename your method to ``prepend_urls``.") |
| 113 | + urlpatterns += overridden_urls |
| 114 | + |
| 115 | + urlpatterns += patterns('', |
| 116 | + *pattern_list |
| 117 | + ) |
| 118 | + return urlpatterns |
| 119 | + |
| 120 | + def top_level(self, request, api_name=None): |
| 121 | + """ |
| 122 | + A view that returns a serialized list of all resources registers |
| 123 | + to the ``Api``. Useful for discovery. |
| 124 | + """ |
| 125 | + available_resources = {} |
| 126 | + |
| 127 | + if api_name is None: |
| 128 | + api_name = self.api_name |
| 129 | + |
| 130 | + for name in sorted(self._registry.keys()): |
| 131 | + available_resources[name] = { |
| 132 | + 'list_endpoint': self._build_reverse_url("api_dispatch_list", kwargs={ |
| 133 | + 'api_name': api_name, |
| 134 | + 'resource_name': name, |
| 135 | + }), |
| 136 | + 'schema': self._build_reverse_url("api_get_schema", kwargs={ |
| 137 | + 'api_name': api_name, |
| 138 | + 'resource_name': name, |
| 139 | + }), |
| 140 | + } |
| 141 | + |
| 142 | + desired_format = determine_format(request, self.serializer) |
| 143 | + |
| 144 | + options = {} |
| 145 | + |
| 146 | + if 'text/javascript' in desired_format: |
| 147 | + callback = request.GET.get('callback', 'callback') |
| 148 | + |
| 149 | + if not is_valid_jsonp_callback_value(callback): |
| 150 | + raise BadRequest('JSONP callback name is invalid.') |
| 151 | + |
| 152 | + options['callback'] = callback |
| 153 | + |
| 154 | + serialized = self.serializer.serialize(available_resources, desired_format, options) |
| 155 | + return HttpResponse(content=serialized, content_type=build_content_type(desired_format)) |
| 156 | + |
| 157 | + def _build_reverse_url(self, name, args=None, kwargs=None): |
| 158 | + """ |
| 159 | + A convenience hook for overriding how URLs are built. |
| 160 | +
|
| 161 | + See ``NamespacedApi._build_reverse_url`` for an example. |
| 162 | + """ |
| 163 | + return reverse(name, args=args, kwargs=kwargs) |
| 164 | + |
| 165 | + |
| 166 | +class NamespacedApi(Api): |
| 167 | + """ |
| 168 | + An API subclass that respects Django namespaces. |
| 169 | + """ |
| 170 | + def __init__(self, api_name="v1", urlconf_namespace=None, **kwargs): |
| 171 | + super(NamespacedApi, self).__init__(api_name=api_name, **kwargs) |
| 172 | + self.urlconf_namespace = urlconf_namespace |
| 173 | + |
| 174 | + def register(self, resource, canonical=True): |
| 175 | + super(NamespacedApi, self).register(resource, canonical=canonical) |
| 176 | + |
| 177 | + if canonical is True: |
| 178 | + # Plop in the namespace here as well. |
| 179 | + resource._meta.urlconf_namespace = self.urlconf_namespace |
| 180 | + |
| 181 | + def _build_reverse_url(self, name, args=None, kwargs=None): |
| 182 | + namespaced = "%s:%s" % (self.urlconf_namespace, name) |
| 183 | + return reverse(namespaced, args=args, kwargs=kwargs) |
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