""" Renderers are used to serialize a response into specific media types. They give us a generic way of being able to handle various media types on the response, such as JSON encoded data or HTML output. REST framework also provides an HTML renderer the renders the browsable API. """ from __future__ import unicode_literals import json import django from django import forms from django.core.exceptions import ImproperlyConfigured from django.http.multipartparser import parse_header from django.template import Context, RequestContext, loader, Template from django.test.client import encode_multipart from django.utils import six from rest_framework import exceptions, serializers, status, VERSION from rest_framework.compat import SHORT_SEPARATORS, LONG_SEPARATORS from rest_framework.exceptions import ParseError from rest_framework.settings import api_settings from rest_framework.request import is_form_media_type, override_method from rest_framework.utils import encoders from rest_framework.utils.breadcrumbs import get_breadcrumbs from rest_framework.utils.field_mapping import ClassLookupDict def zero_as_none(value): return None if value == 0 else value class BaseRenderer(object): """ All renderers should extend this class, setting the `media_type` and `format` attributes, and override the `.render()` method. """ media_type = None format = None charset = 'utf-8' render_style = 'text' def render(self, data, accepted_media_type=None, renderer_context=None): raise NotImplemented('Renderer class requires .render() to be implemented') class JSONRenderer(BaseRenderer): """ Renderer which serializes to JSON. """ media_type = 'application/json' format = 'json' encoder_class = encoders.JSONEncoder ensure_ascii = not api_settings.UNICODE_JSON compact = api_settings.COMPACT_JSON # We don't set a charset because JSON is a binary encoding, # that can be encoded as utf-8, utf-16 or utf-32. # See: http://www.ietf.org/rfc/rfc4627.txt # Also: http://lucumr.pocoo.org/2013/7/19/application-mimetypes-and-encodings/ charset = None def get_indent(self, accepted_media_type, renderer_context): if accepted_media_type: # If the media type looks like 'application/json; indent=4', # then pretty print the result. # Note that we coerce `indent=0` into `indent=None`. base_media_type, params = parse_header(accepted_media_type.encode('ascii')) try: return zero_as_none(max(min(int(params['indent']), 8), 0)) except (KeyError, ValueError, TypeError): pass # If 'indent' is provided in the context, then pretty print the result. # E.g. If we're being called by the BrowsableAPIRenderer. return renderer_context.get('indent', None) def render(self, data, accepted_media_type=None, renderer_context=None): """ Render `data` into JSON, returning a bytestring. """ if data is None: return bytes() renderer_context = renderer_context or {} indent = self.get_indent(accepted_media_type, renderer_context) separators = SHORT_SEPARATORS if (indent is None and self.compact) else LONG_SEPARATORS ret = json.dumps( data, cls=self.encoder_class, indent=indent, ensure_ascii=self.ensure_ascii, separators=separators ) # On python 2.x json.dumps() returns bytestrings if ensure_ascii=True, # but if ensure_ascii=False, the return type is underspecified, # and may (or may not) be unicode. # On python 3.x json.dumps() returns unicode strings. if isinstance(ret, six.text_type): return bytes(ret.encode('utf-8')) return ret class TemplateHTMLRenderer(BaseRenderer): """ An HTML renderer for use with templates. The data supplied to the Response object should be a dictionary that will be used as context for the template. The template name is determined by (in order of preference): 1. An explicit `.template_name` attribute set on the response. 2. An explicit `.template_name` attribute set on this class. 3. The return result of calling `view.get_template_names()`. For example: data = {'users': User.objects.all()} return Response(data, template_name='users.html') For pre-rendered HTML, see StaticHTMLRenderer. """ media_type = 'text/html' format = 'html' template_name = None exception_template_names = [ '%(status_code)s.html', 'api_exception.html' ] charset = 'utf-8' def render(self, data, accepted_media_type=None, renderer_context=None): """ Renders data to HTML, using Django's standard template rendering. The template name is determined by (in order of preference): 1. An explicit .template_name set on the response. 2. An explicit .template_name set on this class. 3. The return result of calling view.get_template_names(). """ renderer_context = renderer_context or {} view = renderer_context['view'] request = renderer_context['request'] response = renderer_context['response'] if response.exception: template = self.get_exception_template(response) else: template_names = self.get_template_names(response, view) template = self.resolve_template(template_names) context = self.resolve_context(data, request, response) return template.render(context) def resolve_template(self, template_names): return loader.select_template(template_names) def resolve_context(self, data, request, response): if response.exception: data['status_code'] = response.status_code return RequestContext(request, data) def get_template_names(self, response, view): if response.template_name: return [response.template_name] elif self.template_name: return [self.template_name] elif hasattr(view, 'get_template_names'): return view.get_template_names() elif hasattr(view, 'template_name'): return [view.template_name] raise ImproperlyConfigured('Returned a template response with no `template_name` attribute set on either the view or response') def get_exception_template(self, response): template_names = [name % {'status_code': response.status_code} for name in self.exception_template_names] try: # Try to find an appropriate error template return self.resolve_template(template_names) except Exception: # Fall back to using eg '404 Not Found' return Template('%d %s' % (response.status_code, response.status_text.title())) # Note, subclass TemplateHTMLRenderer simply for the exception behavior class StaticHTMLRenderer(TemplateHTMLRenderer): """ An HTML renderer class that simply returns pre-rendered HTML. The data supplied to the Response object should be a string representing the pre-rendered HTML content. For example: data = 'example' return Response(data) For template rendered HTML, see TemplateHTMLRenderer. """ media_type = 'text/html' format = 'html' charset = 'utf-8' def render(self, data, accepted_media_type=None, renderer_context=None): renderer_context = renderer_context or {} response = renderer_context['response'] if response and response.exception: request = renderer_context['request'] template = self.get_exception_template(response) context = self.resolve_context(data, request, response) return template.render(context) return data class HTMLFormRenderer(BaseRenderer): """ Renderers serializer data into an HTML form. If the serializer was instantiated without an object then this will return an HTML form not bound to any object, otherwise it will return an HTML form with the appropriate initial data populated from the object. Note that rendering of field and form errors is not currently supported. """ media_type = 'text/html' format = 'form' charset = 'utf-8' template_pack = 'rest_framework/horizontal/' base_template = 'form.html' default_style = ClassLookupDict({ serializers.Field: { 'base_template': 'input.html', 'input_type': 'text' }, serializers.EmailField: { 'base_template': 'input.html', 'input_type': 'email' }, serializers.URLField: { 'base_template': 'input.html', 'input_type': 'url' }, serializers.IntegerField: { 'base_template': 'input.html', 'input_type': 'number' }, serializers.DateTimeField: { 'base_template': 'input.html', 'input_type': 'datetime-local' }, serializers.DateField: { 'base_template': 'input.html', 'input_type': 'date' }, serializers.TimeField: { 'base_template': 'input.html', 'input_type': 'time' }, serializers.BooleanField: { 'base_template': 'checkbox.html' }, serializers.ChoiceField: { 'base_template': 'select.html', # Also valid: 'radio.html' }, serializers.MultipleChoiceField: { 'base_template': 'select_multiple.html', # Also valid: 'checkbox_multiple.html' }, serializers.RelatedField: { 'base_template': 'select.html', # Also valid: 'radio.html' }, serializers.ManyRelatedField: { 'base_template': 'select_multiple.html', # Also valid: 'checkbox_multiple.html' }, serializers.Serializer: { 'base_template': 'fieldset.html' }, serializers.ListSerializer: { 'base_template': 'list_fieldset.html' } }) def render_field(self, field, parent_style): style = dict(self.default_style[field]) style.update(field.style) if 'template_pack' not in style: style['template_pack'] = parent_style.get('template_pack', self.template_pack) style['renderer'] = self if style.get('input_type') == 'datetime-local' and isinstance(field.value, six.text_type): field.value = field.value.rstrip('Z') if 'template' in style: template_name = style['template'] else: template_name = style['template_pack'].strip('/') + '/' + style['base_template'] template = loader.get_template(template_name) context = Context({'field': field, 'style': style}) return template.render(context) def render(self, data, accepted_media_type=None, renderer_context=None): """ Render serializer data and return an HTML form, as a string. """ form = data.serializer meta = getattr(form, 'Meta', None) style = getattr(meta, 'style', {}) if 'template_pack' not in style: style['template_pack'] = self.template_pack if 'base_template' not in style: style['base_template'] = self.base_template style['renderer'] = self # This API needs to be finessed and finalized for 3.1 if 'template' in renderer_context: template_name = renderer_context['template'] elif 'template' in style: template_name = style['template'] else: template_name = style['template_pack'].strip('/') + '/' + style['base_template'] renderer_context = renderer_context or {} request = renderer_context['request'] template = loader.get_template(template_name) context = RequestContext(request, { 'form': form, 'style': style }) return template.render(context) class BrowsableAPIRenderer(BaseRenderer): """ HTML renderer used to self-document the API. """ media_type = 'text/html' format = 'api' template = 'rest_framework/api.html' charset = 'utf-8' form_renderer_class = HTMLFormRenderer def get_default_renderer(self, view): """ Return an instance of the first valid renderer. (Don't use another documenting renderer.) """ renderers = [renderer for renderer in view.renderer_classes if not issubclass(renderer, BrowsableAPIRenderer)] non_template_renderers = [renderer for renderer in renderers if not hasattr(renderer, 'get_template_names')] if not renderers: return None elif non_template_renderers: return non_template_renderers[0]() return renderers[0]() def get_content(self, renderer, data, accepted_media_type, renderer_context): """ Get the content as if it had been rendered by the default non-documenting renderer. """ if not renderer: return '[No renderers were found]' renderer_context['indent'] = 4 content = renderer.render(data, accepted_media_type, renderer_context) render_style = getattr(renderer, 'render_style', 'text') assert render_style in ['text', 'binary'], 'Expected .render_style ' \ '"text" or "binary", but got "%s"' % render_style if render_style == 'binary': return '[%d bytes of binary content]' % len(content) return content def show_form_for_method(self, view, method, request, obj): """ Returns True if a form should be shown for this method. """ if method not in view.allowed_methods: return # Not a valid method if not api_settings.FORM_METHOD_OVERRIDE: return # Cannot use form overloading try: view.check_permissions(request) if obj is not None: view.check_object_permissions(request, obj) except exceptions.APIException: return False # Doesn't have permissions return True def get_rendered_html_form(self, data, view, method, request): """ Return a string representing a rendered HTML form, possibly bound to either the input or output data. In the absence of the View having an associated form then return None. """ # See issue #2089 for refactoring this. serializer = getattr(data, 'serializer', None) if serializer and not getattr(serializer, 'many', False): instance = getattr(serializer, 'instance', None) else: instance = None # If this is valid serializer data, and the form is for the same # HTTP method as was used in the request then use the existing # serializer instance, rather than dynamically creating a new one. if request.method == method and serializer is not None: try: data = request.data except ParseError: data = None existing_serializer = serializer else: data = None existing_serializer = None with override_method(view, request, method) as request: if not self.show_form_for_method(view, method, request, instance): return if method in ('DELETE', 'OPTIONS'): return True # Don't actually need to return a form if ( not getattr(view, 'get_serializer', None) or not any(is_form_media_type(parser.media_type) for parser in view.parser_classes) ): return if existing_serializer is not None: serializer = existing_serializer else: if method in ('PUT', 'PATCH'): serializer = view.get_serializer(instance=instance, data=data) else: serializer = view.get_serializer(data=data) if data is not None: serializer.is_valid() form_renderer = self.form_renderer_class() return form_renderer.render( serializer.data, self.accepted_media_type, dict( list(self.renderer_context.items()) + [('template', 'rest_framework/api_form.html')] ) ) def get_raw_data_form(self, data, view, method, request): """ Returns a form that allows for arbitrary content types to be tunneled via standard HTML forms. (Which are typically application/x-www-form-urlencoded) """ # See issue #2089 for refactoring this. serializer = getattr(data, 'serializer', None) if serializer and not getattr(serializer, 'many', False): instance = getattr(serializer, 'instance', None) else: instance = None with override_method(view, request, method) as request: # If we're not using content overloading there's no point in # supplying a generic form, as the view won't treat the form's # value as the content of the request. if not (api_settings.FORM_CONTENT_OVERRIDE and api_settings.FORM_CONTENTTYPE_OVERRIDE): return None # Check permissions if not self.show_form_for_method(view, method, request, instance): return # If possible, serialize the initial content for the generic form default_parser = view.parser_classes[0] renderer_class = getattr(default_parser, 'renderer_class', None) if (hasattr(view, 'get_serializer') and renderer_class): # View has a serializer defined and parser class has a # corresponding renderer that can be used to render the data. if method in ('PUT', 'PATCH'): serializer = view.get_serializer(instance=instance) else: serializer = view.get_serializer() # Render the raw data content renderer = renderer_class() accepted = self.accepted_media_type context = self.renderer_context.copy() context['indent'] = 4 content = renderer.render(serializer.data, accepted, context) else: content = None # Generate a generic form that includes a content type field, # and a content field. content_type_field = api_settings.FORM_CONTENTTYPE_OVERRIDE content_field = api_settings.FORM_CONTENT_OVERRIDE media_types = [parser.media_type for parser in view.parser_classes] choices = [(media_type, media_type) for media_type in media_types] initial = media_types[0] # NB. http://jacobian.org/writing/dynamic-form-generation/ class GenericContentForm(forms.Form): def __init__(self): super(GenericContentForm, self).__init__() self.fields[content_type_field] = forms.ChoiceField( label='Media type', choices=choices, initial=initial ) self.fields[content_field] = forms.CharField( label='Content', widget=forms.Textarea, initial=content ) return GenericContentForm() def get_name(self, view): return view.get_view_name() def get_description(self, view): return view.get_view_description(html=True) def get_breadcrumbs(self, request): return get_breadcrumbs(request.path) def get_context(self, data, accepted_media_type, renderer_context): """ Returns the context used to render. """ view = renderer_context['view'] request = renderer_context['request'] response = renderer_context['response'] renderer = self.get_default_renderer(view) raw_data_post_form = self.get_raw_data_form(data, view, 'POST', request) raw_data_put_form = self.get_raw_data_form(data, view, 'PUT', request) raw_data_patch_form = self.get_raw_data_form(data, view, 'PATCH', request) raw_data_put_or_patch_form = raw_data_put_form or raw_data_patch_form response_headers = dict(response.items()) renderer_content_type = '' if renderer: renderer_content_type = '%s' % renderer.media_type if renderer.charset: renderer_content_type += ' ;%s' % renderer.charset response_headers['Content-Type'] = renderer_content_type context = { 'content': self.get_content(renderer, data, accepted_media_type, renderer_context), 'view': view, 'request': request, 'response': response, 'description': self.get_description(view), 'name': self.get_name(view), 'version': VERSION, 'breadcrumblist': self.get_breadcrumbs(request), 'allowed_methods': view.allowed_methods, 'available_formats': [renderer_cls.format for renderer_cls in view.renderer_classes], 'response_headers': response_headers, 'put_form': self.get_rendered_html_form(data, view, 'PUT', request), 'post_form': self.get_rendered_html_form(data, view, 'POST', request), 'delete_form': self.get_rendered_html_form(data, view, 'DELETE', request), 'options_form': self.get_rendered_html_form(data, view, 'OPTIONS', request), 'raw_data_put_form': raw_data_put_form, 'raw_data_post_form': raw_data_post_form, 'raw_data_patch_form': raw_data_patch_form, 'raw_data_put_or_patch_form': raw_data_put_or_patch_form, 'display_edit_forms': bool(response.status_code != 403), 'api_settings': api_settings } return context def render(self, data, accepted_media_type=None, renderer_context=None): """ Render the HTML for the browsable API representation. """ self.accepted_media_type = accepted_media_type or '' self.renderer_context = renderer_context or {} template = loader.get_template(self.template) context = self.get_context(data, accepted_media_type, renderer_context) context = RequestContext(renderer_context['request'], context) ret = template.render(context) # Munge DELETE Response code to allow us to return content # (Do this *after* we've rendered the template so that we include # the normal deletion response code in the output) response = renderer_context['response'] if response.status_code == status.HTTP_204_NO_CONTENT: response.status_code = status.HTTP_200_OK return ret class MultiPartRenderer(BaseRenderer): media_type = 'multipart/form-data; boundary=BoUnDaRyStRiNg' format = 'multipart' charset = 'utf-8' BOUNDARY = 'BoUnDaRyStRiNg' if django.VERSION >= (1, 5) else b'BoUnDaRyStRiNg' def render(self, data, accepted_media_type=None, renderer_context=None): return encode_multipart(self.BOUNDARY, data)