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authortom christie tom@tomchristie.com2011-01-30 18:30:39 +0000
committertom christie tom@tomchristie.com2011-01-30 18:30:39 +0000
commit42f2f9b40d1295e18a5b720b0d1f6ad85e928d8a (patch)
tree458f97992bcd1348a413d21a5925f933ba7f74e3 /djangorestframework/emitters.py
parent8a470f031eeccf45625c3e3e18a8743021b38d41 (diff)
downloaddjango-rest-framework-42f2f9b40d1295e18a5b720b0d1f6ad85e928d8a.tar.bz2
Rename to django-rest-framework, get simpleexample working
Diffstat (limited to 'djangorestframework/emitters.py')
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+"""Emitters are used to serialize a Resource's output into specific media types.
+django-rest-framework also provides HTML and PlainText emitters that help self-document the API,
+by serializing the output along with documentation regarding the Resource, output status and headers,
+and providing forms and links depending on the allowed methods, emitters and parsers on the Resource.
+"""
+from django.conf import settings
+from django.template import RequestContext, loader
+from django import forms
+
+from djangorestframework.response import NoContent
+from djangorestframework.utils import dict2xml, url_resolves
+
+from urllib import quote_plus
+import string
+try:
+ import json
+except ImportError:
+ import simplejson as json
+
+
+
+# TODO: Rename verbose to something more appropriate
+# TODO: NoContent could be handled more cleanly. It'd be nice if it was handled by default,
+# and only have an emitter output anything if it explicitly provides support for that.
+
+class BaseEmitter(object):
+ """All emitters must extend this class, set the media_type attribute, and
+ override the emit() function."""
+ media_type = None
+
+ def __init__(self, resource):
+ self.resource = resource
+
+ def emit(self, output=NoContent, verbose=False):
+ """By default emit simply returns the ouput as-is.
+ Override this method to provide for other behaviour."""
+ if output is NoContent:
+ return ''
+
+ return output
+
+
+class TemplateEmitter(BaseEmitter):
+ """Provided for convienience.
+ Emit the output by simply rendering it with the given template."""
+ media_type = None
+ template = None
+
+ def emit(self, output=NoContent, verbose=False):
+ if output is NoContent:
+ return ''
+
+ context = RequestContext(self.resource.request, output)
+ return self.template.render(context)
+
+
+class DocumentingTemplateEmitter(BaseEmitter):
+ """Base class for emitters used to self-document the API.
+ Implementing classes should extend this class and set the template attribute."""
+ template = None
+
+ def _get_content(self, resource, output):
+ """Get the content as if it had been emitted by a non-documenting emitter.
+
+ (Typically this will be the content as it would have been if the Resource had been
+ requested with an 'Accept: */*' header, although with verbose style formatting if appropriate.)"""
+
+ # Find the first valid emitter and emit the content. (Don't use another documenting emitter.)
+ emitters = [emitter for emitter in resource.emitters if not isinstance(emitter, DocumentingTemplateEmitter)]
+ if not emitters:
+ return '[No emitters were found]'
+
+ content = emitters[0](resource).emit(output, verbose=True)
+ if not all(char in string.printable for char in content):
+ return '[%d bytes of binary content]'
+
+ return content
+
+
+ def _get_form_instance(self, resource):
+ """Get a form, possibly bound to either the input or output data.
+ In the absence on of the Resource having an associated form then
+ provide a form that can be used to submit arbitrary content."""
+ # Get the form instance if we have one bound to the input
+ form_instance = resource.form_instance
+
+ # Otherwise if this isn't an error response
+ # then attempt to get a form bound to the response object
+ if not form_instance and resource.response.has_content_body:
+ try:
+ form_instance = resource.get_form(resource.response.raw_content)
+ if form_instance:
+ form_instance.is_valid()
+ except:
+ form_instance = None
+
+ # If we still don't have a form instance then try to get an unbound form
+ if not form_instance:
+ try:
+ form_instance = self.resource.get_form()
+ except:
+ pass
+
+ # If we still don't have a form instance then try to get an unbound form which can tunnel arbitrary content types
+ if not form_instance:
+ form_instance = self._get_generic_content_form(resource)
+
+ return form_instance
+
+
+ def _get_generic_content_form(self, resource):
+ """Returns a form that allows for arbitrary content types to be tunneled via standard HTML forms
+ (Which are typically application/x-www-form-urlencoded)"""
+
+ # NB. http://jacobian.org/writing/dynamic-form-generation/
+ class GenericContentForm(forms.Form):
+ def __init__(self, resource):
+ """We don't know the names of the fields we want to set until the point the form is instantiated,
+ as they are determined by the Resource the form is being created against.
+ Add the fields dynamically."""
+ super(GenericContentForm, self).__init__()
+
+ contenttype_choices = [(media_type, media_type) for media_type in resource.parsed_media_types]
+ initial_contenttype = resource.default_parser.media_type
+
+ self.fields[resource.CONTENTTYPE_PARAM] = forms.ChoiceField(label='Content Type',
+ choices=contenttype_choices,
+ initial=initial_contenttype)
+ self.fields[resource.CONTENT_PARAM] = forms.CharField(label='Content',
+ widget=forms.Textarea)
+
+ # If either of these reserved parameters are turned off then content tunneling is not possible
+ if self.resource.CONTENTTYPE_PARAM is None or self.resource.CONTENT_PARAM is None:
+ return None
+
+ # Okey doke, let's do it
+ return GenericContentForm(resource)
+
+
+ def emit(self, output=NoContent):
+ content = self._get_content(self.resource, output)
+ form_instance = self._get_form_instance(self.resource)
+
+ if url_resolves(settings.LOGIN_URL) and url_resolves(settings.LOGOUT_URL):
+ login_url = "%s?next=%s" % (settings.LOGIN_URL, quote_plus(self.resource.request.path))
+ logout_url = "%s?next=%s" % (settings.LOGOUT_URL, quote_plus(self.resource.request.path))
+ else:
+ login_url = None
+ logout_url = None
+
+ template = loader.get_template(self.template)
+ context = RequestContext(self.resource.request, {
+ 'content': content,
+ 'resource': self.resource,
+ 'request': self.resource.request,
+ 'response': self.resource.response,
+ 'form': form_instance,
+ 'login_url': login_url,
+ 'logout_url': logout_url,
+ })
+
+ 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)
+ if self.resource.response.status == 204:
+ self.resource.response.status = 200
+
+ return ret
+
+
+class JSONEmitter(BaseEmitter):
+ """Emitter which serializes to JSON"""
+ media_type = 'application/json'
+
+ def emit(self, output=NoContent, verbose=False):
+ if output is NoContent:
+ return ''
+ if verbose:
+ return json.dumps(output, indent=4, sort_keys=True)
+ return json.dumps(output)
+
+
+class XMLEmitter(BaseEmitter):
+ """Emitter which serializes to XML."""
+ media_type = 'application/xml'
+
+ def emit(self, output=NoContent, verbose=False):
+ if output is NoContent:
+ return ''
+ return dict2xml(output)
+
+
+class DocumentingHTMLEmitter(DocumentingTemplateEmitter):
+ """Emitter which provides a browsable HTML interface for an API.
+ See the examples listed in the django-rest-framework documentation to see this in actions."""
+ media_type = 'text/html'
+ template = 'emitter.html'
+
+
+class DocumentingXHTMLEmitter(DocumentingTemplateEmitter):
+ """Identical to DocumentingHTMLEmitter, except with an xhtml media type.
+ We need this to be listed in preference to xml in order to return HTML to WebKit based browsers,
+ given their Accept headers."""
+ media_type = 'application/xhtml+xml'
+ template = 'emitter.html'
+
+
+class DocumentingPlainTextEmitter(DocumentingTemplateEmitter):
+ """Emitter that serializes the output with the default emitter, but also provides plain-text
+ doumentation of the returned status and headers, and of the resource's name and description.
+ Useful for browsing an API with command line tools."""
+ media_type = 'text/plain'
+ template = 'emitter.txt'
+
+