def serialize_result(self, result, request, emitter_format):
"""
The request has been executed succefully and we end up here to
serialize the result
@type result: dict
@param result: Result of the execution of the handler, wrapped in a
dictionary. The dictionary contains the I{data} key, whose value is the
result of running the operation. The value can be another dictionary,
list or simply a string. If it's a dictionary or list, it might contain
other dictionaries/lists, strings, or even I{datetime} functions. All
dictionary key/value pairs, and list elements, should be strings, other
than the I{datetime} functions. In anycase, I{self.data} should be
serializable very easily, without any magic.
@type request: HTTPRequest
@param request: Incoming request
@type emitter_format: str
@param emitter_format: Emitter format
"""
# Find the Emitter class, and the corresponding content
# type
emitter_class, mimetype = Emitter.get(emitter_format)
# create instance of the emitter class
serializer = emitter_class(self.handler, result, None)
# serialize the result
serialized_result = serializer.render(request)
return serialized_result, mimetype, emitter_format
def __call__(self, request, *args, **kwargs):
# Support emitter both through (?P<emitter_format>) and ?format=emitter.
em_format = self.determine_emitter(request, *args, **kwargs)
kwargs.pop('emitter_format', None)
response = self.response_class()
try:
emitter, ct = Emitter.get(em_format)
except ValueError:
raise PistonBadRequestException("Invalid output format specified '%s'." % em_format)
if not response.error_message:
meth = None
try:
handler, meth, fields, anonymous = self.process_request(request, response, *args, **kwargs)
except Exception, e:
handler, meth, fields, anonymous = None, None, (), False
self.error_handler(response, e, request, meth)
def __call__(self, request, *args, **kwargs):
# Support emitter both through (?P<emitter_format>) and ?format=emitter.
em_format = self.determine_emitter(request, *args, **kwargs)
kwargs.pop('emitter_format', None)
response = self.response_class()
try:
emitter, ct = Emitter.get(em_format)
except ValueError:
raise PistonBadRequestException(
"Invalid output format specified '%s'." % em_format)
if not response.error_message:
meth = None
try:
handler, meth, fields, anonymous = self.process_request(
request, response, *args, **kwargs)
except Exception, e:
handler, meth, fields, anonymous = None, None, (), False
self.error_handler(response, e, request, meth)
def form_validation_response(self, request, e, em_format):
"""
Method to return form validation error information.
You will probably want to override this in your own
`Resource` subclass.
"""
try:
emitter, ct = Emitter.get(em_format)
fields = self.handler.fields
except ValueError:
result = rc.BAD_REQUEST
result.content = "Invalid output format specified '%s'." % em_format
return result
serialized_errors = dict(
(key, [unicode(v) for v in values])
for key,values in e.form.errors.items()
)
srl = emitter(serialized_errors, typemapper, self.handler, fields, False)
stream = srl.render(request)
resp = HttpResponse(stream, mimetype=ct, status=400)
return resp
class Resource(object):
"""
Resource. Create one for your URL mappings, just
like you would with Django. Takes one argument,
the handler. The second argument is optional, and
is an authentication handler. If not specified,
`NoAuthentication` will be used by default.
"""
callmap = {
'GET': 'read',
'POST': 'create',
'PUT': 'update',
'DELETE': 'delete'
}
def __init__(self, handler, authentication=None):
if not callable(handler):
raise AttributeError("Handler not callable.")
self.handler = handler()
self.csrf_exempt = getattr(self.handler, 'csrf_exempt', True)
if not authentication:
self.authentication = (NoAuthentication(), )
elif isinstance(authentication, (list, tuple)):
self.authentication = authentication
else:
self.authentication = (authentication, )
# Erroring
self.email_errors = getattr(settings, 'PISTON_EMAIL_ERRORS', True)
self.display_errors = getattr(settings, 'PISTON_DISPLAY_ERRORS', True)
self.stream = getattr(settings, 'PISTON_STREAM_OUTPUT', False)
def determine_emitter(self, request, *args, **kwargs):
"""
Function for determening which emitter to use
for output. It lives here so you can easily subclass
`Resource` in order to change how emission is detected.
You could also check for the `Accept` HTTP header here,
since that pretty much makes sense. Refer to `Mimer` for
that as well.
"""
em = kwargs.pop('emitter_format', None)
if not em:
em = request.GET.get('format', 'json')
return em
def form_validation_response(self, e):
"""
Method to return form validation error information.
You will probably want to override this in your own
`Resource` subclass.
"""
resp = rc.BAD_REQUEST
resp.write(u' ' + unicode(e.form.errors))
return resp
@property
def anonymous(self):
"""
Gets the anonymous handler. Also tries to grab a class
if the `anonymous` value is a string, so that we can define
anonymous handlers that aren't defined yet (like, when
you're subclassing your basehandler into an anonymous one.)
"""
if hasattr(self.handler, 'anonymous'):
anon = self.handler.anonymous
if callable(anon):
return anon
for klass in typemapper.keys():
if anon == klass.__name__:
return klass
return None
def authenticate(self, request, rm):
actor, anonymous = False, True
for authenticator in self.authentication:
if not authenticator.is_authenticated(request):
if self.anonymous and \
rm in self.anonymous.allowed_methods:
actor, anonymous = self.anonymous(), True
else:
actor, anonymous = authenticator.challenge, CHALLENGE
else:
return self.handler, self.handler.is_anonymous
return actor, anonymous
@vary_on_headers('Authorization')
def __call__(self, request, *args, **kwargs):
"""
NB: Sends a `Vary` header so we don't cache requests
that are different (OAuth stuff in `Authorization` header.)
"""
rm = request.method.upper()
# Django's internal mechanism doesn't pick up
# PUT request, so we trick it a little here.
if rm == "PUT":
coerce_put_post(request)
actor, anonymous = self.authenticate(request, rm)
if anonymous is CHALLENGE:
return actor()
else:
handler = actor
# Allow for emulated PUT requests -- http://backbonejs.org/#Sync-emulateHTTP
if 'HTTP_X_HTTP_METHOD_OVERRIDE' in request.META:
rm = request.META.get('HTTP_X_HTTP_METHOD_OVERRIDE')
if rm == "PUT":
request.PUT = request.POST
# Translate nested datastructs into `request.data` here.
if rm in ('POST', 'PUT'):
try:
translate_mime(request)
except MimerDataException:
return rc.BAD_REQUEST
if not hasattr(request, 'data'):
if rm == 'POST':
request.data = request.POST
else:
request.data = request.PUT
if not rm in handler.allowed_methods:
return HttpResponseNotAllowed(handler.allowed_methods)
meth = getattr(handler, self.callmap.get(rm, ''), None)
if not meth:
raise Http404
# Support emitter both through (?P<emitter_format>) and ?format=emitter.
em_format = self.determine_emitter(request, *args, **kwargs)
kwargs.pop('emitter_format', None)
# Clean up the request object a bit, since we might
# very well have `oauth_`-headers in there, and we
# don't want to pass these along to the handler.
request = self.cleanup_request(request)
try:
result = meth(request, *args, **kwargs)
except Exception, e:
result = self.error_handler(e, request, meth, em_format)
try:
emitter, ct = Emitter.get(em_format)
fields = handler.fields
if hasattr(handler, 'list_fields') and isinstance(
result, (list, tuple, QuerySet, RawQuerySet)):
fields = handler.list_fields
except ValueError:
result = rc.BAD_REQUEST
result.content = "Invalid output format specified '%s'." % em_format
return result
status_code = 200
# If we're looking at a response object which contains non-string
# content, then assume we should use the emitter to format that
# content
if self._use_emitter(result):
status_code = result.status_code
# Note: We can't use result.content here because that
# method attempts to convert the content into a string
# which we don't want. when
# _is_string/_base_content_is_iter is False _container is
# the raw data
result = result._container
srl = emitter(result, typemapper, handler, fields, anonymous)
try:
"""
Decide whether or not we want a generator here,
or we just want to buffer up the entire result
before sending it to the client. Won't matter for
smaller datasets, but larger will have an impact.
"""
if self.stream:
stream = srl.stream_render(request)
else:
stream = srl.render(request)
if not isinstance(stream, HttpResponse):
resp = HttpResponse(stream,
content_type=ct,
status=status_code)
else:
resp = stream
resp.streaming = self.stream
return resp
except HttpStatusCode, e:
return e.response
def reconfig(self, data):
self.interval = int(data.get('interval', 60))
if self.loghandler:
logger.removeHandler(self.loghandler)
fname = data.get('logfile', '/var/log/sauron.log')
# Set up the logging file
self.loghandler = logging.FileHandler(fname, mode='a')
self.loghandler.setFormatter(formatter)
self.loghandler.setLevel(logging.INFO)
logger.addHandler(self.loghandler)
# Read in /all/ the metrics!
try:
if len(data['metrics']) == 0:
logger.error('No metrics in config file!')
exit(1)
for key,value in data['metrics'].items():
try:
try:
d = dict(value.items())
self.metrics[key].reconfig(**d)
except:
module = value['module']
m = __import__('sauron.metrics.%s' % module)
m = getattr(m, 'metrics')
m = getattr(m, module)
c = getattr(m, module)
del d['module']
d['name'] = key
self.metrics[key] = c(**d)
except KeyError:
logger.exception('No module listed for metric %s' % key)
exit(1)
except ImportError:
logger.exception('Unable to import module %s' % module)
exit(1)
except TypeError as e:
logger.exception('Unable to initialize metric %s' % key)
exit(1)
except MetricException as e:
logger.exception('Module Exception %s' % module)
exit(1)
except KeyError:
logger.error('No metrics in config file!')
exit(1)
# Read in /all/ the emitters!
try:
if self.dryrun:
logger.warn('Skipping all emitters because of --dry-run')
self.emitters[''] = Emitter()
return
if len(data['emitters']) == 0:
logger.error('No metrics in config file!')
exit(1)
for key,value in data['emitters'].items():
try:
m = __import__('sauron.emitters.%s' % key)
m = getattr(m, 'emitters')
m = getattr(m, key)
c = getattr(m, key)
d = dict(value.items())
self.emitters[key] = c(**d)
except ImportError:
logger.exception('Unable to import module %s' % key)
exit(1)
except TypeError as e:
logger.exception('Unable to initialize emitter %s' % key)
exit(1)
except EmitterException as e:
logger.exception('Error with module %s' % module)
exit(1)
except:
logger.exception('Emitter error!')
exit(1)
assert range_start != None
assert range_end != None
return (range_start, range_end)
try:
total = result.count()
start, end = get_range(request_range[0], request_range[1],
total)
result = result[start:end + 1]
content_range = "items %i-%i/%i" % (start, end, total)
except BadRangeException, e:
resp = rc.BAD_RANGE
resp.write("\n%s" % e.value)
return resp
emitter, ct = Emitter.get(em_format)
fields = handler.fields
if hasattr(handler, 'list_fields') and (isinstance(result, list) or
isinstance(result, QuerySet)):
fields = handler.list_fields
srl = emitter(result, typemapper, handler, fields, anonymous)
try:
"""
Decide whether or not we want a generator here,
or we just want to buffer up the entire result
before sending it to the client. Won't matter for
smaller datasets, but larger will have an impact.
"""
if self.stream: stream = srl.stream_render(request)
def __call__(self, request, *args, **kwargs):
"""
NB: Sends a `Vary` header so we don't cache requests
that are different (OAuth stuff in `Authorization` header.)
"""
rm = request.method.upper()
# Django's internal mechanism doesn't pick up
# PUT request, so we trick it a little here.
if rm == "PUT":
coerce_put_post(request)
actor, anonymous = self.authenticate(request, rm)
if anonymous is CHALLENGE:
return actor()
else:
handler = actor
# Translate nested datastructs into `request.data` here.
if rm in ('POST', 'PUT'):
try:
translate_mime(request)
except MimerDataException:
return rc.BAD_REQUEST
if not hasattr(request, 'data'):
if rm == 'POST':
request.data = request.POST
else:
request.data = request.PUT
if not rm in handler.allowed_methods:
return HttpResponseNotAllowed(handler.allowed_methods)
meth = getattr(handler, self.callmap.get(rm, ''), None)
if not meth:
raise Http404
# Support emitter through (?P<emitter_format>) and ?format=emitter
# and lastly Accept: header processing
em_format = self.determine_emitter(request, *args, **kwargs)
if not em_format:
request_has_accept = 'HTTP_ACCEPT' in request.META
if request_has_accept and self.strict_accept:
return rc.NOT_ACCEPTABLE
em_format = self.default_emitter
kwargs.pop('emitter_format', None)
# Clean up the request object a bit, since we might
# very well have `oauth_`-headers in there, and we
# don't want to pass these along to the handler.
request = self.cleanup_request(request)
try:
result = meth(request, *args, **kwargs)
except Exception as e:
result = self.error_handler(e, request, meth, em_format)
try:
emitter, ct = Emitter.get(em_format)
fields = handler.fields
if hasattr(handler, 'list_fields') and isinstance(
result, (list, tuple, QuerySet)):
fields = handler.list_fields
except ValueError:
result = rc.BAD_REQUEST
result.content = "Invalid output format specified '%s'." % em_format
return result
status_code = 200
# If we're looking at a response object which contains non-string
# content, then assume we should use the emitter to format that
# content
if self._use_emitter(result):
status_code = result.status_code
# Note: We can't use result.content here because that
# method attempts to convert the content into a string
# which we don't want. when
# _is_string/_base_content_is_iter is False _container is
# the raw data
result = result._container
srl = emitter(result, typemapper, handler, fields, anonymous)
try:
"""
Decide whether or not we want a generator here,
or we just want to buffer up the entire result
before sending it to the client. Won't matter for
smaller datasets, but larger will have an impact.
"""
if self.stream: stream = srl.stream_render(request)
else: stream = srl.render(request)
if not isinstance(stream, HttpResponse):
resp = HttpResponse(stream,
content_type=ct,
status=status_code)
else:
resp = stream
resp.streaming = self.stream
return resp
except HttpStatusCode as e:
return e.response
receive a basic "500 Internal Server Error" message.
"""
exc_type, exc_value, tb = sys.exc_info()
rep = ExceptionReporter(request, exc_type, exc_value, tb.tb_next)
if self.email_errors:
self.email_exception(rep)
if self.display_errors:
return HttpResponseServerError(
format_error('\n'.join(rep.format_exception())))
else:
raise
# Return serialized data
emitter, ct = Emitter.get(em_format)
srl = emitter(result, recurse_level, typemapper, handler, handler.fields, anonymous)
try:
"""
Decide whether or not we want a generator here,
or we just want to buffer up the entire result
before sending it to the client. Won't matter for
smaller datasets, but larger will have an impact.
"""
if self.stream: stream = srl.stream_render(request)
else: stream = srl.render(request)
resp = HttpResponse(stream, mimetype=ct)
resp.streaming = self.stream
return resp
def __call__(self, request, *args, **kwargs):
"""
NB: Sends a `Vary` header so we don't cache requests
that are different (OAuth stuff in `Authorization` header.)
"""
rm = request.method.upper()
# Django's internal mechanism doesn't pick up
# PUT request, so we trick it a little here.
if rm == "PUT":
coerce_put_post(request)
actor, anonymous = self.authenticate(request, rm)
if anonymous is CHALLENGE:
return actor(request)
else:
handler = actor
# Translate nested datastructs into `request.data` here.
if rm in ('POST', 'PUT'):
try:
translate_mime(request)
except MimerDataException:
return rc.BAD_REQUEST
if not hasattr(request, 'data'):
if rm == 'POST':
request.data = request.POST
else:
request.data = request.PUT
if not rm in handler.allowed_methods:
return HttpResponseNotAllowed(handler.allowed_methods)
meth = getattr(handler, self.callmap.get(rm, ''), None)
if not meth:
raise Http404
# Support emitter both through (?P<emitter_format>) and ?format=emitter.
em_format = self.determine_emitter(request, *args, **kwargs)
kwargs.pop('emitter_format', None)
# Clean up the request object a bit, since we might
# very well have `oauth_`-headers in there, and we
# don't want to pass these along to the handler.
request = self.cleanup_request(request)
result = meth(request, *args, **kwargs)
try:
emitter, ct = Emitter.get(em_format)
fields = handler.fields
if hasattr(handler, 'list_fields') and isinstance(result, (list, tuple, QuerySet)):
fields = handler.list_fields
except ValueError:
result = rc.BAD_REQUEST
result.content = "Invalid output format specified '%s'." % em_format
return result
status_code = 200
# If we're looking at a response object which contains non-string
# content, then assume we should use the emitter to format that
# content
if isinstance(result, HttpResponse) and not result._is_string:
status_code = result.status_code
# Note: We can't use result.content here because that method attempts
# to convert the content into a string which we don't want.
# when _is_string is False _container is the raw data
result = result._container
srl = emitter(result, typemapper, handler, fields, anonymous)
try:
"""
Decide whether or not we want a generator here,
or we just want to buffer up the entire result
before sending it to the client. Won't matter for
smaller datasets, but larger will have an impact.
"""
if self.stream: stream = srl.stream_render(request)
else: stream = srl.render(request)
if not isinstance(stream, HttpResponse):
resp = HttpResponse(stream, mimetype=ct, status=status_code)
else:
resp = stream
resp.streaming = self.stream
return resp
except HttpStatusCode, e:
return e.response
to the caller, so he can tell you what error they got.
If `PISTON_DISPLAY_ERRORS` is not enabled, the caller will
receive a basic "500 Internal Server Error" message.
"""
exc_type, exc_value, tb = sys.exc_info()
rep = ExceptionReporter(request, exc_type, exc_value, tb.tb_next)
if self.email_errors:
self.email_exception(rep)
if self.display_errors:
return HttpResponseServerError(
format_error('\n'.join(rep.format_exception())))
else:
raise
emitter, ct = Emitter.get(em_format)
fields = handler.fields
if hasattr(handler, 'list_fields') and (
isinstance(result, list) or isinstance(result, QuerySet)):
fields = handler.list_fields
srl = emitter(result, typemapper, handler, fields, anonymous)
try:
"""
Decide whether or not we want a generator here,
or we just want to buffer up the entire result
before sending it to the client. Won't matter for
smaller datasets, but larger will have an impact.
"""
class Resource(object):
"""
Resource. Create one for your URL mappings, just
like you would with Django. Takes one argument,
the handler. The second argument is optional, and
is an authentication handler. If not specified,
`NoAuthentication` will be used by default.
"""
callmap = {
'GET': 'read',
'POST': 'create',
'PUT': 'update',
'DELETE': 'delete'
}
def __init__(self, handler, authentication=None):
if not callable(handler):
raise AttributeError, "Handler not callable."
self.handler = handler()
self.csrf_exempt = getattr(self.handler, 'csrf_exempt', True)
if not authentication:
self.authentication = (NoAuthentication(), )
elif isinstance(authentication, (list, tuple)):
self.authentication = authentication
else:
self.authentication = (authentication, )
# Erroring
self.email_errors = getattr(settings, 'PISTON_EMAIL_ERRORS', True)
self.display_errors = getattr(settings, 'PISTON_DISPLAY_ERRORS', True)
self.stream = getattr(settings, 'PISTON_STREAM_OUTPUT', False)
# Emitter selection
self.strict_accept = getattr(settings, 'PISTON_STRICT_ACCEPT_HANDLING',
False)
self.default_emitter = getattr(settings, 'PISTON_DEFAULT_EMITTER',
'json')
def determine_emitter(self, request, *args, **kwargs):
"""
Function for determening which emitter to use
for output. It lives here so you can easily subclass
`Resource` in order to change how emission is detected.
"""
try:
return kwargs['emitter_format']
except KeyError:
pass
if 'format' in request.GET:
return request.GET.get('format')
if mimeparse and 'HTTP_ACCEPT' in request.META:
supported_mime_types = set()
emitter_map = {}
for name, (klass, content_type) in Emitter.EMITTERS.items():
content_type_without_encoding = content_type.split(';')[0]
supported_mime_types.add(content_type_without_encoding)
emitter_map[content_type_without_encoding] = name
preferred_content_type = mimeparse.best_match(
list(supported_mime_types), request.META['HTTP_ACCEPT'])
return emitter_map.get(preferred_content_type, None)
def form_validation_response(self, e):
"""
Method to return form validation error information.
You will probably want to override this in your own
`Resource` subclass.
"""
resp = rc.BAD_REQUEST
resp.write(u' ' + unicode(e.form.errors))
return resp
@property
def anonymous(self):
"""
Gets the anonymous handler. Also tries to grab a class
if the `anonymous` value is a string, so that we can define
anonymous handlers that aren't defined yet (like, when
you're subclassing your basehandler into an anonymous one.)
"""
if hasattr(self.handler, 'anonymous'):
anon = self.handler.anonymous
if callable(anon):
return anon
for klass in typemapper.keys():
if anon == klass.__name__:
return klass
return None
def authenticate(self, request, rm):
actor, anonymous = False, True
for authenticator in self.authentication:
if not authenticator.is_authenticated(request):
if self.anonymous and \
rm in self.anonymous.allowed_methods:
actor, anonymous = self.anonymous(), True
else:
actor, anonymous = authenticator.challenge, CHALLENGE
else:
return self.handler, self.handler.is_anonymous
return actor, anonymous
@vary_on_headers('Authorization')
def __call__(self, request, *args, **kwargs):
"""
NB: Sends a `Vary` header so we don't cache requests
that are different (OAuth stuff in `Authorization` header.)
"""
rm = request.method.upper()
# Django's internal mechanism doesn't pick up
# PUT request, so we trick it a little here.
if rm == "PUT":
coerce_put_post(request)
actor, anonymous = self.authenticate(request, rm)
if anonymous is CHALLENGE:
return actor()
else:
handler = actor
# Translate nested datastructs into `request.data` here.
if rm in ('POST', 'PUT'):
try:
translate_mime(request)
except MimerDataException:
return rc.BAD_REQUEST
if not hasattr(request, 'data'):
if rm == 'POST':
request.data = request.POST
else:
request.data = request.PUT
if not rm in handler.allowed_methods:
return HttpResponseNotAllowed(handler.allowed_methods)
meth = getattr(handler, self.callmap.get(rm, ''), None)
if not meth:
raise Http404
# Support emitter through (?P<emitter_format>) and ?format=emitter
# and lastly Accept: header processing
em_format = self.determine_emitter(request, *args, **kwargs)
if not em_format:
request_has_accept = 'HTTP_ACCEPT' in request.META
if request_has_accept and self.strict_accept:
return rc.NOT_ACCEPTABLE
em_format = self.default_emitter
kwargs.pop('emitter_format', None)
# Clean up the request object a bit, since we might
# very well have `oauth_`-headers in there, and we
# don't want to pass these along to the handler.
request = self.cleanup_request(request)
try:
result = meth(request, *args, **kwargs)
except Exception, e:
result = self.error_handler(e, request, meth, em_format)
try:
emitter, ct = Emitter.get(em_format)
fields = handler.fields
if hasattr(handler, 'list_fields') and isinstance(
result, (list, tuple, QuerySet)):
fields = handler.list_fields
except ValueError:
result = rc.BAD_REQUEST
result.content = "Invalid output format specified '%s'." % em_format
return result
status_code = 200
# If we're looking at a response object which contains non-string
# content, then assume we should use the emitter to format that
# content
if self._use_emitter(result):
status_code = result.status_code
result = result.content
srl = emitter(result, typemapper, handler, fields, anonymous)
try:
"""
Decide whether or not we want a generator here,
or we just want to buffer up the entire result
before sending it to the client. Won't matter for
smaller datasets, but larger will have an impact.
"""
if self.stream:
stream = srl.stream_render(request)
else:
stream = srl.render(request)
if not isinstance(stream, HttpResponse):
if django.VERSION >= (1, 7):
resp = HttpResponse(stream,
content_type=ct,
status=status_code)
else:
resp = HttpResponse(stream,
mimetype=ct,
status=status_code)
else:
resp = stream
resp.streaming = self.stream
return resp
except HttpStatusCode, e:
return e.response
def execute_request(self, request, *args, **kwargs):
"""
This is the entry point for all incoming requests
(To be more precise, the URL mapper calls the
L{resource.Resource.__call__} that does
some pre-processing, which then calls L{execute_request} )
It guides the request through all the necessary steps up to the point
that its result is serialized into a dictionary.
@type request: HTTPRequest object
@param request: Incoming request
@rype: dict
@return: Dictionary of the result. The dictionary contains the
following keys:
* data: Contains the result of running the requested operation. The
value to this key can be a dictionary, list, or string. Within this
data structure, any dictionaries or lists are made of strings, with the
exception of dates, which appear as I{datetime} functions, and will be
serialized by the JSONEmitter.
* total: Is only included if slicing was performed, and indicates the
total result size.
* Any other key can be included, if L{BaseHandler.enrich_response} has
been overridden
"""
# Validate request body data
if hasattr(request, 'data') and request.data is not None:
if request.method.upper() == 'PUT':
# In the case of PUT requests, we first force the evaluation of
# the affected dataset (theferore if there are any
# HttpResourceGone exceptions, they will be raised now), and then in the
# ``validate`` method, we perform any data validations. We
# assign it to parameter ``request.dataset``.
request.dataset = self.data(request, *args, **kwargs)
self.validate(request, *args, **kwargs)
# Pick action to run
action = getattr(self, CALLMAP.get(request.method.upper()))
# Run it
data = action(request, *args, **kwargs)
# Select output fields
fields = self.get_output_fields(request)
# Slice
sliced_data, total = self.response_slice_data(request, data)
# inject fake dynamic fields to the response data
sliced_data = self.inject_fake_dynamic_fields(request, sliced_data, fields)
# Use the emitter to serialize any python objects / data structures
# within I{sliced_data}, to serializable forms(dict, list, string),
# so that the specific emitter we use for returning
# the response, can easily serialize them in some other format,
# The L{Emitter} is responsible for making sure that only fields contained in
# I{fields} will be included in the result.
emitter = Emitter(self, sliced_data, fields)
ser_data = emitter.construct()
# Structure the response data
ret = {'data': ser_data}
if total is not None:
ret['total'] = total
# Add extra metadata
self.enrich_response(ret, data)
if request.method.upper() == 'DELETE':
self.data_safe_for_delete(data)
return ret
