[quest][wip] stateless metadata rendering

api/pls_render_metadata/urls.py

@@ -0,0 +1,8 @@
+from django.urls import path
+
+from . import views
+
+
+urlpatterns = [
+ path('pls-render-metadata', views.pls_render_metadata),
+]

api/pls_render_metadata/views.py

@@ -0,0 +1,54 @@
+"""pls-render-metadata: an amnesiac metadata renderer
+
+a django view that takes a POST request with a raw metadata record in the request body
+
+sidenote: using the pls ("please") prefix to mean we (the server) are:
+ - acting at explicit request of someone else
+ - aiming to help
+ - behaving politely/discreetly (will forget all data/metadata)
+
+"""
+
+import json
+
+from django.http import HttpResponse
+
+from share.util.extensions import Extensions
+from share.regulate import Regulator
+
+
+def pls_render_metadata(request):
+ if request.method != 'POST':
+ return HttpResponse(
+ status=405,
+ headers={'Allow': 'POST'},
+ content='only POST!'
+ )
+
+ transformer_key = request.GET.get('transformer', 'v2_push')
+ normal_graph = pls_normalize(request.body, transformer_key)
+ requested_formats = request.GET.getlist('formats')
+ formatted_records = [
+ pls_render(normal_graph, format_key)
+ for format_key in requested_formats
+ ]
+ return HttpResponse(
+ content=json.dumps(formatted_records),
+ )
+
+
+def pls_normalize(raw_datum, transformer_key):
+ transformer = Extensions.get('share.transformers', transformer_key)()
+ graph = transformer.transform(raw_datum)
+ Regulator().regulate(graph) # in-place
+
+
+def pls_render(graph, record_formats):
+ formatters = [
+ Extensions.get('share.metadata_formats', record_format)()
+ for record_format in record_formats
+ ]
+ return [
+ formatter.format_from_graph(graph)
+ for formatter in formatters
+ ]

api/urls.py

@@ -19,6 +19,8 @@
  url('^', include('api.suids.urls')),
  url('^', include('api.users.urls')),
 
+ url('^', include('api.pls_render_metadata.urls')),
+
  url('^schemas?/', include('api.schemas.urls'), name='schema'),
  url('^search/', include('api.search.urls'), name='search'),
 

share/metadata_formats/base.py

@@ -3,11 +3,18 @@
 
 from share.models.core import NormalizedData
 from share.models.ingest import SourceUniqueIdentifier
+from share.util.graph import MutableGraph
 
 
 class MetadataFormatter(ABC):
- @abstractmethod
  def format(self, normalized_data: NormalizedData) -> Optional[str]:
+ """return a string representation of the given metadata in the formatter's format
+ """
+ mgraph = MutableGraph.from_jsonld(normalized_data.data)
+ return self.format_from_graph(mgraph)
+
+ @abstractmethod
+ def format_from_graph(self, normalized_data: NormalizedData) -> Optional[str]:
  """return a string representation of the given metadata in the formatter's format
  """
  raise NotImplementedError

share/metadata_formats/oai_dc.py

@@ -16,6 +16,9 @@ class OaiDcFormatter(MetadataFormatter):
 
  def format(self, normalized_datum):
  mgraph = MutableGraph.from_jsonld(normalized_datum.data)
+ return self.format_from_graph(mgraph)
+
+ def format_from_graph(self, mgraph):
  central_work = mgraph.get_central_node(guess=True)
 
  if (

share/metadata_formats/sharev2_elastic.py

@@ -58,6 +58,10 @@ def format_as_deleted(self, suid):
  'is_deleted': True,
  })
 
+ def format_from_graph(self, mgraph):
+ # HACK because sharev2_elastic is dumb
+ raise NotImplementedError('sharev2_elastic formatter depends on a NormalizedData')
+
  def format(self, normalized_datum):
  mgraph = MutableGraph.from_jsonld(normalized_datum.data)
  central_work = mgraph.get_central_node(guess=True)

share/transform/base.py

@@ -6,7 +6,7 @@
 
 class BaseTransformer(metaclass=abc.ABCMeta):
 
- def __init__(self, source_config):
+ def __init__(self, source_config=None):
  self.config = source_config
 
  @abc.abstractmethod

share/transform/chain/links.py

@@ -1029,7 +1029,7 @@ def execute(self, obj):
  break
 
  if not final[0]:
- if self._urn_fallback:
+ if self._urn_fallback and getattr(Context(), '_config', None):
  urn = self.FALLBACK_FORMAT.format(source=Context()._config.label, id=urllib.parse.quote(obj))
  return URNLink().execute(urn)
  else: