Document the usable document attributes added by the metadata app using ModelAttribute class, add DocumentMetadataHelper to help retrieve a document metadata value easier

mayan/apps/metadata/__init__.py

@@ -6,6 +6,7 @@ from django.dispatch import receiver
 from django.utils.translation import ugettext_lazy as _
 
 from acls.api import class_permissions
+from common.classes import ModelAttribute
 from common.utils import encapsulate
 from documents.models import Document, DocumentType
 from documents.signals import post_document_type_change
@@ -15,15 +16,14 @@ from project_setup.api import register_setup
 from rest_api.classes import APIEndPoint
 
 from .api import get_metadata_string
-from .classes import DocumentTypeMetadataTypeManager
+from .classes import DocumentMetadataHelper, DocumentTypeMetadataTypeHelper
 from .links import (metadata_add, metadata_edit, metadata_multiple_add,
                     metadata_multiple_edit, metadata_multiple_remove,
                     metadata_remove, metadata_view,
                     setup_document_type_metadata,
                     setup_document_type_metadata_required,
-                    setup_metadata_type_create,
-                    setup_metadata_type_delete, setup_metadata_type_edit,
-                    setup_metadata_type_list)
+                    setup_metadata_type_create, setup_metadata_type_delete,
+                    setup_metadata_type_edit, setup_metadata_type_list)
 from .models import DocumentMetadata, MetadataType
 from .permissions import (PERMISSION_METADATA_DOCUMENT_ADD,
                           PERMISSION_METADATA_DOCUMENT_EDIT,
@@ -51,15 +51,16 @@ def document_metadata(document):
     return document.document_metadata.select_related('metadata_type')
 
 
-DocumentType.add_to_class('metadata_type', DocumentTypeMetadataTypeManager.factory)
+DocumentType.add_to_class('metadata_type', DocumentTypeMetadataTypeHelper.constructor)
 Document.add_to_class('metadata', document_metadata)
+Document.add_to_class('metadata_value_of', DocumentMetadataHelper.constructor)
 
 register_links(['metadata:metadata_add', 'metadata:metadata_edit', 'metadata:metadata_remove', 'metadata:metadata_view'], [metadata_add, metadata_edit, metadata_remove], menu_name='sidebar')
 register_links(Document, [metadata_view], menu_name='form_header')
+register_links([Document], [link_spacer, metadata_multiple_add, metadata_multiple_edit, metadata_multiple_remove], menu_name='multi_item_links')
 register_links(DocumentType, [setup_document_type_metadata, setup_document_type_metadata_required])
 register_links(MetadataType, [setup_metadata_type_edit, setup_metadata_type_delete])
 register_links([MetadataType, 'metadata:setup_metadata_type_list', 'metadata:setup_metadata_type_create'], [setup_metadata_type_list, setup_metadata_type_create], menu_name='secondary_menu')
-register_links([Document], [link_spacer, metadata_multiple_add, metadata_multiple_edit, metadata_multiple_remove], menu_name='multi_item_links')
 
 register_setup(setup_metadata_type_list)
 
@@ -75,3 +76,7 @@ register_model_list_columns(Document, [
 ])
 
 APIEndPoint('metadata')
+ModelAttribute(Document, 'document_metadata__metadata_type__name', label=_('Metadata type name'), type_name='query')
+ModelAttribute(Document, 'document_metadata__value', label=_('Metadata type value'), type_name='query')
+ModelAttribute(Document, 'document_metadata', type_name='related', description=_('Queryset containing a MetadataType instance reference and a value for that metadata type'))
+ModelAttribute(Document, 'metadata_value_of', label=_('Value of a metadata'), description=_('Return the value of a specific document metadata'), type_name=['property', 'indexing'])

mayan/apps/metadata/classes.py

@@ -2,29 +2,17 @@ from django.utils.translation import ugettext_lazy as _
 
 from acls.classes import EncapsulatedObject
 
-from .models import DocumentTypeMetadataType, MetadataType
+from .models import DocumentMetadata, DocumentTypeMetadataType, MetadataType
 
 
-class MetadataClass(object):
-    def __init__(self, dictionary):
-        self.dictionary = dictionary
-
-    def __getattr__(self, name):
-        if name in self.dictionary:
-            return self.dictionary.get(name)
-        else:
-            raise AttributeError(_(u'\'metadata\' object has no attribute \'%s\'') % name)
-
-
-class DocumentTypeMetadataTypeManager(object):
+class DocumentTypeMetadataTypeHelper(object):
     @staticmethod
     @property
-    def factory(document_type):
-        instance = DocumentTypeMetadataTypeManager(document_type)
-        return instance
+    def constructor(source_object):
+        return DocumentTypeMetadataTypeHelper(source_object)
 
-    def __init__(self, document_type):
-        self.document_type = document_type
+    def __init__(self, instance):
+        self.instance = instance
 
     def filter(self, **kwargs):
         return self.get_query_set(**kwargs)
@@ -34,12 +22,29 @@ class DocumentTypeMetadataTypeManager(object):
 
     def get_query_set(self, **kwargs):
         try:
-            return MetadataType.objects.filter(pk__in=self.document_type.documenttypemetadatatype_set.filter(**kwargs).values_list('metadata_type', flat=True))
-        except self.document_type.documenttypemetadatatype_set.model.DoesNotExist:
+            return MetadataType.objects.filter(pk__in=self.instance.documenttypemetadatatype_set.filter(**kwargs).values_list('metadata_type', flat=True))
+        except MetadataType.DoesNotExist:
             return MetadataType.objects.none()
 
     def add(self, metadata_type, required=False):
-        DocumentTypeMetadataType.objects.create(document_type=self.document_type, metadata_type=metadata_type, required=required)
+        DocumentTypeMetadataType.objects.create(document_type=self.instance, metadata_type=metadata_type, required=required)
 
     def remove(self, metadata_type):
-        DocumentTypeMetadataType.objects.get(document_type=self.document_type, metadata_type=metadata_type).delete()
+        DocumentTypeMetadataType.objects.get(document_type=self.instance, metadata_type=metadata_type).delete()
+
+
+class DocumentMetadataHelper(object):
+    @staticmethod
+    @property
+    def constructor(source_object):
+        return DocumentMetadataHelper(source_object)
+
+    def __init__(self, instance):
+        self.instance = instance
+
+    def __getattr__(self, name):
+        try:
+            return self.instance.metadata.get(metadata_type__name=name).value
+        except MetadataType.DoesNotExist:
+            raise AttributeError(_(u'\'metadata\' object has no attribute \'%s\'') % name)
+