object auto-loading by secondary key

doc/factory.rst

@@ -18,6 +18,9 @@ SmartObjectFactory class
 Object auto-loading
 ===================
 
+By primary key
+--------------
+
 If *autoload=True* argument is used on factory creation, the factory will try
 automatically load Smart Objects from the storage when **factory.get()** method
 is called and the object doesn't exist.
@@ -33,6 +36,25 @@ If *allow_empty=False* for the object storage, **factory.get()** method raises
 *LookupError* (for RDBMS storages) or *FileNotFoundError* (for file-based
 storages) exceptions in case if storage doesn't have an object with such PK.
 
+By property
+-----------
+
+SmartObjectFactory also supports loading objects by property as secondary key.
+To use this feature:
+
+* Factory **autoload** option should be set to *True*
+* For get method, **prop** argument should be specified
+* You may also specify storage ID to load missing objects from, if not
+  specified - default storage is used
+* Objects are auto-loaded from the storage in two cases:
+
+   * when object is missing in factory
+   * when *get_all=True* is specified for **factory.get()** method.
+
+.. note::
+
+   Loading objects by prop is supported only for RDBMS storages
+
 Object cache size limit
 =======================
 

smartobject/factory.py

@@ -139,7 +139,7 @@ def touch(self, obj):
                 obj = obj._get_primary_key()
             self._objects_last_access[obj] = time.perf_counter()
 
-    def get(self, key=None, prop=None):
+    def get(self, key=None, prop=None, storage_id=None, get_all=False, opts={}):
         """
         Get Smart Object from factory
 
@@ -148,6 +148,11 @@ def get(self, key=None, prop=None):
                 returned
             prop: object prop (should be indexed). If no prop specified, object
                 is looked up by primary key
+            storage_id: if prop is specified, look up for objects in specified
+                storage, if no objects present in factory. storage should
+                support
+            get_all: always lookup for all objects in storage
+            opts: options for object constructor if loaded from storage
         Raises:
             KeyError: if object with such key doesn't exist (for primary key)
             FileNotFoundError, LookupError: if auto-load is on but object not
@@ -162,9 +167,32 @@ def get(self, key=None, prop=None):
                 return self._objects.copy()
             elif prop is not None:
                 result = []
-                for obj in self._objects_by_prop[prop][key]:
-                    self.touch(obj)
-                    result.append(obj)
+                if not get_all:
+                    for obj in self._objects_by_prop[prop][key]:
+                        self.touch(obj)
+                        result.append(obj)
+                if self.autoload and (get_all or not result):
+                    from . import storage
+                    try:
+                        objects = storage.get_storage(storage_id).load_by_prop(
+                            key, prop)
+                    except RuntimeError:
+                        objects = []
+                    for d in objects:
+                        if 'data' in d:
+                            logger.debug(
+                                f'Creating object {self._object_class.__name__}'
+                            )
+                            o = self._object_class(**opts)
+                            o.set_prop(d['data'],
+                                       _allow_readonly=True,
+                                       sync=False,
+                                       save=False)
+                            o.after_load(opts=d.get('info', {}))
+                            o.sync()
+                            if o._get_primary_key() not in self._objects:
+                                self.create(obj=o, save=False)
+                            result.append(o)
                 return result
             else:
                 try:
@@ -173,7 +201,7 @@ def get(self, key=None, prop=None):
                     return obj
                 except KeyError:
                     if self.autoload:
-                        obj = self._object_class()
+                        obj = self._object_class(**opts)
                         obj._set_primary_key(key)
                         obj.load()
                         self.append(obj)

smartobject/storage.py

@@ -64,6 +64,16 @@ def load(self, pk, **kwargs):
         """
         return {}
 
+    def load_by_prop(self, key, prop, **kwargs):
+        """
+        Load object data from the storage by secondary key
+
+        Args:
+            key: object key value
+            prop: object key name
+        """
+        raise RuntimeError('Not implemented')
+
     def load_all(self, **kwargs):
         """
         Load object data for all objecta and return it as list generator
@@ -260,7 +270,17 @@ def load_all(self, **kwargs):
             while True:
                 d = result.fetchone()
                 if d is None: break
-                yield { 'data':  dict(d) }
+                yield {'data': dict(d)}
+
+    def load_by_prop(self, key, prop, **kwargs):
+        with self.__lock:
+            result = self.get_db().execute(
+                self.sa.text(f'select * from {self.table} where {prop}=:value'),
+                value=key)
+            while True:
+                d = result.fetchone()
+                if d is None: break
+                yield {'data': dict(d)}
 
     def get_prop(self, pk, prop, **kwargs):
         with self.__lock:

tests/test.py

@@ -566,5 +566,29 @@ def test_factory_lru():
     with pytest.raises(RuntimeError):
         factory.cleanup_storage()
 
+def test_factory_load_by_secondary():
+    db = _prepare_t2_db()
+    storage = smartobject.SQLAStorage(db, 't2')
+    smartobject.define_storage(storage)
+    factory = smartobject.SmartObjectFactory(T2, autoload=True, autosave=True)
+    factory.add_index('login')
+    o1 = factory.create()
+    o2 = factory.create()
+    o3 = factory.create()
+    o4 = factory.create()
+    o1.set_prop('login', 'test')
+    o2.set_prop('login', 'test')
+    o3.set_prop('login', 'test2')
+    o4.set_prop('login', 'test3')
+    factory.save()
+    factory.clear()
+    test1 = factory.get(o1.id)
+    tests = factory.get('test', prop='login')
+    assert len(tests) == 1
+    tests = factory.get('test', prop='login', get_all=True)
+    assert len(tests) == 2
+    tests = factory.get('test2', prop='login', get_all=True)
+    assert len(tests) == 1
 
 clean()
+test_factory_load_by_secondary()