Arrayfield support querying by EMF

django_mongodb_backend/fields/array.py

@@ -326,9 +326,7 @@ def get_subquery_wrapping_pipeline(self, compiler, connection, field_name, expr)
     def as_mql(self, compiler, connection):
         lhs_mql = process_lhs(self, compiler, connection)
         value = process_rhs(self, compiler, connection)
-        return {
-            "$and": [{"$ne": [lhs_mql, None]}, {"$size": {"$setIntersection": [value, lhs_mql]}}]
-        }
+        return {"$and": [{"$isArray": lhs_mql}, {"$size": {"$setIntersection": [value, lhs_mql]}}]}
 
 
 @ArrayField.register_lookup
@@ -338,7 +336,7 @@ class ArrayLenTransform(Transform):
 
     def as_mql(self, compiler, connection):
         lhs_mql = process_lhs(self, compiler, connection)
-        return {"$cond": {"if": {"$eq": [lhs_mql, None]}, "then": None, "else": {"$size": lhs_mql}}}
+        return {"$cond": {"if": {"$isArray": lhs_mql}, "then": {"$size": lhs_mql}, "else": None}}
 
 
 @ArrayField.register_lookup

django_mongodb_backend/fields/embedded_model.py

@@ -186,8 +186,11 @@ def as_mql(self, compiler, connection):
             key_transforms.insert(0, previous.key_name)
             previous = previous.lhs
         mql = previous.as_mql(compiler, connection)
-        transforms = ".".join(key_transforms)
-        return f"{mql}.{transforms}"
+        # transform = ".".join(key_transforms)
+        for key in key_transforms:
+            mql = {"$getField": {"input": mql, "field": key}}
+        return mql
+        # return f"{mql}.{transform}"
 
     @property
     def output_field(self):

django_mongodb_backend/fields/embedded_model_array.py

@@ -1,8 +1,16 @@
+import difflib
+
+from django.core.exceptions import FieldDoesNotExist
+from django.db import models
 from django.db.models import Field
+from django.db.models.expressions import Col
+from django.db.models.lookups import Lookup, Transform
 
 from .. import forms
+from ..query_utils import process_lhs, process_rhs
 from . import EmbeddedModelField
 from .array import ArrayField
+from .embedded_model import EMFExact, EMFMixin
 
 
 class EmbeddedModelArrayField(ArrayField):
@@ -44,3 +52,190 @@ def formfield(self, **kwargs):
                 **kwargs,
             },
         )
+
+    def get_transform(self, name):
+        transform = super().get_transform(name)
+        if transform:
+            return transform
+        return KeyTransformFactory(name, self)
+
+
+@EmbeddedModelArrayField.register_lookup
+class EMFArrayExact(EMFExact):
+    def as_mql(self, compiler, connection):
+        lhs_mql = process_lhs(self, compiler, connection)
+        value = process_rhs(self, compiler, connection)
+        if isinstance(self.lhs, KeyTransform):
+            lhs_mql, inner_lhs_mql = lhs_mql
+        else:
+            inner_lhs_mql = "$$item"
+        if isinstance(value, models.Model):
+            value, emf_data = self.model_to_dict(value)
+            # Get conditions for any nested EmbeddedModelFields.
+            conditions = self.get_conditions({inner_lhs_mql: (value, emf_data)})
+            return {
+                "$anyElementTrue": {
+                    "$ifNull": [
+                        {
+                            "$map": {
+                                "input": lhs_mql,
+                                "as": "item",
+                                "in": {"$and": conditions},
+                            }
+                        },
+                        [],
+                    ]
+                }
+            }
+        return {
+            "$anyElementTrue": {
+                "$ifNull": [
+                    {
+                        "$map": {
+                            "input": lhs_mql,
+                            "as": "item",
+                            "in": {"$eq": [inner_lhs_mql, value]},
+                        }
+                    },
+                    [],
+                ]
+            }
+        }
+
+
+@EmbeddedModelArrayField.register_lookup
+class ArrayOverlap(EMFMixin, Lookup):
+    lookup_name = "overlap"
+    get_db_prep_lookup_value_is_iterable = True
+
+    def process_rhs(self, compiler, connection):
+        values = self.rhs
+        if self.get_db_prep_lookup_value_is_iterable:
+            values = [values]
+        # Compute how to serialize each value based on the query target.
+        # If querying a subfield inside the array (i.e., a nested KeyTransform), use the output
+        # field of the subfield. Otherwise, use the base field of the array itself.
+        if isinstance(self.lhs, KeyTransform):
+            get_db_prep_value = self.lhs._lhs.output_field.get_db_prep_value
+        else:
+            get_db_prep_value = self.lhs.output_field.base_field.get_db_prep_value
+        return None, [get_db_prep_value(v, connection, prepared=True) for v in values]
+
+    def as_mql(self, compiler, connection):
+        lhs_mql = process_lhs(self, compiler, connection)
+        values = process_rhs(self, compiler, connection)
+        # Querying a subfield within the array elements (via nested KeyTransform).
+        # Replicates MongoDB's implicit ANY-match by mapping over the array and applying
+        # `$in` on the subfield.
+        if isinstance(self.lhs, KeyTransform):
+            lhs_mql, inner_lhs_mql = lhs_mql
+            return {
+                "$anyElementTrue": {
+                    "$ifNull": [
+                        {
+                            "$map": {
+                                "input": lhs_mql,
+                                "as": "item",
+                                "in": {"$in": [inner_lhs_mql, values]},
+                            }
+                        },
+                        [],
+                    ]
+                }
+            }
+        conditions = []
+        inner_lhs_mql = "$$item"
+        # Querying full embedded documents in the array.
+        # Builds `$or` conditions and maps them over the array to match any full document.
+        for value in values:
+            value, emf_data = self.model_to_dict(value)
+            # Get conditions for any nested EmbeddedModelFields.
+            conditions.append({"$and": self.get_conditions({inner_lhs_mql: (value, emf_data)})})
+        return {
+            "$anyElementTrue": {
+                "$ifNull": [
+                    {
+                        "$map": {
+                            "input": lhs_mql,
+                            "as": "item",
+                            "in": {"$or": conditions},
+                        }
+                    },
+                    [],
+                ]
+            }
+        }
+
+
+class KeyTransform(Transform):
+    # it should be different class than EMF keytransform even most of the methods are equal.
+    def __init__(self, key_name, array_field, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.array_field = array_field
+        self.key_name = key_name
+        # The iteration items begins from the base_field, a virtual column with
+        # base field output type is created.
+        column_target = array_field.base_field.embedded_model._meta.get_field(key_name).clone()
+        column_name = f"$item.{key_name}"
+        column_target.db_column = column_name
+        column_target.set_attributes_from_name(column_name)
+        self._lhs = Col(None, column_target)
+        self._sub_transform = None
+
+    def __call__(self, this, *args, **kwargs):
+        self._lhs = self._sub_transform(self._lhs, *args, **kwargs)
+        return self
+
+    def get_lookup(self, name):
+        return self.output_field.get_lookup(name)
+
+    def _get_missing_field_or_lookup_exception(self, lhs, name):
+        suggested_lookups = difflib.get_close_matches(name, lhs.get_lookups())
+        if suggested_lookups:
+            suggested_lookups = " or ".join(suggested_lookups)
+            suggestion = f", perhaps you meant {suggested_lookups}?"
+        else:
+            suggestion = "."
+        raise FieldDoesNotExist(
+            f"Unsupported lookup '{name}' for "
+            f"{self.array_field.base_field.__class__.__name__} '{self.array_field.base_field.name}'"
+            f"{suggestion}"
+        )
+
+    def get_transform(self, name):
+        """
+        Validate that `name` is either a field of an embedded model or a
+        lookup on an embedded model's field.
+        """
+        # Once the sub lhs is a transform, all the filter are applied over it.
+        transform = (
+            self._lhs.get_transform(name)
+            if isinstance(self._lhs, Transform)
+            else self.array_field.base_field.embedded_model._meta.get_field(
+                self.key_name
+            ).get_transform(name)
+        )
+        if transform:
+            self._sub_transform = transform
+            return self
+        raise self._get_missing_field_or_lookup_exception(
+            self._lhs if isinstance(self._lhs, Transform) else self.base_field, name
+        )
+
+    def as_mql(self, compiler, connection):
+        inner_lhs_mql = self._lhs.as_mql(compiler, connection)
+        lhs_mql = process_lhs(self, compiler, connection)
+        return lhs_mql, inner_lhs_mql
+
+    @property
+    def output_field(self):
+        return self.array_field
+
+
+class KeyTransformFactory:
+    def __init__(self, key_name, base_field):
+        self.key_name = key_name
+        self.base_field = base_field
+
+    def __call__(self, *args, **kwargs):
+        return KeyTransform(self.key_name, self.base_field, *args, **kwargs)

tests/model_fields_/models.py

@@ -165,3 +165,37 @@ class Movie(models.Model):
 
     def __str__(self):
         return self.title
+
+
+class RestorationRecord(EmbeddedModel):
+    date = models.DateField()
+    description = models.TextField()
+    restored_by = models.CharField(max_length=255)
+
+
+class ArtifactDetail(EmbeddedModel):
+    """Details about a specific artifact."""
+
+    name = models.CharField(max_length=255)
+    description = models.CharField(max_length=255)
+    metadata = models.JSONField()
+    restorations = EmbeddedModelArrayField(RestorationRecord, null=True)
+    last_restoration = EmbeddedModelField(RestorationRecord, null=True)
+
+
+class ExhibitSection(EmbeddedModel):
+    """A section within an exhibit, containing multiple artifacts."""
+
+    section_number = models.IntegerField()
+    artifacts = EmbeddedModelArrayField(ArtifactDetail, null=True)
+
+
+class MuseumExhibit(models.Model):
+    """An exhibit in the museum, composed of multiple sections."""
+
+    exhibit_name = models.CharField(max_length=255)
+    sections = EmbeddedModelArrayField(ExhibitSection, null=True)
+    main_section = EmbeddedModelField(ExhibitSection, null=True)
+
+    def __str__(self):
+        return self.exhibit_name