implemented case insensitive search

src/dso_api/dynamic_api/filters/lookups.py

@@ -1,5 +1,6 @@
 """Additional ORM lookups to implement the various DSO filter operators."""
 
+from django.contrib.postgres.fields import ArrayField
 from django.db import models
 from django.db.models import expressions, lookups
 
@@ -45,18 +46,30 @@ def as_sql(self, compiler, connection):
         lhs, lhs_params = self.process_lhs(compiler, connection, lhs=lhs)  # (field, [])
         rhs, rhs_params = self.process_rhs(compiler, connection)  # ("%s", [value])
 
+        field_type = self.lhs.output_field.get_internal_type()
         if lhs_nullable and rhs is not None:
             # Allow field__not=value to return NULL fields too.
-            return (
-                f"({lhs} IS NULL OR {lhs} != {rhs})",
-                list(lhs_params + lhs_params) + rhs_params,
-            )
-
+            if field_type in ["CharField", "TextField"] and not self.lhs.field.primary_key:
+                return (
+                    f"({lhs}) IS NULL OR UPPER({lhs}) != UPPER({rhs}))",
+                    list(lhs_params + lhs_params)
+                    + [rhs.upper() if isinstance(rhs, str) else rhs for rhs in rhs_params],
+                )
+            else:
+                return (
+                    f"({lhs} IS NULL OR {lhs} != {rhs})",
+                    list(lhs_params + lhs_params) + rhs_params,
+                )
         elif rhs_params and rhs_params[0] is None:
             # Allow field__not=None to work.
             return f"{lhs} IS NOT NULL", lhs_params
         else:
-            return f"{lhs} != {rhs}", list(lhs_params) + rhs_params
+            if field_type in ["CharField", "TextField"] and not self.lhs.field.primary_key:
+                return f"UPPER({lhs}) != UPPER({rhs})", list(lhs_params) + [
+                    rhs.upper() if isinstance(rhs, str) else rhs for rhs in rhs_params
+                ]
+            else:
+                return f"{lhs} != {rhs}", list(lhs_params) + rhs_params
 
 
 @models.CharField.register_lookup
@@ -76,7 +89,10 @@ def as_sql(self, compiler, connection):
         lhs, lhs_params = self.process_lhs(compiler, connection)
         rhs, rhs_params = self.process_rhs(compiler, connection)
 
-        return f"{lhs} LIKE {rhs}", lhs_params + rhs_params
+        if self.lhs.field.primary_key:
+            return f"{lhs} LIKE {rhs}", lhs_params + rhs_params
+        else:
+            return f"UPPER({lhs}) LIKE {rhs}", lhs_params + [rhs.upper() for rhs in rhs_params]
 
     def get_db_prep_lookup(self, value, connection):
         """Apply the wildcard logic to the right-hand-side value"""
@@ -95,3 +111,60 @@ def _sql_wildcards(value: str) -> str:
         .replace("*", "%")
         .replace("?", "_")
     )
+
+
+@models.ForeignKey.register_lookup
+class CaseInsensitiveExact(lookups.Lookup):
+    lookup_name = "iexact"
+
+    def as_sql(self, compiler, connection):
+        """Generate the required SQL."""
+        lhs, lhs_params = self.process_lhs(compiler, connection)
+        rhs, rhs_params = self.process_rhs(compiler, connection)
+        if not self.lhs.field.primary_key:
+            return f"UPPER({lhs}) = UPPER({rhs})", lhs_params + rhs_params
+        else:
+            return f"{lhs} = {rhs}", lhs_params + rhs_params
+
+
+@ArrayField.register_lookup
+class ArrayContainsCaseInsensitive(lookups.Lookup):
+    """
+    Override the default "contains" lookup for ArrayFields such that it does a case-insensitive
+    search. It also supports passing a comma separated string of values (or an iterable)
+    and returns matches only when the array field contains ALL of these values.
+    """
+
+    lookup_name = "contains"
+
+    def as_sql(self, compiler, connection):
+        # Process the left-hand side expression (the array column)
+        lhs, lhs_params = self.process_lhs(compiler, connection)
+
+        # If the lookup value is a comma-separated string, split it;
+        # otherwise assume it is an iterable of values or a single value.
+        if isinstance(self.rhs, str):
+            # Split value on commas and filter out any empty strings.
+            values = [val.strip() for val in self.rhs.split(",") if val.strip()]
+        else:
+            try:
+                iter(self.rhs)
+            except TypeError:
+                values = [self.rhs]
+            else:
+                values = list(self.rhs)
+
+        # Convert each search value to uppercase for case-insensitive matching.
+        values = [v.upper() for v in values]
+
+        # Transform the values in the array column to uppercase; this is done by unnesting the
+        # array, applying UPPER() to each element, and reconstructing an array.
+        lhs_sql = f"(ARRAY(SELECT UPPER(x) FROM unnest({lhs}) AS x))"  # noqa: S608
+
+        # Build a comma-separated set of placeholders for each search value.
+        placeholders = ", ".join(["%s"] * len(values))
+
+        # The resulting SQL uses the array "contains" operator @> to ensure that all provided
+        # values are present (case-insensitively) in the array field.
+        sql = f"{lhs_sql} @> ARRAY[{placeholders}]"
+        return sql, lhs_params + values

src/dso_api/dynamic_api/filters/parser.py

@@ -320,12 +320,23 @@ def _translate_lookup(
                         )
                     }
                 ) from None
-
+        # Handle case-insensitive exact matches for string fields only,
+        # but not for relations or formatted fields
         if filter_part.field.format == "date-time" and not isinstance(value, datetime):
             # When something different then a full datetime is given, only compare dates.
             # Otherwise, the "lte" comparison happens against 00:00:00.000 of that date,
             # instead of anything that includes that day itself.
-            lookup = f"date__{lookup or 'exact'}"
+            return f"date__{lookup or 'exact'}"
+
+        # Only apply iexact for direct string field lookups (not through relations)
+        if (
+            not lookup
+            and filter_part.field.type == "string"
+            and filter_part.field.format not in ["date-time", "time", "date"]
+            and not filter_part.field.is_relation
+            and not filter_part.field.is_primary
+        ):
+            return "iexact"
 
         return lookup or "exact"
 

src/tests/test_dynamic_api/test_filters.py

@@ -26,7 +26,7 @@ def test_like_filter_sql(self, django_assert_num_queries):
             list(Dataset.objects.filter(name__like="foo*bar?"))
 
         sql = context.captured_queries[0]["sql"]
-        assert r"""."name" LIKE 'foo%bar_'""" in sql
+        assert r"""."name") LIKE 'FOO%BAR_'""" in sql
 
 
 def test_sql_wildcards():
@@ -96,6 +96,11 @@ def movie2(self, movies_model, movies_category):
             ("url[in]=foobar,http://example.com/someurl", {"movie2"}),
             ("url[like]=http:*", {"movie2"}),
             ("url[isnull]=true", {"movie1"}),
+            # Case insensitive match
+            ("name=movie1", {"movie1"}),
+            ("name=Movie1", {"movie1"}),
+            ("name[like]=movie1", {"movie1"}),
+            ("name[like]=Movie1", {"movie1"}),
         ],
     )
     def test_filter_logic(self, movies_model, movie1, movie2, query, expect):