feat: QueryList: Filter lists of dictionaries w/ nested support

Author: tony

docs/contributing/internals.md

@@ -18,3 +18,8 @@ stability policy.
 .. autoapimodule:: libvcs.types
    :members:
 ```
+
+```{eval-rst}
+.. autoapimodule:: libvcs.utils.query_list
+   :members:
+```

libvcs/utils/__init__.py

@@ -0,0 +1,233 @@
+import dataclasses
+import re
+import traceback
+from typing import Any, Callable, Generic, Optional, Protocol, Sequence, TypeVar, Union
+
+T = TypeVar("T", Any, Any)
+
+
+def keygetter(obj, path):
+    """obj, "foods__breakfast", obj['foods']['breakfast']
+
+    >>> keygetter({ "foods": { "breakfast": "cereal" } }, "foods__breakfast")
+    'cereal'
+    >>> keygetter({ "foods": { "breakfast": "cereal" } }, "foods")
+    {'breakfast': 'cereal'}
+
+    """
+    try:
+        sub_fields = path.split("__")
+        dct = obj
+        for sub_field in sub_fields:
+            dct = dct[sub_field]
+        return dct
+    except Exception as e:
+        traceback.print_exception(e)
+    return None
+
+
+def parse_lookup(obj, path, lookup):
+    """Check if field lookup key, e.g. "my__path__contains" has comparator, return val.
+
+    If comparator not used or value not found, return None.
+
+    mykey__endswith("mykey") -> "mykey" else None
+
+    >>> parse_lookup({ "food": "red apple" }, "food__istartswith", "__istartswith")
+    'red apple'
+    """
+    try:
+        if path.endswith(lookup):
+            if field_name := path.rsplit(lookup)[0]:
+                return keygetter(obj, field_name)
+    except Exception as e:
+        traceback.print_exception(e)
+    return None
+
+
+class LookupProtocol(Protocol):
+    """Protocol for :class:`QueryList` filtering operators."""
+
+    def __call__(self, data: Union[list[str], str], rhs: Union[list[str], str]):
+        """Callback for :class:`QueryList` filtering operators."""
+
+
+def lookup_exact(data, rhs):
+    return rhs == data
+
+
+def lookup_iexact(data, rhs):
+    return rhs.lower() == data.lower()
+
+
+def lookup_contains(data, rhs):
+    return rhs in data
+
+
+def lookup_icontains(data, rhs):
+    return rhs.lower() in data.lower()
+
+
+def lookup_startswith(data, rhs):
+    return data.startswith(rhs)
+
+
+def lookup_istartswith(data, rhs):
+    return data.lower().startswith(rhs.lower())
+
+
+def lookup_endswith(data, rhs):
+    return data.endswith(rhs)
+
+
+def lookup_iendswith(data, rhs):
+    return data.lower().endswith(rhs.lower())
+
+
+def lookup_in(data, rhs):
+    if isinstance(rhs, list):
+        return data in rhs
+    return rhs in data
+
+
+def lookup_nin(data, rhs):
+    if isinstance(rhs, list):
+        return data not in rhs
+    return rhs not in data
+
+
+def lookup_regex(data, rhs):
+    return re.search(rhs, data)
+
+
+def lookup_iregex(data, rhs):
+    return re.search(rhs, data, re.IGNORECASE)
+
+
+LOOKUP_NAME_MAP: dict[str, LookupProtocol] = {
+    "eq": lookup_exact,
+    "exact": lookup_exact,
+    "iexact": lookup_iexact,
+    "contains": lookup_contains,
+    "icontains": lookup_icontains,
+    "startswith": lookup_startswith,
+    "istartswith": lookup_istartswith,
+    "endswith": lookup_endswith,
+    "iendswith": lookup_iendswith,
+    "in": lookup_in,
+    "nin": lookup_nin,
+    "regex": lookup_regex,
+    "iregex": lookup_iregex,
+}
+
+
+@dataclasses.dataclass(eq=False)
+class QueryList(Generic[T]):
+    """Filter list of object/dicts. For small, local datasets. *Experimental, unstable*.
+
+    :py:func:`dataclasses.dataclass` is only used for ``__repr__`` and pytest comparison
+    details.
+
+    >>> query = QueryList(
+    ...     [
+    ...         {
+    ...             "place": "Largo",
+    ...             "city": "Tampa",
+    ...             "state": "Florida",
+    ...             "foods": {"fruit": ["banana", "orange"], "breakfast": "cereal"},
+    ...         },
+    ...         {
+    ...             "place": "Chicago suburbs",
+    ...             "city": "Elmhurst",
+    ...             "state": "Illinois",
+    ...             "foods": {"fruit": ["apple", "cantelope"], "breakfast": "waffles"},
+    ...         },
+    ...     ]
+    ... )
+    >>> query.filter(place="Chicago suburbs").data[0]['city']
+    'Elmhurst'
+    >>> query.filter(place__icontains="chicago").data[0]['city']
+    'Elmhurst'
+    >>> query.filter(foods__breakfast="waffles").data[0]['city']
+    'Elmhurst'
+    >>> query.filter(foods__fruit__in="cantelope").data[0]['city']
+    'Elmhurst'
+    >>> query.filter(foods__fruit__in="orange").data[0]['city']
+    'Tampa'
+    """
+
+    __slots__ = ("data", "pk_key")
+    data: Sequence[T]
+
+    # def __init__(self, data, pk_key: Optional[str] = None):
+    #     self.data: Sequence[T] = data
+    #     #: Primary key for objects, optional.
+    #     #: Use for .get(), .items()
+    #     self.pk_key: Optional[Any] = pk_key
+
+    def items(self):
+        data: Sequence[T]
+
+        if self.pk_key is None:
+            raise Exception("items() require a pk_key exists")
+        return [(getattr(item, self.pk_key), item) for item in self.data]
+
+    def __eq__(self, other):
+        data = other
+        if hasattr(data, "data"):
+            data = getattr(data, "data")
+
+        if not isinstance(self.data, list) or not isinstance(data, list):
+            return False
+
+        if len(self.data) == len(data):
+            for (a, b) in zip(self.data, data):
+                if isinstance(a, dict):
+                    a_keys = a.keys()
+                    if a.keys == b.keys():
+                        for key in a_keys:
+                            if abs(a[key] - b[key]) > 1:
+                                return False
+                else:
+                    if a != b:
+                        return False
+
+            return True
+        return False
+
+    def filter(self, matcher: Optional[Union[Callable[[T], bool], T]] = None, **kwargs):
+        def filter_lookup(obj) -> bool:
+            for path, v in kwargs.items():
+                try:
+                    lhs, op = path.rsplit("__", 1)
+
+                    if op not in LOOKUP_NAME_MAP:
+                        raise ValueError(f"{op} not in LOOKUP_NAME_MAP")
+                except ValueError:
+                    lhs = path
+                    op = "exact"
+
+                assert op in LOOKUP_NAME_MAP
+                path = lhs
+                data = keygetter(obj, path)
+
+                if not LOOKUP_NAME_MAP[op](data, v):
+                    return False
+
+            return True
+
+        if callable(matcher):
+            _filter = matcher
+        elif matcher is not None:
+
+            def val_match(obj):
+                if isinstance(matcher, list):
+                    return obj in matcher
+                else:
+                    return obj == matcher
+
+            _filter = val_match
+        else:
+            _filter = filter_lookup
+
+        return self.__class__(data=[k for k in self.data if _filter(k)])