Try to better isolate filtertransformers modules

optimade/filtertransformers/base_transformer.py

@@ -11,9 +11,31 @@
 
 from lark import Transformer, Tree, v_args
 
-from optimade.exceptions import BadRequest
-from optimade.server.mappers import BaseResourceMapper
-from optimade.warnings import UnknownProviderProperty
+if TYPE_CHECKING:
+    from optimade.server.mappers import BaseResourceMapper
+
+try:
+    from optimade.warnings import UnknownProviderProperty
+except ImportError:
+
+    class UnknownProviderProperty(UserWarning):  # type: ignore[no-redef]
+        """A property with a provider-specific prefix is not recognized by this implementation.
+        This shim class allows the filtertransformer to be used without the full optimade package.
+
+        """
+
+
+class FilterTransformerError(Exception):
+    """Base class for exceptions in this module."""
+
+    status_code: int
+    detail: str = "There was an error while processing the filter."
+
+    def __init__(self, status_code: int = 400, detail: str | None = None):
+        self.status_code = status_code
+        if detail is not None:
+            self.detail = detail
+
 
 if TYPE_CHECKING:  # pragma: no cover
     pass
@@ -82,7 +104,7 @@ class BaseTransformer(Transformer, abc.ABC):
 
     """
 
-    mapper: type[BaseResourceMapper] | None = None
+    mapper: type["BaseResourceMapper"] | None = None
     operator_map: dict[str, str | None] = {
         "<": None,
         "<=": None,
@@ -106,7 +128,7 @@ class BaseTransformer(Transformer, abc.ABC):
     _quantity_type: type[Quantity] = Quantity
     _quantities = None
 
-    def __init__(self, mapper: type[BaseResourceMapper] | None = None):
+    def __init__(self, mapper: type["BaseResourceMapper"] | None = None):
         """Initialise the transformer object, optionally loading in a
         resource mapper for use when post-processing.
 
@@ -264,7 +286,7 @@ def property(self, args: list) -> Any:
 
                     return quantity_name
 
-            raise BadRequest(
+            raise FilterTransformerError(
                 detail=f"'{quantity_name}' is not a known or searchable quantity"
             )
 

optimade/filtertransformers/elasticsearch.py

@@ -4,7 +4,9 @@
 from lark import v_args
 
 from optimade.filtertransformers import BaseTransformer, Quantity
-from optimade.server.mappers import BaseResourceMapper
+
+if TYPE_CHECKING:
+    from optimade.server.mappers import BaseResourceMapper
 
 __all__ = ("ElasticTransformer",)
 
@@ -101,7 +103,7 @@ class ElasticTransformer(BaseTransformer):
 
     def __init__(
         self,
-        mapper: type[BaseResourceMapper],
+        mapper: type["BaseResourceMapper"],
         quantities: dict[str, Quantity] | None = None,
     ):
         if quantities is not None:

optimade/filtertransformers/mongo.py

@@ -10,9 +10,21 @@
 
 from lark import Token, v_args
 
-from optimade.exceptions import BadRequest
-from optimade.filtertransformers.base_transformer import BaseTransformer, Quantity
-from optimade.warnings import TimestampNotRFCCompliant
+from optimade.filtertransformers.base_transformer import (
+    BaseTransformer,
+    FilterTransformerError,
+    Quantity,
+)
+
+try:
+    from optimade.warnings import TimestampNotRFCCompliant
+except ImportError:
+
+    class TimestampNotRFCCompliant(UserWarning):  # type: ignore[no-redef]
+        """A timestamp value was not RFC3339 compliant, which may lead to undefined behaviour.
+        This shim class is only used if the `optimade` package is not installed.
+        """
+
 
 __all__ = ("MongoTransformer",)
 
@@ -425,7 +437,9 @@ def replace_only_filter(subdict: dict, prop: str, expr: dict):
                     "relationships.references.data.id",
                     "relationships.structures.data.id",
                 ):
-                    raise BadRequest(f"Unable to query on unrecognised field {prop}.")
+                    raise FilterTransformerError(
+                        detail=f"Unable to query on unrecognised field {prop}."
+                    )
                 first_part_prop = ".".join(prop.split(".")[:-1])
                 subdict["$and"].append(
                     {

optimade/server/exception_handlers.py

@@ -8,6 +8,7 @@
 from pydantic import ValidationError
 
 from optimade.exceptions import BadRequest, OptimadeHTTPException
+from optimade.filtertransformers.base_transformer import FilterTransformerError
 from optimade.models import ErrorResponse, ErrorSource, OptimadeError
 from optimade.server.config import CONFIG
 from optimade.server.logger import LOGGER
@@ -228,6 +229,7 @@ def general_exception_handler(request: Request, exc: Exception) -> JSONAPIRespon
 ] = [
     (StarletteHTTPException, http_exception_handler),
     (OptimadeHTTPException, http_exception_handler),
+    (FilterTransformerError, http_exception_handler),
     (RequestValidationError, request_validation_exception_handler),
     (ValidationError, validation_exception_handler),
     (VisitError, grammar_not_implemented_handler),