Update dimension_types schema/model

Using `IntEnum` and pydantic's `Field` parameters to perform validation
of the property, `dimension_types` is now represented correctly in the
OpenAPI schema as well.

openapi/openapi.json

@@ -2653,8 +2653,16 @@
           },
           "dimension_types": {
             "title": "Dimension Types",
+            "maxItems": 3,
+            "minItems": 3,
             "type": "array",
-            "items": {},
+            "items": {
+              "enum": [
+                0,
+                1
+              ],
+              "type": "integer"
+            },
             "description": "List of three integers.\n  For each of the three directions indicated by the three lattice vectors (see property `lattice_vectors`_).\n  This list indicates if the direction is periodic (value :val:`1`) or non-periodic (value :val:`0`).\n  Note: the elements in this list each refer to the direction of the corresponding entry in property `lattice_vectors`_ and *not* the Cartesian x, y, z directions.\n- **Type**: list of integers.\n- **Requirements/Conventions**:\n\n  - **Support**: SHOULD be supported, i.e., SHOULD NOT be :val:`null`. Is REQUIRED in this implementation, i.e., MUST NOT be :val:`null`.\n  - **Query**: MUST be a queryable property. Support for equality comparison is REQUIRED, support for other comparison operators are OPTIONAL.\n  - MUST be a list of length 3.\n  - Each integer element MUST assume only the value 0 or 1.\n\n- **Examples**:\n\n  - For a molecule: :val:`[0, 0, 0]`\n  - For a wire along the direction specified by the third lattice vector: :val:`[0, 0, 1]`\n  - For a 2D surface/slab, periodic on the plane defined by the first and third lattice vectors: :val:`[1, 0, 1]`\n  - For a bulk 3D system: :val:`[1, 1, 1]`"
           },
           "lattice_vectors": {

optimade/models/structures.py

@@ -1,4 +1,5 @@
 # pylint: disable=no-self-argument,line-too-long,no-name-in-module
+from enum import IntEnum
 from sys import float_info
 from typing import List, Optional
 
@@ -17,6 +18,11 @@
 EPS = float_info.epsilon
 
 
+class dimension_types_values(IntEnum):
+    ZERO = 0
+    ONE = 1
+
+
 class Species(BaseModel):
     """A list describing the species of the sites of this structure.
     Species can be pure chemical elements, or virtual-crystal atoms representing a statistical occupation of a given site by multiple chemical elements.
@@ -307,7 +313,7 @@ class StructureResourceAttributes(EntryResourceAttributes):
   - A filter that matches an exactly given formula is :filter:`chemical_formula_anonymous="A2B"`.""",
     )
 
-    dimension_types: conlist(len_eq=3) = Field(
+    dimension_types: List[dimension_types_values] = Field(
         ...,
         description="""List of three integers.
   For each of the three directions indicated by the three lattice vectors (see property `lattice_vectors`_).
@@ -327,6 +333,8 @@ class StructureResourceAttributes(EntryResourceAttributes):
   - For a wire along the direction specified by the third lattice vector: :val:`[0, 0, 1]`
   - For a 2D surface/slab, periodic on the plane defined by the first and third lattice vectors: :val:`[1, 0, 1]`
   - For a bulk 3D system: :val:`[1, 1, 1]`""",
+        min_items=3,
+        max_items=3,
     )
 
     lattice_vectors: Optional[List[conlist(len_eq=3)]] = Field(