feat: add hash generation for Resource and ResourceIdentifier

Author: impocode

Makefile

@@ -2,3 +2,7 @@ style:
 	black .
 	isort .
 	flake8 .
+
+test:
+	pytest tests
+

jsonapi_pydantic/utils.py

@@ -0,0 +1,10 @@
+def _generate_resource_hash(resource_type: str, resource_id: str) -> int:
+    hash_ = ""
+    for ch in resource_type:
+        hash_ += str(ord(ch))
+    for ch in resource_id:
+        hash_ += str(ord(ch))
+    return int(hash_)
+
+
+__all__ = ["_generate_resource_hash"]

jsonapi_pydantic/v1_0/resource/resource.py

@@ -1,10 +1,13 @@
+from collections.abc import Hashable
+from random import getrandbits
 from typing import Any, Dict, Optional
 
 from pydantic.config import ConfigDict
 from pydantic.fields import Field
 from pydantic.functional_validators import model_validator
 from pydantic.main import BaseModel
 
+from jsonapi_pydantic.utils import _generate_resource_hash
 from jsonapi_pydantic.v1_0.links import Links as LinksObject
 from jsonapi_pydantic.v1_0.meta import Meta as MetaObject
 from jsonapi_pydantic.v1_0.resource.relationship import Relationship
@@ -16,7 +19,7 @@
 Meta = Optional[MetaObject]
 
 
-class Resource(BaseModel):
+class Resource(BaseModel, Hashable):
     type: str = Field(title="Type")
     id: Id = Field(None, title="Id")
     attributes: Attributes = Field(None, title="Attributes")
@@ -26,6 +29,21 @@ class Resource(BaseModel):
 
     model_config = ConfigDict(frozen=True)
 
+    _hash: int
+
+    def __init__(self, **data):
+        super().__init__(**data)
+        if self.id:
+            self._hash = _generate_resource_hash(resource_type=self.type, resource_id=self.id)
+        else:
+            self._hash = getrandbits(64)
+
+    def __eq__(self, __value: object) -> bool:
+        return self._hash == getattr(__value, "_hash", None)
+
+    def __hash__(self) -> int:
+        return self._hash
+
     @model_validator(mode="after")
     def check_all_values(self) -> "Resource":
         if not self.attributes and not self.relationships:

jsonapi_pydantic/v1_0/resource_identifier.py

@@ -1,20 +1,34 @@
+from collections.abc import Hashable
 from typing import Optional
 
 from pydantic.config import ConfigDict
 from pydantic.fields import Field
 from pydantic.main import BaseModel
 
+from jsonapi_pydantic.utils import _generate_resource_hash
 from jsonapi_pydantic.v1_0.meta import Meta as MetaObject
 
 Meta = Optional[MetaObject]
 
 
-class ResourceIdentifier(BaseModel):
+class ResourceIdentifier(BaseModel, Hashable):
     id: str = Field(title="Id")
     type: str = Field(title="Type")
     meta: Meta = Field(None, title="Meta")
 
     model_config = ConfigDict(frozen=True)
 
+    _hash: int
+
+    def __init__(self, **data):
+        super().__init__(**data)
+        self._hash = _generate_resource_hash(resource_type=self.type, resource_id=self.id)
+
+    def __eq__(self, __value: object) -> bool:
+        return self._hash == getattr(__value, "_hash", None)
+
+    def __hash__(self) -> int:
+        return self._hash
+
 
 __all__ = ["ResourceIdentifier"]

jsonapi_pydantic/v1_0/toplevel.py

@@ -40,14 +40,24 @@ def check_all_values(cls, data: dict) -> dict:
         # More about these restrictions: https://jsonapi.org/format/#document-top-level
         if "data" in data and "errors" in data:
             raise ValueError("The members data and errors MUST NOT coexist in the same document.")
+
         if "included" in data and "data" not in data:
             raise ValueError(
                 "If a document does not contain a top-level data key, the included member MUST NOT be present either."
             )
+
         if "data" not in data and "errors" not in data and "meta" not in data:
             raise ValueError(
                 "A document MUST contain at least one of the following top-level members: data, errors, meta."
             )
+
+        if isinstance(data.get("data"), list):
+            hashes = {d._hash for d in data["data"]}
+            if len(data["data"]) > len(hashes):
+                raise ValueError(
+                    "A compound document MUST NOT include more than one resource object for each type and id pair."
+                )
+
         return data
 
 

pyproject.toml

@@ -36,6 +36,7 @@ pydantic = "^2.1.1"
 black = "^23.12.0"
 isort = "^5.13.2"
 flake8 = "^6.1.0"
+pytest = "^8.1.1"
 
 [tool.isort]
 line_length = 100

tests/v1_0/toplevel_test.py

@@ -0,0 +1,48 @@
+import pytest
+from pydantic import ValidationError
+
+from jsonapi_pydantic.v1_0 import Resource, ResourceIdentifier, TopLevel
+
+
+def test_toplevel_unique_resource():
+    with pytest.raises(
+        ValidationError,
+        match="A compound document MUST NOT include more than one resource object for each type and id pair.",
+    ):
+        TopLevel(
+            data=[
+                Resource(
+                    type="articles",
+                    id="3",
+                    attributes={
+                        "title": "JSON:API paints my bikeshed!",
+                        "body": "The shortest article. Ever.",
+                        "created": "2015-05-22T14:56:29.000Z",
+                        "updated": "2015-05-22T14:56:28.000Z",
+                    },
+                ),
+                Resource(
+                    type="articles",
+                    id="3",
+                    attributes={
+                        "title": "JSON:API paints my bikeshed!",
+                        "body": "The shortest article. Ever.",
+                        "created": "2015-05-22T14:56:29.000Z",
+                        "updated": "2015-05-22T14:56:28.000Z",
+                    },
+                ),
+            ]
+        )
+
+
+def test_toplevel_unique_resource_identifier():
+    with pytest.raises(
+        ValidationError,
+        match="A compound document MUST NOT include more than one resource object for each type and id pair.",
+    ):
+        TopLevel(
+            data=[
+                ResourceIdentifier(type="articles", id="3"),
+                ResourceIdentifier(type="articles", id="3"),
+            ]
+        )