Merge pull request #24 from volfpeter/wrap_as-JinjaContextFactory

Add JinjaContext.wrap_as() utility and tests

fasthx/jinja.py

@@ -1,5 +1,6 @@
 from collections.abc import Callable, Collection, Iterable
 from dataclasses import dataclass, field
+from functools import lru_cache
 from typing import Any, Coroutine
 
 from fastapi import Request, Response
@@ -89,6 +90,41 @@ def unpack_result_with_route_context(
         route_context.update(result)
         return route_context
 
+    @classmethod
+    @lru_cache
+    def wrap_as(cls, result_key: str, context_key: str | None = None) -> JinjaContextFactory:
+        """
+        Creates a `JinjaContextFactory` that wraps the route's result and optionally the route
+        context under user-specified keys.
+
+        `result_key` and `context_key` must be different.
+
+        Arguments:
+            result_key: The key by which the `route_result` should be accessible in templates.
+                See `JinjaContextFactory` for `route_result` details.
+            context_key: The key by whih the `route_context` should be accessible in templates.
+                If `None` (the default), then the `route_context` will not be accessible.
+                See `JinjaContextFactory` for `route_context` details.
+
+        Returns:
+            The created `JinjaContextFactory`.
+
+        Raises:
+            ValueError: If `result_key` and `context_key` are equal.
+        """
+
+        if result_key == context_key:
+            raise ValueError("The two keys must be different, merging is not supported.")
+
+        def wrap(*, route_result: Any, route_context: dict[str, Any]) -> dict[str, Any]:
+            result = {result_key: route_result}
+            if context_key is not None:
+                result[context_key] = route_context
+
+            return result
+
+        return wrap
+
 
 @dataclass(frozen=True, slots=True)
 class TemplateHeader:

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "fasthx"
-version = "1.0.0"
+version = "1.1.0"
 description = "FastAPI data APIs with HTMX support."
 authors = ["Peter Volf <[email protected]>"]
 readme = "README.md"

tests/test_jinja.py

@@ -188,6 +188,22 @@ def test_unpack_methods(self, route_result: Any, route_converted: dict[str, Any]
         )
         assert result == {**route_context, **route_converted}
 
+    def test_wrap_as(self) -> None:
+        result_only = JinjaContext.wrap_as("item")
+        assert result_only is JinjaContext.wrap_as("item")
+
+        result_and_context = JinjaContext.wrap_as("item", "route")
+        route_result, route_context = 22, {"4": 4}
+
+        assert {"item": route_result} == result_only(route_result=route_result, route_context=route_context)
+        assert {"item": route_result, "route": route_context} == result_and_context(
+            route_result=route_result, route_context=route_context
+        )
+
+    def test_wrap_as_name_conflict(self) -> None:
+        with pytest.raises(ValueError):
+            JinjaContext.wrap_as("foo", "foo")
+
     def test_unpack_result_with_route_context_conflict(self) -> None:
         with pytest.raises(ValueError):
             JinjaContext.unpack_result_with_route_context(