expose Template json syntax converters (#458)

Co-authored-by: Victor Moreno <[email protected]>

cedar-policy/CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Marked the `Template::from_json` and `Template::to_json` apis as public
 - New APIs to `Entities` to make it easy to add a collection of entities to an
   existing `Entities` structure. (#276)
 - Export the `cedar_policy_core::evaluator::{EvaluationError, EvaluationErrorKind}` and

cedar-policy/src/api.rs

@@ -2298,8 +2298,7 @@ impl Template {
     /// If `id` is Some, the policy will be given that Policy Id.
     /// If `id` is None, then "JSON policy" will be used.
     /// The behavior around None may change in the future.
-    #[allow(dead_code)] // planned to be a public method in the future
-    fn from_json(
+    pub fn from_json(
         id: Option<PolicyId>,
         json: serde_json::Value,
     ) -> Result<Self, cedar_policy_core::est::FromJsonError> {
@@ -2312,8 +2311,7 @@ impl Template {
     }
 
     /// Get the JSON representation of this `Template`.
-    #[allow(dead_code)] // planned to be a public method in the future
-    fn to_json(&self) -> Result<serde_json::Value, impl std::error::Error> {
+    pub fn to_json(&self) -> Result<serde_json::Value, impl std::error::Error> {
         let est = self.lossless.est()?;
         let json = serde_json::to_value(est)?;
         Ok::<_, PolicyToJsonError>(json)

cedar-policy/src/tests.rs

@@ -2726,3 +2726,28 @@ mod schema_based_parsing_tests {
         );
     }
 }
+
+mod template_tests {
+    use crate::Template;
+
+    #[test]
+    fn test_policy_template_to_json() {
+        let template = Template::parse(
+            None,
+            "permit(principal == ?principal, action, resource in ?resource);",
+        );
+        assert_eq!(
+            template.unwrap().to_json().unwrap().to_string(),
+            r#"{"effect":"permit","principal":{"op":"==","slot":"?principal"},"action":{"op":"All"},"resource":{"op":"in","slot":"?resource"},"conditions":[]}"#
+        );
+    }
+
+    #[test]
+    fn test_policy_template_from_json() {
+        let template = Template::from_json(None, serde_json::from_str(r#"{"effect":"permit","principal":{"op":"==","slot":"?principal"},"action":{"op":"All"},"resource":{"op":"in","slot":"?resource"},"conditions":[]}"#).unwrap());
+        assert_eq!(
+            template.unwrap().to_string(),
+            "permit(principal == ?principal, action, resource in ?resource);".to_string()
+        );
+    }
+}