feat: add JSON support for Enforce() by enabling PushObjectJson (#264)

Author: Copilot

.gitignore

@@ -367,4 +367,4 @@ build_support/
 *.egg-info
 
 # clang-format
-build_support/clang_format_exclusions.txt
+build_support/clang_format_exclusions.txt

casbin/model/evaluator.cpp

@@ -61,7 +61,21 @@ void ExprtkEvaluator::PushObjectString(const std::string& target, const std::str
 
 void ExprtkEvaluator::PushObjectJson(const std::string& target, const std::string& proprity, const nlohmann::json& var) {
     auto identifier = target + "." + proprity;
-    // this->symbol_table.add_stringvar(identifier, const_cast<std::string&>(var));
+    
+    // Recursively flatten JSON object into dot-notation identifiers
+    if (var.is_object()) {
+        for (auto& [key, value] : var.items()) {
+            PushObjectJson(identifier, key, value);
+        }
+    } else if (var.is_string()) {
+        this->AddIdentifier(identifier, var.get<std::string>());
+    } else if (var.is_number()) {
+        // Get as double first to preserve precision, then cast to numerical_type
+        this->AddNumericIdentifier(identifier, static_cast<numerical_type>(var.get<double>()));
+    } else if (var.is_boolean()) {
+        this->AddNumericIdentifier(identifier, static_cast<numerical_type>(var.get<bool>() ? 1 : 0));
+    }
+    // For other types (arrays, null, etc.), we skip them as they're not supported in the expression evaluator
 }
 
 void ExprtkEvaluator::LoadFunctions() {
@@ -118,6 +132,7 @@ void ExprtkEvaluator::Clean(AssertionMap& section, bool after_enforce) {
     this->expression_string_ = "";
     this->Functions.clear();
     this->identifiers_.clear();
+    this->numeric_identifiers_.clear();
 }
 
 void ExprtkEvaluator::AddFunction(const std::string& func_name, std::shared_ptr<exprtk_func_t> func) {
@@ -163,4 +178,12 @@ void ExprtkEvaluator::AddIdentifier(const std::string& identifier, const std::st
     symbol_table.get_stringvar(identifier)->ref() = var;
 }
 
+void ExprtkEvaluator::AddNumericIdentifier(const std::string& identifier, numerical_type value) {
+    if (!symbol_table.symbol_exists(identifier)) {
+        numeric_identifiers_[identifier] = std::make_unique<numerical_type>(0);
+        this->symbol_table.add_variable(identifier, *numeric_identifiers_[identifier]);
+    }
+    *numeric_identifiers_[identifier] = value;
+}
+
 } // namespace casbin

include/casbin/model/evaluator.h

@@ -71,6 +71,7 @@ class ExprtkEvaluator : public IEvaluator {
     parser_t parser;
     std::vector<std::shared_ptr<exprtk_func_t>> Functions;
     std::unordered_map<std::string, std::unique_ptr<std::string>> identifiers_;
+    std::unordered_map<std::string, std::unique_ptr<numerical_type>> numeric_identifiers_;
 
 public:
     ExprtkEvaluator() {
@@ -109,6 +110,8 @@ class ExprtkEvaluator : public IEvaluator {
 
     void AddIdentifier(const std::string& identifier, const std::string& var);
 
+    void AddNumericIdentifier(const std::string& identifier, numerical_type value);
+
     std::unordered_map<std::string, std::string> requestValues() const override;
 };
 } // namespace casbin

tests/enforcer_test.cpp

@@ -155,6 +155,125 @@ TEST(TestEnforcer, TestMapParams) {
     ASSERT_EQ(e.Enforce(params), true);
 }
 
+TEST(TestEnforcer, TestJsonData) {
+    using json = nlohmann::json;
+    casbin::Enforcer e(abac_rule_model_path, abac_rule_policy_path);
+
+    // Test with JSON object containing Age property
+    // Policy: p, r.sub.Age > 18, /data1, read
+    auto sub_json_adult = std::make_shared<json>(json{
+        {"Name", "alice"},
+        {"Age", 30}
+    });
+
+    casbin::DataMap params = {
+        {"sub", sub_json_adult},
+        {"obj", "/data1"},
+        {"act", "read"}
+    };
+
+    // Should be allowed: Age 30 > 18
+    ASSERT_EQ(e.Enforce(params), true);
+
+    // Test with minor (Age < 18)
+    auto sub_json_minor = std::make_shared<json>(json{
+        {"Name", "bob"},
+        {"Age", 16}
+    });
+
+    params = {
+        {"sub", sub_json_minor},
+        {"obj", "/data1"},
+        {"act", "read"}
+    };
+
+    // Should be denied: Age 16 < 18
+    ASSERT_EQ(e.Enforce(params), false);
+
+    // Test policy: p, r.sub.Age < 60, /data2, write
+    auto sub_json_young = std::make_shared<json>(json{
+        {"Name", "charlie"},
+        {"Age", 45}
+    });
+
+    params = {
+        {"sub", sub_json_young},
+        {"obj", "/data2"},
+        {"act", "write"}
+    };
+
+    // Should be allowed: Age 45 < 60
+    ASSERT_EQ(e.Enforce(params), true);
+
+    // Test with senior (Age >= 60)
+    auto sub_json_senior = std::make_shared<json>(json{
+        {"Name", "dave"},
+        {"Age", 65}
+    });
+
+    params = {
+        {"sub", sub_json_senior},
+        {"obj", "/data2"},
+        {"act", "write"}
+    };
+
+    // Should be denied: Age 65 >= 60
+    ASSERT_EQ(e.Enforce(params), false);
+}
+
+TEST(TestEnforcer, TestComplexJsonData) {
+    using json = nlohmann::json;
+    
+    // Create a custom model and policy for testing complex JSON structures
+    // similar to the issue example
+    casbin::Enforcer e(abac_rule_model_path, abac_rule_policy_path);
+
+    // Test with complex nested JSON object like in the issue
+    auto complex_request = std::make_shared<json>(json{
+        {"ID", "zk"},
+        {"proxy", "vpn"},
+        {"Department", "nlp"},
+        {"month", "Jan"},
+        {"week", "Mon"},
+        {"time", "morning"},
+        {"Longitude", 123},
+        {"Latitude", 456},
+        {"Altitude", 789},
+        {"OS", "HarmonyOS"},
+        {"CPU", "XeonPlatinum8480+"},
+        {"NetworkType", "WLan"},
+        {"ProtocolType", "Bluetooth"},
+        {"EncryptionType", "3DES"},
+        {"SecurityProtocol", "HTTPS"},
+        {"Age", 25}  // For testing with existing policy
+    });
+
+    casbin::DataMap params = {
+        {"sub", complex_request},
+        {"obj", "/data1"},
+        {"act", "read"}
+    };
+
+    // Should work with complex JSON - Age 25 > 18
+    ASSERT_EQ(e.Enforce(params), true);
+
+    // Test with object that also contains nested objects
+    auto obj_json = std::make_shared<json>(json{
+        {"SecurityLevel", 3},
+        {"Source", "ISS"},
+        {"DistributionMethod", "C"}
+    });
+
+    params = {
+        {"sub", complex_request},
+        {"obj", obj_json},
+        {"act", "read"}
+    };
+
+    // This should not crash even with JSON in multiple parameters
+    ASSERT_NO_THROW(e.Enforce(params));
+}
+
 template <typename T>
 void TestEnforceEx(casbin::Enforcer& e, T&& params, const bool expect_result, const std::vector<std::string>& expect_explain) {
     std::vector<std::string> actual_explain;