From 02f14b05befe423d3dbc79b8cd7221bfdda77719 Mon Sep 17 00:00:00 2001
From: Mayukha Vadari <mvadari@gmail.com>
Date: Mon, 23 Oct 2023 11:29:09 -0400
Subject: [PATCH] update API changelog

---
 API-CHANGELOG.md                     |  1 +
 src/ripple/rpc/handlers/Feature1.cpp | 23 +++++++++++++++++
 src/ripple/rpc/impl/Handler.cpp      |  2 +-
 src/test/rpc/Feature_test.cpp        | 38 ++++++++++++++++++++++++----
 4 files changed, 58 insertions(+), 6 deletions(-)

diff --git a/API-CHANGELOG.md b/API-CHANGELOG.md
index a3c06399cf5..cf022e4b04f 100644
--- a/API-CHANGELOG.md
+++ b/API-CHANGELOG.md
@@ -33,6 +33,7 @@ The `network_id` field was added in the `server_info` response in version 1.5.0
 Additions are intended to be non-breaking (because they are purely additive).
 
 - `server_definitions`: A new RPC that generates a `definitions.json`-like output that can be used in XRPL libraries.
+- `feature`: A non-admin mode that decodes the hex version of amendment names.
 
 ## XRP Ledger version 1.12.0
 
diff --git a/src/ripple/rpc/handlers/Feature1.cpp b/src/ripple/rpc/handlers/Feature1.cpp
index 1858a062e53..482c1b33b00 100644
--- a/src/ripple/rpc/handlers/Feature1.cpp
+++ b/src/ripple/rpc/handlers/Feature1.cpp
@@ -22,6 +22,7 @@
 #include <ripple/app/misc/AmendmentTable.h>
 #include <ripple/net/RPCErr.h>
 #include <ripple/protocol/ErrorCodes.h>
+#include <ripple/protocol/Feature.h>
 #include <ripple/protocol/jss.h>
 #include <ripple/rpc/Context.h>
 
@@ -37,6 +38,28 @@ doFeature(RPC::JsonContext& context)
     if (context.app.config().reporting())
         return rpcError(rpcREPORTING_UNSUPPORTED);
 
+    if (context.role != Role::ADMIN)
+    {
+        if (!context.params.isMember(jss::feature))
+        {
+            return RPC::missing_field_error(jss::feature);
+        }
+        std::string const& featureStr = context.params[jss::feature].asString();
+        uint256 feature;
+        if (!feature.parseHex(featureStr))
+        {
+            return rpcError(rpcBAD_FEATURE);
+        }
+        std::string const& featureName = featureToName(feature);
+        if (featureName == featureStr)
+        {
+            return rpcError(rpcBAD_FEATURE);
+        }
+        Json::Value jvReply = Json::objectValue;
+        jvReply[jss::feature] = featureName;
+        return jvReply;
+    }
+
     // Get majority amendment status
     majorityAmendments_t majorities;
 
diff --git a/src/ripple/rpc/impl/Handler.cpp b/src/ripple/rpc/impl/Handler.cpp
index b69d2608b0e..24fc06f377a 100644
--- a/src/ripple/rpc/impl/Handler.cpp
+++ b/src/ripple/rpc/impl/Handler.cpp
@@ -92,7 +92,7 @@ Handler const handlerArray[]{
     {"gateway_balances", byRef(&doGatewayBalances), Role::USER, NO_CONDITION},
 #endif
     {"get_counts", byRef(&doGetCounts), Role::ADMIN, NO_CONDITION},
-    {"feature", byRef(&doFeature), Role::ADMIN, NO_CONDITION},
+    {"feature", byRef(&doFeature), Role::USER, NO_CONDITION},
     {"fee", byRef(&doFee), Role::USER, NEEDS_CURRENT_LEDGER},
     {"fetch_info", byRef(&doFetchInfo), Role::ADMIN, NO_CONDITION},
     {"ledger_accept",
diff --git a/src/test/rpc/Feature_test.cpp b/src/test/rpc/Feature_test.cpp
index dcd95c8a968..2de93521052 100644
--- a/src/test/rpc/Feature_test.cpp
+++ b/src/test/rpc/Feature_test.cpp
@@ -205,11 +205,39 @@ class Feature_test : public beast::unit_test::suite
                     return cfg;
                 })};
 
-        auto jrr = env.rpc("feature")[jss::result];
-        // The current HTTP/S ServerHandler returns an HTTP 403 error code here
-        // rather than a noPermission JSON error. The JSONRPCClient just eats
-        // that error and returns an null result.
-        BEAST_EXPECT(jrr.isNull());
+        {
+            auto result = env.rpc("feature")[jss::result];
+            BEAST_EXPECT(result[jss::error] == "invalidParams");
+            BEAST_EXPECT(
+                result[jss::error_message] == "Missing field 'feature'.");
+        }
+
+        {
+            Json::Value params;
+            // invalid feature
+            params[jss::feature] =
+                "1234567890ABCDEF1234567890ABCDEF1234567890ABCDEF1234567890ABCD"
+                "EF";
+            auto const result = env.rpc(
+                "json",
+                "feature",
+                boost::lexical_cast<std::string>(params))[jss::result];
+            BEAST_EXPECT(result[jss::error] == "badFeature");
+            BEAST_EXPECT(
+                result[jss::error_message] == "Feature unknown or invalid.");
+        }
+
+        {
+            Json::Value params;
+            params[jss::feature] =
+                "93E516234E35E08CA689FA33A6D38E103881F8DCB53023F728C307AA89D515"
+                "A7";
+            auto const result = env.rpc(
+                "json",
+                "feature",
+                boost::lexical_cast<std::string>(params))[jss::result];
+            BEAST_EXPECT(result[jss::feature] == "XRPFees");
+        }
     }
 
     void