[FIX] XRPLF#5034 -- book_changes rpc method accepts conventional ledg…

…er-strings

src/test/rpc/BookChanges_test.cpp

@@ -0,0 +1,96 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2024 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <test/jtx.h>
+#include <xrpl/json/json_reader.h>
+#include <xrpl/json/json_value.h>
+#include <xrpl/protocol/jss.h>
+
+namespace ripple {
+namespace test {
+
+class BookChanges_test : public beast::unit_test::suite
+{
+public:
+    void
+    testConventionalLedgerInputStrings()
+    {
+        testcase("Specify well-known strings as ledger input");
+        jtx::Env env(*this);
+        Json::Value params, resp;
+
+        // As per convention in XRPL, ledgers can be specified with strings
+        // "closed", "validated" or "current"
+        params["ledger"] = "validated";
+        resp = env.rpc("json", "book_changes", to_string(params));
+        BEAST_EXPECT(!resp[jss::result].isMember(jss::error));
+        BEAST_EXPECT(resp[jss::result][jss::status] == "success");
+
+        params["ledger"] = "current";
+        resp = env.rpc("json", "book_changes", to_string(params));
+        BEAST_EXPECT(!resp[jss::result].isMember(jss::error));
+        BEAST_EXPECT(resp[jss::result][jss::status] == "success");
+
+        params["ledger"] = "closed";
+        resp = env.rpc("json", "book_changes", to_string(params));
+        BEAST_EXPECT(!resp[jss::result].isMember(jss::error));
+        BEAST_EXPECT(resp[jss::result][jss::status] == "success");
+
+        // non-conventional ledger input should throw an error
+        params["ledger"] = "non_conventional_ledger_input";
+        resp = env.rpc("json", "book_changes", to_string(params));
+        BEAST_EXPECT(resp[jss::result].isMember(jss::error));
+        BEAST_EXPECT(resp[jss::result][jss::status] != "success");
+    }
+
+    void
+    testLedgerInputDefaultBehavior()
+    {
+        testcase(
+            "If ledger_hash or ledger_index is not specified, the behavior "
+            "must default to the `current` ledger");
+        jtx::Env env(*this);
+
+        // As per convention in XRPL, ledgers can be specified with strings
+        // "closed", "validated" or "current"
+        Json::Value const resp =
+            env.rpc("json", "book_changes", to_string(Json::Value{}));
+        BEAST_EXPECT(!resp[jss::result].isMember(jss::error));
+        BEAST_EXPECT(resp[jss::result][jss::status] == "success");
+
+        // I dislike asserting the below statement, because its dependent on the
+        // unit-test framework BEAST_EXPECT(resp[jss::result][jss::ledger_index]
+        // == 3);
+    }
+
+    void
+    run() override
+    {
+        testConventionalLedgerInputStrings();
+        testLedgerInputDefaultBehavior();
+
+        // Note: Other aspects of the book_changes rpc are fertile grounds for
+        // unit-testing purposes. It can be included in future work
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(BookChanges, app, ripple);
+
+}  // namespace test
+}  // namespace ripple

src/xrpld/rpc/handlers/BookOffers.cpp

@@ -204,13 +204,13 @@ doBookOffers(RPC::JsonContext& context)
 Json::Value
 doBookChanges(RPC::JsonContext& context)
 {
-    auto res = RPC::getLedgerByContext(context);
+    std::shared_ptr<ReadView const> ledger;
 
-    if (std::holds_alternative<Json::Value>(res))
-        return std::get<Json::Value>(res);
+    Json::Value result = RPC::lookupLedger(ledger, context);
+    if (ledger == nullptr)
+        return result;
 
-    return RPC::computeBookChanges(
-        std::get<std::shared_ptr<Ledger const>>(res));
+    return RPC::computeBookChanges(ledger);
 }
 
 }  // namespace ripple