add ledger entry handler (should have been added in prior commit)

handlers/LedgerEntry.cpp

@@ -0,0 +1,55 @@
+#include <ripple/protocol/Indexes.h>
+#include <ripple/protocol/STLedgerEntry.h>
+#include <boost/json.hpp>
+#include <handlers/RPCHelpers.h>
+#include <reporting/BackendInterface.h>
+// {
+//   ledger_hash : <ledger>
+//   ledger_index : <ledger_index>
+//   ...
+// }
+boost::json::object
+doLedgerEntry(
+    boost::json::object const& request,
+    BackendInterface const& backend)
+{
+    boost::json::object response;
+    bool binary =
+        request.contains("binary") ? request.at("binary").as_bool() : false;
+    auto ledgerSequence = ledgerSequenceFromRequest(request, backend);
+    if (!ledgerSequence)
+    {
+        response["error"] = "Empty database";
+        return response;
+    }
+    ripple::uint256 key;
+    if (!key.parseHex(request.at("index").as_string().c_str()))
+    {
+        response["error"] = "Error parsing index";
+        return response;
+    }
+    auto start = std::chrono::system_clock::now();
+    auto dbResponse = backend.fetchLedgerObject(key, *ledgerSequence);
+    auto end = std::chrono::system_clock::now();
+    auto time =
+        std::chrono::duration_cast<std::chrono::microseconds>(end - start)
+            .count();
+    if (!dbResponse or dbResponse->size() == 0)
+    {
+        response["error"] = "Object not found";
+        return response;
+    }
+    if (binary)
+    {
+        response["object"] = ripple::strHex(*dbResponse);
+    }
+    else
+    {
+        ripple::STLedgerEntry sle{
+            ripple::SerialIter{dbResponse->data(), dbResponse->size()}, key};
+        response["object"] = getJson(sle);
+    }
+
+    return response;
+}
+