Fixed warning message to be XRPL standard compliant (#229)

All warnings now contain Warning Objects, which have ID, Message, and Details as fields

src/rpc/RPC.cpp

@@ -91,6 +91,38 @@ make_HttpContext(
         clientIp};
 }
 
+constexpr static WarningInfo warningInfos[]{
+    {warnUNKNOWN, "Unknown warning"},
+    {warnRPC_CLIO,
+     "This is a clio server. clio only serves validated data. If you "
+     "want to talk to rippled, include 'ledger_index':'current' in your "
+     "request"},
+    {warnRPC_OUTDATED, "This server may be out of date"},
+    {warnRPC_RATE_LIMIT, "You are about to be rate limited"}};
+
+WarningInfo const&
+get_warning_info(warning_code code)
+{
+    for (WarningInfo const& info : warningInfos)
+    {
+        if (info.code == code)
+        {
+            return info;
+        }
+    }
+    throw(std::out_of_range("Invalid warning_code"));
+}
+
+boost::json::object
+make_warning(warning_code code)
+{
+    boost::json::object json;
+    WarningInfo const& info(get_warning_info(code));
+    json["id"] = code;
+    json["message"] = static_cast<std::string>(info.message);
+    return json;
+}
+
 boost::json::object
 make_error(Error err)
 {

src/rpc/RPC.h

@@ -162,6 +162,33 @@ public:
     }
 };
 
+enum warning_code {
+    warnUNKNOWN = -1,
+    warnRPC_CLIO = 2001,
+    warnRPC_OUTDATED = 2002,
+    warnRPC_RATE_LIMIT = 2003
+};
+
+struct WarningInfo
+{
+    constexpr WarningInfo() : code(warnUNKNOWN), message("unknown warning")
+    {
+    }
+
+    constexpr WarningInfo(warning_code code_, char const* message_)
+        : code(code_), message(message_)
+    {
+    }
+    warning_code code;
+    std::string_view const message;
+};
+
+WarningInfo const&
+get_warning_info(warning_code code);
+
+boost::json::object
+make_warning(warning_code code);
+
 boost::json::object
 make_error(Status const& status);
 

src/webserver/HttpBase.h

@@ -417,18 +417,17 @@ handle_request(
         }
 
         boost::json::array warnings;
-        warnings.emplace_back(
+        warnings.emplace_back(RPC::make_warning(RPC::warnRPC_CLIO));
-            "This is a clio server. clio only serves validated data. If you "
-            "want to talk to rippled, include 'ledger_index':'current' in your "
-            "request");
         auto lastCloseAge = context->etl->lastCloseAgeSeconds();
         if (lastCloseAge >= 60)
-            warnings.emplace_back("This server may be out of date");
+            warnings.emplace_back(RPC::make_warning(RPC::warnRPC_OUTDATED));
         response["warnings"] = warnings;
         responseStr = boost::json::serialize(response);
         if (!dosGuard.add(ip, responseStr.size()))
         {
             response["warning"] = "load";
+            warnings.emplace_back(RPC::make_warning(RPC::warnRPC_RATE_LIMIT));
+            response["warnings"] = warnings;
             // reserialize when we need to include this warning
             responseStr = boost::json::serialize(response);
         }

src/webserver/WsBase.h

@@ -330,19 +330,19 @@ public:
         }
 
         boost::json::array warnings;
-        warnings.emplace_back(
+
-            "This is a clio server. clio only serves validated data. If you "
+        warnings.emplace_back(RPC::make_warning(RPC::warnRPC_CLIO));
-            "want to talk to rippled, include 'ledger_index':'current' in your "
-            "request");
 
         auto lastCloseAge = etl_->lastCloseAgeSeconds();
         if (lastCloseAge >= 60)
-            warnings.emplace_back("This server may be out of date");
+            warnings.emplace_back(RPC::make_warning(RPC::warnRPC_OUTDATED));
         response["warnings"] = warnings;
         std::string responseStr = boost::json::serialize(response);
         if (!dosGuard_.add(*ip, responseStr.size()))
         {
             response["warning"] = "load";
+            warnings.emplace_back(RPC::make_warning(RPC::warnRPC_RATE_LIMIT));
+            response["warnings"] = warnings;
             // reserialize if we need to include this warning
             responseStr = boost::json::serialize(response);
         }