Implement base for nextgen rpc subsystem (#487)

Fixes #494

src/rpc/common/Validators.cpp

@@ -0,0 +1,89 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2023, the clio developers.
+
+    Permission to use, copy, modify, and 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 <rpc/common/Validators.h>
+
+#include <boost/json/value.hpp>
+
+#include <string_view>
+
+namespace RPCng::validation {
+
+[[nodiscard]] MaybeError
+Section::verify(boost::json::value const& value, std::string_view key) const
+{
+    if (not value.is_object() or not value.as_object().contains(key.data()))
+        return {};  // ignore. field does not exist, let 'required' fail
+                    // instead
+
+    auto const& res = value.at(key.data());
+    for (auto const& spec : specs)
+    {
+        if (auto const ret = spec.validate(res); not ret)
+            return Error{ret.error()};
+    }
+    return {};
+}
+
+[[nodiscard]] MaybeError
+Required::verify(boost::json::value const& value, std::string_view key) const
+{
+    if (not value.is_object() or not value.as_object().contains(key.data()))
+        return Error{RPC::Status{
+            RPC::RippledError::rpcINVALID_PARAMS,
+            "Required field '" + std::string{key} + "' missing"}};
+
+    return {};
+}
+
+[[nodiscard]] MaybeError
+ValidateArrayAt::verify(boost::json::value const& value, std::string_view key)
+    const
+{
+    if (not value.is_object() or not value.as_object().contains(key.data()))
+        return {};  // ignore. field does not exist, let 'required' fail
+                    // instead
+
+    if (not value.as_object().at(key.data()).is_array())
+        return Error{RPC::Status{RPC::RippledError::rpcINVALID_PARAMS}};
+
+    auto const& arr = value.as_object().at(key.data()).as_array();
+    if (idx_ >= arr.size())
+        return Error{RPC::Status{RPC::RippledError::rpcINVALID_PARAMS}};
+
+    auto const& res = arr.at(idx_);
+    for (auto const& spec : specs_)
+        if (auto const ret = spec.validate(res); not ret)
+            return Error{ret.error()};
+
+    return {};
+}
+
+[[nodiscard]] MaybeError
+CustomValidator::verify(boost::json::value const& value, std::string_view key)
+    const
+{
+    if (not value.is_object() or not value.as_object().contains(key.data()))
+        return {};  // ignore. field does not exist, let 'required' fail
+                    // instead
+
+    return validator_(value.as_object().at(key.data()), key);
+}
+
+}  // namespace RPCng::validation