Modifiers.hpp

//------------------------------------------------------------------------------
/*
    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.
*/
//==============================================================================
 
#pragma once
 
#include "rpc/Errors.hpp"
#include "rpc/common/Types.hpp"
#include "util/JsonUtils.hpp"
 
#include <boost/json/value.hpp>
#include <boost/json/value_to.hpp>
#include <xrpl/protocol/ErrorCodes.h>
 
#include <concepts>
#include <exception>
#include <functional>
#include <string>
#include <string_view>
 
namespace rpc::modifiers {

template <typename Type>
class Clamp final {
    Type min_;
    Type max_;
 
public:
    explicit Clamp(Type min, Type max) : min_{min}, max_{max}
    {
    }

    [[nodiscard]] MaybeError
    modify(boost::json::value& value, std::string_view key) const
    {
        using boost::json::value_to;
 
        if (not value.is_object() or not value.as_object().contains(key))
            return {};  // ignore. field does not exist, let 'required' fail instead
 
        // clamp to min_ and max_
        auto const oldValue = value_to<Type>(value.as_object().at(key));
        value.as_object()[key] = std::clamp<Type>(oldValue, min_, max_);
 
        return {};
    }
};

struct ToLower final {
    [[nodiscard]] static MaybeError
    modify(boost::json::value& value, std::string_view key)
    {
        if (not value.is_object() or not value.as_object().contains(key))
            return {};  // ignore. field does not exist, let 'required' fail instead
 
        if (not value.as_object().at(key).is_string())
            return {};  // ignore for non-string types
 
        value.as_object()[key] =
            util::toLower(boost::json::value_to<std::string>(value.as_object().at(key)));
        return {};
    }
};

struct ToNumber final {
    [[nodiscard]] static MaybeError
    modify(boost::json::value& value, std::string_view key)
    {
        if (not value.is_object() or not value.as_object().contains(key))
            return {};  // ignore. field does not exist, let 'required' fail instead
 
        if (not value.as_object().at(key).is_string())
            return {};  // ignore for non-string types
 
        auto const strInt = boost::json::value_to<std::string>(value.as_object().at(key));
        if (strInt.find('.') != std::string::npos)
            return Error{Status{RippledError::rpcINVALID_PARAMS}};  // maybe a float
 
        try {
            value.as_object()[key] = std::stoi(strInt);
        } catch (std::exception& e) {
            return Error{Status{RippledError::rpcINVALID_PARAMS}};
        }
        return {};
    }
};

class CustomModifier final {
    std::function<MaybeError(boost::json::value&, std::string_view)> modifier_;
 
public:
    template <typename Fn>
        requires std::invocable<Fn, boost::json::value&, std::string_view>
    explicit CustomModifier(Fn&& fn) : modifier_{std::forward<Fn>(fn)}
    {
    }

    [[nodiscard]] MaybeError
    modify(boost::json::value& value, std::string_view key) const
    {
        if (not value.is_object() or not value.as_object().contains(key))
            return {};  // ignore. field does not exist, let 'required' fail instead
 
        return modifier_(value.as_object().at(key), key);
    };
};
 
}  // namespace rpc::modifiers