WebHandlers.hpp

//------------------------------------------------------------------------------
/*
    This file is part of clio: https://github.com/XRPLF/clio
    Copyright (c) 2024, 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 "util/log/Logger.hpp"
#include "web/AdminVerificationStrategy.hpp"
#include "web/SubscriptionContextInterface.hpp"
#include "web/dosguard/DOSGuardInterface.hpp"
#include "web/ng/Connection.hpp"
#include "web/ng/Request.hpp"
#include "web/ng/Response.hpp"
 
#include <boost/asio/spawn.hpp>
#include <boost/beast/http/status.hpp>
#include <boost/json/array.hpp>
#include <boost/json/parse.hpp>
 
#include <exception>
#include <functional>
#include <memory>
#include <utility>
 
namespace app {
 
class OnConnectCheck {
    std::reference_wrapper<web::dosguard::DOSGuardInterface> dosguard_;
 
public:
    OnConnectCheck(web::dosguard::DOSGuardInterface& dosguard);
 
    std::expected<void, web::ng::Response>
    operator()(web::ng::Connection const& connection);
};
 
class DisconnectHook {
    std::reference_wrapper<web::dosguard::DOSGuardInterface> dosguard_;
 
public:
    DisconnectHook(web::dosguard::DOSGuardInterface& dosguard);
 
    void
    operator()(web::ng::Connection const& connection);
};
 
class MetricsHandler {
    std::shared_ptr<web::AdminVerificationStrategy> adminVerifier_;
 
public:
    MetricsHandler(std::shared_ptr<web::AdminVerificationStrategy> adminVerifier);
 
    web::ng::Response
    operator()(
        web::ng::Request const& request,
        web::ng::ConnectionMetadata& connectionMetadata,
        web::SubscriptionContextPtr,
        boost::asio::yield_context
    );
};
 
class HealthCheckHandler {
public:
    web::ng::Response
    operator()(
        web::ng::Request const& request,
        web::ng::ConnectionMetadata&,
        web::SubscriptionContextPtr,
        boost::asio::yield_context
    );
};
 
template <typename RpcHandlerType>
class RequestHandler {
    util::Logger webServerLog_{"WebServer"};
    std::shared_ptr<web::AdminVerificationStrategy> adminVerifier_;
    std::reference_wrapper<RpcHandlerType> rpcHandler_;
    std::reference_wrapper<web::dosguard::DOSGuardInterface> dosguard_;
 
public:
    RequestHandler(
        std::shared_ptr<web::AdminVerificationStrategy> adminVerifier,
        RpcHandlerType& rpcHandler,
        web::dosguard::DOSGuardInterface& dosguard
    )
        : adminVerifier_(std::move(adminVerifier)), rpcHandler_(rpcHandler), dosguard_(dosguard)
    {
    }
 
    web::ng::Response
    operator()(
        web::ng::Request const& request,
        web::ng::ConnectionMetadata& connectionMetadata,
        web::SubscriptionContextPtr subscriptionContext,
        boost::asio::yield_context yield
    )
    {
        if (not dosguard_.get().request(connectionMetadata.ip())) {
            auto error = rpc::makeError(rpc::RippledError::rpcSLOW_DOWN);
 
            if (not request.isHttp()) {
                try {
                    auto requestJson = boost::json::parse(request.message());
                    if (requestJson.is_object() && requestJson.as_object().contains("id"))
                        error["id"] = requestJson.as_object().at("id");
                    error["request"] = request.message();
                } catch (std::exception const&) {
                    error["request"] = request.message();
                }
            }
            return web::ng::Response{boost::beast::http::status::service_unavailable, error, request};
        }
        LOG(webServerLog_.info()) << connectionMetadata.tag()
                                  << "Received request from ip = " << connectionMetadata.ip()
                                  << " - posting to WorkQueue";
 
        connectionMetadata.setIsAdmin([this, &request, &connectionMetadata]() {
            return adminVerifier_->isAdmin(request.httpHeaders(), connectionMetadata.ip());
        });
 
        try {
            auto response = rpcHandler_(request, connectionMetadata, std::move(subscriptionContext), yield);
 
            if (not dosguard_.get().add(connectionMetadata.ip(), response.message().size())) {
                auto jsonResponse = boost::json::parse(response.message()).as_object();
                jsonResponse["warning"] = "load";
                if (jsonResponse.contains("warnings") && jsonResponse["warnings"].is_array()) {
                    jsonResponse["warnings"].as_array().push_back(rpc::makeWarning(rpc::WarnRpcRateLimit));
                } else {
                    jsonResponse["warnings"] = boost::json::array{rpc::makeWarning(rpc::WarnRpcRateLimit)};
                }
                response.setMessage(jsonResponse);
            }
 
            return response;
        } catch (std::exception const&) {
            return web::ng::Response{
                boost::beast::http::status::internal_server_error,
                rpc::makeError(rpc::RippledError::rpcINTERNAL),
                request
            };
        }
    }
};
 
}  // namespace app