RPCHandler.cpp

#include <xrpld/rpc/RPCHandler.h>
 
#include <xrpld/app/ledger/LedgerMaster.h>  // IWYU pragma: keep
#include <xrpld/app/main/Application.h>
#include <xrpld/core/Config.h>
#include <xrpld/rpc/Context.h>
#include <xrpld/rpc/Role.h>
#include <xrpld/rpc/Status.h>
#include <xrpld/rpc/detail/Handler.h>
#include <xrpld/rpc/detail/Tuning.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/core/Job.h>
#include <xrpl/core/JobQueue.h>
#include <xrpl/core/PerfLog.h>
#include <xrpl/json/to_string.h>  // IWYU pragma: keep
#include <xrpl/protocol/ErrorCodes.h>
#include <xrpl/protocol/jss.h>
#include <xrpl/resource/Fees.h>
 
#include <atomic>
#include <chrono>
#include <cstdint>
#include <exception>
#include <string>
#include <string_view>
 
namespace xrpl::rpc {
 
namespace {

 
ErrorCodeI
fillHandler(JsonContext& context, Handler const*& result)
{
    if (!isUnlimited(context.role))
    {
        // Count all jobs at jtCLIENT priority or higher.
        int const jobCount = context.app.getJobQueue().getJobCountGE(JtClient);
        if (jobCount > tuning::kMaxJobQueueClients)
        {
            JLOG(context.j.debug()) << "Too busy for command: " << jobCount;
            return RpcTooBusy;
        }
    }
 
    if (!context.params.isMember(jss::command) && !context.params.isMember(jss::method))
        return RpcCommandMissing;
    if (context.params.isMember(jss::command) && context.params.isMember(jss::method))
    {
        if (context.params[jss::command].asString() != context.params[jss::method].asString())
            return RpcUnknownCommand;
    }
 
    std::string const strCommand = context.params.isMember(jss::command)
        ? context.params[jss::command].asString()
        : context.params[jss::method].asString();
 
    JLOG(context.j.trace()) << "COMMAND:" << strCommand;
    JLOG(context.j.trace()) << "REQUEST:" << context.params;
    auto handler = getHandler(context.apiVersion, context.app.config().betaRpcApi, strCommand);
 
    if (handler == nullptr)
        return RpcUnknownCommand;
 
    if (handler->role == Role::ADMIN && context.role != Role::ADMIN)
        return RpcNoPermission;
 
    ErrorCodeI const res = conditionMet(handler->condition, context);
    if (res != RpcSuccess)
    {
        return res;
    }
 
    result = handler;
    return RpcSuccess;
}
 
Status
callMethod(JsonContext& context, Handler::Method method, std::string_view name, json::Value& result)
{
    static std::atomic<std::uint64_t> kRequestId{0};
    auto& perfLog = context.app.getPerfLog();
    std::uint64_t const curId = ++kRequestId;
    try
    {
        perfLog.rpcStart(name, curId);
        auto v =
            context.app.getJobQueue().makeLoadEvent(JtGeneric, std::string{"cmd:"}.append(name));
 
        auto start = std::chrono::system_clock::now();
        auto ret = method(context, result);
        auto end = std::chrono::system_clock::now();
 
        JLOG(context.j.debug()) << "RPC call " << name << " completed in "
                                << ((end - start).count() / 1000000000.0) << "seconds";
        perfLog.rpcFinish(name, curId);
        return ret;
    }
    catch (std::exception& e)
    {
        perfLog.rpcError(name, curId);
        JLOG(context.j.info()) << "Caught throw: " << e.what();
 
        if (context.loadType == resource::kFeeReferenceRpc)
            context.loadType = resource::kFeeExceptionRpc;
 
        injectError(RpcInternal, result);
        return RpcInternal;
    }
}
 
}  // namespace
 
Status
doCommand(rpc::JsonContext& context, json::Value& result)
{
    Handler const* handler = nullptr;
    if (auto error = fillHandler(context, handler))
    {
        injectError(error, result);
        return error;
    }
 
    // No null check on the method: Handler::Method has no default constructor, so
    // every entry in the dispatch table names one.
    if (!context.headers.user.empty() || !context.headers.forwardedFor.empty())
    {
        JLOG(context.j.debug()) << "start command: " << handler->name
                                << ", user: " << context.headers.user
                                << ", forwarded for: " << context.headers.forwardedFor;
 
        auto const ret = callMethod(context, handler->valueMethod, handler->name, result);
 
        JLOG(context.j.debug()) << "finish command: " << handler->name
                                << ", user: " << context.headers.user
                                << ", forwarded for: " << context.headers.forwardedFor;
 
        return ret;
    }
 
    return callMethod(context, handler->valueMethod, handler->name, result);
}
 
Role
roleRequired(unsigned int version, bool betaEnabled, std::string_view method)
{
    auto handler = rpc::getHandler(version, betaEnabled, method);
 
    if (handler == nullptr)
        return Role::FORBID;
 
    return handler->role;
}
 
}  // namespace xrpl::rpc