http/routing.hpp

#pragma once

#ifdef BMCWEB_ENABLE_GRPC
#include "absl/log/log.h"
#include "authorizer_enums.h"
#include "bmcweb_authorizer_singleton.h"
#include "uri_to_entity.h"
#endif

#include "async_resp.hpp"
#include "common.hpp"
#include "dbus_utils.hpp"
#include "http_request.hpp"
#include "http_response.hpp"
#include "logging.hpp"
#include "managed_store.hpp"
#include "privileges.hpp"
#include "sessions.hpp"
#include "utility.hpp"
#include "verb.hpp"
#include "websocket.hpp"

#include <boost/beast/ssl/ssl_stream.hpp>
#include <boost/container/flat_map.hpp>
#include <sdbusplus/unpack_properties.hpp>

#include <cerrno>
#include <cstdint>
#include <cstdlib>
#include <limits>
#include <memory>
#include <optional>
#include <tuple>
#include <utility>
#include <vector>

#ifdef UNIT_TEST_BUILD
#include "test/g3/mock_managed_store.hpp" // NOLINT
#endif

namespace crow
{

class BaseRule
{
  public:
    explicit BaseRule(std::string_view thisRule) : rule(thisRule)
    {}

    virtual ~BaseRule() = default;

    BaseRule(const BaseRule&) = delete;
    BaseRule(BaseRule&&) = delete;
    BaseRule& operator=(const BaseRule&) = delete;
    BaseRule& operator=(const BaseRule&&) = delete;

    virtual void validate() = 0;
    std::unique_ptr<BaseRule> upgrade()
    {
        if (ruleToUpgrade)
        {
            return std::move(ruleToUpgrade);
        }
        return {};
    }

    virtual void handle(const Request& /*req*/,
                        const std::shared_ptr<bmcweb::AsyncResp>&,
                        const RoutingParams&) = 0;
#ifndef BMCWEB_ENABLE_SSL
    virtual void
        handleUpgrade(const Request& /*req*/,
                      const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                      boost::asio::ip::tcp::socket&& /*adaptor*/)
    {
        asyncResp->res.result(boost::beast::http::status::not_found);
    }
#else
    virtual void handleUpgrade(
        const Request& /*req*/,
        const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
        boost::beast::ssl_stream<boost::asio::ip::tcp::socket>&& /*adaptor*/)
    {
        asyncResp->res.result(boost::beast::http::status::not_found);
    }
#endif

    size_t getMethods() const
    {
        return methodsBitfield;
    }

    bool checkPrivileges(const redfish::Privileges& userPrivileges)
    {
        // If there are no privileges assigned, assume no privileges
        // required
        if (privilegesSet.empty())
        {
            return true;
        }

        for (const redfish::Privileges& requiredPrivileges : privilegesSet)
        {
            if (userPrivileges.isSupersetOf(requiredPrivileges))
            {
                return true;
            }
        }
        return false;
    }

    size_t methodsBitfield{1 << static_cast<size_t>(HttpVerb::Get)};
    static_assert(std::numeric_limits<decltype(methodsBitfield)>::digits >
                      methodNotAllowedIndex,
                  "Not enough bits to store bitfield");

    std::vector<redfish::Privileges> privilegesSet;

    std::string rule;
    std::string nameStr;

    std::unique_ptr<BaseRule> ruleToUpgrade;

    friend class Router;
    template <typename T>
    friend struct RuleParameterTraits;
};

namespace detail
{
namespace routing_handler_call_helper
{
template <typename T, int Pos>
struct CallPair
{
    using type = T;
    static const int pos = Pos;
};

template <typename H1>
struct CallParams
{
    H1& handler;
    const RoutingParams& params;
    const Request& req;
    const std::shared_ptr<bmcweb::AsyncResp>& asyncResp;
};

template <typename F, int NInt, int NUint, int NDouble, int NString,
          typename S1, typename S2>
struct Call
{};

template <typename F, int NInt, int NUint, int NDouble, int NString,
          typename... Args1, typename... Args2>
struct Call<F, NInt, NUint, NDouble, NString, black_magic::S<int64_t, Args1...>,
            black_magic::S<Args2...>>
{
    void operator()(F cparams)
    {
        using pushed = typename black_magic::S<Args2...>::template push_back<
            CallPair<int64_t, NInt>>;
        Call<F, NInt + 1, NUint, NDouble, NString, black_magic::S<Args1...>,
             pushed>()(cparams);
    }
};

template <typename F, int NInt, int NUint, int NDouble, int NString,
          typename... Args1, typename... Args2>
struct Call<F, NInt, NUint, NDouble, NString,
            black_magic::S<uint64_t, Args1...>, black_magic::S<Args2...>>
{
    void operator()(F cparams)
    {
        using pushed = typename black_magic::S<Args2...>::template push_back<
            CallPair<uint64_t, NUint>>;
        Call<F, NInt, NUint + 1, NDouble, NString, black_magic::S<Args1...>,
             pushed>()(cparams);
    }
};

template <typename F, int NInt, int NUint, int NDouble, int NString,
          typename... Args1, typename... Args2>
struct Call<F, NInt, NUint, NDouble, NString, black_magic::S<double, Args1...>,
            black_magic::S<Args2...>>
{
    void operator()(F cparams)
    {
        using pushed = typename black_magic::S<Args2...>::template push_back<
            CallPair<double, NDouble>>;
        Call<F, NInt, NUint, NDouble + 1, NString, black_magic::S<Args1...>,
             pushed>()(cparams);
    }
};

template <typename F, int NInt, int NUint, int NDouble, int NString,
          typename... Args1, typename... Args2>
struct Call<F, NInt, NUint, NDouble, NString,
            black_magic::S<std::string, Args1...>, black_magic::S<Args2...>>
{
    void operator()(F cparams)
    {
        using pushed = typename black_magic::S<Args2...>::template push_back<
            CallPair<std::string, NString>>;
        Call<F, NInt, NUint, NDouble, NString + 1, black_magic::S<Args1...>,
             pushed>()(cparams);
    }
};

template <typename F, int NInt, int NUint, int NDouble, int NString,
          typename... Args1>
struct Call<F, NInt, NUint, NDouble, NString, black_magic::S<>,
            black_magic::S<Args1...>>
{
    void operator()(F cparams)
    {
        cparams.handler(
            cparams.req, cparams.asyncResp,
            cparams.params.template get<typename Args1::type>(Args1::pos)...);
    }
};

template <typename Func, typename... ArgsWrapped>
struct Wrapped
{
    template <typename... Args>
    void set(
        Func f,
        typename std::enable_if<
            !std::is_same<
                typename std::tuple_element<0, std::tuple<Args..., void>>::type,
                const Request&>::value,
            int>::type /*enable*/
        = 0)
    {
        handler = [f = std::forward<Func>(f)](
                      const Request&,
                      const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                      Args... args) { asyncResp->res.result(f(args...)); };
    }

    template <typename Req, typename... Args>
    struct ReqHandlerWrapper
    {
        explicit ReqHandlerWrapper(Func fIn) : f(std::move(fIn))
        {}

        void operator()(const Request& req,
                        const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                        Args... args)
        {
            asyncResp->res.result(f(req, args...));
        }

        Func f;
    };

    template <typename... Args>
    void set(
        Func f,
        typename std::enable_if<
            std::is_same<
                typename std::tuple_element<0, std::tuple<Args..., void>>::type,
                const Request&>::value &&
                !std::is_same<typename std::tuple_element<
                                  1, std::tuple<Args..., void, void>>::type,
                              const std::shared_ptr<bmcweb::AsyncResp>&>::value,
            int>::type /*enable*/
        = 0)
    {
        handler = ReqHandlerWrapper<Args...>(std::move(f));
        /*handler = (
            [f = std::move(f)]
            (const Request& req, Response& res, Args... args){
                 res.result(f(req, args...));
                 res.end();
            });*/
    }

    template <typename... Args>
    void set(
        Func f,
        typename std::enable_if<
            std::is_same<
                typename std::tuple_element<0, std::tuple<Args..., void>>::type,
                const Request&>::value &&
                std::is_same<typename std::tuple_element<
                                 1, std::tuple<Args..., void, void>>::type,
                             const std::shared_ptr<bmcweb::AsyncResp>&>::value,
            int>::type /*enable*/
        = 0)
    {
        handler = std::move(f);
    }

    template <typename... Args>
    struct HandlerTypeHelper
    {
        using type = std::function<void(
            const crow::Request& /*req*/,
            const std::shared_ptr<bmcweb::AsyncResp>&, Args...)>;
        using args_type =
            black_magic::S<typename black_magic::PromoteT<Args>...>;
    };

    template <typename... Args>
    struct HandlerTypeHelper<const Request&, Args...>
    {
        using type = std::function<void(
            const crow::Request& /*req*/,
            const std::shared_ptr<bmcweb::AsyncResp>&, Args...)>;
        using args_type =
            black_magic::S<typename black_magic::PromoteT<Args>...>;
    };

    template <typename... Args>
    struct HandlerTypeHelper<const Request&,
                             const std::shared_ptr<bmcweb::AsyncResp>&, Args...>
    {
        using type = std::function<void(
            const crow::Request& /*req*/,
            const std::shared_ptr<bmcweb::AsyncResp>&, Args...)>;
        using args_type =
            black_magic::S<typename black_magic::PromoteT<Args>...>;
    };

    typename HandlerTypeHelper<ArgsWrapped...>::type handler;

    void operator()(const Request& req,
                    const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                    const RoutingParams& params)
    {
        detail::routing_handler_call_helper::Call<
            detail::routing_handler_call_helper::CallParams<decltype(handler)>,
            0, 0, 0, 0, typename HandlerTypeHelper<ArgsWrapped...>::args_type,
            black_magic::S<>>()(
            detail::routing_handler_call_helper::CallParams<decltype(handler)>{
                handler, params, req, asyncResp});
    }
};
} // namespace routing_handler_call_helper
} // namespace detail

class WebSocketRule : public BaseRule
{
    using self_t = WebSocketRule;

  public:
    explicit WebSocketRule(const std::string& ruleIn) : BaseRule(ruleIn)
    {}

    void validate() override
    {}

    void handle(const Request& /*req*/,
                const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                const RoutingParams& /*params*/) override
    {
        asyncResp->res.result(boost::beast::http::status::not_found);
    }

#ifndef BMCWEB_ENABLE_SSL
    void handleUpgrade(const Request& req,
                       const std::shared_ptr<bmcweb::AsyncResp>& /*asyncResp*/,
                       boost::asio::ip::tcp::socket&& adaptor) override
    {
        BMCWEB_LOG_DEBUG << "Websocket handles upgrade";
        std::shared_ptr<
            crow::websocket::ConnectionImpl<boost::asio::ip::tcp::socket>>
            myConnection = std::make_shared<
                crow::websocket::ConnectionImpl<boost::asio::ip::tcp::socket>>(
                req, std::move(adaptor), openHandler, messageHandler,
                messageExHandler, closeHandler, errorHandler);
        myConnection->start();
    }
#else
    void handleUpgrade(const Request& req,
                       const std::shared_ptr<bmcweb::AsyncResp>& /*asyncResp*/,
                       boost::beast::ssl_stream<boost::asio::ip::tcp::socket>&&
                           adaptor) override
    {
        BMCWEB_LOG_DEBUG << "Websocket handles upgrade";
        std::shared_ptr<crow::websocket::ConnectionImpl<
            boost::beast::ssl_stream<boost::asio::ip::tcp::socket>>>
            myConnection = std::make_shared<crow::websocket::ConnectionImpl<
                boost::beast::ssl_stream<boost::asio::ip::tcp::socket>>>(
                req, std::move(adaptor), openHandler, messageHandler,
                messageExHandler, closeHandler, errorHandler);
        myConnection->start();
    }
#endif

    template <typename Func>
    self_t& onopen(Func f)
    {
        openHandler = f;
        return *this;
    }

    template <typename Func>
    self_t& onmessage(Func f)
    {
        messageHandler = f;
        return *this;
    }

    template <typename Func>
    self_t& onmessageex(Func f)
    {
        messageExHandler = f;
        return *this;
    }

    template <typename Func>
    self_t& onclose(Func f)
    {
        closeHandler = f;
        return *this;
    }

    template <typename Func>
    self_t& onerror(Func f)
    {
        errorHandler = f;
        return *this;
    }

  protected:
    std::function<void(crow::websocket::Connection&)> openHandler;
    std::function<void(crow::websocket::Connection&, const std::string&, bool)>
        messageHandler;
    std::function<void(crow::websocket::Connection&, std::string_view,
                       crow::websocket::MessageType type,
                       std::function<void()>&& whenComplete)>
        messageExHandler;
    std::function<void(crow::websocket::Connection&, const std::string&)>
        closeHandler;
    std::function<void(crow::websocket::Connection&)> errorHandler;
};

template <typename T>
struct RuleParameterTraits
{
    using self_t = T;
    WebSocketRule& websocket()
    {
        self_t* self = static_cast<self_t*>(this);
        WebSocketRule* p = new WebSocketRule(self->rule);
        self->ruleToUpgrade.reset(p);
        return *p;
    }

    self_t& name(std::string_view name) noexcept
    {
        self_t* self = static_cast<self_t*>(this);
        self->nameStr = name;
        return *self;
    }

    self_t& methods(boost::beast::http::verb method)
    {
        self_t* self = static_cast<self_t*>(this);
        std::optional<HttpVerb> verb = httpVerbFromBoost(method);
        if (verb)
        {
            self->methodsBitfield = 1U << static_cast<size_t>(*verb);
        }
        return *self;
    }

    template <typename... MethodArgs>
    self_t& methods(boost::beast::http::verb method, MethodArgs... argsMethod)
    {
        self_t* self = static_cast<self_t*>(this);
        methods(argsMethod...);
        std::optional<HttpVerb> verb = httpVerbFromBoost(method);
        if (verb)
        {
            self->methodsBitfield |= 1U << static_cast<size_t>(*verb);
        }
        return *self;
    }

    self_t& notFound()
    {
        self_t* self = static_cast<self_t*>(this);
        self->methodsBitfield = 1U << notFoundIndex;
        return *self;
    }

    self_t& methodNotAllowed()
    {
        self_t* self = static_cast<self_t*>(this);
        self->methodsBitfield = 1U << methodNotAllowedIndex;
        return *self;
    }

    self_t& privileges(
        const std::initializer_list<std::initializer_list<const char*>>& p)
    {
        self_t* self = static_cast<self_t*>(this);
        for (const std::initializer_list<const char*>& privilege : p)
        {
            self->privilegesSet.emplace_back(privilege);
        }
        return *self;
    }

    template <size_t N, typename... MethodArgs>
    self_t& privileges(const std::array<redfish::Privileges, N>& p)
    {
        self_t* self = static_cast<self_t*>(this);
        for (const redfish::Privileges& privilege : p)
        {
            self->privilegesSet.emplace_back(privilege);
        }
        return *self;
    }
};

class DynamicRule : public BaseRule, public RuleParameterTraits<DynamicRule>
{
  public:
    explicit DynamicRule(const std::string& ruleIn) : BaseRule(ruleIn)
    {}

    void validate() override
    {
        if (!erasedHandler)
        {
            throw std::runtime_error(nameStr + (!nameStr.empty() ? ": " : "") +
                                     "no handler for url " + rule);
        }
    }

    void handle(const Request& req,
                const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                const RoutingParams& params) override
    {
        erasedHandler(req, asyncResp, params);
    }

    template <typename Func>
    void operator()(Func f)
    {
        using boost::callable_traits::args_t;
        constexpr size_t arity = std::tuple_size<args_t<Func>>::value;
        constexpr auto is = std::make_integer_sequence<unsigned, arity>{};
        erasedHandler = wrap(std::move(f), is);
    }

    // enable_if Arg1 == request && Arg2 == Response
    // enable_if Arg1 == request && Arg2 != response
    // enable_if Arg1 != request

    template <typename Func, unsigned... Indices>
    std::function<void(const Request&,
                       const std::shared_ptr<bmcweb::AsyncResp>&,
                       const RoutingParams&)>
        wrap(Func f, std::integer_sequence<unsigned, Indices...> /*is*/)
    {
        using function_t = crow::utility::FunctionTraits<Func>;

        if (!black_magic::isParameterTagCompatible(
                black_magic::getParameterTag(rule),
                black_magic::computeParameterTagFromArgsList<
                    typename function_t::template arg<Indices>...>::value))
        {
            throw std::runtime_error("routeDynamic: Handler type is mismatched "
                                     "with URL parameters: " +
                                     rule);
        }
        auto ret = detail::routing_handler_call_helper::Wrapped<
            Func, typename function_t::template arg<Indices>...>();
        ret.template set<typename function_t::template arg<Indices>...>(
            std::move(f));
        return ret;
    }

    template <typename Func>
    void operator()(std::string name, Func&& f)
    {
        nameStr = std::move(name);
        (*this).template operator()<Func>(std::forward(f));
    }

  private:
    std::function<void(const Request&,
                       const std::shared_ptr<bmcweb::AsyncResp>&,
                       const RoutingParams&)>
        erasedHandler;
};

template <typename... Args>
class TaggedRule :
    public BaseRule,
    public RuleParameterTraits<TaggedRule<Args...>>
{
  public:
    using self_t = TaggedRule<Args...>;

    explicit TaggedRule(std::string_view ruleIn) : BaseRule(ruleIn)
    {}

    void validate() override
    {
        if (!handler)
        {
            throw std::runtime_error(nameStr + (!nameStr.empty() ? ": " : "") +
                                     "no handler for url " + rule);
        }
    }

    template <typename Func>
    typename std::enable_if<
        black_magic::CallHelper<Func, black_magic::S<Args...>>::value,
        void>::type
        operator()(Func&& f)
    {
        static_assert(
            black_magic::CallHelper<Func, black_magic::S<Args...>>::value ||
                black_magic::CallHelper<
                    Func, black_magic::S<crow::Request, Args...>>::value,
            "Handler type is mismatched with URL parameters");
        static_assert(
            !std::is_same<void, decltype(f(std::declval<Args>()...))>::value,
            "Handler function cannot have void return type; valid return "
            "types: "
            "string, int, crow::response, nlohmann::json");

        handler = [f = std::forward<Func>(f)](
                      const Request&,
                      const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                      Args... args) { asyncResp->res.result(f(args...)); };
    }

    template <typename Func>
    typename std::enable_if<
        !black_magic::CallHelper<Func, black_magic::S<Args...>>::value &&
            black_magic::CallHelper<
                Func, black_magic::S<crow::Request, Args...>>::value,
        void>::type
        operator()(Func&& f)
    {
        static_assert(
            black_magic::CallHelper<Func, black_magic::S<Args...>>::value ||
                black_magic::CallHelper<
                    Func, black_magic::S<crow::Request, Args...>>::value,
            "Handler type is mismatched with URL parameters");
        static_assert(
            !std::is_same<void, decltype(f(std::declval<crow::Request>(),
                                           std::declval<Args>()...))>::value,
            "Handler function cannot have void return type; valid return "
            "types: "
            "string, int, crow::response,nlohmann::json");

        handler = [f = std::forward<Func>(f)](
                      const crow::Request& req,
                      const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                      Args... args) { asyncResp->res.result(f(req, args...)); };
    }

    template <typename Func>
    typename std::enable_if<
        !black_magic::CallHelper<Func, black_magic::S<Args...>>::value &&
            !black_magic::CallHelper<
                Func, black_magic::S<crow::Request, Args...>>::value,
        void>::type
        operator()(Func&& f)
    {
        static_assert(
            black_magic::CallHelper<Func, black_magic::S<Args...>>::value ||
                black_magic::CallHelper<
                    Func, black_magic::S<crow::Request, Args...>>::value ||
                black_magic::CallHelper<
                    Func, black_magic::S<crow::Request,
                                         std::shared_ptr<bmcweb::AsyncResp>&,
                                         Args...>>::value,
            "Handler type is mismatched with URL parameters");
        static_assert(
            std::is_same<
                void,
                decltype(f(std::declval<crow::Request>(),
                           std::declval<std::shared_ptr<bmcweb::AsyncResp>&>(),
                           std::declval<Args>()...))>::value,
            "Handler function with response argument should have void "
            "return "
            "type");

        handler = std::forward<Func>(f);
    }

    template <typename Func>
    void operator()(std::string_view name, Func&& f)
    {
        nameStr = name;
        (*this).template operator()<Func>(std::forward(f));
    }

    template <typename Func>
    void replaceHandler(Func&& f)
    {
        this->operator()(f);
    }

    template <typename Func>
    void appendHandler(Func&& f)
    {
        this->operator()(
            [f = std::forward<Func>(f), previousFunc = this->handler](
                const crow::Request & req,
                const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                Args... args) {
            if (previousFunc)
            {
                previousFunc(req, asyncResp, args...);
            }
            std::function<void(crow::Response&)> previousCompleteFunc =
                asyncResp->res.releaseCompleteRequestHandler();
            auto strand = asyncResp->strand_;

            asyncResp->res.setCompleteRequestHandler(
                [req, previousCompleteFunc(std::move(previousCompleteFunc)),
                 args..., f, strand,
                 delegatedExpandLevel(asyncResp->delegatedExpandLevel)](
                        crow::Response& resIn) mutable {
                std::shared_ptr<bmcweb::AsyncResp> newAsyncResp =
                    std::make_shared<bmcweb::AsyncResp>(std::move(resIn), strand);

                // Pass delegatedExpandLevel so that hanlder in plugin can
                // handler efficient expand appending accordingly
                newAsyncResp->delegatedExpandLevel = delegatedExpandLevel;

                // previousCompleteFunc contains callback functions including
                // Redfish params and writing bytes to socket
                newAsyncResp->res.setCompleteRequestHandler(
                    [previousCompleteFunc(std::move(previousCompleteFunc))](
                        crow::Response& resp) {
                    if (previousCompleteFunc)
                    {
                        previousCompleteFunc(resp);
                    }
                });
                f(req, newAsyncResp, args...);
            });
        });
    }

    void handle(const Request& req,
                const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                const RoutingParams& params) override
    {
        detail::routing_handler_call_helper::Call<
            detail::routing_handler_call_helper::CallParams<decltype(handler)>,
            0, 0, 0, 0, black_magic::S<Args...>, black_magic::S<>>()(
            detail::routing_handler_call_helper::CallParams<decltype(handler)>{
                handler, params, req, asyncResp});
    }

  private:
    std::function<void(const crow::Request&,
                       const std::shared_ptr<bmcweb::AsyncResp>&, Args...)>
        handler;
};

class Trie
{
  public:
    struct Node
    {
        unsigned ruleIndex{};
        std::array<size_t, static_cast<size_t>(ParamType::MAX)>
            paramChildrens{};
        using ChildMap = boost::container::flat_map<
            std::string, unsigned, std::less<>,
            std::vector<std::pair<std::string, unsigned>>>;
        ChildMap children;

        bool isSimpleNode() const
        {
            return ruleIndex == 0 &&
                   std::all_of(std::begin(paramChildrens),
                               std::end(paramChildrens),
                               [](size_t x) { return x == 0U; });
        }
    };

    Trie() : nodes(1)
    {}

  private:
    void optimizeNode(Node* node);

    void optimize()
    {
        optimizeNode(head());
    }

  public:
    void validate()
    {
        optimize();
    }

    void findRouteIndexes(const std::string& reqUrl,
                          std::vector<unsigned>& routeIndexes,
                          const Node* node = nullptr, unsigned pos = 0) const;

    std::pair<unsigned, RoutingParams>
        find(std::string_view reqUrl, const Node* node = nullptr,
             size_t pos = 0, RoutingParams* params = nullptr) const;

    void add(const std::string& url, unsigned ruleIndex);

  private:
    void debugNodePrint(Node* n, size_t level);

  public:
    void debugPrint()
    {
        debugNodePrint(head(), 0U);
    }

  private:
    const Node* head() const
    {
        return &nodes.front();
    }

    Node* head()
    {
        return &nodes.front();
    }

    unsigned newNode()
    {
        nodes.resize(nodes.size() + 1);
        return static_cast<unsigned>(nodes.size() - 1);
    }

    std::vector<Node> nodes;
};

class Router
{
  public:
    explicit Router(bool allowSessionEmpty) :
        allowSessionEmpty(allowSessionEmpty)
    {}

    DynamicRule& newRuleDynamic(const std::string& rule)
    {
        std::unique_ptr<DynamicRule> ruleObject =
            std::make_unique<DynamicRule>(rule);
        DynamicRule* ptr = ruleObject.get();
        allRules.emplace_back(std::move(ruleObject));

        return *ptr;
    }

    template <uint64_t N>
    typename black_magic::Arguments<N>::type::template rebind<TaggedRule>&
        newRuleTagged(std::string_view rule)
    {
        using RuleT = typename black_magic::Arguments<N>::type::template rebind<
            TaggedRule>;
        std::unique_ptr<RuleT> ruleObject = std::make_unique<RuleT>(rule);
        RuleT* ptr = ruleObject.get();
        allRules.emplace_back(std::move(ruleObject));

        return *ptr;
    }

    template <uint64_t Tag>
    void removeRuleTagged(std::string_view url,
                          boost::beast::http::verb boostVerb)
    {
        auto iter = findRuleByUrlAndVerb<Tag>(url, boostVerb);
        if (iter == allRules.end())
        {
            throwHandlerNotFound(url, boostVerb);
        }
        allRules.erase(iter);
    }

    void internalAddRuleObject(const std::string& rule, BaseRule* ruleObject);

    void validate();

    struct FindRoute
    {
        BaseRule* rule = nullptr;
        RoutingParams params;
    };

    struct FindRouteResponse
    {
        std::string allowHeader;
        FindRoute route;
    };

    FindRoute findRouteByIndex(std::string_view url, size_t index) const;

    FindRouteResponse findRoute(Request& req) const;

    template <typename CallbackFn>
    void afterGetUserInfo(Request& req,
                          const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                          BaseRule& rule, CallbackFn&& callback,
                          const boost::system::error_code& ec,
                          const dbus::utility::DBusPropertiesMap& userInfoMap)
    {
        if (ec)
        {
            BMCWEB_LOG_ERROR << "GetUserInfo failed...";
            asyncResp->res.result(
                boost::beast::http::status::internal_server_error);
            return;
        }

        if (!isUserPrivileged(req, asyncResp, rule, userInfoMap))
        {
            // User is not privileged
            BMCWEB_LOG_ERROR << "Insufficient Privilege";
            asyncResp->res.result(boost::beast::http::status::forbidden);
            return;
        }
        callback(req);
    }

    template <typename CallbackFn>
    void validatePrivilege(Request& req,
                           const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                           BaseRule& rule, CallbackFn&& callback)
    {
        if (req.session == nullptr)
        {
            BMCWEB_LOG_DEBUG
                << "validatePrivilege: no session to validatePrivilege:";

            if (allowSessionEmpty)
            {
                callback(req);
            }

            return;
        }

        if (managedStore::GetManagedObjectStore()
                    ->GetDeprecatedThreadUnsafeSystemBus() != nullptr &&
            req.session)
        {
            BMCWEB_LOG_DEBUG << "validatePrivilege: GetUserInfo";
            const std::string username = req.session->username;
            // TODO: WHY ARE WE DOING THIS FOR EVERY REQUEST ?!?! OMG. this is
            // absurd!
            managedStore::GetManagedObjectStore()
                ->PostDbusCallToIoContextThreadSafe(
                    asyncResp->strand_,
                    [this, &req, asyncResp, &rule,
                     callback(std::forward<CallbackFn>(callback))](
                        const boost::system::error_code& ec,
                        const dbus::utility::DBusPropertiesMap&
                            userInfoMap) mutable {
                afterGetUserInfo(req, asyncResp, rule,
                                 std::forward<CallbackFn>(callback), ec,
                                 userInfoMap);
            },
                    "xyz.openbmc_project.User.Manager",
                    "/xyz/openbmc_project/user",
                    "xyz.openbmc_project.User.Manager", "GetUserInfo",
                    username);
        }
        else
        {
            // systemBus = null is most likely unit testing
            callback(req);
        }
    }

    template <typename Adaptor>
    void handleUpgrade(Request& req,
                       const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
                       Adaptor&& adaptor)
    {
        std::optional<HttpVerb> verb = httpVerbFromBoost(req.method());
        if (!verb || static_cast<size_t>(*verb) >= perMethods.size())
        {
            asyncResp->res.result(boost::beast::http::status::not_found);
            return;
        }
        PerMethod& perMethod = perMethods[static_cast<size_t>(*verb)];
        Trie& trie = perMethod.trie;
        std::vector<BaseRule*>& rules = perMethod.rules;

        const std::pair<unsigned, RoutingParams>& found =
            trie.find(req.url().encoded_path());
        unsigned ruleIndex = found.first;
        if (ruleIndex == 0U)
        {
            BMCWEB_LOG_DEBUG << "Cannot match rules "
                             << req.url().encoded_path();
            asyncResp->res.result(boost::beast::http::status::not_found);
            return;
        }

        if (ruleIndex >= rules.size())
        {
            throw std::runtime_error("Trie internal structure corrupted!");
        }

        BaseRule& rule = *rules[ruleIndex];
        size_t methods = rule.getMethods();
        if ((methods & (1U << static_cast<size_t>(*verb))) == 0)
        {
            BMCWEB_LOG_DEBUG
                << "Rule found but method mismatch: "
                << req.url().encoded_path() << " with " << req.methodString()
                << "(" << static_cast<uint32_t>(*verb) << ") / " << methods;
            asyncResp->res.result(boost::beast::http::status::not_found);
            return;
        }

        BMCWEB_LOG_DEBUG << "Matched rule (upgrade) '" << rule.rule << "' "
                         << static_cast<uint32_t>(*verb) << " / " << methods;

        // TODO(ed) This should be able to use std::bind_front, but it doesn't
        // appear to work with the std::move on adaptor.
        validatePrivilege(
            req, asyncResp, rule,
            [&rule, asyncResp, adaptor(std::forward<Adaptor>(adaptor))](
                Request& thisReq) mutable {
            rule.handleUpgrade(thisReq, asyncResp, std::move(adaptor));
        });
    }

    template <uint64_t Tag>
    std::vector<std::unique_ptr<BaseRule>>::iterator
        findRuleByUrlAndVerb(std::string_view url,
                             boost::beast::http::verb boostVerb)
    {
        std::optional<HttpVerb> verb = httpVerbFromBoost(boostVerb);
        if (!verb)
        {
            return allRules.end();
        }

        for (auto iter = allRules.begin(); iter != allRules.end(); ++iter)
        {
            if ((*iter)->rule == url && ((*iter)->methodsBitfield &
                                         (1 << static_cast<size_t>(*verb))) > 0)
            {
                return iter;
            }
        }
        return allRules.end();
    }

    void handle(Request& req,
                const std::shared_ptr<bmcweb::AsyncResp>& asyncResp);

    void debugPrint();

    std::vector<const std::string*> getRoutes(const std::string& parent);

    static void throwHandlerNotFound(std::string_view url,
                                     boost::beast::http::verb boostVerb);

    template <uint64_t Tag, typename Func>
    void replaceHandler(std::string_view url,
                        boost::beast::http::verb boostVerb, Func&& func)
    {
        auto iter = findRuleByUrlAndVerb<Tag>(url, boostVerb);
        if (iter == allRules.end())
        {
            throwHandlerNotFound(url, boostVerb);
        }
        using RuleT =
            black_magic::Arguments<Tag>::type::template rebind<TaggedRule>;
        RuleT* rule = dynamic_cast<RuleT*>(iter->get());
        rule->replaceHandler(func);
    }

    template <uint64_t Tag, typename Func>
    void appendHandler(std::string_view url, boost::beast::http::verb boostVerb,
                       Func&& func)
    {
        auto iter = findRuleByUrlAndVerb<Tag>(url, boostVerb);
        if (iter == allRules.end())
        {
            throwHandlerNotFound(url, boostVerb);
        }
        using RuleT = typename black_magic::Arguments<
            Tag>::type::template rebind<TaggedRule>;
        RuleT* rule = dynamic_cast<RuleT*>(iter->get());

        rule->appendHandler(func);
    }

  private:
    static bool isUserPrivileged(
        Request& req, const std::shared_ptr<bmcweb::AsyncResp>& asyncResp,
        BaseRule& rule, const dbus::utility::DBusPropertiesMap& userInfoMap);

    struct PerMethod
    {
        std::vector<BaseRule*> rules;
        Trie trie;
        // rule index 0 has special meaning; preallocate it to avoid
        // duplication.
        PerMethod() : rules(1)
        {}
    };

    std::array<PerMethod, methodNotAllowedIndex + 1> perMethods;
    std::vector<std::unique_ptr<BaseRule>> allRules;

    bool allowSessionEmpty = false;
};
} // namespace crow