RouterDispatcher.cpp

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/*
 * SNode.C - A Slim Toolkit for Network Communication
 * Copyright (C) Volker Christian <me@vchrist.at>
 *               2020, 2021, 2022, 2023, 2024, 2025
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 * This program is free software: you can redistribute it and/or modify
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 */
 
/*
 * MIT License
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#include "express/dispatcher/RouterDispatcher.h"
 
#include "core/socket/stream/SocketConnection.h"
#include "express/Controller.h"
#include "express/Request.h"
#include "express/Response.h"
#include "express/Route.h"
#include "express/dispatcher/regex_utils.h"
#include "web/http/server/SocketContext.h"
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include "log/Logger.h"
 
#include <cstddef>
#include <string_view>
#include <tuple>
#include <unordered_map>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
namespace express::dispatcher {
 
    std::list<Route>& RouterDispatcher::getRoutes() {
        return routes;
    }
 
    bool RouterDispatcher::setStrictRouting(bool strictRouting) {
        const bool oldStrictRouting = this->strictRouting;
 
        this->strictRouting = strictRouting;
 
        return oldStrictRouting;
    }
 
    bool RouterDispatcher::getStrictRouting() const {
        return strictRouting;
    }
 
    bool RouterDispatcher::setCaseInsensitiveRouting(bool caseInsensitiveRouting) {
        const bool oldCaseInsensitiveRouting = this->caseInsensitiveRouting;
 
        this->caseInsensitiveRouting = caseInsensitiveRouting;
 
        return oldCaseInsensitiveRouting;
    }
 
    bool RouterDispatcher::getCaseInsensitiveRouting() const {
        return caseInsensitiveRouting;
    }
 
    bool
    RouterDispatcher::dispatch(express::Controller& controller, const std::string& parentMountPath, const express::MountPoint& mountPoint) {
        bool dispatched = false;
 
        const std::string absoluteMountPath = parentMountPath + mountPoint.relativeMountPath;
 
        // Split mount & request into path + query
        std::string_view mountPath;
        std::string_view mountQueryString;
        splitPathAndQuery(absoluteMountPath, mountPath, mountQueryString);
        const std::unordered_map<std::string, std::string> requiredQueryPairs = parseQuery(mountQueryString);
 
        std::string_view requestPath;
        std::string_view requestQueryString;
        splitPathAndQuery(controller.getRequest()->originalUrl, requestPath, requestQueryString);
        const std::unordered_map<std::string, std::string> requestQueryPairs = parseQuery(requestQueryString);
 
        // Normalize single trailing slash if not strict
        if (!controller.getStrictRouting()) {
            mountPath = trimOneTrailingSlash(mountPath);
            requestPath = trimOneTrailingSlash(requestPath);
        }
        if (mountPath.empty()) {
            mountPath = "/";
        }
 
        // Router is **prefix** with boundary (like app.use)
        bool pathMatches = false;
        if (absoluteMountPath.find(':') != std::string::npos) {
            if (regex.mark_count() == 0) {
                LOG(TRACE) << "RouterDispatcher: precompiled regex";
                std::tie(regex, names) = compileParamRegex(mountPath,
                                                           /*isPrefix*/ true,
                                                           controller.getStrictRouting(),
                                                           controller.getCaseInsensitiveRouting());
            } else {
                LOG(TRACE) << "RouterDispatcher: using precompiled regex";
            }
 
            pathMatches = matchAndFillParams(regex, names, requestPath, *controller.getRequest());
        } else {
            pathMatches = boundaryPrefix(requestPath, mountPath, controller.getCaseInsensitiveRouting());
        }
        const bool queryMatches = querySupersetMatches(requestQueryPairs, requiredQueryPairs);
 
        const bool requestMatched = (pathMatches && queryMatches);
 
        LOG(TRACE) << controller.getResponse()->getSocketContext()->getSocketConnection()->getConnectionName()
                   << " HTTP Express: router -> " << (requestMatched ? "MATCH" : "NO MATCH");
        LOG(TRACE) << "           RequestMethod: " << controller.getRequest()->method;
        LOG(TRACE) << "              RequestUrl: " << controller.getRequest()->url;
        LOG(TRACE) << "             RequestPath: " << controller.getRequest()->path;
        LOG(TRACE) << "       AbsoluteMountPath: " << absoluteMountPath;
        LOG(TRACE) << "           StrictRouting: " << controller.getStrictRouting();
        LOG(TRACE) << "  CaseInsensitiveRouting: " << controller.getCaseInsensitiveRouting();
 
        if (requestMatched) {
            // Compute remainder and temporarily **rewrite req.path** for subtree
            std::size_t consumedLength = 0;
            if (absoluteMountPath.find(':') != std::string::npos) {
                // Run (or reuse) the param regex match and take its full-match length
                std::cmatch regexMatches;
                auto [regex, names] =
                    compileParamRegex(mountPath, /*isPrefix*/ true, controller.getStrictRouting(), controller.getCaseInsensitiveRouting());
                if (!std::regex_search(requestPath.begin(), requestPath.end(), regexMatches, regex)) {
                    return false; // should not happen because pathMatches was true, but be safe
                }
                consumedLength = static_cast<std::size_t>(regexMatches.length(0)); // <-- ACTUAL matched prefix
            } else {
                // Literal boundary prefix: consume exactly the base length
                consumedLength = mountPath.size();
            }
 
            // Now compute remainder using 'consumedLength'
            std::string_view remainderPath{};
            if (requestPath.size() > consumedLength) {
                remainderPath = requestPath.substr(consumedLength);
                if (!remainderPath.empty() && remainderPath.front() == '/') {
                    remainderPath.remove_prefix(1);
                }
            }
 
            auto& req = *controller.getRequest();
            const std::string previousPathBackup = req.path;
            req.path = remainderPath.empty() ? "/" : ("/" + std::string(remainderPath));
 
            req.queries.insert(requestQueryPairs.begin(), requestQueryPairs.end());
 
            for (Route& route : routes) {
                const bool oldStrictRouting = controller.setStrictRouting(strictRouting);
 
                dispatched = route.dispatch(controller, absoluteMountPath);
 
                controller.setStrictRouting(oldStrictRouting);
 
                if (dispatched) {
                    LOG(TRACE) << "Express: R - Dispatched";
 
                    break;
                }
                if (controller.nextRouterCalled()) {
                    LOG(TRACE) << "Express: R - NextRouter called - breaking dispatching";
 
                    break;
                }
            }
 
            req.path = previousPathBackup;
        }
 
        return dispatched;
    }
 
    std::list<std::string> RouterDispatcher::getRoutes(const std::string& parentMountPath, const MountPoint& mountPoint) const {
        return getRoutes(parentMountPath, mountPoint, strictRouting);
    }
 
    std::list<std::string>
    RouterDispatcher::getRoutes(const std::string& parentMountPath, const MountPoint& mountPoint, bool strictRouting) const {
        std::list<std::string> collectedRoutes;
 
        for (const Route& route : routes) {
            collectedRoutes.splice(
                collectedRoutes.end(),
                route.getRoute(parentMountPath + "$" + mountPoint.relativeMountPath + "$", this->strictRouting ? true : strictRouting));
        }
 
        return collectedRoutes;
    }
 
} // namespace express::dispatcher