MiddlewareDispatcher.cpp

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/*
 * SNode.C - A Slim Toolkit for Network Communication
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 * MIT License
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#include "express/dispatcher/MiddlewareDispatcher.h"
 
#include "core/socket/stream/SocketConnection.h"
#include "express/Next.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 <algorithm>
#include <cstddef>
#include <list>
#include <regex>
#include <string_view>
#include <tuple>
#include <unordered_map>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
namespace express::dispatcher {
 
    MiddlewareDispatcher::MiddlewareDispatcher(
        const std::function<void(const std::shared_ptr<Request>&, const std::shared_ptr<Response>&, express::Next&)>& lambda)
        : lambda(lambda) {
    }
 
    bool MiddlewareDispatcher::dispatch(express::Controller& controller, const std::string& parentMountPath, const MountPoint& mountPoint) {
        bool requestMatched = false;
 
        if (controller.getRequest()->method == mountPoint.method || mountPoint.method == "use" || mountPoint.method == "all") {
            const std::string absoluteMountPath = parentMountPath + mountPoint.relativeMountPath;
 
            if ((controller.getFlags() & Controller::NEXT) == 0) {
                // Split mount & request into path + query
                std::string_view mountPath;
                std::string_view mountQueryString;
                splitPathAndQuery(absoluteMountPath, mountPath, mountQueryString);
                auto requiredQueryPairs = parseQuery(mountQueryString);
 
                std::string_view requestPath;
                std::string_view requestQueryString;
                splitPathAndQuery(controller.getRequest()->originalUrl, requestPath, requestQueryString);
                auto requestQueryPairs = parseQuery(requestQueryString);
 
                // Normalize single trailing slash if not strict
                if (!controller.getStrictRouting()) {
                    mountPath = trimOneTrailingSlash(mountPath);
                    requestPath = trimOneTrailingSlash(requestPath);
                }
                if (mountPath.empty()) {
                    mountPath = "/";
                }
 
                // Middleware is **prefix** with boundary (Express: app.use)
                bool pathMatches = false;
                std::size_t consumedLength = 0;
                if (absoluteMountPath.find(':') != std::string::npos) {
                    // Param mount: compile once, match once, fill params, and record matched prefix length
                    if (regex.mark_count() == 0) {
                        if (regex.mark_count() == 0) {
                            LOG(TRACE) << "MiddlewarDispatchere: precompiled regex";
                            std::tie(regex, names) = compileParamRegex(mountPath,
                                                                       /*isPrefix*/ true,
                                                                       controller.getStrictRouting(),
                                                                       controller.getCaseInsensitiveRouting());
                        } else {
                            LOG(TRACE) << "MiddlewareDispatcher: using precompiled regex";
                        }
                    }
                    std::cmatch regexMatches;
                    pathMatches = std::regex_search(requestPath.begin(), requestPath.end(), regexMatches, regex);
                    if (pathMatches) {
                        // regexMatches[0] = full matched prefix starting at 0 (anchored by compile_param_regex)
                        consumedLength = static_cast<std::size_t>(regexMatches.length(0));
 
                        // fill named params
                        const std::size_t groups = !regexMatches.empty() ? (regexMatches.size() - 1) : 0;
                        const std::size_t n = std::min(names.size(), groups);
                        for (std::size_t i = 0; i < n; ++i) {
                            controller.getRequest()->params[names[i]] = regexMatches[i + 1].str();
                        }
                    }
                } else {
                    // Literal boundary prefix
                    pathMatches = boundaryPrefix(requestPath, mountPath, controller.getCaseInsensitiveRouting());
                    if (pathMatches) {
                        consumedLength = mountPath.size(); // IMPORTANT: literal consumes exactly its base length
                    }
                }
 
                const bool queryMatches = querySupersetMatches(requestQueryPairs, requiredQueryPairs);
                requestMatched = (pathMatches && queryMatches);
 
                LOG(TRACE) << controller.getResponse()->getSocketContext()->getSocketConnection()->getConnectionName()
                           << " HTTP Express: middleware -> " << (requestMatched ? "MATCH" : "NO MATCH");
                LOG(TRACE) << "           RequestMethod: " << controller.getRequest()->method;
                LOG(TRACE) << "              RequestUrl: " << controller.getRequest()->url;
                LOG(TRACE) << "             RequestPath: " << controller.getRequest()->path;
                LOG(TRACE) << "       Mountpoint Method: " << mountPoint.method;
                LOG(TRACE) << " Mountpoint RelativePath: " << mountPoint.relativeMountPath;
                LOG(TRACE) << " Mountpoint AbsolutePath: " << absoluteMountPath;
                LOG(TRACE) << "           StrictRouting: " << controller.getStrictRouting();
                LOG(TRACE) << "  CaseInsensitiveRouting: " << controller.getCaseInsensitiveRouting();
 
                if (requestMatched) {
                    // Compute remainder and temporarily **rewrite req.path**
                    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());
 
                    if (hasResult(absoluteMountPath)) {
                        setParams(absoluteMountPath, *controller.getRequest());
                    }
 
                    Next next(controller);
                    lambda(controller.getRequest(), controller.getResponse(), next);
 
                    // If next() was called synchronously continue current route-tree traversal
                    if ((next.controller.getFlags() & express::Controller::NEXT) != 0) {
                        LOG(TRACE) << "Express: M - Next called - set to NO MATCH";
                        requestMatched = false;
                        controller = next.controller;
                    }
 
                    // Restore
                    req.path = previousPathBackup;
                }
            } else {
                LOG(TRACE) << controller.getResponse()->getSocketContext()->getSocketConnection()->getConnectionName()
                           << " HTTP Express: middleware -> next(...) called";
                LOG(TRACE) << "           RequestMethod: " << controller.getRequest()->method;
                LOG(TRACE) << "              RequestUrl: " << controller.getRequest()->url;
                LOG(TRACE) << "             RequestPath: " << controller.getRequest()->path;
                LOG(TRACE) << "       AbsoluteMountPath: " << absoluteMountPath;
            }
        }
 
        return requestMatched;
    }
 
    std::list<std::string>
    MiddlewareDispatcher::getRoutes(const std::string& parentMountPath, const MountPoint& mountPoint, bool strictRouting) const {
        std::list<std::string> routes{"M " + parentMountPath + mountPoint.relativeMountPath + (!strictRouting ? "*" : "")};
        routes.push_back("  " + mountPoint.method + " " + mountPoint.relativeMountPath);
 
        if (nextRoute) {
            routes.splice(routes.end(), nextRoute->getRoute(parentMountPath, strictRouting));
        }
 
        return routes;
    }
 
} // namespace express::dispatcher