regex_utils.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
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
/*
 * MIT License
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * furnished to do so, subject to the following conditions:
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 * The above copyright notice and this permission notice shall be included in
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#include "express/dispatcher/regex_utils.h"
 
#include "express/Request.h"
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include <cstddef>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
namespace express::dispatcher {
 
    std::string path_concat(const std::vector<std::string>& stringvec) {
        std::string s;
 
        for (std::vector<std::string>::size_type i = 0; i < stringvec.size(); i++) {
            if (!stringvec[i].empty() && stringvec[i].front() != ' ') {
                s += "\\/" + stringvec[i];
            }
        }
 
        return s;
    }
 
    std::vector<std::string> explode(const std::string& input, char delim) {
        std::vector<std::string> result;
        std::string current;
        int parenDepth = 0;
 
        for (const char ch : input) {
            if (ch == '(') {
                parenDepth++;
                current += ch;
            } else if (ch == ')') {
                parenDepth--;
                current += ch;
            } else if (ch == delim && parenDepth == 0) {
                result.push_back(current);
                current.clear();
            } else {
                current += ch;
            }
        }
 
        if (!current.empty()) {
            result.push_back(current);
        }
 
        return result;
    }
 
#define PATH_REGEX ":[a-zA-Z0-9]+(\\‍(.+\\‍))?"
    const std::regex& pathRegex() {
        static const std::regex pathregex(PATH_REGEX);
 
        return pathregex;
    }
 
    std::smatch matchResult(const std::string& cpath) {
        std::smatch smatch;
 
        std::regex_search(cpath, smatch, pathRegex());
 
        return smatch;
    }
 
    bool hasResult(const std::string& cpath) {
        std::smatch smatch;
 
        return std::regex_search(cpath, smatch, pathRegex());
    }
 
    bool matchFunction(const std::string& cpath, const std::string& reqpath) {
        std::vector<std::string> explodedString = explode(cpath, '/');
 
        for (std::vector<std::string>::size_type i = 0; i < explodedString.size(); i++) {
            if (explodedString[i].front() == ':') {
                const std::smatch smatch = matchResult(explodedString[i]);
                std::string regex = "(.*)";
 
                if (smatch.size() > 1) {
                    if (smatch[1] != "") {
                        regex = smatch[1];
                    } else if (i == explodedString.size() - 1) {
                        regex = "([^/]+)(/)?$";
                    }
                }
 
                explodedString[i] = regex;
            }
        }
 
        const std::string regexPath = path_concat(explodedString);
 
        return std::regex_match(reqpath, std::regex(regexPath));
    }
 
    void setParams(const std::string& cpath, Request& req) {
        std::vector<std::string> explodedString = explode(cpath, '/');
        std::vector<std::string> explodedReqString = explode(req.url, '/');
 
        for (std::vector<std::string>::size_type i = 0; i < explodedString.size() && i < explodedReqString.size(); i++) {
            if (explodedString[i].front() == ':') {
                const std::smatch smatch = matchResult(explodedString[i]);
                std::string regex = "(.*)";
 
                if (smatch.size() > 1) {
                    if (smatch[1] != "") {
                        regex = smatch[1];
                    }
                }
 
                if (std::regex_match(explodedReqString[i], std::regex(regex))) {
                    std::string attributeName = smatch[0];
                    attributeName.erase(0, 1);
                    attributeName.erase((attributeName.length() - static_cast<std::size_t>(smatch[1].length())),
                                        static_cast<std::size_t>(smatch[1].length()));
 
                    req.params[attributeName] = explodedReqString[i];
                }
            }
        }
    }
 
    bool checkForUrlMatch(const std::string& cpath, const std::string& reqpath) {
        return hasResult(cpath) && matchFunction(cpath, reqpath);
    }
 
} // namespace express::dispatcher