regex_utils.h

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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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 * GNU Lesser General Public License for more details.
 *
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 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
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 * MIT License
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#ifndef EXPRESS_DISPATCHER_REGEX_UTILS_H
#define EXPRESS_DISPATCHER_REGEX_UTILS_H
 
namespace express {
    class Request;
} // namespace express
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
 
#include <algorithm>
#include <cctype>
#include <cstddef>
#include <iterator>
#include <regex>
#include <string>
#include <string_view>
#include <unordered_map>
#include <utility>
#include <vector>
 
#endif /* DOXYGEN_SHOULD_SKIP_THIS */
 
namespace express::dispatcher {
 
    std::vector<std::string> explode(const std::string& s, char delim);
 
    const std::regex& pathRegex();
 
    std::smatch matchResult(const std::string& cpath);
 
    bool hasResult(const std::string& cpath);
 
    void setParams(const std::string& cpath, express::Request& req);
 
    // ---------- URL split & query parsing ----------
    void splitPathAndQuery(std::string_view url, std::string_view& path, std::string_view& query);
 
    std::unordered_map<std::string, std::string> parseQuery(std::string_view qs);
 
    // ---------- path normalization & comparisons ----------
    std::string_view trimOneTrailingSlash(std::string_view s);
 
    inline bool ieq(char a, char b) {
        return std::tolower(static_cast<unsigned char>(a)) == std::tolower(static_cast<unsigned char>(b));
    }
 
    bool equalPath(std::string_view a, std::string_view b, bool caseInsensitive);
 
    // prefix with **segment boundary** (so "/api" won't match "/apix")
    bool boundaryPrefix(std::string_view path, std::string_view base, bool caseInsensitive);
 
    bool querySupersetMatches(const std::unordered_map<std::string, std::string>& rq,
                              const std::unordered_map<std::string, std::string>& need);
 
    // ---------- param path → regex compiler ----------
    // Converts "/api/:id(\\d+)/files/:rest(.*)" into:
    //   ^/api/(\d+)/files/(.*)(?:/|$)        (prefix mode, router/middleware)
    //   ^/api/(\d+)/files/(.*)/?$            (end-anchored (strict=false), application)
    // and returns capture group names in order: ["id","rest"]
    std::pair<std::regex, std::vector<std::string>> compileParamRegex(std::string_view mountPath,
                                                                      bool isPrefix, // router/middleware=true, application=false
                                                                      bool strictRouting,
                                                                      bool caseInsensitive);
 
    template <typename RequestLike>
    inline bool
    matchAndFillParams(const std::regex& rx, const std::vector<std::string>& names, std::string_view reqPath, RequestLike& req) {
        std::cmatch m;
        if (!std::regex_search(reqPath.begin(), reqPath.end(), m, rx)) {
            return false;
        }
        const size_t g = (!m.empty()) ? (m.size() - 1) : 0;
        const size_t n = std::min(names.size(), g);
        for (size_t i = 0; i < n; ++i) {
            req.params[names[i]] = m[i + 1].str();
        }
        return true;
    }
 
} // namespace express::dispatcher
 
#endif // EXPRESS_DISPATCHER_REGEX_UTILS_H