EffectiveUrlCache.h

// -*- mode: c++; c-basic-offset:4 -*-
 
// This file is part of the BES http package, part of the Hyrax data server.
 
// Copyright (c) 2020 OPeNDAP, Inc.
// Author: Nathan Potter <ndp@opendap.org>
//
// This library 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 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// 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 library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.
 
// Authors:
//      ndp       Nathan Potter <ndp@opendap.org>
 
#ifndef _bes_http_EffectiveUrlCache_h_
#define _bes_http_EffectiveUrlCache_h_ 1
 
#include <memory>
#include <map>
#include <unordered_map>
#include <string>
#include <mutex>
 
#include "BESObj.h"
#include "BESRegex.h"   // for std::unique_ptr<BESRegex>
 
namespace http {
 
class EffectiveUrl;
class url;

class EffectiveUrlCache : public BESObj {
private:
    EffectiveUrlCache() = default;
 
    std::mutex d_cache_lock_mutex;
 
    std::map<std::string, std::shared_ptr<http::EffectiveUrl>> d_effective_urls;
 
    // URLs that match are not cached.
    std::unique_ptr<BESRegex> d_skip_regex = nullptr;
 
    int d_enabled = -1;
 
    std::shared_ptr<EffectiveUrl> get_cached_eurl(std::string const &url_key);
 
    void set_skip_regex();
 
    bool is_enabled();
 
    friend class EffectiveUrlCacheTest;
 
public:
    static EffectiveUrlCache *TheCache() {
        // Create a local static object the first time the function is called
        static EffectiveUrlCache instance;
        return &instance;
    }
 
    EffectiveUrlCache(const EffectiveUrlCache &src) = delete;
    EffectiveUrlCache &operator=(const EffectiveUrlCache &rhs) = delete;
 
    ~EffectiveUrlCache() override = default;
 
    std::shared_ptr<EffectiveUrl> get_effective_url(std::shared_ptr<url> source_url);
 
    void dump(std::ostream &strm) const override;
 
private:
    std::string dump() const {
        std::stringstream sstrm;
        dump(sstrm);
        return sstrm.str();
    }
};
 
} // namespace http
 
#endif // _bes_http_EffectiveUrlCache_h_