Merge branch '10.20' into 'master'10.20

add upstream 10.20

See merge request opensource-tracking/FreeFileSync!17

3 files changed, 399 insertions, 0 deletions

diff --git a/libcurl/curl_wrap.h b/libcurl/curl_wrap.h
new file mode 100644
index 00000000..dca056fc
--- /dev/null
+++ b/libcurl/curl_wrap.h
@@ -0,0 +1,162 @@
+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under    *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#ifndef CURL_WRAP_H_2879058325032785032789645
+#define CURL_WRAP_H_2879058325032785032789645
+
+#include <zen/scope_guard.h>
+#include <zen/sys_error.h>
+
+
+
+//-------------------------------------------------
+#include <curl/curl.h>
+//-------------------------------------------------
+
+#ifndef CURLINC_CURL_H
+    #error curl.h header guard changed
+#endif
+
+namespace zen
+{
+struct CurlOption
+{
+    template <class T>
+    CurlOption(CURLoption o, T val) : option(o), value(static_cast<uint64_t>(val)) { static_assert(sizeof(val) <= sizeof(value)); }
+
+    template <class T>
+    CurlOption(CURLoption o, T* val) : option(o), value(reinterpret_cast<uint64_t>(val)) { static_assert(sizeof(val) <= sizeof(value)); }
+
+    CURLoption option = CURLOPT_LASTENTRY;
+    uint64_t value = 0;
+};
+
+namespace
+{
+std::wstring formatCurlStatusCode(CURLcode sc)
+{
+    switch (sc)
+    {
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OK);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_UNSUPPORTED_PROTOCOL);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FAILED_INIT);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_URL_MALFORMAT);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_NOT_BUILT_IN);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_COULDNT_RESOLVE_PROXY);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_COULDNT_RESOLVE_HOST);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_COULDNT_CONNECT);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_WEIRD_SERVER_REPLY);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_REMOTE_ACCESS_DENIED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_ACCEPT_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_WEIRD_PASS_REPLY);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_ACCEPT_TIMEOUT);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_WEIRD_PASV_REPLY);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_WEIRD_227_FORMAT);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_CANT_GET_HOST);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_HTTP2);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_COULDNT_SET_TYPE);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_PARTIAL_FILE);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_COULDNT_RETR_FILE);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE20);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_QUOTE_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_HTTP_RETURNED_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_WRITE_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE24);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_UPLOAD_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_READ_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OUT_OF_MEMORY);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OPERATION_TIMEDOUT);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE29);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_PORT_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_COULDNT_USE_REST);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE32);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_RANGE_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_HTTP_POST_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_CONNECT_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_BAD_DOWNLOAD_RESUME);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FILE_COULDNT_READ_FILE);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_LDAP_CANNOT_BIND);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_LDAP_SEARCH_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE40);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FUNCTION_NOT_FOUND);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_ABORTED_BY_CALLBACK);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_BAD_FUNCTION_ARGUMENT);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE44);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_INTERFACE_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE46);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_TOO_MANY_REDIRECTS);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_UNKNOWN_OPTION);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_TELNET_OPTION_SYNTAX);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE50);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE51);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_PEER_FAILED_VERIFICATION);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_GOT_NOTHING);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_ENGINE_NOTFOUND);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_ENGINE_SETFAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SEND_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_RECV_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_OBSOLETE57);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_CERTPROBLEM);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_CIPHER);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_BAD_CONTENT_ENCODING);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_LDAP_INVALID_URL);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FILESIZE_EXCEEDED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_USE_SSL_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SEND_FAIL_REWIND);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_ENGINE_INITFAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_LOGIN_DENIED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_TFTP_NOTFOUND);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_TFTP_PERM);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_REMOTE_DISK_FULL);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_TFTP_ILLEGAL);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_TFTP_UNKNOWNID);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_REMOTE_FILE_EXISTS);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_TFTP_NOSUCHUSER);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_CONV_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_CONV_REQD);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_CACERT_BADFILE);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_REMOTE_FILE_NOT_FOUND);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSH);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_SHUTDOWN_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_AGAIN);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_CRL_BADFILE);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_ISSUER_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_PRET_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_RTSP_CSEQ_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_RTSP_SESSION_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_FTP_BAD_FILE_LIST);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_CHUNK_FAILED);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_NO_CONNECTION_AVAILABLE);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_PINNEDPUBKEYNOTMATCH);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_SSL_INVALIDCERTSTATUS);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_HTTP2_STREAM);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_RECURSIVE_API_CALL);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_AUTH_ERROR);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURLE_HTTP3);
+            ZEN_CHECK_CASE_FOR_CONSTANT(CURL_LAST);
+    }
+    static_assert(CURL_LAST == CURLE_HTTP3 + 1);
+
+    return replaceCpy<std::wstring>(L"Curl status %x.", L"%x", numberTo<std::wstring>(static_cast<int>(sc)));
+}
+
+
+void applyCurlOptions(CURL* easyHandle, const std::vector<CurlOption>& options) //throw SysError
+{
+    for (const CurlOption& opt : options)
+    {
+        const CURLcode rc = ::curl_easy_setopt(easyHandle, opt.option, opt.value);
+        if (rc != CURLE_OK)
+            throw SysError(formatSystemError(L"curl_easy_setopt " + numberTo<std::wstring>(static_cast<int>(opt.option)),
+                                             formatCurlStatusCode(rc), utfTo<std::wstring>(::curl_easy_strerror(rc))));
+    }
+}
+}
+}
+
+#else
+#error Why is this header already defined? Do not include in other headers: encapsulate the gory details!
+#endif //CURL_WRAP_H_2879058325032785032789645
diff --git a/libcurl/rest.cpp b/libcurl/rest.cpp
new file mode 100644
index 00000000..22583483
--- /dev/null
+++ b/libcurl/rest.cpp
@@ -0,0 +1,185 @@
+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under    *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#include "rest.h"
+#include <zen/system.h>
+#include <zen/http.h>
+
+using namespace zen;
+
+
+HttpSession::HttpSession(const Zstring& server, const Zstring& caCertFilePath, std::chrono::seconds timeOut) : //throw SysError
+    server_(utfTo<std::string>(server)),
+    caCertFilePath_(utfTo<std::string>(caCertFilePath)),
+    timeOutSec_(timeOut) {}
+
+
+HttpSession::~HttpSession()
+{
+    if (easyHandle_)
+        ::curl_easy_cleanup(easyHandle_);
+}
+
+
+HttpSession::Result HttpSession::perform(const std::string& serverRelPath,
+                                         const std::vector<std::string>& extraHeaders, const std::vector<CurlOption>& extraOptions, //throw SysError
+                                         const std::function<void  (const void* buffer, size_t bytesToWrite)>& writeResponse /*throw X*/, //optional
+                                         const std::function<size_t(      void* buffer, size_t bytesToRead )>& readRequest   /*throw X*/) //
+{
+    if (!easyHandle_)
+    {
+        easyHandle_ = ::curl_easy_init();
+        if (!easyHandle_)
+            throw SysError(formatSystemError(L"curl_easy_init", formatCurlStatusCode(CURLE_OUT_OF_MEMORY), std::wstring()));
+    }
+    else
+        ::curl_easy_reset(easyHandle_);
+
+
+    std::vector<CurlOption> options;
+
+    char curlErrorBuf[CURL_ERROR_SIZE] = {};
+    options.emplace_back(CURLOPT_ERRORBUFFER, curlErrorBuf);
+
+    options.emplace_back(CURLOPT_USERAGENT, "FreeFileSync"); //default value; may be overwritten by caller
+
+    //lifetime: keep alive until after curl_easy_setopt() below
+    std::string curlPath = "https://" + server_ + serverRelPath;
+    options.emplace_back(CURLOPT_URL, curlPath.c_str());
+
+    options.emplace_back(CURLOPT_ACCEPT_ENCODING, "gzip"); //won't hurt + used by Google Drive
+
+    options.emplace_back(CURLOPT_NOSIGNAL, 1L); //thread-safety: https://curl.haxx.se/libcurl/c/threadsafe.html
+
+    options.emplace_back(CURLOPT_CONNECTTIMEOUT, timeOutSec_.count());
+
+    //CURLOPT_TIMEOUT: "Since this puts a hard limit for how long time a request is allowed to take, it has limited use in dynamic use cases with varying transfer times."
+    options.emplace_back(CURLOPT_LOW_SPEED_TIME, timeOutSec_.count());
+    options.emplace_back(CURLOPT_LOW_SPEED_LIMIT, 1L); //[bytes], can't use "0" which means "inactive", so use some low number
+
+
+    //libcurl forwards this char-string to OpenSSL as is, which - thank god - accepts UTF8
+    options.emplace_back(CURLOPT_CAINFO, caCertFilePath_.c_str()); //hopefully latest version from https://curl.haxx.se/docs/caextract.html
+    //CURLOPT_SSL_VERIFYPEER => already active by default
+    //CURLOPT_SSL_VERIFYHOST =>
+
+    //---------------------------------------------------
+    std::exception_ptr userCallbackException;
+
+    auto onBytesReceived = [&](const void* buffer, size_t len)
+    {
+        try
+        {
+            writeResponse(buffer, len); //throw X
+            return len;
+        }
+        catch (...)
+        {
+            userCallbackException = std::current_exception();
+            return len + 1; //signal error condition => CURLE_WRITE_ERROR
+        }
+    };
+    using ReadCbType = decltype(onBytesReceived);
+    using ReadCbWrapperType =          size_t (*)(const void* buffer, size_t size, size_t nitems, ReadCbType* callbackData); //needed for cdecl function pointer cast
+    ReadCbWrapperType onBytesReceivedWrapper = [](const void* buffer, size_t size, size_t nitems, ReadCbType* callbackData)
+    {
+        return (*callbackData)(buffer, size * nitems); //free this poor little C-API from its shackles and redirect to a proper lambda
+    };
+    //---------------------------------------------------
+    auto getBytesToSend = [&](void* buffer, size_t len) -> size_t
+    {
+        try
+        {
+            //libcurl calls back until 0 bytes are returned (Posix read() semantics), or,
+            //if CURLOPT_INFILESIZE_LARGE was set, after exactly this amount of bytes
+            const size_t bytesRead = readRequest(buffer, len);//throw X; return "bytesToRead" bytes unless end of stream!
+            return bytesRead;
+        }
+        catch (...)
+        {
+            userCallbackException = std::current_exception();
+            return CURL_READFUNC_ABORT; //signal error condition => CURLE_ABORTED_BY_CALLBACK
+        }
+    };
+    using WriteCbType = decltype(getBytesToSend);
+    using WriteCbWrapperType =         size_t (*)(void* buffer, size_t size, size_t nitems, WriteCbType* callbackData);
+    WriteCbWrapperType getBytesToSendWrapper = [](void* buffer, size_t size, size_t nitems, WriteCbType* callbackData)
+    {
+        return (*callbackData)(buffer, size * nitems); //free this poor little C-API from its shackles and redirect to a proper lambda
+    };
+    //---------------------------------------------------
+    if (writeResponse)
+    {
+        options.emplace_back(CURLOPT_WRITEDATA, &onBytesReceived);
+        options.emplace_back(CURLOPT_WRITEFUNCTION, onBytesReceivedWrapper);
+    }
+    if (readRequest)
+    {
+        if (std::all_of(extraOptions.begin(), extraOptions.end(), [](const CurlOption& o) { return o.option != CURLOPT_POST; }))
+        options.emplace_back(CURLOPT_UPLOAD, 1L); //issues HTTP PUT
+        options.emplace_back(CURLOPT_READDATA, &getBytesToSend);
+        options.emplace_back(CURLOPT_READFUNCTION, getBytesToSendWrapper);
+    }
+
+    if (std::any_of(extraOptions.begin(), extraOptions.end(), [](const CurlOption& o) { return o.option == CURLOPT_WRITEFUNCTION || o.option == CURLOPT_READFUNCTION; }))
+    throw std::logic_error("Contract violation! " + std::string(__FILE__) + ":" + numberTo<std::string>(__LINE__)); //Option already used here!
+
+    if (readRequest && std::any_of(extraOptions.begin(), extraOptions.end(), [](const CurlOption& o) { return o.option == CURLOPT_POSTFIELDS; }))
+    throw std::logic_error("Contract violation! " + std::string(__FILE__) + ":" + numberTo<std::string>(__LINE__)); //Contradicting options: CURLOPT_READFUNCTION, CURLOPT_POSTFIELDS
+
+    //---------------------------------------------------
+    curl_slist* headers = nullptr; //"libcurl will not copy the entire list so you must keep it!"
+    ZEN_ON_SCOPE_EXIT(::curl_slist_free_all(headers));
+
+    for (const std::string& headerLine : extraHeaders)
+        headers = ::curl_slist_append(headers, headerLine.c_str());
+
+    //WTF!!! 1 sec delay when server doesn't support "Expect: 100-continue!! https://stackoverflow.com/questions/49670008/how-to-disable-expect-100-continue-in-libcurl
+    headers = ::curl_slist_append(headers, "Expect:"); //guess, what: www.googleapis.com doesn't support it! e.g. gdriveUploadFile()
+
+    if (headers)
+        options.emplace_back(CURLOPT_HTTPHEADER, headers);
+    //---------------------------------------------------
+
+    append(options, extraOptions);
+
+    applyCurlOptions(easyHandle_, options); //throw SysError
+
+    //=======================================================================================================
+    const CURLcode rcPerf = ::curl_easy_perform(easyHandle_);
+    //WTF: curl_easy_perform() considers FTP response codes 4XX, 5XX as failure, but for HTTP response codes 4XX are considered success!! CONSISTENCY, people!!!
+    //=> at least libcurl is aware: CURLOPT_FAILONERROR: "request failure on HTTP response >= 400"; default: "0, do not fail on error"
+    //https://curl.haxx.se/docs/faq.html#curl_doesn_t_return_error_for_HT
+    //=> Curiously Google also screws up in their REST API design and returns HTTP 4XX status for domain-level errors!
+    //=> let caller handle HTTP status to work around this mess!
+
+    if (userCallbackException)
+        std::rethrow_exception(userCallbackException); //throw X
+    //=======================================================================================================
+
+    long httpStatusCode = 0; //optional
+    /*const CURLcode rc = */ ::curl_easy_getinfo(easyHandle_, CURLINFO_RESPONSE_CODE, &httpStatusCode);
+
+    if (rcPerf != CURLE_OK)
+    {
+        std::wstring errorMsg = trimCpy(utfTo<std::wstring>(curlErrorBuf)); //optional
+
+        if (httpStatusCode != 0) //optional
+            errorMsg += (errorMsg.empty() ? L"" : L"\n") + formatHttpStatusCode(httpStatusCode);
+#if 0
+        //utfTo<std::wstring>(::curl_easy_strerror(ec)) is uninteresting
+        //use CURLINFO_OS_ERRNO ?? https://curl.haxx.se/libcurl/c/CURLINFO_OS_ERRNO.html
+        long nativeErrorCode = 0;
+        if (::curl_easy_getinfo(easyHandle, CURLINFO_OS_ERRNO, &nativeErrorCode) == CURLE_OK)
+            if (nativeErrorCode != 0)
+                errorMsg += (errorMsg.empty() ? L"" : L"\n") + std::wstring(L"Native error code: ") + numberTo<std::wstring>(nativeErrorCode);
+#endif
+        throw SysError(formatSystemError(L"curl_easy_perform", formatCurlStatusCode(rcPerf), errorMsg));
+    }
+
+    lastSuccessfulUseTime_ = std::chrono::steady_clock::now();
+    return { static_cast<int>(httpStatusCode) /*, contentType ? contentType : ""*/ };
+}
diff --git a/libcurl/rest.h b/libcurl/rest.h
new file mode 100644
index 00000000..df41a3cc
--- /dev/null
+++ b/libcurl/rest.h
@@ -0,0 +1,52 @@
+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under    *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#ifndef REST_H_07018456781346523454
+#define REST_H_07018456781346523454
+
+#include <chrono>
+#include <functional>
+#include <zen/sys_error.h>
+#include <zen/zstring.h>
+#include "curl_wrap.h" //DON'T include <curl/curl.h> directly!
+
+
+namespace zen
+{
+//Initialization requirement: 1. WSAStartup 2. OpenSSL 3. curl_global_init()
+// => use UniCounterCookie!
+
+class HttpSession
+{
+public:
+    HttpSession(const Zstring& server, const Zstring& caCertFilePath, std::chrono::seconds timeOut); //throw SysError
+    ~HttpSession();
+
+    struct Result
+    {
+        int statusCode = 0;
+        //std::string contentType;
+    };
+    Result perform(const std::string& serverRelPath,
+                   const std::vector<std::string>& extraHeaders, const std::vector<CurlOption>& extraOptions, //throw SysError
+                   const std::function<void  (const void* buffer, size_t bytesToWrite)>& writeResponse /*throw X*/, //optional
+                   const std::function<size_t(      void* buffer, size_t bytesToRead )>& readRequest   /*throw X*/); //
+
+    std::chrono::steady_clock::time_point getLastUseTime() const { return lastSuccessfulUseTime_; }
+
+private:
+    HttpSession           (const HttpSession&) = delete;
+    HttpSession& operator=(const HttpSession&) = delete;
+
+    const std::string server_;
+    const std::string caCertFilePath_;
+    const std::chrono::seconds timeOutSec_;
+    CURL* easyHandle_ = nullptr;
+    std::chrono::steady_clock::time_point lastSuccessfulUseTime_ = std::chrono::steady_clock::now();
+};
+}
+
+#endif //REST_H_07018456781346523454