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// *****************************************************************************
// * 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/sys_info.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("curl_easy_init", formatCurlStatusCode(CURLE_OUT_OF_MEMORY), L""));
}
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 httpStatus = 0; //optional
/*const CURLcode rc = */ ::curl_easy_getinfo(easyHandle_, CURLINFO_RESPONSE_CODE, &httpStatus);
if (rcPerf != CURLE_OK)
{
std::wstring errorMsg = trimCpy(utfTo<std::wstring>(curlErrorBuf)); //optional
if (httpStatus != 0) //optional
errorMsg += (errorMsg.empty() ? L"" : L"\n") + formatHttpError(httpStatus);
#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("curl_easy_perform", formatCurlStatusCode(rcPerf), errorMsg));
}
lastSuccessfulUseTime_ = std::chrono::steady_clock::now();
return { static_cast<int>(httpStatus) /*, contentType ? contentType : ""*/ };
}
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