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/**
* @file llhttpretrypolicy.h
* @brief Header for a retry policy class intended for use with http responders.
*
* $LicenseInfo:firstyear=2013&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2013, Linden Research, Inc.
*
* 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;
* version 2.1 of the License only.
*
* 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
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#include "llviewerprecompiledheaders.h"
#include "llhttpretrypolicy.h"
LLAdaptiveRetryPolicy::LLAdaptiveRetryPolicy(F32 min_delay, F32 max_delay, F32 backoff_factor, U32 max_retries):
mMinDelay(min_delay),
mMaxDelay(max_delay),
mBackoffFactor(backoff_factor),
mMaxRetries(max_retries),
mDelay(min_delay),
mRetryCount(0),
mShouldRetry(true)
{
}
bool LLAdaptiveRetryPolicy::getRetryAfter(const LLSD& headers, F32& retry_header_time)
{
return (headers.has(HTTP_IN_HEADER_RETRY_AFTER)
&& getSecondsUntilRetryAfter(headers[HTTP_IN_HEADER_RETRY_AFTER].asStringRef(), retry_header_time));
}
bool LLAdaptiveRetryPolicy::getRetryAfter(const LLCore::HttpHeaders *headers, F32& retry_header_time)
{
// Look for matching header. Hopefully it's correct enough to let
// us extract the field we are looking for. Does not purport to be
// in any way a viable general HTTP header parser.
if (headers)
{
for (std::vector<std::string>::const_iterator it = headers->mHeaders.begin();
it != headers->mHeaders.end();
++it)
{
const std::string& str = *it;
const std::string match = HTTP_IN_HEADER_RETRY_AFTER + ":";
size_t pos = str.find(match);
if ((pos != std::string::npos) &&
(pos+match.length() <= str.length()))
{
retry_header_time = strtod(str.substr(pos+match.length()).c_str(), NULL);
return true;
}
}
}
return false;
}
void LLAdaptiveRetryPolicy::onFailure(S32 status, const LLSD& headers)
{
F32 retry_header_time;
bool has_retry_header_time = getRetryAfter(headers,retry_header_time);
onFailureCommon(status, has_retry_header_time, retry_header_time);
}
// TODO: replace this parsing junk once CoreHttp has its own header parsing capabilities.
void LLAdaptiveRetryPolicy::onFailure(const LLCore::HttpResponse *response)
{
F32 retry_header_time;
const LLCore::HttpHeaders *headers = response->getHeaders();
bool has_retry_header_time = getRetryAfter(headers,retry_header_time);
onFailureCommon(response->getStatus().mType, has_retry_header_time, retry_header_time);
}
void LLAdaptiveRetryPolicy::onFailureCommon(S32 status, bool has_retry_header_time, F32 retry_header_time)
{
if (!mShouldRetry)
{
llinfos << "keep on failing" << llendl;
return;
}
if (mRetryCount > 0)
{
mDelay = llclamp(mDelay*mBackoffFactor,mMinDelay,mMaxDelay);
}
// Honor server Retry-After header.
// Status 503 may ask us to wait for a certain amount of time before retrying.
F32 wait_time = mDelay;
if (has_retry_header_time)
{
wait_time = retry_header_time;
}
if (mRetryCount>=mMaxRetries)
{
llinfos << "Too many retries " << mRetryCount << ", will not retry" << llendl;
mShouldRetry = false;
}
if (!isHttpServerErrorStatus(status))
{
llinfos << "Non-server error " << status << ", will not retry" << llendl;
mShouldRetry = false;
}
if (mShouldRetry)
{
llinfos << "Retry count " << mRetryCount << " should retry after " << wait_time << llendl;
mRetryTimer.reset();
mRetryTimer.setTimerExpirySec(wait_time);
}
mRetryCount++;
}
bool LLAdaptiveRetryPolicy::shouldRetry(F32& seconds_to_wait) const
{
if (mRetryCount == 0)
{
// Called shouldRetry before any failure.
seconds_to_wait = F32_MAX;
return false;
}
seconds_to_wait = mShouldRetry ? mRetryTimer.getRemainingTimeF32() : F32_MAX;
return mShouldRetry;
}
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