mirror of
https://github.com/klzgrad/naiveproxy.git
synced 2024-11-24 22:36:09 +03:00
70 lines
2.8 KiB
C++
70 lines
2.8 KiB
C++
// Copyright 2018 The Chromium Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
#ifndef NET_HTTP_PROXY_FALLBACK_H_
|
|
#define NET_HTTP_PROXY_FALLBACK_H_
|
|
|
|
// ------------------------------------------------------------
|
|
// Proxy Fallback Overview
|
|
// ------------------------------------------------------------
|
|
//
|
|
// Proxy fallback is a feature that is split between the proxy resolution layer
|
|
// and the HTTP layers.
|
|
//
|
|
// The proxy resolution layer is responsible for:
|
|
// * Obtaining a list of proxies to use
|
|
// (ProxyResolutionService::ResolveProxy). Proxy lists are (usually) the
|
|
// result of having evaluated a PAC script, such as:
|
|
// return "PROXY foobar1:8080; HTTPS foobar2:8080; DIRECT";
|
|
//
|
|
// * Re-ordering the proxy list such that proxies that have recently failed
|
|
// are given lower priority (ProxyInfo::DeprioritizeBadProxies)
|
|
//
|
|
// * Maintaining the expiring cache of proxies that have recently failed.
|
|
//
|
|
//
|
|
// The HTTP layer is responsible for:
|
|
// * Attempting to issue the URLRequest through each of the
|
|
// proxies, in the order specified by the list.
|
|
//
|
|
// * Deciding whether this attempt was successful, whether it was a failure
|
|
// but should keep trying other proxies, or whether it was a failure and
|
|
// should stop trying other proxies.
|
|
//
|
|
// * Upon successful completion of an attempt though a proxy, calling
|
|
// ProxyResolutionService::ReportSuccess to inform it of all the failed
|
|
// attempts that were made. (A proxy is only considered to be "bad"
|
|
// if the request was able to be completed through some other proxy).
|
|
//
|
|
//
|
|
// Exactly how to interpret the proxy lists returned by PAC is not specified by
|
|
// a standard. The justifications for what errors are considered for fallback
|
|
// are given beside the implementation.
|
|
|
|
#include "net/base/net_export.h"
|
|
|
|
namespace net {
|
|
|
|
class ProxyServer;
|
|
|
|
// Returns true if a failed request issued through a proxy server should be
|
|
// re-tried using the next proxy in the fallback list.
|
|
//
|
|
// The proxy fallback logic is a compromise between compatibility and
|
|
// increasing odds of success, and may choose not to retry a request on the
|
|
// next proxy option, even though that could work.
|
|
//
|
|
// - |proxy| is the proxy server that failed the request.
|
|
// - |error| is the error for the request when it was sent through |proxy|.
|
|
// - |final_error| is an out parameter that is set with the "final" error to
|
|
// report to the caller. The error is only re-written in cases where
|
|
// CanFalloverToNextProxy() returns false.
|
|
NET_EXPORT bool CanFalloverToNextProxy(const ProxyServer& proxy,
|
|
int error,
|
|
int* final_error);
|
|
|
|
} // namespace net
|
|
|
|
#endif // NET_HTTP_PROXY_FALLBACK_H_
|