| // 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 { |
| |
| // Returns true if the request should be re-tried using the next proxy in the |
| // fallback list. |
| // |
| // |*error| is the network error that the request failed with. When returning |
| // false it may be replaced with a different error. |
| NET_EXPORT bool CanFalloverToNextProxy(int* error); |
| |
| } // namespace net |
| |
| #endif // NET_HTTP_PROXY_FALLBACK_H_ |
