Disable the http cache when fetching PAC scripts. Also adds an extra log stat...

net/proxy/proxy_script_fetcher.cc

 // Copyright (c) 2008 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.
 
 #include "net/proxy/proxy_script_fetcher.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/ref_counted.h"
 #include "base/string_util.h"
 #include "net/base/io_buffer.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
+#include "net/http/http_response_headers.h"
 #include "net/url_request/url_request.h"
 
 // TODO(eroman):
 //   - Support auth-prompts.
 
 namespace net {
 
 namespace {
 
 // The maximum size (in bytes) allowed for a PAC script. Responses exceeding
@@ skipping 120 matching lines @@
 
   DCHECK(callback);
   DCHECK(bytes);
 
   cur_request_.reset(new URLRequest(url, this));
   cur_request_->set_context(url_request_context_);
   cur_request_->set_method("GET");
 
   // Make sure that the PAC script is downloaded using a direct connection,
   // to avoid circular dependencies (fetching is a part of proxy resolution).
-  cur_request_->set_load_flags(LOAD_BYPASS_PROXY);
+  // Also disable the use of the disk cache. The cache is disabled so that if
+  // the user switches networks we don't potentially use the cached response
+  // from old network when we should in fact be re-fetching on the new network.
+  cur_request_->set_load_flags(LOAD_BYPASS_PROXY | LOAD_DISABLE_CACHE);
 
   // Save the caller's info for notification on completion.
   callback_ = callback;
   result_bytes_ = bytes;
   result_bytes_->clear();
 
   // Post a task to timeout this request if it takes too long.
   cur_request_id_ = ++next_id_;
   MessageLoop::current()->PostDelayedTask(FROM_HERE,
       task_factory_.NewRunnableMethod(&ProxyScriptFetcherImpl::OnTimeout,
@@ skipping 41 matching lines @@
   if (!request->status().is_success()) {
     OnResponseCompleted(request);
     return;
   }
 
   // Require HTTP responses to have a success status code.
   if (request->url().SchemeIs("http") || request->url().SchemeIs("https")) {
     // NOTE about status codes: We are like Firefox 3 in this respect.
     // {IE 7, Safari 3, Opera 9.5} do not care about the status code.
     if (request->GetResponseCode() != 200) {
+      LOG(INFO) << "Fetched PAC script had (bad) status line: "
+                << request->response_headers()->GetStatusLine();
       result_code_ = ERR_PAC_STATUS_NOT_OK;
       request->Cancel();
       return;
     }
 
     // NOTE about mime types: We do not enforce mime types on PAC files.
     // This is for compatibility with {IE 7, Firefox 3, Opera 9.5}. We will
     // however log mismatches to help with debugging.
-    if (logging::GetMinLogLevel() <= logging::LOG_INFO) {
-      std::string mime_type;
-      cur_request_->GetMimeType(&mime_type);
-      if (!IsPacMimeType(mime_type)) {
-        LOG(INFO) << "Fetched PAC script does not have a proper mime type: "
-                  << mime_type;
-      }
+    std::string mime_type;
+    cur_request_->GetMimeType(&mime_type);
+    if (!IsPacMimeType(mime_type)) {
+      LOG(INFO) << "Fetched PAC script does not have a proper mime type: "
+                << mime_type;
     }
   }
 
   ReadBody(request);
 }
 
 void ProxyScriptFetcherImpl::OnReadCompleted(URLRequest* request,
                                              int num_bytes) {
   DCHECK(request == cur_request_.get());
   if (num_bytes > 0) {
@@ skipping 79 matching lines @@
 }
 
 // static
 size_t ProxyScriptFetcher::SetSizeConstraintForUnittest(size_t size_bytes) {
   size_t prev = max_response_bytes;
   max_response_bytes = size_bytes;
   return prev;
 }
 
 }  // namespace net