Add read-only access to POST data for webRequest's onBeforeRequest

chrome/browser/extensions/api/web_request/web_request_api.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/api/web_request/web_request_api.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
 #include "base/string_util.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/chrome_content_browser_client.h"
 #include "chrome/browser/extensions/api/declarative_webrequest/webrequest_rule.h"
 #include "chrome/browser/extensions/api/declarative_webrequest/webrequest_rules_registry.h"
 #include "chrome/browser/extensions/api/web_navigation/web_navigation_api_helpers.h"
+#include "chrome/browser/extensions/api/web_request/post_data_parser.h"
 #include "chrome/browser/extensions/api/web_request/web_request_api_constants.h"
 #include "chrome/browser/extensions/api/web_request/web_request_api_helpers.h"
 #include "chrome/browser/extensions/api/web_request/web_request_time_tracker.h"
 #include "chrome/browser/extensions/event_router.h"
 #include "chrome/browser/extensions/extension_info_map.h"
 #include "chrome/browser/extensions/extension_prefs.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_tab_id_map.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ skipping 11 matching lines @@
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/resource_request_info.h"
 #include "googleurl/src/gurl.h"
 #include "grit/generated_resources.h"
 #include "net/base/auth.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/url_request.h"
 #include "ui/base/l10n/l10n_util.h"
 
+using chrome::VersionInfo;
 using content::BrowserMessageFilter;
 using content::BrowserThread;
 using content::ResourceRequestInfo;
 using extensions::Extension;
 
 using extensions::web_navigation_api_helpers::GetFrameId;
 
 namespace helpers = extension_web_request_api_helpers;
 namespace keys = extension_web_request_api_constants;
 
 namespace {
 
 // List of all the webRequest events.
 static const char* const kWebRequestEvents[] = {
   keys::kOnBeforeRedirect,
   keys::kOnBeforeRequest,
   keys::kOnBeforeSendHeaders,
   keys::kOnCompleted,
   keys::kOnErrorOccurred,
   keys::kOnSendHeaders,
   keys::kOnAuthRequired,
   keys::kOnResponseStarted,
   keys::kOnHeadersReceived,
 };
 
 #define ARRAYEND(array) (array + arraysize(array))
 
+static bool g_channel_cached_ = false;
+static VersionInfo::Channel g_channel_ = VersionInfo::CHANNEL_UNKNOWN;
+static bool g_post_data_enabled_ = false;

[wtc, 2012/08/03 00:57:19]

Nit: these three variables (and also the existing
kWebRequestEvents constant above) are inside an anonymous
namespace, so they don't need to be declared 'static'.

Nit: these three variables are not class members, so they
should not have the trailing underscore '_'.

[vabr (Chromium), 2012/08/05 18:54:46]

Done.

+
+bool PostDataEnabledOnChannel() {

[wtc, 2012/08/03 00:57:19]

Nit: This function operates on the global variable g_channel_.
This is not obvious.  I recommend having this function
take the channel as input.

[vabr (Chromium), 2012/08/05 18:54:46]

The function was removed in the meantime.

+  return g_channel_ == VersionInfo::CHANNEL_UNKNOWN ||
+         g_channel_ == VersionInfo::CHANNEL_CANARY ||
+         g_channel_ == VersionInfo::CHANNEL_DEV;

[Matt Perry, 2012/08/02 10:11:03]

note: the channels go in increasing order of stability so that you can do things
like (channel_ <= DEV).

[vabr (Chromium), 2012/08/05 18:54:46]

Good to know! If that's the convention, then the test is much simpler to write.

+}
+
+// PostData feature (crbug.com/91191/) is currently only enabled in dev
+// and canary channels. This function caches the release channel info from
+// chrome::VersionInfo.
+bool IsWebRequestPostDataEnabled() {
+  if (!g_channel_cached_) {
+    // Find out the correct channel and flip |g_post_data_enabled_| accordingly.

[Matt Perry, 2012/08/02 10:11:03]

This comment is fairly obvious from the code. Take a look at the "Dont's"
section of
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Implementation...
.

[vabr (Chromium), 2012/08/05 18:54:46]

Comment removed.

+    g_channel_ = VersionInfo::GetChannel();
+    g_channel_cached_ = true;
+    g_post_data_enabled_  = PostDataEnabledOnChannel();

[Matt Perry, 2012/08/02 10:11:03]

no need to cache this imo

[wtc, 2012/08/03 00:57:19]

I agree that the result of PostDataEnabledOnChannel() is
not worth caching.

Is VersionInfo::GetChannel() expensive?  If not, we don't
need to cache the result of VersionInfo::GetChannel() either.

[vabr (Chromium), 2012/08/05 18:54:46]

With switching to channel <= DEV instead of the three equalities my last
argument for caching disappeared. In addition, due to absence of caching the
"enabled" flag and the simplicity of the channel <= DEV test, I could get rid of
PostDataEnabledOnChannel completely. :)

+  }
+  return g_post_data_enabled_;
+}
+
 bool IsWebRequestEvent(const std::string& event_name) {
   return std::find(kWebRequestEvents, ARRAYEND(kWebRequestEvents),
                    event_name) != ARRAYEND(kWebRequestEvents);
 }
 
 // Returns whether |request| has been triggered by an extension in
 // |extension_info_map|.
 bool IsRequestFromExtension(const net::URLRequest* request,
                             const ExtensionInfoMap* extension_info_map) {
   // |extension_info_map| is NULL for system-level requests.
@@ skipping 60 matching lines @@
                  base::Uint64ToString(request->identifier()));
   out->SetString(keys::kUrlKey, request->url().spec());
   out->SetString(keys::kMethodKey, request->method());
   out->SetInteger(keys::kFrameIdKey, frame_id_for_extension);
   out->SetInteger(keys::kParentFrameIdKey, parent_frame_id_for_extension);
   out->SetInteger(keys::kTabIdKey, tab_id);
   out->SetString(keys::kTypeKey, helpers::ResourceTypeToString(resource_type));
   out->SetDouble(keys::kTimeStampKey, base::Time::Now().ToDoubleT() * 1000);
 }
 
+// Extracts the POST data from |request| and writes the data into |out|.
+// This can be expensive, so it's separated from ExtractRequestInfo().
+void ExtractRequestInfoPost(const net::URLRequest* request,
+                            DictionaryValue* out) {
+  if (request->method() != "POST")
+    return;  // Need to exit without "out->Set(keys::kPostDataKey, ...);" .
+
+  DictionaryValue* post_data = new DictionaryValue();
+  out->Set(keys::kPostDataKey, post_data);
+
+  // Chunked encoding (defined in RFC 2616) is currently not supported.
+  std::string transfer_encoding;
+  if (request->extra_request_headers().GetHeader(
+      net::HttpRequestHeaders::kTransferEncoding, &transfer_encoding)) {
+    if (base::strcasecmp(transfer_encoding.c_str(), "chunked") == 0) {
+      post_data->SetString(keys::kPostDataErrorKey, "chunked_encoding");
+      return;
+    }
+  }
+
+  scoped_ptr<DictionaryValue> form_data =
+      extensions::PostDataParser::ParseURLRequestData(request);
+  if (form_data.get() != NULL)
+    post_data->Set(keys::kPostDataFormKey, form_data.release());
+}
+
 // Converts a HttpHeaders dictionary to a |name|, |value| pair. Returns
 // true if successful.
 bool FromHeaderDictionary(const DictionaryValue* header_value,
                           std::string* name,
                           std::string* value) {
   if (!header_value->GetString(keys::kHeaderNameKey, name))
     return false;
 
   // We require either a "value" or a "binaryValue" entry.
   if (!(header_value->HasKey(keys::kHeaderValueKey) ^
@@ skipping 74 matching lines @@
       SendExtensionWebRequestStatusToHost(host);
   }
 }
 
 void ClearCacheOnNavigationOnUI() {
   WebCacheManager::GetInstance()->ClearCacheOnNavigation();
 }
 
 }  // namespace
 
+// Sets the fake channel |c| and flips |g_post_data_enabled_| accordingly.
+void SetChannelForTestingWebRequest(VersionInfo::Channel channel) {

[wtc, 2012/08/03 00:57:19]

You name the argument |c| in the header file but name it
|channel| here.  The comment on line 305 uses the name |c|.

[vabr (Chromium), 2012/08/05 18:54:46]

Header synced with implementation. Comment removed in the meantime.

+  g_channel_ = channel;
+  g_channel_cached_ = true;
+  g_post_data_enabled_  = PostDataEnabledOnChannel();
+}
+
+void ResetChannelForTestingWebRequest() {
+  g_channel_cached_ = false;
+}
+
 // Represents a single unique listener to an event, along with whatever filter
 // parameters and extra_info_spec were specified at the time the listener was
 // added.
 struct ExtensionWebRequestEventRouter::EventListener {
   std::string extension_id;
   std::string extension_name;
   std::string sub_event_name;
   RequestFilter filter;
   int extra_info_spec;
   base::WeakPtr<IPC::Sender> ipc_sender;
@@ skipping 138 matching lines @@
       return false;
 
     if (str == "requestHeaders")
       *extra_info_spec |= REQUEST_HEADERS;
     else if (str == "responseHeaders")
       *extra_info_spec |= RESPONSE_HEADERS;
     else if (str == "blocking")
       *extra_info_spec |= BLOCKING;
     else if (str == "asyncBlocking")
       *extra_info_spec |= ASYNC_BLOCKING;
+    else if (str == "postData")
+      *extra_info_spec |= IsWebRequestPostDataEnabled() ? POST_DATA : 0;
     else
       return false;
 
     // BLOCKING and ASYNC_BLOCKING are mutually exclusive.
     if ((*extra_info_spec & BLOCKING) && (*extra_info_spec & ASYNC_BLOCKING))
       return false;
   }
   return true;
 }
 
@@ skipping 69 matching lines @@
 
   int extra_info_spec = 0;
   std::vector<const EventListener*> listeners =
       GetMatchingListeners(profile, extension_info_map, keys::kOnBeforeRequest,
                            request, &extra_info_spec);
   if (!listeners.empty() &&
       !GetAndSetSignaled(request->identifier(), kOnBeforeRequest)) {
     ListValue args;
     DictionaryValue* dict = new DictionaryValue();
     ExtractRequestInfo(request, dict);
+    if (extra_info_spec & ExtraInfoSpec::POST_DATA)
+      ExtractRequestInfoPost(request, dict);
     args.Append(dict);
 
     initialize_blocked_requests |=
         DispatchEvent(profile, request, listeners, args);
   }
 
   if (!initialize_blocked_requests)
     return net::OK;  // Nobody saw a reason for modifying the request.
 
   blocked_requests_[request->identifier()].event = kOnBeforeRequest;
@@ skipping 1309 matching lines @@
       } else if ((*it)->name().find("AdBlock") != std::string::npos) {
         adblock = true;
       } else {
         other = true;
       }
     }
   }
 
   host->Send(new ExtensionMsg_UsingWebRequestAPI(adblock, adblock_plus, other));
 }