chrome/browser/extensions/api/tab_capture/tab_capture_api.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Implements the Chrome Extensions Tab Capture API.
   6
   7 #include "chrome/browser/extensions/api/tab_capture/tab_capture_api.h"
   8
   9 #include <set>
  10 #include <string>
  11 #include <vector>
  12
  13 #include "base/command_line.h"
  14 #include "base/strings/stringprintf.h"
  15 #include "base/values.h"
  16 #include "chrome/browser/extensions/api/tab_capture/tab_capture_registry.h"
  17 #include "chrome/browser/extensions/extension_renderer_state.h"
  18 #include "chrome/browser/profiles/profile.h"
  19 #include "chrome/browser/sessions/session_tab_helper.h"
  20 #include "chrome/browser/ui/browser.h"
  21 #include "chrome/browser/ui/browser_finder.h"
  22 #include "chrome/browser/ui/tabs/tab_strip_model.h"
  23 #include "content/public/browser/render_frame_host.h"
  24 #include "content/public/browser/render_process_host.h"
  25 #include "extensions/common/features/feature.h"
  26 #include "extensions/common/features/feature_provider.h"
  27 #include "extensions/common/features/simple_feature.h"
  28 #include "extensions/common/permissions/permissions_data.h"
  29 #include "extensions/common/switches.h"
  30
  31 using extensions::api::tab_capture::MediaStreamConstraint;
  32
  33 namespace TabCapture = extensions::api::tab_capture;
  34 namespace GetCapturedTabs = TabCapture::GetCapturedTabs;
  35
  36 namespace extensions {
  37 namespace {
  38
  39 const char kCapturingSameTab[] = "Cannot capture a tab with an active stream.";
  40 const char kFindingTabError[] = "Error finding tab to capture.";
  41 const char kNoAudioOrVideo[] = "Capture failed. No audio or video requested.";
  42 const char kGrantError[] =
  43     "Extension has not been invoked for the current page (see activeTab "
  44     "permission). Chrome pages cannot be captured.";
  45
  46 // Keys/values for media stream constraints.
  47 const char kMediaStreamSource[] = "chromeMediaSource";
  48 const char kMediaStreamSourceId[] = "chromeMediaSourceId";
  49 const char kMediaStreamSourceTab[] = "tab";
  50
  51 // Tab Capture-specific video constraint to enable automatic resolution/rate
  52 // throttling mode in the capture pipeline.
  53 const char kEnableAutoThrottlingKey[] = "enableAutoThrottling";
  54
  55 }  // namespace
  56
  57 // Whitelisted extensions that do not check for a browser action grant because
  58 // they provide API's. If there are additional extension ids that need
  59 // whitelisting and are *not* the Chromecast extension, add them to a new
  60 // kWhitelist array.
  61 //
  62 // This list is also used by CastConfigDelegateChromeos to find official Cast
  63 // extensions.
  64 const char* const kChromecastExtensionIds[] = {
  65     "enhhojjnijigcajfphajepfemndkmdlo",  // Dev
  66     "pkedcjkdefgpdelpbcmbmeomcjbeemfm",  // Dogfood
  67     "fmfcbgogabcbclcofgocippekhfcmgfj",  // Staging
  68     "hfaagokkkhdbgiakmmlclaapfelnkoah",  // Canary
  69     "dliochdbjfkdbacpmhlcpmleaejidimm",  // Google Cast Beta
  70     "boadgeojelhgndaghljhdicfkmllpafd",  // Google Cast Stable
  71     "hlgmmjhlnlapooncikdpiiokdjcdpjme",  // Test cast extension
  72 };
  73
  74 bool TabCaptureCaptureFunction::RunSync() {
  75   scoped_ptr<api::tab_capture::Capture::Params> params =
  76       TabCapture::Capture::Params::Create(*args_);
  77   EXTENSION_FUNCTION_VALIDATE(params.get());
  78
  79   // Figure out the active WebContents and retrieve the needed ids.
  80   Browser* target_browser = chrome::FindAnyBrowser(
  81       GetProfile(), include_incognito(), chrome::GetActiveDesktop());
  82   if (!target_browser) {
  83     error_ = kFindingTabError;
  84     return false;
  85   }
  86
  87   content::WebContents* target_contents =
  88       target_browser->tab_strip_model()->GetActiveWebContents();
  89   if (!target_contents) {
  90     error_ = kFindingTabError;
  91     return false;
  92   }
  93
  94   const std::string& extension_id = extension()->id();
  95
  96   // Make sure either we have been granted permission to capture through an
  97   // extension icon click or our extension is whitelisted.
  98   if (!extension()->permissions_data()->HasAPIPermissionForTab(
  99           SessionTabHelper::IdForTab(target_contents),
 100           APIPermission::kTabCaptureForTab) &&
 101       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
 102           switches::kWhitelistedExtensionID) != extension_id &&
 103       !SimpleFeature::IsIdInArray(extension_id, kChromecastExtensionIds,
 104                                   arraysize(kChromecastExtensionIds))) {
 105     error_ = kGrantError;
 106     return false;
 107   }
 108
 109   // Create a constraints vector. We will modify all the constraints in this
 110   // vector to append our chrome specific constraints.
 111   std::vector<MediaStreamConstraint*> constraints;
 112   bool has_audio = params->options.audio.get() && *params->options.audio.get();
 113   bool has_video = params->options.video.get() && *params->options.video.get();
 114
 115   if (!has_audio && !has_video) {
 116     error_ = kNoAudioOrVideo;
 117     return false;
 118   }
 119
 120   if (has_audio) {
 121     if (!params->options.audio_constraints.get())
 122       params->options.audio_constraints.reset(new MediaStreamConstraint);
 123
 124     constraints.push_back(params->options.audio_constraints.get());
 125   }
 126
 127   bool enable_auto_throttling = false;
 128   if (has_video) {
 129     if (params->options.video_constraints.get()) {
 130       // Check for the Tab Capture-specific video constraint for enabling
 131       // automatic resolution/rate throttling mode in the capture pipeline.  See
 132       // implementation comments for content::WebContentsVideoCaptureDevice.
 133       base::DictionaryValue& props =
 134           params->options.video_constraints->mandatory.additional_properties;
 135       if (!props.GetBooleanWithoutPathExpansion(
 136               kEnableAutoThrottlingKey, &enable_auto_throttling)) {
 137         enable_auto_throttling = false;
 138       }
 139       // Remove the key from the properties to avoid an "unrecognized
 140       // constraint" error in the renderer.
 141       props.RemoveWithoutPathExpansion(kEnableAutoThrottlingKey, nullptr);
 142     } else {
 143       params->options.video_constraints.reset(new MediaStreamConstraint);
 144     }
 145
 146     constraints.push_back(params->options.video_constraints.get());
 147   }
 148
 149   // Device id we use for Tab Capture.
 150   content::RenderFrameHost* const main_frame = target_contents->GetMainFrame();
 151   // TODO(miu): We should instead use a "randomly generated device ID" scheme,
 152   // like that employed by the desktop capture API.  http://crbug.com/163100
 153   const std::string device_id = base::StringPrintf(
 154       "web-contents-media-stream://%i:%i%s",
 155       main_frame->GetProcess()->GetID(),
 156       main_frame->GetRoutingID(),
 157       enable_auto_throttling ? "?throttling=auto" : "");
 158
 159   // Append chrome specific tab constraints.
 160   for (std::vector<MediaStreamConstraint*>::iterator it = constraints.begin();
 161        it != constraints.end(); ++it) {
 162     base::DictionaryValue* constraint = &(*it)->mandatory.additional_properties;
 163     constraint->SetString(kMediaStreamSource, kMediaStreamSourceTab);
 164     constraint->SetString(kMediaStreamSourceId, device_id);
 165   }
 166
 167   TabCaptureRegistry* registry = TabCaptureRegistry::Get(GetProfile());
 168   if (!registry->AddRequest(target_contents, extension_id)) {
 169     error_ = kCapturingSameTab;
 170     return false;
 171   }
 172
 173   // Copy the result from our modified input parameters. This will be
 174   // intercepted by custom bindings which will build and send the special
 175   // WebRTC user media request.
 176   base::DictionaryValue* result = new base::DictionaryValue();
 177   result->MergeDictionary(params->options.ToValue().get());
 178
 179   SetResult(result);
 180   return true;
 181 }
 182
 183 bool TabCaptureGetCapturedTabsFunction::RunSync() {
 184   TabCaptureRegistry* registry = TabCaptureRegistry::Get(GetProfile());
 185   base::ListValue* const list = new base::ListValue();
 186   if (registry)
 187     registry->GetCapturedTabs(extension()->id(), list);
 188   SetResult(list);
 189   return true;
 190 }
 191
 192 }  // namespace extensions