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CefMediaRouter ​

Header: cef_media_router.h
Interfaces: CefMediaRouter, CefMediaObserver, CefMediaRoute, CefMediaRouteCreateCallback, CefMediaSink, CefMediaSinkDeviceInfoCallback, CefMediaSource
Category: System Utilities

Overview ​

Tasks, threads, parsers, streams, cookies, URL requests, scheme registration, and constant tables.

CefMediaRouter ​

Source File: include/cef_media_router.h

Process / Thread Context: Browser Process / any browser-process thread (unless otherwise indicated). Callbacks fire on the UI thread.

Purpose: Library-provided interface to Chromium's Media Router (Cast and DIAL). Supports discovery of media sinks, creating routes between sources and sinks, registering observers, and retrieving CefMediaSource objects from URNs.

Methods ​

static CefRefPtr<CefMediaRouter> GetGlobalMediaRouter(CefRefPtr<CefCompletionCallback> callback) ​

Parameters:

  • callback — optional completion callback executed asynchronously on the UI thread after the manager's storage has been initialized.

Return Value: The MediaRouter associated with the global request context. Equivalent to CefRequestContext::GetGlobalContext()->GetMediaRouter().

Usage Instruction: If you need to perform immediate operations after init, pass a CefCompletionCallback.

Threading Constraint: Safe to call on any browser-process thread.

virtual CefRefPtr<CefRegistration> AddObserver(CefRefPtr<CefMediaObserver> observer) ​

Parameters:

  • observer — client-implemented observer.

Return Value: CefRegistration handle; the observer remains registered until this handle is destroyed.

Usage Instruction: Hold the returned registration in a long-lived member; release it to unregister.

Threading Constraint: Browser process.

virtual CefRefPtr<CefMediaSource> GetSource(const CefString& urn) ​

Parameters:

  • urn — media source URN. Supported schemes: cast: and dial: (e.g. "cast:<appId>?clientId=<clientId>").

Return Value: A CefMediaSource object for the URN, or possibly empty/invalid for unsupported URNs.

Usage Instruction: Pair with CefMediaSink::IsCompatibleWith before calling CreateRoute.

Threading Constraint: Browser process.

virtual void NotifyCurrentSinks() ​

Parameters:

  • None.

Return Value: None.

Usage Instruction: Triggers an asynchronous CefMediaObserver::OnSinks on all registered observers with the current sink list. Useful to refresh UI without waiting for a change event.

Threading Constraint: Browser process.

virtual void CreateRoute(CefRefPtr<CefMediaSource> source, CefRefPtr<CefMediaSink> sink, CefRefPtr<CefMediaRouteCreateCallback> callback) ​

Parameters:

  • source, sink — must be valid, compatible (per CefMediaSink::IsCompatibleWith), and must not already have a route. callback — invoked on success or failure.

Return Value: None (result via callback).

Usage Instruction: On success, observers also receive an asynchronous OnRoutes notification.

Threading Constraint: Browser process; callback invoked on UI thread.

virtual void NotifyCurrentRoutes() ​

Parameters:

  • None.

Return Value: None.

Usage Instruction: Triggers an asynchronous CefMediaObserver::OnRoutes on all registered observers with the current route list.

Threading Constraint: Browser process.

CefMediaObserver ​

Source File: include/cef_media_router.h

Process / Thread Context: Browser Process / UI Thread (all callbacks).

Purpose: Client-implemented observer of Media Router events (sink list changes, route list changes, route state changes, route messages). Registered via CefMediaRouter::AddObserver.

Methods ​

void OnSinks(const std::vector<CefRefPtr<CefMediaSink>>& sinks) ​

Parameters:

  • sinks — current list of available media sinks.

Return Value: None.

Usage Instruction: Triggered when the sink list changes or when CefMediaRouter::NotifyCurrentSinks is called.

Threading Constraint: UI thread.

void OnRoutes(const std::vector<CefRefPtr<CefMediaRoute>>& routes) ​

Parameters:

  • routes — current list of active routes.

Return Value: None.

Usage Instruction: Triggered when the route list changes or when CefMediaRouter::NotifyCurrentRoutes is called.

Threading Constraint: UI thread.

void OnRouteStateChanged(CefRefPtr<CefMediaRoute> route, ConnectionState state) ​

Parameters:

  • route — affected route; state — new connection state.

Return Value: None.

Usage Instruction: Use to update UI reflecting route connectivity.

Threading Constraint: UI thread.

void OnRouteMessageReceived(CefRefPtr<CefMediaRoute> route, const void* message, size_t message_size) ​

Parameters:

  • route — route that received the message. message — raw message buffer; only valid for the scope of this callback — copy if needed beyond it. message_size — size in bytes.

Return Value: None.

Usage Instruction: Copy the bytes you need before returning.

Threading Constraint: UI thread.

CefMediaRoute ​

Source File: include/cef_media_router.h

Process / Thread Context: Any browser-process thread.

Purpose: Represents a route between a CefMediaSource and CefMediaSink. Created via CefMediaRouter::CreateRoute and retrieved via CefMediaObserver::OnRoutes.

Methods ​

virtual CefString GetId() ​

Return Value: Route ID.

Threading Constraint: Threading constraint not specified in source.

virtual CefRefPtr<CefMediaSource> GetSource() ​

Return Value: Source associated with this route.

Threading Constraint: Threading constraint not specified in source.

virtual CefRefPtr<CefMediaSink> GetSink() ​

Return Value: Sink associated with this route.

Threading Constraint: Threading constraint not specified in source.

virtual void SendRouteMessage(const void* message, size_t message_size) ​

Parameters:

  • Raw message buffer + size; copied if necessary.

Usage Instruction: Application-protocol-specific payload.

Threading Constraint: Threading constraint not specified in source.

virtual void Terminate() ​

Usage Instruction: Ends the route; triggers an asynchronous CefMediaObserver::OnRoutes on all registered observers.

Threading Constraint: Threading constraint not specified in source.

CefMediaRouteCreateCallback ​

Source File: include/cef_media_router.h

Process / Thread Context: Browser Process / UI Thread (callback).

Purpose: Client-implemented callback passed to CefMediaRouter::CreateRoute; invoked when route creation finishes.

Methods ​

void OnMediaRouteCreateFinished(RouteCreateResult result, const CefString& error, CefRefPtr<CefMediaRoute> route) ​

Parameters:

  • result — CEF_MRCR_OK on success. error — human-readable error description (empty on success). route — the resulting route, or empty on failure.

Return Value: None.

Usage Instruction: Check result; on success, store the route reference to send messages / terminate later.

Threading Constraint: UI thread.

CefMediaSink ​

Source File: include/cef_media_router.h

Process / Thread Context: Any browser-process thread.

Purpose: Represents a sink (renderer/device) to which media can be routed. Retrieved via CefMediaObserver::OnSinks.

Methods ​

virtual CefString GetId() ​

Return Value: Sink ID.

Threading Constraint: Threading constraint not specified in source.

virtual CefString GetName() ​

Return Value: Human-readable sink name.

Threading Constraint: Threading constraint not specified in source.

virtual IconType GetIconType() ​

Return Value: Icon type (default CEF_MSIT_GENERIC).

Threading Constraint: Threading constraint not specified in source.

virtual void GetDeviceInfo(CefRefPtr<CefMediaSinkDeviceInfoCallback> callback) ​

Parameters:

  • callback — invoked asynchronously with CefMediaSinkDeviceInfo.

Usage Instruction: Use to fetch extended device capabilities (e.g., Cast capabilities, DIAL app info).

Threading Constraint: Threading constraint not specified in source.

virtual bool IsCastSink() ​

Return Value: true if this sink accepts content via Cast.

Threading Constraint: Threading constraint not specified in source.

virtual bool IsDialSink() ​

Return Value: true if this sink accepts content via DIAL.

Threading Constraint: Threading constraint not specified in source.

virtual bool IsCompatibleWith(CefRefPtr<CefMediaSource> source) ​

Return Value: true if this sink is compatible with source; check before CreateRoute.

Threading Constraint: Threading constraint not specified in source.

CefMediaSinkDeviceInfoCallback ​

Source File: include/cef_media_router.h

Process / Thread Context: Browser Process / UI Thread (callback).

Purpose: Client-implemented callback for CefMediaSink::GetDeviceInfo.

Methods ​

void OnMediaSinkDeviceInfo(const CefMediaSinkDeviceInfo& device_info) ​

Parameters:

  • device_info — populated structure (defined in cef_types.h).

Usage Instruction: Copy the contents out before returning if you need to persist them.

Threading Constraint: Threading constraint not specified in source.

CefMediaSource ​

Source File: include/cef_media_router.h

Process / Thread Context: Any browser-process thread.

Purpose: Represents a source from which media can be routed. Retrieved via CefMediaRouter::GetSource.

Methods ​

virtual CefString GetId() ​

Return Value: ID (media source URN or URL).

Threading Constraint: Threading constraint not specified in source.

virtual bool IsCastSource() ​

Return Value: true if this source outputs via Cast.

Threading Constraint: Threading constraint not specified in source.

virtual bool IsDialSource() ​

Return Value: true if this source outputs via DIAL.

Threading Constraint: Threading constraint not specified in source.

Usage Example ​

cpp
class MyCastUI : public CefMediaObserver {
  CefRefPtr<CefRegistration> obs_reg_;
  CefRefPtr<CefMediaRouter> router_;
  CefRefPtr<CefMediaRoute> current_route_;

 public:
  void Start() {
    router_ = CefMediaRouter::GetGlobalMediaRouter(
        CefCompletionCallback::Create([]() { /* storage initialized */ }));
    obs_reg_ = router_->AddObserver(this);
    router_->NotifyCurrentSinks();  // refresh the sink list now
  }

  // CefMediaObserver:
  void OnSinks(const std::vector<CefRefPtr<CefMediaSink>>& sinks) override {
    for (auto& sink : sinks) {
      DLOG(INFO) << "Sink: " << sink->GetName().ToString()
                 << " cast=" << sink->IsCastSink()
                 << " dial=" << sink->IsDialSink();
    }
  }
  void OnRoutes(const std::vector<CefRefPtr<CefMediaRoute>>& routes) override {
    DLOG(INFO) << "Active routes: " << routes.size();
  }
  void OnRouteStateChanged(CefRefPtr<CefMediaRoute> route,
                           ConnectionState state) override {}
  void OnRouteMessageReceived(CefRefPtr<CefMediaRoute> route,
                              const void* msg, size_t n) override {
    std::string s(static_cast<const char*>(msg), n);
    DLOG(INFO) << "Msg from " << route->GetId().ToString() << ": " << s;
  }

  void CastTo(const CefString& urn, CefRefPtr<CefMediaSink> sink) {
    CefRefPtr<CefMediaSource> source = router_->GetSource(urn);
    if (source && sink->IsCompatibleWith(source)) {
      router_->CreateRoute(source, sink,
                           CefMediaRouteCreateCallback::Create(
                               [](RouteCreateResult r, const CefString& e,
                                  CefRefPtr<CefMediaRoute> route) {
                                 if (r == CEF_MRCR_OK) {
                                   // store route, send messages, terminate later
                                 }
                               }));
    }
  }
};

Derived from the CEF C++ headers — © Marshall A. Greenblatt, Google Inc. & contributors (BSD-style license). Not an official CEF project.

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