LibWeb/EME: Implement navigator.requestMediaKeySystemAccess

Author: https://github.com/stelar7
Commit: f9a13ecb13
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/5665
Reviewed-by: https://github.com/gmta ✅
Reviewed-by: https://github.com/trflynn89

Libraries/LibWeb/CMakeLists.txt

@@ -331,6 +331,7 @@ set(SOURCES
     Encoding/TextEncoderStream.cpp
     EncryptedMediaExtensions/Algorithms.cpp
     EncryptedMediaExtensions/MediaKeySystemAccess.cpp
+    EncryptedMediaExtensions/NavigatorEncryptedMediaExtensionsPartial.cpp
     EntriesAPI/FileSystemEntry.cpp
     EventTiming/PerformanceEventTiming.cpp
     Fetch/Body.cpp

Libraries/LibWeb/EncryptedMediaExtensions/MediaKeySystemAccess.idl

@@ -35,3 +35,12 @@ enum MediaKeySessionType {
     "temporary",
     "persistent-license"
 };
+
+// https://w3c.github.io/encrypted-media/#navigator-extension-requestmediakeysystemaccess
+[Exposed=Window]
+partial interface Navigator {
+    [SecureContext] Promise<MediaKeySystemAccess> requestMediaKeySystemAccess(
+        Utf16DOMString keySystem, 
+        sequence<MediaKeySystemConfiguration> supportedConfigurations
+    );
+};

Libraries/LibWeb/EncryptedMediaExtensions/NavigatorEncryptedMediaExtensionsPartial.cpp

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2025, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/EncryptedMediaExtensions/Algorithms.h>
+#include <LibWeb/EncryptedMediaExtensions/MediaKeySystemAccess.h>
+#include <LibWeb/EncryptedMediaExtensions/NavigatorEncryptedMediaExtensionsPartial.h>
+#include <LibWeb/HTML/Navigator.h>
+#include <LibWeb/HTML/Scripting/TemporaryExecutionContext.h>
+#include <LibWeb/HTML/Window.h>
+#include <LibWeb/Platform/EventLoopPlugin.h>
+
+namespace Web::EncryptedMediaExtensions {
+
+// https://w3c.github.io/encrypted-media/#dom-navigator-requestmediakeysystemaccess
+WebIDL::ExceptionOr<GC::Ref<WebIDL::Promise>> NavigatorEncryptedMediaExtensionsPartial::request_media_key_system_access(Utf16String key_system, Vector<Bindings::MediaKeySystemConfiguration> supported_configurations)
+{
+    auto& navigator = as<HTML::Navigator>(*this);
+    auto& realm = navigator.realm();
+
+    // 1. If this's relevant global object's associated Document is not allowed to use the encrypted-media feature, then throw a "SecurityError" DOMException and abort these steps.
+    auto& associated_document = as<HTML::Window>(HTML::relevant_global_object(navigator)).associated_document();
+    if (!associated_document.is_allowed_to_use_feature(DOM::PolicyControlledFeature::EncryptedMedia))
+        return WebIDL::SecurityError::create(realm, "This document is not allowed to use the encrypted-media feature"_utf16);
+
+    // 2. If keySystem is the empty string, return a promise rejected with a newly created TypeError.
+    if (key_system.is_empty())
+        return WebIDL::create_rejected_promise(realm, JS::TypeError::create(realm, "keySystem must not be empty"_utf16));
+
+    // 3. If supportedConfigurations is empty, return a promise rejected with a newly created TypeError.
+    if (supported_configurations.is_empty())
+        return WebIDL::create_rejected_promise(realm, JS::TypeError::create(realm, "supportedConfigurations must not be empty"_utf16));
+
+    // 4. Let document be the calling context's Document.
+    // FIXME: Is this the same as the associated document?
+    auto& document = associated_document;
+
+    // 5. Let origin be the origin of document.
+    auto origin = document.origin();
+
+    // 6. Let promise be a new promise.
+    auto promise = WebIDL::create_promise(realm);
+
+    // 7. Run the following steps in parallel:
+    Platform::EventLoopPlugin::the().deferred_invoke(GC::create_function(realm.heap(), [&realm, key_system, supported_configurations, origin, promise]() {
+        HTML::TemporaryExecutionContext context(realm, HTML::TemporaryExecutionContext::CallbacksEnabled::Yes);
+
+        // 1. If keySystem is not one of the Key Systems supported by the user agent, reject promise with a NotSupportedError. String comparison is case-sensitive.
+        if (!is_supported_key_system(key_system))
+            return WebIDL::reject_promise(realm, promise, WebIDL::NotSupportedError::create(realm, "Unsupported key system"_utf16));
+
+        // 2. Let implementation be the implementation of keySystem.
+        auto implementation = key_system_from_string(key_system);
+
+        // 3. For each value in supportedConfigurations:
+        for (auto const& candidate_configuration : supported_configurations) {
+            // 1. Let candidate configuration be the value.
+
+            // 2. Let supported configuration be the result of executing the Get Supported Configuration algorithm on implementation, candidate configuration, and origin.
+            auto supported_configuration = get_supported_configuration(*implementation, candidate_configuration, origin);
+
+            // 3. If supported configuration is not NotSupported, run the following steps:
+            if (supported_configuration.has_value()) {
+                // 1. Let access be a new MediaKeySystemAccess object, and initialize it as follows:
+                // 1. Set the keySystem attribute to keySystem.
+                // 2. Let the configuration value be supported configuration.
+                // 3. Let the cdm implementation value be implementation.
+                auto access = MediaKeySystemAccess::create(realm, key_system, *supported_configuration->configuration, move(implementation));
+
+                // 2. Resolve promise with access and abort the parallel steps of this algorithm.
+                return WebIDL::resolve_promise(realm, promise, access);
+            }
+        }
+
+        // 4. Reject promise with a NotSupportedError.
+        WebIDL::reject_promise(realm, promise, WebIDL::NotSupportedError::create(realm, "No supported configurations found for the requested key system"_utf16));
+    }));
+
+    // 8. Return promise.
+    return promise;
+}
+
+}

Libraries/LibWeb/EncryptedMediaExtensions/NavigatorEncryptedMediaExtensionsPartial.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2025, stelar7 <dudedbz@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibGC/Ptr.h>
+#include <LibWeb/EncryptedMediaExtensions/EncryptedMediaExtensions.h>
+#include <LibWeb/WebIDL/ExceptionOr.h>
+#include <LibWeb/WebIDL/Promise.h>
+
+namespace Web::EncryptedMediaExtensions {
+
+class NavigatorEncryptedMediaExtensionsPartial {
+public:
+    WebIDL::ExceptionOr<GC::Ref<WebIDL::Promise>> request_media_key_system_access(Utf16String, Vector<Bindings::MediaKeySystemConfiguration>);
+
+private:
+    virtual ~NavigatorEncryptedMediaExtensionsPartial() = default;
+
+    friend class HTML::Navigator;
+};
+
+}

Libraries/LibWeb/HTML/Navigator.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <LibWeb/Bindings/PlatformObject.h>
+#include <LibWeb/EncryptedMediaExtensions/NavigatorEncryptedMediaExtensionsPartial.h>
 #include <LibWeb/Gamepad/NavigatorGamepad.h>
 #include <LibWeb/HTML/MimeTypeArray.h>
 #include <LibWeb/HTML/NavigatorBeacon.h>
@@ -28,6 +29,7 @@ class Navigator : public Bindings::PlatformObject
     , public NavigatorConcurrentHardwareMixin
     , public NavigatorDeviceMemoryMixin
     , public Gamepad::NavigatorGamepadPartial
+    , public EncryptedMediaExtensions::NavigatorEncryptedMediaExtensionsPartial
     , public NavigatorIDMixin
     , public NavigatorLanguageMixin
     , public NavigatorOnLineMixin

Libraries/LibWeb/HTML/Navigator.idl

@@ -1,5 +1,6 @@
 #import <Clipboard/Clipboard.idl>
 #import <CredentialManagement/CredentialsContainer.idl>
+#import <EncryptedMediaExtensions/MediaKeySystemAccess.idl>
 #import <Gamepad/Gamepad.idl>
 #import <Geolocation/Geolocation.idl>
 #import <HTML/MimeTypeArray.idl>