fix: Youtube palyer issue by adding configurable native Referer header

android/capacitor/src/main/java/com/getcapacitor/CapConfig.java

@@ -35,6 +35,7 @@ public class CapConfig {
     // Server Config
     private boolean html5mode = true;
     private String serverUrl;
+    private String requestReferer;
     private String hostname = "localhost";
     private String androidScheme = CAPACITOR_HTTPS_SCHEME;
     private String[] allowNavigation;
@@ -158,6 +159,7 @@ private CapConfig(Builder builder) {
         // Server Config
         this.html5mode = builder.html5mode;
         this.serverUrl = builder.serverUrl;
+        this.requestReferer = builder.requestReferer;
         this.hostname = builder.hostname;
 
         if (this.validateScheme(builder.androidScheme)) {
@@ -247,6 +249,7 @@ private void deserializeConfig(@Nullable Context context) {
         // Server
         html5mode = JSONUtils.getBoolean(configJSON, "server.html5mode", html5mode);
         serverUrl = JSONUtils.getString(configJSON, "server.url", null);
+        requestReferer = JSONUtils.getString(configJSON, "server.referer", null);
         hostname = JSONUtils.getString(configJSON, "server.hostname", hostname);
         errorPath = JSONUtils.getString(configJSON, "server.errorPath", null);
         startPath = JSONUtils.getString(configJSON, "server.appStartPath", null);
@@ -342,6 +345,10 @@ public String getErrorPath() {
         return errorPath;
     }
 
+    public String getRequestReferer() {
+        return requestReferer;
+    }
+
     public String getHostname() {
         return hostname;
     }
@@ -563,6 +570,7 @@ public static class Builder {
         // Server Config Values
         private boolean html5mode = true;
         private String serverUrl;
+        private String requestReferer;
         private String errorPath;
         private String hostname = "localhost";
         private String androidScheme = CAPACITOR_HTTPS_SCHEME;
@@ -626,6 +634,11 @@ public Builder setServerUrl(String serverUrl) {
             return this;
         }
 
+        public Builder setRequestReferer(String requestReferer) {
+            this.requestReferer = requestReferer;
+            return this;
+        }
+
         public Builder setErrorPath(String errorPath) {
             this.errorPath = errorPath;
             return this;

android/capacitor/src/main/java/com/getcapacitor/WebViewLocalServer.java

@@ -273,14 +273,7 @@ private WebResourceResponse handleCapacitorHttpRequest(WebResourceRequest reques
             headers.put(header.getKey(), header.getValue());
         }
 
-        // a workaround for the following android web view issue:
-        // https://issues.chromium.org/issues/40450316
-        // x-cap-user-agent contains the user agent set in JavaScript
-        String userAgentValue = headers.getString("x-cap-user-agent");
-        if (userAgentValue != null) {
-            headers.put("User-Agent", userAgentValue);
-        }
-        headers.remove("x-cap-user-agent");
+        HttpRequestHandler.applyDefaultRequestHeaders(headers, bridge);
 
         HttpRequestHandler.HttpURLConnectionBuilder connectionBuilder = new HttpRequestHandler.HttpURLConnectionBuilder()
             .setUrl(url)

android/capacitor/src/main/java/com/getcapacitor/plugin/util/HttpRequestHandler.java

@@ -30,6 +30,49 @@
 
 public class HttpRequestHandler {
 
+    public static void applyDefaultRequestHeaders(JSObject headers, Bridge bridge) {
+        if (headers == null || bridge == null) {
+            return;
+        }
+
+        // a workaround for the following android web view issue:
+        // https://issues.chromium.org/issues/40450316
+        // x-cap-user-agent contains the user agent set in JavaScript
+        String userAgentValue = headers.getString("x-cap-user-agent");
+        if (userAgentValue != null) {
+            headers.put("User-Agent", userAgentValue);
+        }
+        headers.remove("x-cap-user-agent");
+
+        if (!headers.has("User-Agent") && !headers.has("user-agent")) {
+            String overriddenUserAgent = bridge.getConfig().getOverriddenUserAgentString();
+            if (overriddenUserAgent != null) {
+                headers.put("User-Agent", overriddenUserAgent);
+            }
+        }
+
+        if (!headers.has("Referer") && !headers.has("referer")) {
+            String refererValue = bridge.getConfig().getRequestReferer();
+            if (isValidHttpReferer(refererValue)) {
+                headers.put("Referer", refererValue);
+            }
+        }
+    }
+
+    public static boolean isValidHttpReferer(String refererValue) {
+        if (refererValue == null || refererValue.isBlank()) {
+            return false;
+        }
+
+        try {
+            URL refererUrl = new URL(refererValue);
+            String protocol = refererUrl.getProtocol();
+            return ("http".equalsIgnoreCase(protocol) || "https".equalsIgnoreCase(protocol)) && refererUrl.getHost() != null;
+        } catch (MalformedURLException ex) {
+            return false;
+        }
+    }
+
     /**
      * An enum specifying conventional HTTP Response Types
      * See https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/responseType
@@ -398,18 +441,7 @@ public static JSObject request(PluginCall call, String httpMethod, Bridge bridge
 
         boolean isHttpMutate = method.equals("DELETE") || method.equals("PATCH") || method.equals("POST") || method.equals("PUT");
 
-        // a workaround for the following android web view issue:
-        // https://issues.chromium.org/issues/40450316
-        // x-cap-user-agent contains the user agent set in JavaScript
-        String userAgentValue = headers.getString("x-cap-user-agent");
-        if (userAgentValue != null) {
-            headers.put("User-Agent", userAgentValue);
-        }
-        headers.remove("x-cap-user-agent");
-
-        if (!headers.has("User-Agent") && !headers.has("user-agent")) {
-            headers.put("User-Agent", bridge.getConfig().getOverriddenUserAgentString());
-        }
+        applyDefaultRequestHeaders(headers, bridge);
 
         URL url = new URL(urlString);
         HttpURLConnectionBuilder connectionBuilder = new HttpURLConnectionBuilder()

android/capacitor/src/test/java/com/getcapacitor/ConfigBuildingTest.java

@@ -54,6 +54,7 @@ public void setup() {
                 .setBackgroundColor("red")
                 .setPluginsConfiguration(pluginConfig)
                 .setServerUrl("http://www.google.com")
+                .setRequestReferer("https://example.com/app")
                 .setResolveServiceWorkerRequests(false)
                 .create();
         } catch (Exception e) {
@@ -74,6 +75,7 @@ public void getCoreConfigValues() {
         assertTrue(config.isWebContentsDebuggingEnabled());
         assertEquals("red", config.getBackgroundColor());
         assertEquals("http://www.google.com", config.getServerUrl());
+        assertEquals("https://example.com/app", config.getRequestReferer());
         assertFalse(config.isResolveServiceWorkerRequests());
     }
 

android/capacitor/src/test/java/com/getcapacitor/ConfigReadingTest.java

@@ -108,6 +108,7 @@ public void server() {
             CapConfig config = CapConfig.loadDefault(context);
             assertEquals("myhost", config.getHostname());
             assertEquals("http://192.168.100.1:2057", config.getServerUrl());
+            assertEquals("https://example.com/app", config.getRequestReferer());
             assertEquals("override", config.getAndroidScheme());
         } catch (IOException e) {
             fail();

android/capacitor/src/test/java/com/getcapacitor/plugin/util/HttpRequestHandlerTest.java

@@ -2,10 +2,14 @@
 
 import static org.junit.Assert.*;
 
+import android.app.Activity;
+import com.getcapacitor.Bridge;
+import com.getcapacitor.CapConfig;
 import com.getcapacitor.JSObject;
 import com.getcapacitor.plugin.util.HttpRequestHandler.HttpURLConnectionBuilder;
 import java.net.URL;
 import org.junit.Test;
+import org.mockito.Mockito;
 
 public class HttpRequestHandlerTest {
 
@@ -35,4 +39,44 @@ public void testHttpURLConnectionBuilderSetUrlParamsNotEncoded() throws Exceptio
             .url.toString();
         assertEquals(expectedUrl, actualUrl);
     }
+
+    @Test
+    public void testApplyDefaultRequestHeadersAddsRefererWhenMissing() {
+        Bridge bridge = Mockito.mock(Bridge.class);
+        Activity context = Mockito.mock(Activity.class);
+        CapConfig config = new CapConfig.Builder(context)
+            .setRequestReferer("https://example.com/app")
+            .setWebContentsDebuggingEnabled(false)
+            .create();
+
+        Mockito.when(bridge.getConfig()).thenReturn(config);
+
+        JSObject headers = new JSObject();
+        HttpRequestHandler.applyDefaultRequestHeaders(headers, bridge);
+
+        assertEquals("https://example.com/app", headers.getString("Referer"));
+    }
+
+    @Test
+    public void testApplyDefaultRequestHeadersDoesNotOverrideReferer() {
+        Bridge bridge = Mockito.mock(Bridge.class);
+        Activity context = Mockito.mock(Activity.class);
+        CapConfig config = new CapConfig.Builder(context)
+            .setRequestReferer("https://example.com/app")
+            .setWebContentsDebuggingEnabled(false)
+            .create();
+
+        Mockito.when(bridge.getConfig()).thenReturn(config);
+
+        JSObject headers = new JSObject();
+        headers.put("Referer", "https://request.example/app");
+        HttpRequestHandler.applyDefaultRequestHeaders(headers, bridge);
+
+        assertEquals("https://request.example/app", headers.getString("Referer"));
+    }
+
+    @Test
+    public void testIsValidHttpRefererRejectsInvalidScheme() {
+        assertFalse(HttpRequestHandler.isValidHttpReferer("capacitor://localhost"));
+    }
 }

android/capacitor/src/test/resources/configs/server.json

@@ -10,6 +10,7 @@
     "androidScheme": "override",
     "allowNavigation": ["capacitorjs.com", "ionic.io", "192.168.0.1"],
     "hostname": "myhost",
+    "referer": "https://example.com/app",
     "url": "http://192.168.100.1:2057"
   },
   "plugins": {
@@ -18,4 +19,4 @@
     }
   },
   "cordova": {}
-}
+}

cli/src/declarations.ts

@@ -617,6 +617,21 @@ export interface CapacitorConfig {
      */
     url?: string;
 
+    /**
+     * Set a default HTTP `Referer` header for Capacitor's native HTTP requests.
+     *
+     * This is only applied when a request does not already define its own
+     * `Referer` header, and the configured value must be a valid `http://` or
+     * `https://` URL.
+     *
+     * This can be useful on platforms that use a custom app scheme, where some
+     * backends require an HTTP(S) referrer instead of `capacitor://localhost`.
+     *
+     * @since 8.4.0
+     * @default undefined
+     */
+    referer?: string;
+
     /**
      * Allow cleartext traffic in the Web View.
      *

ios/Capacitor/Capacitor/CAPBridgeViewController.swift

@@ -41,6 +41,7 @@ import Cordova
         let assetHandler = WebViewAssetHandler(router: router())
         assetHandler.setAssetPath(configuration.appLocation.path)
         assetHandler.setServerUrl(configuration.serverURL)
+        assetHandler.setRequestConfiguration(configuration)
         let delegationHandler = WebViewDelegationHandler()
         prepareWebView(with: configuration, assetHandler: assetHandler, delegationHandler: delegationHandler)
         view = webView

ios/Capacitor/Capacitor/CAPInstanceConfiguration.h

@@ -14,6 +14,7 @@ NS_SWIFT_NAME(InstanceConfiguration)
 @property (nonatomic, readonly, nonnull) NSURL *localURL;
 @property (nonatomic, readonly, nonnull) NSURL *serverURL;
 @property (nonatomic, readonly, nullable) NSString *errorPath;
+@property (nonatomic, readonly, nullable) NSString *requestReferer;
 @property (nonatomic, readonly, nonnull) NSDictionary *pluginConfigurations;
 @property (nonatomic, readonly) BOOL loggingEnabled;
 @property (nonatomic, readonly) BOOL scrollingEnabled;

ios/Capacitor/Capacitor/CAPInstanceConfiguration.m

@@ -17,6 +17,7 @@ - (instancetype)initWithDescriptor:(CAPInstanceDescriptor *)descriptor isDebug:(
         _overridenUserAgentString = descriptor.overridenUserAgentString;
         _backgroundColor = descriptor.backgroundColor;
         _allowedNavigationHostnames = descriptor.allowedNavigationHostnames;
+        _requestReferer = descriptor.requestReferer;
         switch (descriptor.loggingBehavior) {
             case CAPInstanceLoggingBehaviorProduction:
                 _loggingEnabled = true;
@@ -65,6 +66,7 @@ - (instancetype)initWithConfiguration:(CAPInstanceConfiguration*)configuration a
         _localURL = [[configuration localURL] copy];
         _serverURL = [[configuration serverURL] copy];
         _errorPath = [[configuration errorPath] copy];
+        _requestReferer = [[configuration requestReferer] copy];
         _pluginConfigurations = [[configuration pluginConfigurations] copy];
         _loggingEnabled = configuration.loggingEnabled;
         _scrollingEnabled = configuration.scrollingEnabled;

ios/Capacitor/Capacitor/CAPInstanceDescriptor.h

@@ -58,6 +58,11 @@ NS_SWIFT_NAME(InstanceDescriptor)
  @discussion Defaults to nil.
  */
 @property (nonatomic, copy, nullable) NSString *errorPath;
+/**
+ @brief The default HTTP `Referer` header to use for native requests when one is not explicitly set.
+ @discussion Defaults to nil. Set by @c server.referer in the configuration file.
+ */
+@property (nonatomic, copy, nullable) NSString *requestReferer;
 /**
  @brief The hostname that will be used for the server URL.
  @discussion Defaults to @c localhost. Set by @c server.hostname in the configuration file.

ios/Capacitor/Capacitor/CAPInstanceDescriptor.swift

@@ -99,6 +99,9 @@ internal extension InstanceDescriptor {
             if let errorPathString = (config[keyPath: "server.errorPath"] as? String) {
                 errorPath = errorPathString
             }
+            if let referer = config[keyPath: "server.referer"] as? String {
+                requestReferer = referer
+            }
             if let insetBehavior = config[keyPath: "ios.contentInset"] as? String {
                 let availableInsets: [String: UIScrollView.ContentInsetAdjustmentBehavior] = ["automatic": .automatic,
                                                                                               "scrollableAxes": .scrollableAxes,

ios/Capacitor/Capacitor/Plugins/HttpRequestHandler.swift

@@ -49,6 +49,36 @@ private func lowerCaseHeaderDictionary(_ headers: [AnyHashable: Any]) -> [String
     }))
 }
 
+private func isValidHttpReferer(_ referer: String?) -> Bool {
+    guard
+        let referer,
+        let url = URL(string: referer),
+        url.host != nil,
+        let scheme = url.scheme?.lowercased(),
+        scheme == "http" || scheme == "https"
+    else {
+        return false
+    }
+
+    return true
+}
+
+func applyCapacitorDefaultRequestHeaders(_ headers: inout [String: Any], _ config: InstanceConfiguration?) {
+    if let userAgentString = config?.overridenUserAgentString, headers["User-Agent"] == nil, headers["user-agent"] == nil {
+        headers["User-Agent"] = userAgentString
+    }
+
+    if headers["Referer"] == nil, headers["referer"] == nil, let referer = config?.requestReferer, isValidHttpReferer(referer) {
+        headers["Referer"] = referer
+    }
+}
+
+func applyCapacitorDefaultRequestHeaders(_ request: inout URLRequest, _ config: InstanceConfiguration?) {
+    if request.value(forHTTPHeaderField: "Referer") == nil, let referer = config?.requestReferer, isValidHttpReferer(referer) {
+        request.setValue(referer, forHTTPHeaderField: "Referer")
+    }
+}
+
 open class HttpRequestHandler {
     open class CapacitorHttpRequestBuilder {
         public var url: URL?
@@ -194,9 +224,7 @@ open class HttpRequestHandler {
             .openConnection()
             .build()
 
-        if let userAgentString = config?.overridenUserAgentString, headers["User-Agent"] == nil, headers["user-agent"] == nil {
-            headers["User-Agent"] = userAgentString
-        }
+        applyCapacitorDefaultRequestHeaders(&headers, config)
 
         request.setRequestHeaders(headers)
 

ios/Capacitor/Capacitor/WebViewAssetHandler.swift

@@ -6,6 +6,7 @@ import UniformTypeIdentifiers
 open class WebViewAssetHandler: NSObject, WKURLSchemeHandler {
     private var router: Router
     private var serverUrl: URL?
+    private var requestConfiguration: InstanceConfiguration?
 
     public init(router: Router) {
         self.router = router
@@ -20,6 +21,10 @@ open class WebViewAssetHandler: NSObject, WKURLSchemeHandler {
         self.serverUrl = serverUrl
     }
 
+    open func setRequestConfiguration(_ config: InstanceConfiguration?) {
+        self.requestConfiguration = config
+    }
+
     private func isUsingLiveReload(_ localUrl: URL) -> Bool {
         return self.serverUrl != nil && self.serverUrl?.scheme != localUrl.scheme
     }
@@ -138,6 +143,7 @@ open class WebViewAssetHandler: NSObject, WKURLSchemeHandler {
            !targetUrl.isEmpty {
             urlRequest.url = URL(string: targetUrl)
         }
+        applyCapacitorDefaultRequestHeaders(&urlRequest, requestConfiguration)
 
         let urlSession = URLSession.shared
         let task = urlSession.dataTask(with: urlRequest) { (data, response, error) in