feat(firebaseai): add proper headers for X-Android-Package, X-Android-Cert and x-ios-bundle-identifier

packages/firebase_ai/firebase_ai/android/build.gradle

@@ -0,0 +1,49 @@
+group 'io.flutter.plugins.firebase.ai'
+version '1.0-SNAPSHOT'
+
+apply plugin: 'com.android.library'
+apply from: file("local-config.gradle")
+
+// AGP 9+ has built-in Kotlin support; older versions need the plugin explicitly.
+def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0] as int
+if (agpMajor < 9) {
+  apply plugin: 'kotlin-android'
+}
+
+buildscript {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+android {
+    if (project.android.hasProperty("namespace")) {
+      namespace 'io.flutter.plugins.firebase.ai'
+    }
+
+    compileSdkVersion project.ext.compileSdk
+
+    defaultConfig {
+        minSdkVersion project.ext.minSdk
+    }
+
+    compileOptions {
+        sourceCompatibility project.ext.javaVersion
+        targetCompatibility project.ext.javaVersion
+    }
+
+    if (agpMajor < 9) {
+      kotlinOptions {
+          jvmTarget = project.ext.javaVersion
+      }
+    }
+
+    sourceSets {
+        main.java.srcDirs += "src/main/kotlin"
+    }
+
+    lintOptions {
+        disable 'InvalidPackage'
+    }
+}

packages/firebase_ai/firebase_ai/android/local-config.gradle

@@ -0,0 +1,7 @@
+ext {
+    compileSdk=34
+    minSdk=23
+    targetSdk=34
+    javaVersion = JavaVersion.toVersion(17)
+    androidGradlePluginVersion = '8.3.0'
+}

packages/firebase_ai/firebase_ai/android/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="io.flutter.plugins.firebase.ai">
+</manifest>

packages/firebase_ai/firebase_ai/android/src/main/kotlin/io/flutter/plugins/firebase/ai/FirebaseAiPlugin.kt

@@ -0,0 +1,101 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package io.flutter.plugins.firebase.ai
+
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.Build
+import android.util.Log
+import io.flutter.embedding.engine.plugins.FlutterPlugin
+import io.flutter.plugin.common.MethodCall
+import io.flutter.plugin.common.MethodChannel
+import java.security.MessageDigest
+import java.security.NoSuchAlgorithmException
+
+class FirebaseAiPlugin : FlutterPlugin, MethodChannel.MethodCallHandler {
+    private lateinit var channel: MethodChannel
+    private lateinit var context: Context
+
+    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        context = binding.applicationContext
+        channel = MethodChannel(binding.binaryMessenger, "plugins.flutter.io/firebase_ai")
+        channel.setMethodCallHandler(this)
+    }
+
+    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
+        channel.setMethodCallHandler(null)
+    }
+
+    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
+        when (call.method) {
+            "getPlatformHeaders" -> {
+                val headers = mapOf(
+                    "X-Android-Package" to context.packageName,
+                    "X-Android-Cert" to (getSigningCertFingerprint() ?: "")
+                )
+                result.success(headers)
+            }
+            else -> result.notImplemented()
+        }
+    }
+
+    @OptIn(ExperimentalStdlibApi::class)
+    private fun getSigningCertFingerprint(): String? {
+        val packageName = context.packageName
+        val signature = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+            val packageInfo = try {
+                context.packageManager.getPackageInfo(
+                    packageName,
+                    PackageManager.GET_SIGNING_CERTIFICATES
+                )
+            } catch (e: PackageManager.NameNotFoundException) {
+                Log.d(TAG, "PackageManager couldn't find the package \"$packageName\"")
+                return null
+            }
+            val signingInfo = packageInfo?.signingInfo ?: return null
+            if (signingInfo.hasMultipleSigners()) {
+                signingInfo.apkContentsSigners.firstOrNull()
+            } else {
+                signingInfo.signingCertificateHistory.lastOrNull()
+            }
+        } else {
+            @Suppress("DEPRECATION")
+            val packageInfo = try {
+                context.packageManager.getPackageInfo(
+                    packageName,
+                    PackageManager.GET_SIGNATURES
+                )
+            } catch (e: PackageManager.NameNotFoundException) {
+                Log.d(TAG, "PackageManager couldn't find the package \"$packageName\"")
+                return null
+            }
+            @Suppress("DEPRECATION")
+            packageInfo?.signatures?.firstOrNull()
+        } ?: return null
+
+        return try {
+            val messageDigest = MessageDigest.getInstance("SHA-1")
+            val digest = messageDigest.digest(signature.toByteArray())
+            digest.toHexString(HexFormat.UpperCase)
+        } catch (e: NoSuchAlgorithmException) {
+            Log.w(TAG, "No support for SHA-1 algorithm found.", e)
+            null
+        }
+    }
+
+    companion object {
+        private const val TAG = "FirebaseAiPlugin"
+    }
+}

packages/firebase_ai/firebase_ai/ios/firebase_ai.podspec

@@ -0,0 +1,28 @@
+require 'yaml'
+
+pubspec = YAML.load_file(File.join('..', 'pubspec.yaml'))
+library_version = pubspec['version'].gsub('+', '-')
+
+Pod::Spec.new do |s|
+  s.name             = pubspec['name']
+  s.version          = library_version
+  s.summary          = pubspec['description']
+  s.description      = pubspec['description']
+  s.homepage         = pubspec['homepage']
+  s.license          = { :file => '../LICENSE' }
+  s.authors          = 'The Chromium Authors'
+  s.source           = { :path => '.' }
+
+  s.source_files     = 'firebase_ai/Sources/firebase_ai/**/*.swift'
+
+  s.ios.deployment_target = '15.0'
+  s.dependency 'Flutter'
+
+  s.swift_version = '5.0'
+
+  s.static_framework = true
+  s.pod_target_xcconfig = {
+    'GCC_PREPROCESSOR_DEFINITIONS' => "LIBRARY_VERSION=\\\"#{library_version}\\\" LIBRARY_NAME=\\\"flutter-fire-ai\\\"",
+    'DEFINES_MODULE' => 'YES'
+  }
+end

packages/firebase_ai/firebase_ai/ios/firebase_ai/Sources/firebase_ai/FirebaseAiPlugin.swift

@@ -0,0 +1,49 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#if canImport(FlutterMacOS)
+  import FlutterMacOS
+#else
+  import Flutter
+#endif
+
+public class FirebaseAiPlugin: NSObject, FlutterPlugin {
+  public static func register(with registrar: FlutterPluginRegistrar) {
+    #if canImport(FlutterMacOS)
+      let messenger = registrar.messenger
+    #else
+      let messenger = registrar.messenger()
+    #endif
+
+    let channel = FlutterMethodChannel(
+      name: "plugins.flutter.io/firebase_ai",
+      binaryMessenger: messenger
+    )
+    let instance = FirebaseAiPlugin()
+    registrar.addMethodCallDelegate(instance, channel: channel)
+  }
+
+  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
+    switch call.method {
+    case "getPlatformHeaders":
+      var headers: [String: String] = [:]
+      if let bundleId = Bundle.main.bundleIdentifier {
+        headers["x-ios-bundle-identifier"] = bundleId
+      }
+      result(headers)
+    default:
+      result(FlutterMethodNotImplemented)
+    }
+  }
+}

packages/firebase_ai/firebase_ai/lib/src/base_model.dart

@@ -36,6 +36,7 @@ import 'imagen/imagen_edit.dart';
 import 'imagen/imagen_reference.dart';
 import 'live_api.dart';
 import 'live_session.dart';
+import 'platform_header_helper.dart';
 import 'tool.dart';
 
 part 'generative_model.dart';
@@ -300,6 +301,10 @@ abstract class BaseModel {
       if (app != null && app.isAutomaticDataCollectionEnabled) {
         headers['X-Firebase-AppId'] = app.options.appId;
       }
+      // Add platform-specific headers for API key restrictions.
+      // Android: X-Android-Package + X-Android-Cert
+      // iOS/macOS: x-ios-bundle-identifier
+      headers.addAll(await getPlatformSecurityHeaders());
       return headers;
     };
   }

packages/firebase_ai/firebase_ai/lib/src/platform_header_helper.dart

@@ -0,0 +1,50 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
+
+/// Method channel for the native platform helper plugin.
+@visibleForTesting
+const platformHeaderChannel = MethodChannel('plugins.flutter.io/firebase_ai');
+
+Map<String, String>? _cachedHeaders;
+
+/// Clears the cached platform headers. Only for use in tests.
+@visibleForTesting
+void clearPlatformSecurityHeadersCache() {
+  _cachedHeaders = null;
+}
+
+/// Returns platform-specific security headers for API key restrictions.
+///
+/// Each platform's native plugin returns the appropriate headers:
+/// - **Android**: `X-Android-Package` and `X-Android-Cert`
+/// - **iOS/macOS**: `x-ios-bundle-identifier`
+/// - **Web/other**: empty map (no plugin registered)
+///
+/// Results are cached since platform identity does not change at runtime.
+Future<Map<String, String>> getPlatformSecurityHeaders() async {
+  if (kIsWeb) return const {};
+  if (_cachedHeaders != null) return _cachedHeaders!;
+
+  try {
+    final result = await platformHeaderChannel
+        .invokeMapMethod<String, String>('getPlatformHeaders');
+    _cachedHeaders = result ?? const {};
+  } catch (_) {
+    _cachedHeaders = const {};
+  }
+  return _cachedHeaders!;
+}

packages/firebase_ai/firebase_ai/macos/firebase_ai.podspec

@@ -0,0 +1,28 @@
+require 'yaml'
+
+pubspec = YAML.load_file(File.join('..', 'pubspec.yaml'))
+library_version = pubspec['version'].gsub('+', '-')
+
+Pod::Spec.new do |s|
+  s.name             = pubspec['name']
+  s.version          = library_version
+  s.summary          = pubspec['description']
+  s.description      = pubspec['description']
+  s.homepage         = pubspec['homepage']
+  s.license          = { :file => '../LICENSE' }
+  s.authors          = 'The Chromium Authors'
+  s.source           = { :path => '.' }
+
+  s.source_files     = 'firebase_ai/Sources/firebase_ai/**/*.swift'
+
+  s.platform = :osx, '10.15'
+  s.swift_version = '5.0'
+
+  s.dependency 'FlutterMacOS'
+
+  s.static_framework = true
+  s.pod_target_xcconfig = {
+    'GCC_PREPROCESSOR_DEFINITIONS' => "LIBRARY_VERSION=\\\"#{library_version}\\\" LIBRARY_NAME=\\\"flutter-fire-ai\\\"",
+    'DEFINES_MODULE' => 'YES'
+  }
+end

packages/firebase_ai/firebase_ai/macos/firebase_ai/Sources/firebase_ai/FirebaseAiPlugin.swift

@@ -0,0 +1 @@
+../../../../ios/firebase_ai/Sources/firebase_ai/FirebaseAiPlugin.swift

packages/firebase_ai/firebase_ai/pubspec.yaml

@@ -37,3 +37,14 @@ dev_dependencies:
   matcher: ^0.12.16
   mockito: ^5.0.0
   plugin_platform_interface: ^2.1.3
+
+flutter:
+  plugin:
+    platforms:
+      android:
+        package: io.flutter.plugins.firebase.ai
+        pluginClass: FirebaseAiPlugin
+      ios:
+        pluginClass: FirebaseAiPlugin
+      macos:
+        pluginClass: FirebaseAiPlugin