feat: add database support

example/basic/database.rules.json

@@ -0,0 +1,6 @@
+{
+  "rules": {
+    ".read": true,
+    ".write": true
+  }
+}

example/basic/firebase.json

@@ -16,8 +16,14 @@
     "firestore": {
       "port": 8080
     },
+    "database": {
+      "port": 9000
+    },
     "ui": {
       "enabled": false
     }
+  },
+  "database": {
+    "rules": "database.rules.json"
   }
 }

example/basic/lib/main.dart

@@ -137,6 +137,75 @@ void main(List<String> args) {
       },
     );
 
+    // ==========================================================================
+    // Realtime Database trigger examples
+    // ==========================================================================
+
+    // Database onValueCreated - triggers when data is created
+    firebase.database.onValueCreated(
+      ref: 'messages/{messageId}',
+      (event) async {
+        final data = event.data?.val();
+        print('Database value created: messages/${event.params['messageId']}');
+        print('  Data: $data');
+        print('  Instance: ${event.instance}');
+        print('  Ref: ${event.ref}');
+      },
+    );
+
+    // Database onValueUpdated - triggers when data is updated
+    firebase.database.onValueUpdated(
+      ref: 'messages/{messageId}',
+      (event) async {
+        final before = event.data?.before?.val();
+        final after = event.data?.after?.val();
+        print('Database value updated: messages/${event.params['messageId']}');
+        print('  Before: $before');
+        print('  After: $after');
+      },
+    );
+
+    // Database onValueDeleted - triggers when data is deleted
+    firebase.database.onValueDeleted(
+      ref: 'messages/{messageId}',
+      (event) async {
+        final data = event.data?.val();
+        print('Database value deleted: messages/${event.params['messageId']}');
+        print('  Final data: $data');
+      },
+    );
+
+    // Database onValueWritten - triggers on any write (create, update, delete)
+    firebase.database.onValueWritten(
+      ref: 'messages/{messageId}',
+      (event) async {
+        final before = event.data?.before;
+        final after = event.data?.after;
+        print('Database value written: messages/${event.params['messageId']}');
+        if (before == null || !before.exists()) {
+          print('  Operation: CREATE');
+          print('  New data: ${after?.val()}');
+        } else if (after == null || !after.exists()) {
+          print('  Operation: DELETE');
+          print('  Deleted data: ${before.val()}');
+        } else {
+          print('  Operation: UPDATE');
+          print('  Before: ${before.val()}');
+          print('  After: ${after.val()}');
+        }
+      },
+    );
+
+    // Nested path database trigger
+    firebase.database.onValueWritten(
+      ref: 'users/{userId}/status',
+      (event) async {
+        final after = event.data?.after?.val();
+        print('User status changed: ${event.params['userId']}');
+        print('  New status: $after');
+      },
+    );
+
     print('Functions registered successfully!');
   });
 }

example/nodejs_reference/index.js

@@ -6,6 +6,8 @@
 
 const { onRequest } = require("firebase-functions/v2/https");
 const { onMessagePublished } = require("firebase-functions/v2/pubsub");
+const { onDocumentCreated, onDocumentUpdated, onDocumentDeleted, onDocumentWritten } = require("firebase-functions/v2/firestore");
+const { onValueCreated, onValueUpdated, onValueDeleted, onValueWritten } = require("firebase-functions/v2/database");
 const { defineString, defineInt, defineBoolean } = require("firebase-functions/params");
 
 // =============================================================================
@@ -69,3 +71,127 @@ exports.onMessagePublished_mytopic = onMessagePublished(
     console.log("  Attributes:", message.attributes);
   }
 );
+
+// =============================================================================
+// Firestore trigger examples
+// =============================================================================
+
+exports.onDocumentCreated_users_userId = onDocumentCreated(
+  "users/{userId}",
+  (event) => {
+    const data = event.data?.data();
+    console.log("Document created: users/" + event.params.userId);
+    console.log("  Name:", data?.name);
+    console.log("  Email:", data?.email);
+  }
+);
+
+exports.onDocumentUpdated_users_userId = onDocumentUpdated(
+  "users/{userId}",
+  (event) => {
+    const before = event.data?.before?.data();
+    const after = event.data?.after?.data();
+    console.log("Document updated: users/" + event.params.userId);
+    console.log("  Before:", before);
+    console.log("  After:", after);
+  }
+);
+
+exports.onDocumentDeleted_users_userId = onDocumentDeleted(
+  "users/{userId}",
+  (event) => {
+    const data = event.data?.data();
+    console.log("Document deleted: users/" + event.params.userId);
+    console.log("  Final data:", data);
+  }
+);
+
+exports.onDocumentWritten_users_userId = onDocumentWritten(
+  "users/{userId}",
+  (event) => {
+    const before = event.data?.before?.data();
+    const after = event.data?.after?.data();
+    console.log("Document written: users/" + event.params.userId);
+    if (!before && after) {
+      console.log("  Operation: CREATE");
+    } else if (before && after) {
+      console.log("  Operation: UPDATE");
+    } else if (before && !after) {
+      console.log("  Operation: DELETE");
+    }
+  }
+);
+
+exports.onDocumentCreated_posts_postId_comments_commentId = onDocumentCreated(
+  "posts/{postId}/comments/{commentId}",
+  (event) => {
+    const data = event.data?.data();
+    console.log("Comment created: posts/" + event.params.postId + "/comments/" + event.params.commentId);
+    console.log("  Text:", data?.text);
+    console.log("  Author:", data?.author);
+  }
+);
+
+// =============================================================================
+// Realtime Database trigger examples
+// =============================================================================
+
+exports.onValueCreated_messages_messageId = onValueCreated(
+  "/messages/{messageId}",
+  (event) => {
+    const data = event.data?.val();
+    console.log("Database value created: messages/" + event.params.messageId);
+    console.log("  Data:", data);
+    console.log("  Instance:", event.instance);
+    console.log("  Ref:", event.ref);
+  }
+);
+
+exports.onValueUpdated_messages_messageId = onValueUpdated(
+  "/messages/{messageId}",
+  (event) => {
+    const before = event.data?.before?.val();
+    const after = event.data?.after?.val();
+    console.log("Database value updated: messages/" + event.params.messageId);
+    console.log("  Before:", before);
+    console.log("  After:", after);
+  }
+);
+
+exports.onValueDeleted_messages_messageId = onValueDeleted(
+  "/messages/{messageId}",
+  (event) => {
+    const data = event.data?.val();
+    console.log("Database value deleted: messages/" + event.params.messageId);
+    console.log("  Final data:", data);
+  }
+);
+
+exports.onValueWritten_messages_messageId = onValueWritten(
+  "/messages/{messageId}",
+  (event) => {
+    const before = event.data?.before;
+    const after = event.data?.after;
+    console.log("Database value written: messages/" + event.params.messageId);
+    if (!before?.exists() && after?.exists()) {
+      console.log("  Operation: CREATE");
+      console.log("  New data:", after.val());
+    } else if (before?.exists() && !after?.exists()) {
+      console.log("  Operation: DELETE");
+      console.log("  Deleted data:", before.val());
+    } else {
+      console.log("  Operation: UPDATE");
+      console.log("  Before:", before?.val());
+      console.log("  After:", after?.val());
+    }
+  }
+);
+
+exports.onValueWritten_users_userId_status = onValueWritten(
+  "/users/{userId}/status",
+  (event) => {
+    const after = event.data?.after?.val();
+    console.log("User status changed:", event.params.userId);
+    console.log("  New status:", after);
+  }
+);

lib/builder.dart

@@ -26,6 +26,8 @@ class _TypeCheckers {
   static final pubsubNamespace = TypeChecker.fromRuntime(ff.PubSubNamespace);
   static final firestoreNamespace =
       TypeChecker.fromRuntime(ff.FirestoreNamespace);
+  static final databaseNamespace =
+      TypeChecker.fromRuntime(ff.DatabaseNamespace);
 }
 
 /// The main builder that generates functions.yaml.
@@ -132,6 +134,16 @@ class _FirebaseFunctionsVisitor extends RecursiveAstVisitor<void> {
       }
     }
 
+    // Check for Database function declarations
+    if (target != null && _isDatabaseNamespace(target)) {
+      if (methodName == 'onValueCreated' ||
+          methodName == 'onValueUpdated' ||
+          methodName == 'onValueDeleted' ||
+          methodName == 'onValueWritten') {
+        _extractDatabaseFunction(node, methodName);
+      }
+    }
+
     // Check for parameter definitions (top-level function calls with no target)
     if (target == null && _isParamDefinition(methodName)) {
       _extractParameterFromMethod(node, methodName);
@@ -236,6 +248,13 @@ class _FirebaseFunctionsVisitor extends RecursiveAstVisitor<void> {
     return _TypeCheckers.firestoreNamespace.isExactlyType(staticType);
   }
 
+  /// Checks if the target is firebase.database.
+  bool _isDatabaseNamespace(Expression target) {
+    final staticType = target.staticType;
+    if (staticType == null) return false;
+    return _TypeCheckers.databaseNamespace.isExactlyType(staticType);
+  }
+
   /// Checks if this is a parameter definition function.
   bool _isParamDefinition(String name) =>
       name == 'defineString' ||
@@ -336,6 +355,44 @@ class _FirebaseFunctionsVisitor extends RecursiveAstVisitor<void> {
     );
   }
 
+  /// Extracts a Database function declaration.
+  void _extractDatabaseFunction(MethodInvocation node, String methodName) {
+    // Extract ref path from named argument
+    final refArg = _findNamedArg(node, 'ref');
+    if (refArg == null) return;
+
+    final refPath = _extractStringLiteral(refArg);
+    if (refPath == null) return;
+
+    // Extract options if present (for instance)
+    final optionsArg = _findNamedArg(node, 'options');
+    String? instance;
+
+    if (optionsArg is InstanceCreationExpression) {
+      instance = _extractStringField(optionsArg, 'instance');
+    }
+
+    // Generate function name from ref path and event type
+    // Similar to how we do it in database_namespace.dart
+    final sanitizedPath = refPath
+        .replaceAll(RegExp(r'^/+|/+$'), '') // Remove leading/trailing slashes
+        .replaceAll('/', '_')
+        .replaceAll('{', '')
+        .replaceAll('}', '')
+        .replaceAll('-', '');
+    final functionName = '${methodName}_$sanitizedPath';
+
+    endpoints[functionName] = _EndpointSpec(
+      name: functionName,
+      type: 'database',
+      databaseEventType: methodName,
+      refPath: refPath,
+      instance: instance ?? '*',
+      options: optionsArg is InstanceCreationExpression ? optionsArg : null,
+      variableToParamName: _variableToParamName,
+    );
+  }
+
   /// Extracts a parameter definition from FunctionExpressionInvocation.
   void _extractParameter(
     FunctionExpressionInvocation node,
@@ -538,16 +595,22 @@ class _EndpointSpec {
     this.documentPath,
     this.database,
     this.namespace,
+    this.databaseEventType,
+    this.refPath,
+    this.instance,
     this.options,
     this.variableToParamName = const {},
   });
   final String name;
-  final String type; // 'https', 'callable', 'pubsub', 'firestore'
+  final String type; // 'https', 'callable', 'pubsub', 'firestore', 'database'
   final String? topic; // For Pub/Sub functions
   final String? firestoreEventType; // For Firestore: onDocumentCreated, etc.
   final String? documentPath; // For Firestore: users/{userId}
   final String? database; // For Firestore: (default) or database name
   final String? namespace; // For Firestore: (default) or namespace
+  final String? databaseEventType; // For Database: onValueCreated, etc.
+  final String? refPath; // For Database: /users/{userId}
+  final String? instance; // For Database: database instance or '*'
   final InstanceCreationExpression? options;
   final Map<String, String> variableToParamName;
 
@@ -1261,6 +1324,27 @@ String _generateYaml(
           buffer.writeln('        document: "${endpoint.documentPath}"');
         }
 
+        buffer.writeln('      retry: false');
+      } else if (endpoint.type == 'database' &&
+          endpoint.databaseEventType != null &&
+          endpoint.refPath != null) {
+        // Map Dart method name to Database CloudEvent type
+        final eventType = _mapDatabaseEventType(endpoint.databaseEventType!);
+
+        buffer.writeln('    eventTrigger:');
+        buffer.writeln('      eventType: "$eventType"');
+        // Database triggers use empty eventFilters
+        buffer.writeln('      eventFilters: {}');
+
+        // Both ref and instance go in eventFilterPathPatterns
+        // The ref path should not have a leading slash to match Node.js format
+        final normalizedRef = endpoint.refPath!.startsWith('/')
+            ? endpoint.refPath!.substring(1)
+            : endpoint.refPath!;
+        buffer.writeln('      eventFilterPathPatterns:');
+        buffer.writeln('        ref: "$normalizedRef"');
+        buffer.writeln('        instance: "${endpoint.instance ?? '*'}"');
+
         buffer.writeln('      retry: false');
       }
     }
@@ -1278,6 +1362,15 @@ String _mapFirestoreEventType(String methodName) => switch (methodName) {
       _ => throw ArgumentError('Unknown Firestore event type: $methodName'),
     };
 
+/// Maps Database method name to CloudEvent event type.
+String _mapDatabaseEventType(String methodName) => switch (methodName) {
+      'onValueCreated' => 'google.firebase.database.ref.v1.created',
+      'onValueUpdated' => 'google.firebase.database.ref.v1.updated',
+      'onValueDeleted' => 'google.firebase.database.ref.v1.deleted',
+      'onValueWritten' => 'google.firebase.database.ref.v1.written',
+      _ => throw ArgumentError('Unknown Database event type: $methodName'),
+    };
+
 /// Converts a value to YAML format.
 String _yamlValue(dynamic value) {
   if (value is String) {

lib/firebase_functions.dart

@@ -67,6 +67,8 @@ export 'src/common/expression.dart';
 export 'src/common/on_init.dart' show onInit;
 export 'src/common/options.dart';
 export 'src/common/params.dart';
+// Database triggers
+export 'src/database/database.dart';
 // Core firebase instance
 export 'src/firebase.dart' show Firebase;
 // Firestore triggers