Add deploy Dart on Firebase Functions codelab sample

Dart/codelab-dart-functions/.gitignore

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+# Miscellaneous
+*.class
+*.log
+*.pyc
+*.swp
+.DS_Store
+.atom/
+.build/
+.buildlog/
+.history
+.svn/
+.swiftpm/
+migrate_working_dir/
+
+# IntelliJ related
+*.iml
+*.ipr
+*.iws
+.idea/
+
+# The .vscode folder contains launch configuration and tasks you configure in
+# VS Code which you may wish to be included in version control, so this line
+# is commented out by default.
+#.vscode/
+
+# Flutter/Dart/Pub related
+**/doc/api/
+**/ios/Flutter/.last_build_id
+.dart_tool/
+.flutter-plugins-dependencies
+.pub-cache/
+.pub/
+/build/
+/coverage/
+
+# Symbolication related
+app.*.symbols
+
+# Obfuscation related
+app.*.map.json
+
+# Android Studio will place build artifacts here
+/android/app/debug
+/android/app/profile
+/android/app/release

Dart/codelab-dart-functions/README.md

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+# Codelab Dart Functions
+
+This project contains the source code for the "Deploy Dart on Firebase Functions" codelab.
+
+See [the codelab](https://codelabs.developers.google.com/deploy-dart-on-firebase-functions) for full instructions.
+
+## Running locally
+
+This uses the Firebase emulator suite to test without deploying.
+
+1. Ensure Firebase CLI is installed.
+2. Initialize emulators in the root of the project: `firebase init emulators`
+3. Start the emulators: `firebase emulators:start`
+4. Run the flutter application `flutter run`.

Dart/codelab-dart-functions/analysis_options.yaml

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+# This file configures the analyzer, which statically analyzes Dart code to
+# check for errors, warnings, and lints.
+#
+# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
+# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
+# invoked from the command line by running `flutter analyze`.
+
+# The following line activates a set of recommended lints for Flutter apps,
+# packages, and plugins designed to encourage good coding practices.
+include: package:flutter_lints/flutter.yaml
+
+linter:
+  # The lint rules applied to this project can be customized in the
+  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
+  # included above or to enable additional rules. A list of all available lints
+  # and their documentation is published at https://dart.dev/lints.
+  #
+  # Instead of disabling a lint rule for the entire project in the
+  # section below, it can also be suppressed for a single line of code
+  # or a specific dart file by using the `// ignore: name_of_lint` and
+  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
+  # producing the lint.
+  rules:
+    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
+    # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
+
+# Additional information about this file can be found at
+# https://dart.dev/guides/language/analysis-options

Dart/codelab-dart-functions/firebase.json

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+{
+  "functions": [
+    {
+      "source": "functions",
+      "codebase": "dart-codelab-dart-functions",
+      "ignore": [
+        "node_modules",
+        ".git",
+        "firebase-debug.log",
+        "firebase-debug.*.log",
+        "*.local"
+      ],
+      "predeploy": [
+        "dart pub get --directory=\"$RESOURCE_DIR\"",
+        "dart run build_runner build --delete-conflicting-outputs --directory=\"$RESOURCE_DIR\""
+      ]
+    }
+  ]
+}

Dart/codelab-dart-functions/functions/bin/server.dart

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+import 'dart:convert';
+import 'package:firebase_functions/firebase_functions.dart';
+import 'package:google_cloud_firestore/google_cloud_firestore.dart'
+    show FieldValue;
+import 'package:shared/shared.dart';
+
+void main(List<String> args) async {
+  await fireUp(args, (firebase) {
+
+    // Listen for calls to the http request and name defined in the shared package.
+    firebase.https.onRequest(name: incrementCallable, (request) async {
+
+      // In a production app, verify the user with request.auth?.uid here.
+      // ignore: avoid_print
+      print('Incrementing counter on the server...');
+
+      // Get firestore database instance
+      final firestore = firebase.adminApp.firestore();
+
+      // Get a reference to the counter document
+      final counterDoc = firestore.collection('counters').doc('global');
+
+      // Get the current snapshot for the count data
+      final snapshot = await counterDoc.get();
+
+      // Increment response we will send back
+      IncrementResponse incrementResponse;
+
+      // Check for the current count and if the snapshot exists
+      if (snapshot.data() case {'count': int value} when snapshot.exists) {
+        if (request.method == 'GET') {
+          // Get the current result
+          incrementResponse = IncrementResponse(
+            success: true,
+            message: 'Read-only sync complete',
+            newCount: value,
+          );
+        } else if (request.method == 'POST') {
+          // Increment count by one
+          final step = request.url.queryParameters['step'] as int? ?? 1;
+          await counterDoc.update({'count': FieldValue.increment(step)});
+          incrementResponse = IncrementResponse(
+            success: true,
+            message: 'Atomic increment complete',
+            newCount: value + step,
+          );
+        } else {
+          throw FailedPreconditionError(
+            'only GET and POST requests are allowed',
+          );
+        }
+      } else {
+        // Create a new document with a count of 1
+        await counterDoc.set({'count': 1});
+        incrementResponse = const IncrementResponse(
+          success: true,
+          message: 'Cloud-sync complete',
+          newCount: 1,
+        );
+      }
+
+      // Return the response as JSON
+      return Response(
+        200,
+        body: jsonEncode(incrementResponse.toJson()),
+        headers: {'Content-Type': 'application/json'},
+      );
+    });
+
+  });
+}

Dart/codelab-dart-functions/functions/build.yaml

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+targets:
+  $default:
+    sources:
+      - "bin/**"
+      - "lib/**"