Flutter Firebase规则管理插件firebase_rules的使用

firebase_rules 是一个类型安全的Firebase规则生成器，适用于Firestore、Storage和Realtime Database。它提供了一种在Dart中定义Firebase规则的方法，并通过代码补全和自定义lint规则来确保规则的质量。

功能特性

• 类型安全：为Firestore、Storage和Realtime Database创建规则时提供类型安全的环境。
• 自定义Lint规则：在部署前捕捉问题。
• 语法相似性：模仿Firebase规则语法，便于迁移。
• 易读性和维护性：规则更易于阅读和维护，并且可以在Realtime Database规则中添加注释。

限制

• Realtime Database规则不是真正类型的，但提供了代码补全的好处。

安装

为了防止潜在的问题，建议在一个专门的项目中创建规则。以下是安装步骤：

pubspec.yaml

dependencies:
  firebase_rules: latest
  # 如果你正在使用来自 `cloud_firestore_platform_interface` 的类型
  firebase_rules_convert: latest

dev_dependencies:
  build_runner: latest
  firebase_rules_generator: latest

  # 使用 `firebase_rules_linter`
  custom_lint: latest
  firebase_rules_linter: latest

analysis_options.yaml

# 使用 `firebase_rules_linter`
analyzer:
  plugins:
    - custom_lint

使用指南

注解

所有规则的起点是注解。Firestore、Storage和Database规则应分别定义在不同的文件中以避免冲突。

import 'package:firebase_rules/database.dart';
import 'package:firebase_rules/firebase.dart';

/// 创建Firestore规则
@FirebaseRules(service: Service.firestore)
final firestoreRules = [];

/// 创建Storage规则
@FirebaseRules(service: Service.storage)
final storageRules = [];

/// 创建Realtime Database规则
@DatabaseRules()
final databaseRules = [];

匹配规则（Matches）

现在可以开始定义匹配语句。

import 'package:firebase_rules/firebase.dart';
import 'shared.dart';

@FirebaseRules(service: Service.firestore)
final firestoreRules = [
  Match<FirestoreResource>(
    firestoreRoot,
    matches: (database, request, resource) => [
      Match<FirestoreResource<User>>(
        '/users/{userId}',
        rules: (userId, request, resource) => [],
      ),
      Match<FirestoreResource>(
        '/other/stuff',
        rules: (_, request, resource) => [],
      ),
    ],
  ),
];

@FirebaseRules(service: Service.storage)
final storageRules = [
  Match<StorageResource>(
    storageRoot,
    matches: (bucket, request, resource) => [
      Match<StorageResource>(
        '/images/{imageId}',
      ),
    ],
  ),
];

规则定义（Rules）

规则是核心部分。

import 'package:firebase_rules/firebase.dart';
import 'shared.dart';

@FirebaseRules(service: Service.firestore)
final firestoreRules = [
  Match<FirestoreResource>(
    firestoreRoot,
    matches: (database, request, resource) => [
      Match<FirestoreResource<User>>(
        '/users/{userId}',
        rules: (userId, request, resource) => [
          Allow([Operation.read], resource.data.userId.rules() == userId),
        ],
      ),
    ],
  ),
];

规则语言

该包包含了一个用Dart重新实现的Firebase规则语言。这些调用将由生成器转换为正确的Firebase规则语法。

import 'package:firebase_rules/firebase.dart';

void example() {
  ''.rules().range(0, 1);
  [].rules<RulesString>().concat([].rules());
  rules.string(true);
  rules.raw<bool>("foo.bar.baz == 'qux'");
}

函数

顶级函数可以用作规则函数。

import 'package:firebase_rules/firebase.dart';

bool isSignedIn() {
  return request.auth?.uid != null;
}

@FirebaseRules(
  service: Service.firestore,
  functions: [isSignedIn],
)
final rules = [
  Match<FirestoreResource>(firestoreRoot),
];

组织

匹配语句的任何函数参数都可以拆分以进行组织。

import 'package:firebase_rules/firebase.dart';
import 'shared.dart';

List<Match> detached(
  RulesString database,
  RulesRequest<FirestoreResource> request,
  FirestoreResource resource,
) =>
    [
      Match<FirestoreResource<User>>(
        '/users/{userId}',
        rules: (userId, request, resource) => [
          Allow([Operation.read], resource.data.userId.rules() == userId),
        ],
      ),
    ];

@FirebaseRules(service: Service.firestore)
final firestoreRules = [
  Match<FirestoreResource>(firestoreRoot, matches: detached),
];

枚举

枚举可以通过生成器替换为原始字符串。

import 'package:firebase_rules/firebase.dart';

@FirebaseRules(
  service: Service.firestore,
  enums: [Test.map],
)
final firestoreRules = [
  Match<FirestoreResource>(
    firestoreRoot,
    matches: (database, request, resource) => [
      Match<FirestoreResource<TestResource>>(
        '/test',
        rules: (_, request, resource) => [
          Allow([Operation.read], resource.data.test == Test.a),
        ],
      ),
    ],
  ),
];

enum Test { a, b, c }

abstract class TestResource {
  Test get test;
}

生成规则

最后，可以运行生成器。

$ dart pub run build_runner build

对于每个rules.dart文件，这将在同一目录下生成一个rules.rules文件。将你的Firebase配置指向这个文件以使用规则。

Realtime Database规则

数据库规则与Firestore和Storage规则类似，但有一些不同之处：

• 第一个匹配必须以rules开头，这是数据库的根。
• 通配符用$表示。

import 'package:firebase_rules/database.dart';

@DatabaseRules()
final databaseRules = [
  Match(
    r'rules/users/$userId',
    read: (userId) => auth != null && auth?.uid == userId,
    write: (userId) => userId == 'user1'.rules(),
    validate: (userId) => !data.exists(),
    indexOn: ['uid', 'email'],
    matches: (userId) => [
      Match(
        r'contracts/$contractId',
        read: (contractId) =>
            root.child('users'.rules()).child(userId).child(contractId).val<int?>() != null,
        write: (contractId) =>
            root.child('users'.rules()).child(userId).child(contractId).val() != null,
      ),
    ],
  ),
];

示例代码

以下是一个完整的示例，展示了如何使用firebase_rules定义Firestore规则。

import 'package:firebase_rules/firebase.dart';
import 'package:cloud_firestore_platform_interface/cloud_firestore_platform_interface.dart';

bool isSignedIn(RulesRequest request) => request.auth != null;

bool isOwner(RulesRequest request, RulesString uid) {
  final requestingUid = request.auth?.uid;
  return requestingUid == uid;
}

@FirebaseRules(
  service: Service.firestore,
  functions: [isSignedIn, isOwner],
)
final firestoreRules = [
  Match<FirestoreResource>(
    firestoreRoot,
    rules: (database, request, resource) => [
      Allow([Operation.read], request.auth?.uid == 'god'.rules()),
    ],
    matches: (database, request, resource) => [
      Match<FirestoreResource<User>>(
        '/users/{userId}',
        rules: (userId, request, resource) => [
          Allow([Operation.read], isSignedIn(request)),
          Allow([Operation.create, Operation.update], isOwner(request, userId)),
        ],
      ),
      Match<FirestoreResource<Content>>(
        '/content/{contentId}',
        rules: (contentId, request, resource) => [
          Allow([Operation.read], isSignedIn(request) && resource.data.public),
          Allow(
            [Operation.write],
            rules.firestore.get<User>(rules.path('/users/${request.auth?.uid}'.rules())).data.contentIds.rules<RulesString>().contains(contentId) &&
                rules.firestore.exists(rules.path('/users/${request.auth?.uid}'.rules(), database: 'default')),
          ),
        ],
      ),
    ],
  ),
];

abstract class User {
  List<String> get contentIds;
  Blob get profileImage;
}

abstract class Content {
  bool get public;
}

希望以上内容能帮助你更好地理解和使用firebase_rules插件。如果有任何问题或需要进一步的帮助，请随时提问！