--- name: api-design description: REST API设计模式，包括资源命名、状态码、分页、过滤、错误响应、版本控制和生产API的速率限制。 origin: ECC --- # API 设计模式 用于设计一致、对开发者友好的 REST API 的约定和最佳实践。 ## 何时启用 * 设计新的 API 端点时 * 审查现有的 API 契约时 * 添加分页、过滤或排序功能时 * 为 API 实现错误处理时 * 规划 API 版本策略时 * 构建面向公众或合作伙伴的 API 时 ## 资源设计 ### URL 结构 ``` # Resources are nouns, plural, lowercase, kebab-case GET /api/v1/users GET /api/v1/users/:id POST /api/v1/users PUT /api/v1/users/:id PATCH /api/v1/users/:id DELETE /api/v1/users/:id # Sub-resources for relationships GET /api/v1/users/:id/orders POST /api/v1/users/:id/orders # Actions that don't map to CRUD (use verbs sparingly) POST /api/v1/orders/:id/cancel POST /api/v1/auth/login POST /api/v1/auth/refresh ``` ### 命名规则 ``` # GOOD /api/v1/team-members # kebab-case for multi-word resources /api/v1/orders?status=active # query params for filtering /api/v1/users/123/orders # nested resources for ownership # BAD /api/v1/getUsers # verb in URL /api/v1/user # singular (use plural) /api/v1/team_members # snake_case in URLs /api/v1/users/123/getOrders # verb in nested resource ``` ## HTTP 方法和状态码 ### 方法语义 | 方法 | 幂等性 | 安全性 | 用途 | |--------|-----------|------|---------| | GET | 是 | 是 | 检索资源 | | POST | 否 | 否 | 创建资源，触发操作 | | PUT | 是 | 否 | 完全替换资源 | | PATCH | 否\* | 否 | 部分更新资源 | | DELETE | 是 | 否 | 删除资源 | \*通过适当的实现，PATCH 可以实现幂等 ### 状态码参考 ``` # Success 200 OK — GET, PUT, PATCH (with response body) 201 Created — POST (include Location header) 204 No Content — DELETE, PUT (no response body) # Client Errors 400 Bad Request — Validation failure, malformed JSON 401 Unauthorized — Missing or invalid authentication 403 Forbidden — Authenticated but not authorized 404 Not Found — Resource doesn't exist 409 Conflict — Duplicate entry, state conflict 422 Unprocessable Entity — Semantically invalid (valid JSON, bad data) 429 Too Many Requests — Rate limit exceeded # Server Errors 500 Internal Server Error — Unexpected failure (never expose details) 502 Bad Gateway — Upstream service failed 503 Service Unavailable — Temporary overload, include Retry-After ``` ### 常见错误 ``` # BAD: 200 for everything { "status": 200, "success": false, "error": "Not found" } # GOOD: Use HTTP status codes semantically HTTP/1.1 404 Not Found { "error": { "code": "not_found", "message": "User not found" } } # BAD: 500 for validation errors # GOOD: 400 or 422 with field-level details # BAD: 200 for created resources # GOOD: 201 with Location header HTTP/1.1 201 Created Location: /api/v1/users/abc-123 ``` ## 响应格式 ### 成功响应 ```json { "data": { "id": "abc-123", "email": "alice@example.com", "name": "Alice", "created_at": "2025-01-15T10:30:00Z" } } ``` ### 集合响应（带分页） ```json { "data": [ { "id": "abc-123", "name": "Alice" }, { "id": "def-456", "name": "Bob" } ], "meta": { "total": 142, "page": 1, "per_page": 20, "total_pages": 8 }, "links": { "self": "/api/v1/users?page=1&per_page=20", "next": "/api/v1/users?page=2&per_page=20", "last": "/api/v1/users?page=8&per_page=20" } } ``` ### 错误响应 ```json { "error": { "code": "validation_error", "message": "Request validation failed", "details": [ { "field": "email", "message": "Must be a valid email address", "code": "invalid_format" }, { "field": "age", "message": "Must be between 0 and 150", "code": "out_of_range" } ] } } ``` ### 响应包装器变体 ```typescript // Option A: Envelope with data wrapper (recommended for public APIs) interface ApiResponse { data: T; meta?: PaginationMeta; links?: PaginationLinks; } interface ApiError { error: { code: string; message: string; details?: FieldError[]; }; } // Option B: Flat response (simpler, common for internal APIs) // Success: just return the resource directly // Error: return error object // Distinguish by HTTP status code ``` ## 分页 ### 基于偏移量（简单） ``` GET /api/v1/users?page=2&per_page=20 # Implementation SELECT * FROM users ORDER BY created_at DESC LIMIT 20 OFFSET 20; ``` **优点：** 易于实现，支持“跳转到第 N 页” **缺点：** 在大偏移量时速度慢（例如 OFFSET 100000），并发插入时结果不一致 ### 基于游标（可扩展） ``` GET /api/v1/users?cursor=eyJpZCI6MTIzfQ&limit=20 # Implementation SELECT * FROM users WHERE id > :cursor_id ORDER BY id ASC LIMIT 21; -- fetch one extra to determine has_next ``` ```json { "data": [...], "meta": { "has_next": true, "next_cursor": "eyJpZCI6MTQzfQ" } } ``` **优点：** 无论位置如何，性能一致；在并发插入时结果稳定 **缺点：** 无法跳转到任意页面；游标是不透明的 ### 何时使用哪种 | 用例 | 分页类型 | |----------|----------------| | 管理仪表板，小数据集 (<10K) | 偏移量 | | 无限滚动，信息流，大数据集 | 游标 | | 公共 API | 游标（默认）配合偏移量（可选） | | 搜索结果 | 偏移量（用户期望有页码） | ## 过滤、排序和搜索 ### 过滤 ``` # Simple equality GET /api/v1/orders?status=active&customer_id=abc-123 # Comparison operators (use bracket notation) GET /api/v1/products?price[gte]=10&price[lte]=100 GET /api/v1/orders?created_at[after]=2025-01-01 # Multiple values (comma-separated) GET /api/v1/products?category=electronics,clothing # Nested fields (dot notation) GET /api/v1/orders?customer.country=US ``` ### 排序 ``` # Single field (prefix - for descending) GET /api/v1/products?sort=-created_at # Multiple fields (comma-separated) GET /api/v1/products?sort=-featured,price,-created_at ``` ### 全文搜索 ``` # Search query parameter GET /api/v1/products?q=wireless+headphones # Field-specific search GET /api/v1/users?email=alice ``` ### 稀疏字段集 ``` # Return only specified fields (reduces payload) GET /api/v1/users?fields=id,name,email GET /api/v1/orders?fields=id,total,status&include=customer.name ``` ## 认证和授权 ### 基于令牌的认证 ``` # Bearer token in Authorization header GET /api/v1/users Authorization: Bearer eyJhbGciOiJIUzI1NiIs... # API key (for server-to-server) GET /api/v1/data X-API-Key: sk_live_abc123 ``` ### 授权模式 ```typescript // Resource-level: check ownership app.get("/api/v1/orders/:id", async (req, res) => { const order = await Order.findById(req.params.id); if (!order) return res.status(404).json({ error: { code: "not_found" } }); if (order.userId !== req.user.id) return res.status(403).json({ error: { code: "forbidden" } }); return res.json({ data: order }); }); // Role-based: check permissions app.delete("/api/v1/users/:id", requireRole("admin"), async (req, res) => { await User.delete(req.params.id); return res.status(204).send(); }); ``` ## 速率限制 ### 响应头 ``` HTTP/1.1 200 OK X-RateLimit-Limit: 100 X-RateLimit-Remaining: 95 X-RateLimit-Reset: 1640000000 # When exceeded HTTP/1.1 429 Too Many Requests Retry-After: 60 { "error": { "code": "rate_limit_exceeded", "message": "Rate limit exceeded. Try again in 60 seconds." } } ``` ### 速率限制层级 | 层级 | 限制 | 时间窗口 | 用例 | |------|-------|--------|----------| | 匿名用户 | 30/分钟 | 每个 IP | 公共端点 | | 认证用户 | 100/分钟 | 每个用户 | 标准 API 访问 | | 高级用户 | 1000/分钟 | 每个 API 密钥 | 付费 API 套餐 | | 内部服务 | 10000/分钟 | 每个服务 | 服务间调用 | ## 版本控制 ### URL 路径版本控制（推荐） ``` /api/v1/users /api/v2/users ``` **优点：** 明确，易于路由，可缓存 **缺点：** 版本间 URL 会变化 ### 请求头版本控制 ``` GET /api/users Accept: application/vnd.myapp.v2+json ``` **优点：** URL 简洁 **缺点：** 测试更困难，容易忘记 ### 版本控制策略 ``` 1. Start with /api/v1/ — don't version until you need to 2. Maintain at most 2 active versions (current + previous) 3. Deprecation timeline: - Announce deprecation (6 months notice for public APIs) - Add Sunset header: Sunset: Sat, 01 Jan 2026 00:00:00 GMT - Return 410 Gone after sunset date 4. Non-breaking changes don't need a new version: - Adding new fields to responses - Adding new optional query parameters - Adding new endpoints 5. Breaking changes require a new version: - Removing or renaming fields - Changing field types - Changing URL structure - Changing authentication method ``` ## 实现模式 ### TypeScript (Next.js API 路由) ```typescript import { z } from "zod"; import { NextRequest, NextResponse } from "next/server"; const createUserSchema = z.object({ email: z.string().email(), name: z.string().min(1).max(100), }); export async function POST(req: NextRequest) { const body = await req.json(); const parsed = createUserSchema.safeParse(body); if (!parsed.success) { return NextResponse.json({ error: { code: "validation_error", message: "Request validation failed", details: parsed.error.issues.map(i => ({ field: i.path.join("."), message: i.message, code: i.code, })), }, }, { status: 422 }); } const user = await createUser(parsed.data); return NextResponse.json( { data: user }, { status: 201, headers: { Location: `/api/v1/users/${user.id}` }, }, ); } ``` ### Python (Django REST Framework) ```python from rest_framework import serializers, viewsets, status from rest_framework.response import Response class CreateUserSerializer(serializers.Serializer): email = serializers.EmailField() name = serializers.CharField(max_length=100) class UserSerializer(serializers.ModelSerializer): class Meta: model = User fields = ["id", "email", "name", "created_at"] class UserViewSet(viewsets.ModelViewSet): serializer_class = UserSerializer permission_classes = [IsAuthenticated] def get_serializer_class(self): if self.action == "create": return CreateUserSerializer return UserSerializer def create(self, request): serializer = CreateUserSerializer(data=request.data) serializer.is_valid(raise_exception=True) user = UserService.create(**serializer.validated_data) return Response( {"data": UserSerializer(user).data}, status=status.HTTP_201_CREATED, headers={"Location": f"/api/v1/users/{user.id}"}, ) ``` ### Go (net/http) ```go func (h *UserHandler) CreateUser(w http.ResponseWriter, r *http.Request) { var req CreateUserRequest if err := json.NewDecoder(r.Body).Decode(&req); err != nil { writeError(w, http.StatusBadRequest, "invalid_json", "Invalid request body") return } if err := req.Validate(); err != nil { writeError(w, http.StatusUnprocessableEntity, "validation_error", err.Error()) return } user, err := h.service.Create(r.Context(), req) if err != nil { switch { case errors.Is(err, domain.ErrEmailTaken): writeError(w, http.StatusConflict, "email_taken", "Email already registered") default: writeError(w, http.StatusInternalServerError, "internal_error", "Internal error") } return } w.Header().Set("Location", fmt.Sprintf("/api/v1/users/%s", user.ID)) writeJSON(w, http.StatusCreated, map[string]any{"data": user}) } ``` ## API 设计清单 发布新端点前请检查： * \[ ] 资源 URL 遵循命名约定（复数、短横线连接、不含动词） * \[ ] 使用了正确的 HTTP 方法（GET 用于读取，POST 用于创建等） * \[ ] 返回了适当的状态码（不要所有情况都返回 200） * \[ ] 使用模式（Zod, Pydantic, Bean Validation）验证了输入 * \[ ] 错误响应遵循带代码和消息的标准格式 * \[ ] 列表端点实现了分页（游标或偏移量） * \[ ] 需要认证（或明确标记为公开） * \[ ] 检查了授权（用户只能访问自己的资源） * \[ ] 配置了速率限制 * \[ ] 响应未泄露内部细节（堆栈跟踪、SQL 错误） * \[ ] 与现有端点命名一致（camelCase 对比 snake\_case） * \[ ] 已记录（更新了 OpenAPI/Swagger 规范）