文档JavaScript 后端

从 Express 到 Nexy

在 Nexy 中,Express 路由变成 src/routes/ 下的 Python 文件:app.get 是 GET 函数,req 变成类型参数,res.json 变成返回值,app.use 变成配置字段或 middleware.py。

下面的每个部分都显示了 Express 习惯,然后是 Nexy 中的相同内容。

一条路线

索引.js
import express from "express"; const app = express(); app.get("/api/hello", (req, res) => {  res.json({ message: "Hello" });}); app.listen(3000);

文件路径是 URL,函数名称是方法,返回值是 JSON 正文:

src/routes/api/hello.py
async def GET():    return {"message": "Hello"}

req.params

索引.js
app.get("/api/users/:id", (req, res) => {  const id = Number(req.params.id);  if (Number.isNaN(id)) return res.status(404).end();  res.json({ id });});

:id 是一个 [id] 段,类型注释进行转换,404:

src/routes/api/users/[id].py
async def GET(id: int):    return {"id": id}

* 通配符是 [...rest].py 文件。

req.query

索引.js
app.get("/api/search", (req, res) => {  const q = req.query.q ?? "";  const page = Number(req.query.page ?? 1);  res.json({ q, page });});
src/routes/api/search.py
async def GET(q: str = "", page: int = 1):    return {"q": q, "page": page}

?page=abc 使用失败的参数回答 422,而不是 NaN。

req.body 和验证

索引.js
import { z } from "zod"; app.use(express.json()); const NewItem = z.object({ name: z.string(), price: z.number().positive() }); app.post("/api/items", (req, res) => {  const parsed = NewItem.safeParse(req.body);  if (!parsed.success) return res.status(422).json(parsed.error);  res.status(201).json(parsed.data);});

在函数运行之前,根据 Pydantic 模型对主体进行解析和验证:

src/routes/api/items.py
from pydantic import BaseModel, Field from nexy.http import JSONResponse  class NewItem(BaseModel):    name: str    price: float = Field(gt=0)  async def POST(item: NewItem):    return JSONResponse(item.model_dump(), status_code=201)

express.Router()

路线/admin.js
const admin = express.Router(); admin.get("/stats", (req, res) => res.json({ users: 3 })); app.use("/admin", admin);

该文件夹是挂载路径:

src/routes/admin/stats.py
async def GET():    return {"users": 3}

路由中间件

路线/admin.js
function requireAdmin(req, res, next) {  if (req.get("x-role") !== "admin") return res.status(403).json({ error: "Admins only" });  next();} admin.use(requireAdmin);

dependencies.py 在其文件夹的每个路由之前运行。引发会停止请求,就像不调用 next() 一样:

src/routes/admin/dependency.py
from nexy.http import Header, HTTPException  def require_admin(x_role: str = Header("")) -> None:    if x_role != "admin":        raise HTTPException(status_code=403, detail="Admins only")  dependencies = [require_admin]

app.use 中间件

索引.js
app.use((req, res, next) => {  const start = Date.now();  res.on("finish", () => console.log(req.method, req.url, Date.now() - start));  next();});

路由根部的 middleware.py 包装每个请求; call_next 是 next():

src/routes/middleware.py
import time from nexy.http import Request  async def middleware(request: Request, call_next):    start = time.perf_counter()    response = await call_next(request)    response.headers["x-time-ms"] = f"{(time.perf_counter() - start) * 1000:.1f}"    return response

cors、compression、helmet 型主机

索引.js
import compression from "compression";import cors from "cors"; app.use(cors({ origin: "https://example.com" }));app.use(compression());
nexyconfig.py
from nexy.core.models import NexyConfigModel  class NexyConfig(NexyConfigModel):    useCORS = {"allow_origins": ["https://example.com"]}    useGZip = {"minimum_size": 1000}    useTrustedHost = {"allowed_hosts": ["example.com", "*.example.com"]}    useSession = {"secret_key": "change-me"}

饼干

索引.js
import cookieParser from "cookie-parser"; app.use(cookieParser()); app.post("/api/theme", (req, res) => {  res.cookie("theme", "dark").json({ theme: "dark" });}); app.get("/api/theme", (req, res) => res.json({ theme: req.cookies.theme ?? "light" }));

cookie是读取的参数,写入响应的方法:

src/routes/api/theme.py
from nexy.http import Cookie, JSONResponse  async def GET(theme: str = Cookie("light")):    return {"theme": theme}  async def POST():    response = JSONResponse({"theme": "dark"})    response.set_cookie("theme", "dark")    return response

express-session

索引.js
import session from "express-session"; app.use(session({ secret: "change-me" })); app.post("/api/login", (req, res) => {  req.session.user = req.body.name;  res.json({ user: req.session.user });});

nexyconfig.py(上面)中的 useSession 打开会话; request.session 是一个字典:

src/routes/api/login.py
from pydantic import BaseModel from nexy.http import Request  class Login(BaseModel):    name: str  async def POST(request: Request, body: Login):    request.session["user"] = body.name    return {"user": body.name}

res.redirect

索引.js
app.get("/old", (req, res) => res.redirect(301, "/new"));
src/routes/old.py
from nexy.http import RedirectResponse  async def GET():    return RedirectResponse("/new", status_code=301)

使用 multer 上传文件

索引.js
import multer from "multer"; const upload = multer({ limits: { fileSize: 1_000_000 } }); app.post("/api/upload", upload.single("file"), (req, res) => {  res.json({ name: req.file.originalname, size: req.file.size });});
src/routes/api/upload.py
from nexy.http import HTTPException, UploadFile  async def POST(file: UploadFile):    data = await file.read()    if len(data) > 1_000_000:        raise HTTPException(status_code=413, detail="File too large")    return {"name": file.filename, "size": len(data)}

使用 EJS 或 Pug 的视图

索引.js
app.set("view engine", "ejs"); app.get("/users", (req, res) => {  res.render("users", { users: [{ name: "Ada" }, { name: "Alan" }] });});
视图/users.ejs
<ul>  <% users.forEach((user) => { %>  <li><%= user.name %></li>  <% }) %></ul>

.nexy 页面同时包含路线和视图:

src/routes/users.nexy
---users = [{"name": "Ada"}, {"name": "Alan"}]---<ul>  {% for user in users %}  <li>{{ user.name }}</li>  {% endfor %}</ul>

<%= %> 转义,而 {{ }} 不转义:转义访问者用 {{ value | e }} 键入的内容。

express.static

索引.js
app.use(express.static("public"));

没什么可写的:public/ 的服务地点是 /。

404 处理程序和错误处理程序

索引.js
app.use((req, res) => res.status(404).send("<h1>Not found</h1>")); app.use((err, req, res, next) => {  console.error(err);  res.status(500).send("<h1>Something broke</h1>");});

路由根目录下有两个文件。 API 客户端仍然获取 JSON,浏览器获取页面:

src/routes/notfound.nexy
<h1>Not found</h1>
src/routes/errors.nexy
<h1>Something broke</h1>

WebSockets 与 ws

索引.js
import { WebSocketServer } from "ws"; const wss = new WebSocketServer({ server, path: "/ws/echo" });wss.on("connection", (socket) => socket.on("message", (data) => socket.send(data)));
src/routes/ws/echo.py
from fastapi import WebSocket  async def SOCKET(websocket: WebSocket):    await websocket.accept()    await websocket.send_text(await websocket.receive_text())

使用 Jest 和 Supertest 进行测试

索引.test.js
import request from "supertest";import { app } from "./app.js"; test("hello", async () => {  const res = await request(app).get("/api/hello");  expect(res.body).toEqual({ message: "Hello" });});
测试/test_hello.py
from fastapi.testclient import TestClient from nexy.app import app  def test_hello():    assert TestClient(app).get("/api/hello").json() == {"message": "Hello"}

跑步

快递 内克西
npm init + npm i express nx new
nodemon index.js nx dev
NODE_ENV=production node index.js nx build,然后 nx start
npm test nx test
没有 API 文档 /docs,列出每条 .py 路线

保留您的 React 前端

如果 Express 应用程序提供 React SPA,则组件将移动到 src/components/ 并呈现为 .nexy 页面的岛屿,或者整个站点移动到使用 useCSR = True 的客户端路由。参见岛屿 和CSR。

后续步骤

在 GitHub 上编辑

Enter 打开结果,Esc 关闭。