Node.js 中 cors 依赖示例详解

# 使用 npm 安装
npm install cors

const express = require("express");
const cors = require("cors");
const app = express();
// 使用 cors 中间件
app.use(cors());
app.get("/data", (req, res) => {
  res.json({ message: "This is some data from the server" });
});
const port = 3000;
app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});

// 允许单个源
const corsOptions = {
  origin: "http://example.com",
};
app.use(cors(corsOptions));
// 允许多个源
const corsOptionsMultiple = {
  origin: ["http://example1.com", "http://example2.com"],
};
app.use(cors(corsOptionsMultiple));
// 使用函数动态配置 origin
const corsOptionsFunction = {
  origin: (origin, callback) => {
    const allowedOrigins = ["http://example.com", "http://test.com"];
    if (!origin || allowedOrigins.includes(origin)) {
      callback(null, true);
    } else {
      callback(new Error("Not allowed by CORS"));
    }
  },
};
app.use(cors(corsOptionsFunction));

const corsOptionsMethods = {
  methods: "GET,POST",
};
app.use(cors(corsOptionsMethods));

const corsOptionsHeaders = {
  allowedHeaders: "Content-Type,Authorization",
};
app.use(cors(corsOptionsHeaders));

const corsOptionsExposed = {
  exposedHeaders: "X-Custom-Header",
};
app.use(cors(corsOptionsExposed));

const corsOptionsCredentials = {
  credentials: true,
};
app.use(cors(corsOptionsCredentials));

const express = require("express");
const cors = require("cors");
const app = express();
const corsOptions = {
  origin: "http://example.com",
};
// 只允许特定路由跨域
app.get("/data", cors(corsOptions), (req, res) => {
  res.json({ message: "This is some data from the server" });
});
const port = 3000;
app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});