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  • express处理跨域问题,中间件 CORS

    CORS是一个W3C标准,全称是"跨域资源共享"(Cross-origin resource sharing)。

    1、不用中间件的话可以这样写:

    app.all('*', function (req, res, next) {
        res.header("Access-Control-Allow-Origin", "*");
        res.header("Access-Control-Allow-Headers", "Content-Type,Content-Length, Authorization, Accept,X-Requested-With");
        res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
        res.header("X-Powered-By",' 3.2.1')
        if(req.method=="OPTIONS") res.send(200);/*让options请求快速返回*/
        else  next();
    })

    2、使用CORS,和其他中间件的用法一样,app.use()即可:

    var express = require('express')
    var cors = require('cors')
    var app = express()
    
    app.use(cors())
    
    app.get('/products/:id', function (req, res, next) {
      res.json({msg: 'This is CORS-enabled for all origins!'})
    })
    
    app.listen(80, function () {
      console.log('CORS-enabled web server listening on port 80')
    })

    如果要单独为某个接口实现允许跨域请求,在回调函数之前先用cors()方法进行跨域处理即可:

    var express = require('express')
    var cors = require('cors')
    var app = express()
    
    app.get('/products/:id', cors(), function (req, res, next) {
      res.json({msg: 'This is CORS-enabled for a Single Route'})
    })
    
    app.listen(80, function () {
      console.log('CORS-enabled web server listening on port 80')
    })

    还可以自己手动配置:

    var express = require('express')
    var cors = require('cors')
    var app = express()
    
    var corsOptions = {
      origin: 'http://example.com',
      optionsSuccessStatus: 200 // some legacy browsers (IE11, various SmartTVs) choke on 204
    }
    
    app.get('/products/:id', cors(corsOptions), function (req, res, next) {
      res.json({msg: 'This is CORS-enabled for only example.com.'})
    })
    
    app.listen(80, function () {
      console.log('CORS-enabled web server listening on port 80')
    })

    更多信息请参考官网:CORS

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  • 原文地址:https://www.cnblogs.com/yourstars/p/6897626.html
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