Vue解决ajax 跨域请求，无需后台（php）改返回信息header头

开启 proxyTable，注意此方法只能在开发环境起作用，build之后的项目依然无法跨域，后面会介绍修改apache/nginx的url重写（或反向代理）实现跨域。

此方法以 vue脚手架生成的标准项目为准。一般在项目config目录下面有个index文件。里面格式如下：

'use strict'
// Template version: 1.3.1
// see http://vuejs-templates.github.io/webpack for documentation.

const path = require('path')

module.exports = {
  dev: {

    // Paths
    assetsSubDirectory: 'static',
    assetsPublicPath: '/',
    proxyTable: {
      '/api': {
        target:'http://www.test.com:8080',//不填端口将默认80
        // secure: false, // 如果是https接口，需要配置这个参数
        changeOrigin:true,
        pathRewrite:{
          '^/api': ''
        }
      }
    },

    // Various Dev Server settings
    host: 'myvue.com', // can be overwritten by process.env.HOST
    port: 8080, // can be overwritten by process.env.PORT, if port is in use, a free one will be determined
    autoOpenBrowser: false,
    errorOverlay: true,
    notifyOnErrors: true,
    poll: false, // https://webpack.js.org/configuration/dev-server/#devserver-watchoptions-

    // Use Eslint Loader?
    // If true, your code will be linted during bundling and
    // linting errors and warnings will be shown in the console.
    useEslint: true,
    // If true, eslint errors and warnings will also be shown in the error overlay
    // in the browser.
    showEslintErrorsInOverlay: false,

    /**
     * Source Maps
     */

    // https://webpack.js.org/configuration/devtool/#development
    devtool: 'cheap-module-eval-source-map',

    // If you have problems debugging vue-files in devtools,
    // set this to false - it *may* help
    // https://vue-loader.vuejs.org/en/options.html#cachebusting
    cacheBusting: true,

    cssSourceMap: true
  },

  build: {
    // Template for index.html
    index: path.resolve(__dirname, '../dist/index.html'),

    // Paths
    assetsRoot: path.resolve(__dirname, '../dist'),
    assetsSubDirectory: 'static',
    assetsPublicPath: '/',

    /**
     * Source Maps
     */

    productionSourceMap: true,
    // https://webpack.js.org/configuration/devtool/#production
    devtool: '#source-map',

    // Gzip off by default as many popular static hosts such as
    // Surge or Netlify already gzip all static assets for you.
    // Before setting to `true`, make sure to:
    // npm install --save-dev compression-webpack-plugin
    productionGzip: false,
    productionGzipExtensions: ['js', 'css'],

    // Run the build command with an extra argument to
    // View the bundle analyzer report after build finishes:
    // `npm run build --report`
    // Set to `true` or `false` to always turn it on or off
    bundleAnalyzerReport: process.env.npm_config_report
  }
}

上面配置中，我们根据实际情况只需要修改proxyTable对应配置即可。假设我后端请求地址是http://www.test.com:8080，所有api的接口url都以/api开头。所以首先需要匹配所有以/api开头的.然后修改target的地址为http://www.test.com:8080。即修改pathRewrite配置。再次注意：这个方式只能在开发环境中使用。

bulid之后的项目，修改ngnix配置，添加如下（反向代理），当然也可以配置重写方式，下边给出反向代理配置：

location /api/ {

    proxy_set_header X-Real-IP $remote_addr;

    proxy_set_header X-Forwarded $proxy_add_x_forwarded_for;

    proxy_pass http://www.test.com/;

}

注释：其实只需  proxy_pass  http://www.test.com/;   一句就行；前面两句可以使后台程序获取前端访问者的真实IP地址，具体的原理自行查阅资料。