How to send request to an API on remote server via webpack devlopment server using axios

问题

I want to fetch some data from my remote server supporting REST API. I am using axios and web-dev-server. My frontend is sending request and I have used both firefox and chrome to open my frontend. However every time I tries to make request I encounter cors error. Also I don't want to make any changes on my server. The firefox and chrome are sending this header.

Accept:*/*
Accept-Encoding:gzip, deflate
Accept-Language :en-US,en;q=0.5
Connection:keep-alive
Host:my.ip.to.host:port
Origin:http://localhost:3000
Referer:http://localhost:3000/login
User-Agent:Mozilla/5.0 (X11; Ubuntu; Linu…) Gecko/20100101 Firefox/67.0

I have tried to run my simple request code on an online platform without web-dev-server and there it runs perfectly fine.

Here is my code

      //********** my request*********
    return axios
        .get('http://my.ip.to.host:port/api/User/login', {
            headers: {
                Accept: '/'
            }
        })
        .then(function(response) {
            console.log(response);
            return 'user';
        })
        .catch(function(error) {
            console.log(error);
            return 'err';
        });
     //*****************************
    

     //*****webpack.config.js********
    var HtmlWebpackPlugin = require('html-webpack-plugin');
    require('babel-polyfill');
    module.exports = {
        mode: 'development',
        entry: [ 'babel-polyfill', './src' ],
        resolve: {
            extensions: [ '.js', '.jsx' ]
        },
        module: {
            rules: [
                {
                    test: /.jsx?$/,
                    loader: 'babel-loader'
                }
            ]
        },
        plugins: [
            new HtmlWebpackPlugin({
                template: './src/index.html'
            })
        ],
        devServer: {
            historyApiFallback: true,
            port: 3000
        },
        externals: {
            // global app config object
            config: JSON.stringify({
                apiUrl: 'http://localhost:4000',
                checkLogin: 'http://my.ip.to.host:port/api/User/login'
            })
        }
    };
    

Here is the error I am getting.

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://my.ip.to.host:port/api/User/login. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing).`enter code here`

回答1:

You need to set withCredentials as true in axios config. Cors Setting

let HttpInterceptor = axios.create({
  headers: {
    Accept: "*/*"
  }
});

HttpInterceptor.interceptors.request.use(
  function(config) {  
    config.withCredentials = true; // To enable CORS
    return config;
  },
  function(error) {
    return promise.reject(error);
  }
);



//********** Your request*********
    return HttpInterceptor
        .get('http://my.ip.to.host:port/api/User/login')
        .then(function(response) {
            console.log(response);
            return 'user';
        })
        .catch(function(error) {
            console.log(error);
            return 'err';
        });

回答2:

Here Google has explained the cors(Cross-origin requests) very nicely.

I have worked around this by hosting a proxy server(on the same local server where I am hosting my client) and redirecting all my single page app request via that.

First of all, I created a proxy setting in devsever key of webpack config file, like this.

    devServer: {
        proxy: {
    //abc is REST API request endpoint on my backend
            '/abc': {
                //target is where your proxy server is hosted
                target: 'http://localhost:5000',
                secure: 'false'
            },
    //xyz is REST API request endpoint on my backend
            '/xyz': {
                //target is where your proxy server is hosted
                target: 'http://localhost:5000',
                secure: 'false'
            }
        },......// rest of the setting
      }

Then, For a particular invocation of a action via my client I make request to my backend like this.

    axios
        .get('/startAppkey', { withCredentials: true })// withCredential enables passing of cookies and session id. If you dont want to creat session you can avoid this.
        .then((response) => {
                           // do stuff with response
                            })
                        .catch(function() {
                         //do stuff
                        });

Our client is all set. Now time for proxy server. First install http-proxy-middleware,Like this.

    sudo npm i --save http-proxy-middleware
    //it is also avilable on yarn

then, To setup proxy server here is few lines of code.

    import * as express from 'express'; // using express to support my middleware
    import * as proxy from 'http-proxy-middleware';
    const app = express();
    // the path /abc and /xyz should be same as you have declared in in webpack config file
    app.use('/abc', proxy({ target: 'http://your/backend/api/endpoint'}));
    app.use('/xyz', proxy({ target: 'http://your/backend/api/endpoint'}));
    //that's it you are done here. 

来源：https://stackoverflow.com/questions/56730369/how-to-send-request-to-an-api-on-remote-server-via-webpack-devlopment-server-usi