在基於以太坊進行DAPP開發中，會使用到web3.js與以太坊時行互動，當產品釋出時會使用公共以太坊結點，因產品的域名和公共以太坊結點域名不一致，出現瀏覽器跨域問題，瀏覽器會出現如下錯誤資訊：

已攔截跨源請求：同源策略禁止讀取位於 https://ropsten.infura.io/<your-key>的遠端資源。
（原因：CORS 請求未能成功）。

可使用代理ropsten網路已解決問題，操作如下：

一、開發環境配置(vue+webpack)

proxyTable: {
  '/<your-key>': {
     target: 'https://ropsten.infura.io',
     changeOrigin: true
  }
},
 

二、生產環境配置

1、

web3 = new Web3.providers.HttpProvider('http://yourhost/<your-key')

2、配置Nginx

location /<you-key> {

	if ($request_method = 'OPTIONS') {
		add_header 'Access-Control-Allow-Origin' '*';
		add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
		#
		# Custom headers and headers various browsers *should* be OK with but aren't
		#
		add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
		#
		# Tell client that this pre-flight info is valid for 20 days
		#
		add_header 'Access-Control-Max-Age' 1728000;
		add_header 'Content-Type' 'text/plain; charset=utf-8';
		add_header 'Content-Length' 0;
		return 204;
	 }
	 if ($request_method = 'POST') {
		add_header 'Access-Control-Allow-Origin' '*';
		add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
		add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
		add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
	 }
	 if ($request_method = 'GET') {
		add_header 'Access-Control-Allow-Origin' '*';
		add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
		add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range';
		add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range';
	 }

	#proxy_pass_header Server;
	#proxy_set_header Host $http_host;
	#proxy_redirect off;
	#proxy_set_header X-Real-IP $remote_addr;
	#proxy_set_header X-Scheme $scheme;
	proxy_pass https://ropsten.infura.io/<your-key>;
}