Nginx 設置cors跨域

在我們的開發中，經常遇到跨域，這個時候，可以通過cors來解決。

解決的方法可以在服務端的代碼層或者在web服務器進行設置

在web服務器上進行設置cors 跨域，這樣就不必改動代碼。以nginx為例子

提示：有時候我們的后端是PHP文件，則需要把跨域的代碼加 location ~ \.php(.*)$ 中。

location / {
     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';
     }
}

　　另外一種可以設置反向代理

location ^~ /api/v1 {
	add_header 'Access-Control-Allow-Origin' "$http_origin"; 
	add_header 'Access-Control-Allow-Methods' 'GET, POST, PUT, DELETE, OPTIONS'; 
	add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type    '; 
	add_header 'Access-Control-Allow-Credentials' 'true'; 
	if ($request_method = 'OPTIONS') { 
		add_header 'Access-Control-Allow-Origin' "$http_origin"; 
		add_header 'Access-Control-Allow-Methods' 'GET, POST, PUT, DELETE, OPTIONS'; 
		add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type    '; 
		add_header 'Access-Control-Allow-Credentials' 'true'; 
		add_header 'Access-Control-Max-Age' 1728000; # 20 天 
		add_header 'Content-Type' 'text/html charset=UTF-8'; 
		add_header 'Content-Length' 0; 
		return 200; 
	} 
    # 這下面是要被代理的后端服務器，它們就不需要修改代碼來支持跨域了
	proxy_pass http://127.0.0.1:8085; 
	proxy_set_header Host $host; 
	proxy_redirect off; 
	proxy_set_header X-Real-IP $remote_addr; 
	proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; 
	proxy_connect_timeout 60; 
	proxy_read_timeout 60; 
	proxy_send_timeout 60; 

}