在Nginx上配置CORS

Cross-Origin Resource Sharing (CORS)是W3C出的一个标准，是用来解决JavaScript跨域调用的问题。以下是在Nginx上面配置CORS。

location / {
        if ($request_method = 'OPTIONS') {
        add_header 'Access-Control-Allow-Origin' '$http_origin';
        #
        # Om nom nom cookies
        #
        add_header 'Access-Control-Allow-Credentials' 'true';
        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' 'Authorization,Content-Type,Accept,Origin,User-Agent,DNT,Cache-Control,X-Mx-ReqToken,Keep-Alive,X-Requested-With,If-Modified-Since';
        #
        # 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 ($request_method = 'POST') {
        add_header 'Access-Control-Allow-Origin' '$http_origin';
        add_header 'Access-Control-Allow-Credentials' 'true';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        }

        if ($request_method = 'GET') {
        add_header 'Access-Control-Allow-Origin' '$http_origin';
        add_header 'Access-Control-Allow-Credentials' 'true';
        add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';
        }

}

在如上的配置当中，'Access-Control-Allow-Origin'用了'$http_origin'，这样是适用于开发环境，这样多台开发测试设备都可以跨域请求。当上了生产环境，出于安全考虑，最好设置一个白名单来限制访问的设备。