通常,我们提到的跨域指:CORS。
CORS是一个W3C标准,全称是"跨域资源共享"(Cross-origin resource sharing), 它需要浏览器和服务器同时支持他,允许浏览器向跨源服务器发送XMLHttpRequest请求,从而克服 AJAX 只能同源使用的限制。
浏览器跨域报错
跨域问题的起因
浏览器安全机制限制,不允许网站使用非同源网站上的资源。
同源是指:协议、域名、端口号完全相同。
出现跨域问题的实例
下表给出了与 URL http://www.training.com/dir/page.html 的源进行对比的示例:
跨域解决方案
后端服务器配置支持跨域请求即可。
Nginx跨域解决方案
server {
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' '*' always;
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range' always;
add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
}
if ($request_method = 'GET') {
add_header 'Access-Control-Allow-Origin' '*' always;
add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS' always;
add_header 'Access-Control-Allow-Headers' 'DNT,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Range' always;
add_header 'Access-Control-Expose-Headers' 'Content-Length,Content-Range' always;
}
root /data/client/;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /usr/share/nginx/html;
}
}