SpringBoot跨域配置
我們的后端使用Spring Boot。Spring Boot跨域非常簡單，只需書寫以下代碼即可。
@Configuration
public class CustomCORSConfiguration {private CorsConfiguration buildConfig() {CorsConfiguration corsConfiguration = new CorsConfiguration();corsConfiguration.addAllowedOrigin("*");corsConfiguration.addAllowedHeader("*");corsConfiguration.addAllowedMethod("*");return corsConfiguration;}@Beanpublic CorsFilter corsFilter() {UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();source.registerCorsConfiguration("/**", buildConfig());return new CorsFilter(source);}
}Nginx跨域配置
某天，我們將Spring Boot應用用Nginx反向代理。而前端跨域請求的需求不減，于是乎。
Nginx跨域也比較簡單，只需添加以下配置即可。
location / {proxy_pass http://localhost:8080;if ($request_method = 'OPTIONS') {add_header 'Access-Control-Allow-Origin' '*';add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,Token';add_header 'Access-Control-Max-Age' 1728000;add_header 'Content-Type' 'text/plain; charset=utf-8';add_header 'Content-Length' 0;return 204;}if ($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,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,Token';add_header 'Access-Control-Expose-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,Token';}if ($request_method = 'GET') {add_header 'Access-Control-Allow-Origin' '*';add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,Token';add_header 'Access-Control-Expose-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range,Token';}
}其中： add_header 'Access-Control-Expose-Headers' 務必加上你請求時所帶的header。例如本例中的“Token”，其實是前端傳給后端過來的。如果記不得也沒有關系，瀏覽器的調試器會有詳細說明。
參考文檔：https://enable-cors.org/server_nginx.html
B.T.W，阿里云中文檔描述到Nginx也可通過crossdomain.xml配置文件跨域：https://helpcdn.aliyun.com/knowledge_detail/41123.html ，不過筆者并未采用這種方式。
CORS on Nginx
The following Nginx configuration enables CORS, with support for preflight requests.
#
# Wide-open CORS config for nginx
#
location / {if ($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,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,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 ($request_method = 'POST') {add_header 'Access-Control-Allow-Origin' '*';add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';add_header 'Access-Control-Allow-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';add_header 'Access-Control-Expose-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';}if ($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,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';add_header 'Access-Control-Expose-Headers' 'DNT,X-CustomHeader,Keep-Alive,User-Agent,X-Requested-With,If-Modified-Since,Cache-Control,Content-Type,Content-Range,Range';}
}瀏覽器設置跨域
Chrome、Firefox本身是可以通過配置支持跨域請求的。
- Chrome跨域：參考文檔：http://www.cnblogs.com/laden666666/p/5544572.html
- Firefox跨域：參考文檔：https://segmentfault.com/q/1010000002532581/a-1020000002533699
