为了方便ASMX服务的多域访问，我在全局中创建了这个函数。asax文件:

protected void Application_BeginRequest(object sender, EventArgs e)
{
    string CORSServices = "/account.asmx|/account2.asmx";
    if (CORSServices.IndexOf(HttpContext.Current.Request.Url.AbsolutePath) > -1)
    {
        string allowedDomains = "http://xxx.yyy.example|http://aaa.bbb.example";

        if(allowedDomains.IndexOf(HttpContext.Current.Request.Headers["Origin"]) > -1)
            HttpContext.Current.Response.AddHeader("Access-Control-Allow-Origin", HttpContext.Current.Request.Headers["Origin"]);

        if(HttpContext.Current.Request.HttpMethod == "OPTIONS")
            HttpContext.Current.Response.End();
    }
}

这也允许CORS处理OPTIONS动词。

下面是一个Java web应用的解决方案，基于yesthatguy的回答。

我使用的是Jersey REST 1.x

配置web.xml以识别Jersey REST和CORSResponseFilter

<!-- Jersey REST config -->
<servlet>
  <servlet-name>JAX-RS Servlet</servlet-name>
  <servlet-class>com.sun.jersey.spi.container.servlet.ServletContainer</servlet-class>
  <init-param>
    <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
    <param-value>true</param-value>
  </init-param>
  <init-param>
    <param-name>com.sun.jersey.spi.container.ContainerResponseFilters</param-name>
    <param-value>com.your.package.CORSResponseFilter</param-value>
  </init-param>
  <init-param>
    <param-name>com.sun.jersey.config.property.packages</param-name>
    <param-value>com.your.package</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
  <servlet-name>JAX-RS Servlet</servlet-name>
  <url-pattern>/ws/*</url-pattern>
</servlet-mapping>

下面是CORSResponseFilter的代码

import com.sun.jersey.spi.container.ContainerRequest;
import com.sun.jersey.spi.container.ContainerResponse;
import com.sun.jersey.spi.container.ContainerResponseFilter;


public class CORSResponseFilter implements ContainerResponseFilter{

    @Override
    public ContainerResponse filter(ContainerRequest request,
            ContainerResponse response) {
        
        String[] allowDomain = {"http://localhost:9000","https://my.domain.example"};
        Set<String> allowedOrigins = new HashSet<String>(Arrays.asList (allowDomain));                  
        
        String originHeader = request.getHeaderValue("Origin");
        
        if(allowedOrigins.contains(originHeader)) {
            response.getHttpHeaders().add("Access-Control-Allow-Origin", originHeader);
                        
            response.getHttpHeaders().add("Access-Control-Allow-Headers",
                    "origin, content-type, accept, authorization");
            response.getHttpHeaders().add("Access-Control-Allow-Credentials", "true");
            response.getHttpHeaders().add("Access-Control-Allow-Methods",
                    "GET, POST, PUT, DELETE, OPTIONS, HEAD");
        }
        
        return response;
    }
}

这招对我很管用:

SetEnvIf Origin "^http(s)?://(.+\.)?(domain\.example|domain2\.example)$" origin_is=$0 
Header always set Access-Control-Allow-Origin %{origin_is}e env=origin_is

当放入。htaccess时，它肯定会工作。

如上所述，Access-Control-Allow-Origin应该是唯一的，如果您位于CDN(内容分发网络)后面，则应该将Vary设置为Origin。

Nginx配置的相关部分:

if ($http_origin ~* (https?://.*\.mydomain\.com(:[0-9]+)?)) {
  set $cors "true";
}
if ($http_origin ~* (https?://.*\.my-other-domain\.com(:[0-9]+)?)) {
  set $cors "true";
}

if ($cors = "true") {
  add_header 'Access-Control-Allow-Origin' "$http_origin";
  add_header 'X-Frame-Options' "ALLOW FROM $http_origin";
  add_header 'Access-Control-Allow-Credentials' 'true';
  add_header 'Vary' 'Origin';
}

只能为Access-Control-Allow-Origin标头指定一个原点。但是您可以根据请求在响应中设置原点。不要忘记设置Vary标头。在PHP中，我将做以下工作:

/**
 * Enable CORS for the passed origins.
 * Adds the Access-Control-Allow-Origin header to the response with the origin that matched the one in the request.
 * @param array $origins
 * @return string|null returns the matched origin or null
*/
function allowOrigins($origins)
{
    $val = $_SERVER['HTTP_ORIGIN'] ?? null;
    if (in_array($val, $origins, true)) {
        header('Access-Control-Allow-Origin: '.$val);
        header('Vary: Origin');
        
        return $val;
    }
        
    return null;
}
    
if (allowOrigins(['http://localhost', 'https://localhost'])) {
   echo your response here, e.g. token
}

为了对. net应用程序进行相当简单的复制/粘贴，我写这个代码是从全局变量中启用CORS。asax文件。这段代码遵循当前接受的回答中给出的建议，将请求中给出的任何原点反映到响应中。这有效地实现了'*'而不使用它。

这样做的原因是它支持多种其他CORS功能，包括发送带有'withCredentials'属性设置为'true'的AJAX XMLHttpRequest的能力。

void Application_BeginRequest(object sender, EventArgs e)
{
    if (Request.HttpMethod == "OPTIONS")
    {
        Response.AddHeader("Access-Control-Allow-Methods", "GET, POST");
        Response.AddHeader("Access-Control-Allow-Headers", "Content-Type, Accept");
        Response.AddHeader("Access-Control-Max-Age", "1728000");
        Response.End();
    }
    else
    {
        Response.AddHeader("Access-Control-Allow-Credentials", "true");

        if (Request.Headers["Origin"] != null)
            Response.AddHeader("Access-Control-Allow-Origin" , Request.Headers["Origin"]);
        else
            Response.AddHeader("Access-Control-Allow-Origin" , "*");
    }
}