No 'Access-Control-Allow-Origin' header is

问题:

I am working on a webapplication comprises UI-Angular , Server-Java , RestEasy 3.0.9.Final for rest api calls

When i tried to access the rest service from another domain am getting below error

CANNOT LOAD Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8080' is therefore not allowed access.

I configured my server side to respond with the cross domain calls and this is working with the GET Call but POST Call is creating ERROR

web.xml

<context-param>
    <param-name>resteasy.providers</param-name>
    <param-value>com.test.sample.app.CorsFeature</param-value>
</context-param>

<listener>
    <listener-class>
        org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap</listener-class>
</listener>


<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
    <servlet-name>resteasy-servlet</servlet-name>
    <servlet-class>
        org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher</servlet-class>
    <init-param>
        <param-name>javax.ws.rs.Application</param-name>
        <param-value>com.test.sample.app.Application</param-value>
    </init-param>
</servlet>

<servlet-mapping>
    <servlet-name>resteasy-servlet</servlet-name>
    <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

<context-param>
    <param-name>resteasy.servlet.mapping.prefix</param-name>
    <param-value>/rest</param-value>
</context-param>
<context-param>
    <param-name>resteasy.scan</param-name>
    <param-value>true</param-value>
</context-param>

Service class

@GET
@Path("/getnameAtt")
@Produces(MediaType.APPLICATION_JSON)
public Response getHostnameAttributes() {
return Response
.status(200)
.header("Access-Control-Allow-Origin", "*")
.header("Access-Control-Allow-Headers",
        "origin, content-type, accept, authorization")
.header("Access-Control-Allow-Credentials", "true")
.header("Access-Control-Allow-Methods",
        "GET, POST, PUT, DELETE, OPTIONS, HEAD")
.header("Access-Control-Max-Age", "1209600")
.entity(new TestImpl().getHostNameAttributes())
.build();
}

@POST
@Path("/getSeq")
@Produces(MediaType.APPLICATION_JSON)
public Response getCurrentSequence(String request) {
return Response
.status(200)
.header("Access-Control-Allow-Origin", "*")
.header("Access-Control-Allow-Headers",
        "origin, content-type, accept, authorization")
.header("Access-Control-Allow-Credentials", "true")
.header("Access-Control-Allow-Methods",
        "GET, POST, PUT, DELETE, OPTIONS, HEAD")
.header("Access-Control-Max-Age", "1209600")
.entity(new TestImpl().getCurrentSeq(request))
.build();
}

Since i am new to resteasy not able to figure out why this was not working. Any help would be greatly appreciated . Waiting for your response.

Thanks

回答1:

Your resource methods won't get hit, so their headers will never get set. The reason is that there is what's called a preflight request before the actual request, which is an OPTIONS request. So the error comes from the fact that the preflight request doesn't produce the necessary headers.

For RESTeasy, you should use CorsFilter. You can see here for some example how to configure it. This filter will handle the preflight request. So you can remove all those headers you have in your resource methods.

See Also:

• HTTP access control (CORS)

回答2:

Seems your resource POSTmethod won't get hit as @peeskillet mention. Most probably your ~POST~ request won't work, because it may not be a simple request. The only simple requests are GET, HEAD or POST and request headers are simple(The only simple headers are Accept, Accept-Language, Content-Language, Content-Type= application/x-www-form-urlencoded, multipart/form-data, text/plain).

Since in you already add Access-Control-Allow-Origin headers to your Response, you can add new OPTIONS method to your resource class.

    @OPTIONS
@Path("{path : .*}")
public Response options() {
    return Response.ok("")
            .header("Access-Control-Allow-Origin", "*")
            .header("Access-Control-Allow-Headers", "origin, content-type, accept, authorization")
            .header("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, HEAD")
            .header("Access-Control-Max-Age", "2000")
            .build();
}