Merge pull request #1165 from sobolewsk/cors-interceptor

Add CORS interceptor

modules/cpr/src/main/java/org/atmosphere/interceptor/CorsInterceptor.java

@@ -0,0 +1,55 @@
+package org.atmosphere.interceptor;
+
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.atmosphere.cpr.Action;
+import org.atmosphere.cpr.AtmosphereConfig;
+import org.atmosphere.cpr.AtmosphereInterceptor;
+import org.atmosphere.cpr.AtmosphereRequest;
+import org.atmosphere.cpr.AtmosphereResource;
+import org.atmosphere.cpr.AtmosphereResponse;
+
+/**
+ * CORS support
+ *
+ * @author Janusz Sobolewski
+ */
+public class CorsInterceptor implements AtmosphereInterceptor {
+
+    @Override
+    public void configure(AtmosphereConfig arg0) {
+    }
+
+    @Override
+    public Action inspect(AtmosphereResource resource) {
+
+        AtmosphereRequest req = resource.getRequest();                                   
+        AtmosphereResponse res = resource.getResponse();
+
+        if(req.getHeader("Origin") != null){
+            res.addHeader("Access-Control-Allow-Origin", req.getHeader("Origin"));
+            res.addHeader("Access-Control-Expose-Headers", "X-Cache-Date, X-Atmosphere-tracking-id");
+            res.setHeader("Access-Control-Allow-Credentials", "true");
+        }
+
+        if("OPTIONS".equals(req.getMethod())){
+            res.setHeader("Access-Control-Allow-Methods", "OPTIONS, GET, POST");
+            res.setHeader("Access-Control-Allow-Headers",
+                    "Origin, Content-Type, X-Atmosphere-Framework, X-Cache-Date, X-Atmosphere-tracking-id, X-Atmosphere-Transport");
+            res.setHeader("Access-Control-Max-Age", "-1");
+
+            final AtomicReference<String> emptyMessage = new AtomicReference<String>("");
+            res.write(emptyMessage.get());
+
+            return Action.SKIP_ATMOSPHEREHANDLER;
+        } 
+
+        return Action.CONTINUE;
+    }
+
+    @Override
+    public void postInspect(AtmosphereResource resource) {
+
+    }
+
+}