ATEST-259:

- adding simple CORS filter which includes some standard cors headers

src/main/java/ch/psi/daq/queryrest/config/QueryRestConfig.java

@@ -9,6 +9,7 @@ import java.util.function.Function;
 
 import javax.annotation.PostConstruct;
 import javax.annotation.Resource;
+import javax.servlet.Filter;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -41,6 +42,7 @@ import ch.psi.daq.query.model.Query;
 import ch.psi.daq.query.model.QueryField;
 import ch.psi.daq.query.model.impl.AbstractQuery;
 import ch.psi.daq.queryrest.controller.validator.QueryValidator;
+import ch.psi.daq.queryrest.filter.SimpleCORSFilter;
 import ch.psi.daq.queryrest.model.PropertyFilterMixin;
 import ch.psi.daq.queryrest.response.JsonByteArraySerializer;
 import ch.psi.daq.queryrest.response.JsonStreamSerializer;
@@ -178,6 +180,11 @@ public class QueryRestConfig extends WebMvcConfigurerAdapter {
    public Validator queryValidator() {
       return new QueryValidator();
    }
+   
+   @Bean
+   public Filter simpleCORSFilter() {
+      return new SimpleCORSFilter();
+   }
 
    // ==========================================================================================
    // TODO: This is simply for initial / rudimentary testing - remove once further evolved

src/main/java/ch/psi/daq/queryrest/filter/SimpleCORSFilter.java

@@ -0,0 +1,41 @@
+package ch.psi.daq.queryrest.filter;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Component;
+
+@Component
+public class SimpleCORSFilter implements Filter {
+
+    @Value("${queryrest.enableCORS}")
+    private boolean enableCORS;
+
+    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException,
+            ServletException {
+
+        if (enableCORS) {
+            HttpServletResponse response = (HttpServletResponse) res;
+            response.setHeader("Access-Control-Allow-Origin", "*");
+            response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
+            response.setHeader("Access-Control-Max-Age", "3600");
+            response.setHeader("Access-Control-Allow-Headers",
+                    "Content-Type, Cache-Control, Accept, Authorization, X-Requested-With");
+        }
+        chain.doFilter(req, res);
+    }
+
+    public void init(FilterConfig filterConfig) {
+    }
+
+    public void destroy() {
+    }
+}

src/main/resources/queryrest.properties

@@ -1,4 +1,9 @@
 # defines the fields that are included in the response 
 # if no fields have been specified by the user
 queryrest.default.response.fields=channel,pulseId,globalMillis,globalNanos,iocMillis,iocNanos,shape,value
-queryrest.default.response.aggregations=min,max,sum
+
+# aggregation which are included in the response by default if aggregation is enabled for a given query
+queryrest.default.response.aggregations=min,max,sum
+
+# enables / disables the CORS servlet filter. Adds multiple CORS headers to the response
+queryrest.enableCORS=true