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package org.glassfish.jersey.server.internal;
import java.io.IOException;
import java.lang.annotation.Annotation;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.ws.rs.Priorities;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.UriInfo;
import javax.ws.rs.ext.InterceptorContext;
import javax.ws.rs.ext.WriterInterceptor;
import javax.ws.rs.ext.WriterInterceptorContext;
import javax.annotation.Priority;
import javax.inject.Inject;
import javax.inject.Provider;
import org.glassfish.jersey.server.ContainerRequest;
import org.glassfish.jersey.server.JSONP;
/**
* A {@link WriterInterceptor} implementation for JSONP format. This interceptor wraps a JSON stream obtained by a underlying
* JSON provider into a callback function that can be defined by the {@link JSONP} annotation.
*
* @author Michal Gajdos (michal.gajdos at oracle.com)
* @see JSONP
*/
@Priority(Priorities.HEADER_DECORATOR)
public class JsonWithPaddingInterceptor implements WriterInterceptor {
private final Map<String, Set<String>> javascriptTypes;
private Provider<ContainerRequest> containerRequestProvider;
@Inject
public JsonWithPaddingInterceptor(Provider<ContainerRequest> containerRequestProvider) {
this.containerRequestProvider = containerRequestProvider;
javascriptTypes = new HashMap<String, Set<String>>();
javascriptTypes.put("application", new HashSet<String>(
Arrays.asList("x-javascript", "ecmascript", "javascript")));
javascriptTypes.put("text", new HashSet<String>(
Arrays.asList("javascript", "x-javascript", "ecmascript", "jscript")));
}
@Override
public void aroundWriteTo(final WriterInterceptorContext context) throws IOException, WebApplicationException {
final boolean isJavascript = isJavascript(context.getMediaType());
if (isJavascript) {
context.setMediaType(MediaType.APPLICATION_JSON_TYPE);
context.getOutputStream().write(getCallbackName(context).getBytes());
context.getOutputStream().write('(');
}
context.proceed();
if (isJavascript) {
context.getOutputStream().write(')');
}
}
/**
* Returns a flag whether the given {@link MediaType media type} belongs to the group of JavaScript media types.
*
* @param m media type to check.
* @return {@code true} if the given media type is a JavaScript type, {@code false} otherwise (or if the media type is
* {@code null}}
*/
private boolean isJavascript(MediaType m) {
if (m == null) {
return false;
}
Set<String> subtypes = javascriptTypes.get(m.getType());
return subtypes != null && subtypes.contains(m.getSubtype());
}
/**
* Returns a JavaScript callback name to wrap the JSON result into. The callback name is determined either from the {@link
* JSONP} annotation or is set to the {@value JSONP#DEFAULT_CALLBACK} if the name cannot be obtained from the {@link
* JSONP} annotation.
*
* @param context context to determine the callback name from.
* @return a JavaScript callback name.
*/
private String getCallbackName(final InterceptorContext context) {
String callback = JSONP.DEFAULT_CALLBACK;
JSONP jsonp = getJsonpAnnotation(context);
if (jsonp != null) {
callback = jsonp.callback();
if (!"".equals(jsonp.queryParam())) {
final ContainerRequest containerRequest = containerRequestProvider.get();
final UriInfo uriInfo = containerRequest.getUriInfo();
final MultivaluedMap<String, String> queryParameters = uriInfo.getQueryParameters();
final List<String> queryParameter = queryParameters.get(jsonp.queryParam());
callback = (queryParameter != null && !queryParameter.isEmpty()) ? queryParameter.get(0) : callback;
}
}
return callback;
}
/**
* Returns a {@link JSONP} annotation of the resource method responsible for handling the current request.
*
* @param context an {@link InterceptorContext interceptor context} to obtain the annotation from.
* @return {@link JSONP} annotation or {@code null} if the resource method is not annotated with this annotation.
* @see javax.ws.rs.ext.InterceptorContext#getAnnotations()
*/
private JSONP getJsonpAnnotation(final InterceptorContext context) {
final Annotation[] annotations = context.getAnnotations();
if (annotations != null && annotations.length > 0) {
for (Annotation annotation : annotations) {
if (annotation instanceof JSONP) {
return (JSONP) annotation;
}
}
}
return null;
}
}