How to add user HTTP Headers in CXF response? - web-services

Question

For some reason there is no 'Content-Length' HTTP headers in CXF response.
I've decided to implement interceptor that does it, but unfortunately there is no added header in sent data (intercepted using Wireshark). I can set breakpoint and i can see interceptor is invoked. What's wrong?
/**
* Adds Content-Length header for the outcoming messages
*/
public class AddContentLengthInterceptor extends AbstractLoggingInterceptor {
private static final String CONTENT_LENGTH_ADDED = AddContentLengthInterceptor.class.getName() + ".log-setup";
public AddContentLengthInterceptor(String phase) {
super(phase);
addBefore(StaxOutInterceptor.class.getName());
}
public AddContentLengthInterceptor() {
this(Phase.PRE_PROTOCOL); // before streaming
}
#Override
protected Logger getLogger() {
return null;
}
#Override
public void handleMessage(Message message) throws Fault {
final OutputStream os = message.getContent(OutputStream.class);
final Writer iowriter = message.getContent(Writer.class);
if (os == null && iowriter == null) {
return;
}
// ignore double processing of the message
boolean hasAddedHeader = message.containsKey(CONTENT_LENGTH_ADDED);
if (!hasAddedHeader) {
message.put(CONTENT_LENGTH_ADDED, Boolean.TRUE);
if (os != null) {
// Write the output while caching it for adding header later
final CacheAndWriteOutputStream newOut = new CacheAndWriteOutputStream(os);
message.setContent(OutputStream.class, newOut);
newOut.registerCallback(new LoggingCallback(message, os));
}
}
}
class LoggingCallback implements CachedOutputStreamCallback {
private final Message message;
private final OutputStream origStream;
public LoggingCallback(final Message msg, final OutputStream os) {
this.message = msg;
this.origStream = os;
}
public void onFlush(CachedOutputStream cos) {
}
public void onClose(CachedOutputStream cos) {
long contentLength = cos.size();
Map<String, List<String>> headers = (Map<String, List<String>>) message.get(Message.PROTOCOL_HEADERS);
if (headers == null)
headers = new HashMap<String, List<String>>();
headers.put("Content-Length", Arrays.asList(String.valueOf(contentLength)));
message.put(Message.PROTOCOL_HEADERS, headers);
try {
// empty out the cache
cos.lockOutputStream();
cos.resetOut(null, false);
} catch (Exception ex) {
//ignore
}
message.setContent(OutputStream.class, origStream);
}
}
}
This is now server-side endpoints are created:
mediaService = new MediaService(ip, rtspPort, streamUri);
ProviderImpl provider = new ProviderImpl();
mediaEndpoint = (EndpointImpl) provider.createEndpoint(null, mediaService);
String mediaServiceURL = MessageFormat.format("http://{0}:{1}/onvif/media_service", ip, String.valueOf(port));
mediaEndpoint.publish(mediaServiceURL);
// add "Content-Length" header
mediaEndpoint.getServer().getEndpoint().getOutInterceptors().add(contentLengthInterceptor);

Answer 1

I think you are using Transfer-Encoding as chunked. Which results in no content-length header since it is defined that way in RFC.
Messages MUST NOT include both a Content-Length header field and a
non-identity transfer-coding. If the message does include a
non-identity transfer-coding, the Content-Length MUST be ignored.
I am not exactly sure but, either cxf removes your header since it is not allowed or it sets but sub layers remove it. As far as I know cxf uses HttpUrlConnection to transport your message. And that layer sets Content-length header on normal cases. But since you are using chunked transfer, that layer may override it.
In order to fix it you must change your Transfer-Encoding. And since CXF's itself sets content-length header you are no longer need to write your Interceptor.
By the way, if you use a custom header, you will realise that your interceptor works like a charm.