How to construct message header for a HEAD response with restlet
I'm trying to create a HEAD response with restlet. Unfortunatly there is ony a @Get
annotation, but the restlet author states, that you have to use a @Get
, and then compare the Method.
As the documentation/specification says, there can be no body, but only a message header.
Now how to create a message header that will be send to the server, because the following code does not work, it sends this headers: HTTP/1.1 204 No Content, Content-Length: 0
protected void addResponseHeader(String name, String value) {
Form responseHeaders = (Form)getResponse().getAttributes().get(HeaderConstants.ATTRIBUTE_HEADERS);
if (responseHeaders == null) {
responseHeaders = new Form();
getResponse().getAttributes().put(HeaderConstants.ATTRIBUTE_HEADERS, responseHeaders);
}
responseHeaders.add(new Parameter(name, value));
}
The concrete code on server-side:
@Get
public void execute() {开发者_如何学C
if (Method.HEAD.equals(getMethod())) {
//optional: getResponse().getEntity().setMediaType(MediaType.TEXT_PLAIN);
getResponse().setStatus(Status.SUCCESS_OK, "hello head");
addResponseHeader("X-my-header", "value");
}
}
The client code:
@Test
public void head() {
Request request = new Request(Method.HEAD, url);
Response response = query(request);
assertEquals(Status.SUCCESS_OK, response.getStatus());
Form form = (Form)response.getAttributes().get(HeaderConstants.ATTRIBUTE_HEADERS);
assertEquals("value", form.getFirstValue("X-my-value")); // does fail because it is null
}
You just need to implement @Get for real : should work with a HTTP GET fine first. Then if you issue a HTTP HEAD, it will be handled automatically by the framework, nothing else to do on your side. Just focus on getting GET implemented correctly.
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