how to change standard header value in restlets?

Question

Whether the server closes the connection or not, depends on whether the client request asks for the connection to close or not.

Here is a sample Server code:

import org.restlet.data.Form;
import org.restlet.data.MediaType;
import org.restlet.data.Parameter;
import org.restlet.resource.Get;
import org.restlet.resource.ServerResource;
import org.restlet.util.Series;

public class TestRestlet extends ServerResource {
    @Get
    public String getImpl(){
        return "Sample Response Text\r\n";
    }
}

And here is what i got on linux commmand line (using only telnet): [Please note that the last line in request-header in each request is followed by 2 newlines] [To avoid any confusion, some of the requests do not contain request-body.]

[root@mylinuxserver]# telnet 172.16.101.34 6060
Trying 172.16.101.34...
Connected to win7comp01 (172.16.101.34).
Escape character is '^]'.
GET /TestRestlet HTTP/1.1
Host: 172.16.101.34:6060

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=C2E77F4D0437E525A0FC66498EF09E8B; Path=/hotelSoft
Date: Wed, 31 Jul 2013 08:25:44 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.0.15
Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept
Content-Type: application/json;charset=UTF-8
Content-Length: 22

Sample Response Text

GET /TestRestlet HTTP/1.1
Host: 172.16.101.34:6060
Connection: Keep-Alive

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=1873DE26443F5DF62379B895AEA0F004; Path=/hotelSoft
Date: Wed, 31 Jul 2013 08:25:48 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.0.15
Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept
Content-Type: application/json;charset=UTF-8
Content-Length: 22

Sample Response Text

GET /TestRestlet HTTP/1.1
Host: 172.16.101.34:6060
Connection: close

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=43EC7C9AACC6C0CEF6FAC8F608B1D79C; Path=/hotelSoft
Date: Wed, 31 Jul 2013 08:25:57 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.0.15
Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept
Content-Type: application/json;charset=UTF-8
Content-Length: 22
Connection: close

Sample Response Text
Connection closed by foreign host.
[root@mylinuxserver]# telnet 172.16.101.34 6060
Trying 172.16.101.34...
Connected to win7comp01 (172.16.101.34).
Escape character is '^]'.
GET /TestRestlet HTTP/1.0

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=2C879A91F2501DD9D3B39EF50C3F46CA; Path=/hotelSoft
Date: Wed, 31 Jul 2013 08:26:09 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.0.15
Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept
Content-Type: application/json;charset=UTF-8
Content-Length: 22
Connection: close

Sample Response Text
Connection closed by foreign host.
[root@mylinuxserver]# telnet 172.16.101.34 6060
Trying 172.16.101.34...
Connected to win7comp01 (172.16.101.34).
Escape character is '^]'.
GET /TestRestlet

Sample Response Text
Connection closed by foreign host.
[root@mylinuxserver]#

In the above examples, several types of HTTP connections are made.

The response to the 1st request:

GET /TestRestlet HTTP/1.1
Host: 172.16.101.34:6060

[Note: the line Host: 172.16.101.34:6060 is followed by 2 \r\n: \r\n\r\n]

is:

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=C2E77F4D0437E525A0FC66498EF09E8B; Path=/hotelSoft
Date: Wed, 31 Jul 2013 08:25:44 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.0.15
Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept
Content-Type: application/json;charset=UTF-8
Content-Length: 22

Sample Response Text

The connection is not closed yet, and we send another request:

GET /TestRestlet HTTP/1.1
Host: 172.16.101.34:6060
Connection: Keep-Alive

That gets the response:

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=1873DE26443F5DF62379B895AEA0F004; Path=/hotelSoft
Date: Wed, 31 Jul 2013 08:25:48 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.0.15
Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept
Content-Type: application/json;charset=UTF-8
Content-Length: 22

Still the connection is not closed.

However on the 3rd request:

GET /TestRestlet HTTP/1.1
Host: 172.16.101.34:6060
Connection: close

The connection is closed, because the request contains Connection: close header. You can see the telnet exits after displaying a message: Connection closed by foreign host.

There are 2 more sample request-response in the above given examples:

1.An HTTP 1.0 request:

GET /TestRestlet HTTP/1.0

With response:

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=2C879A91F2501DD9D3B39EF50C3F46CA; Path=/hotelSoft
Date: Wed, 31 Jul 2013 08:26:09 GMT
Accept-Ranges: bytes
Server: Restlet-Framework/2.0.15
Vary: Accept-Charset, Accept-Encoding, Accept-Language, Accept
Content-Type: application/json;charset=UTF-8
Content-Length: 22
Connection: close

Sample Response Text

And the telnet exits after displaying: Connection closed by foreign host.

2.A request without HTTP version mentioned:

GET /TestRestlet

And response is: (Without headers)

Sample Response Text

And the telnet exits with a message: Connection closed by foreign host.

Conclusion:

Whatever is your client / client-program , make it send an HTTP-1.0 request , or a HTTP-1.1 request with Connection: close header.

In Java, you achieve this by:

import java.net.HttpURLConnection;
import java.net.URL;
.
.
.
HttpURLConnection httpURLConnection = (HttpURLConnection) new URL("http://....").openConnection();
httpURLConnection.setRequestProperty("Connection","close");
// rest of the code here....

Also check if a statement like this:

httpURLConnection.disconnect();

can help you disconnect the connection.