This tutorial uses NIST SIP JAIN Reference Implementation. Download the NIST source code from
here.
Note: To understand the Authorization process for handling 401 response code from server please go through
this tutorial.
REGISTER request is used to update the current location of a user on the REGISTRAR server. The application sends a REGISTER message informing the server its current location which in turn is stored in location server. When a caller calls a user the proxy server uses this information to find the location of the callee.
Register request should be sent by the client periodically. The validity of the REGISTER request is determined by the
Expires header.
Flow
Sample Request[code]
REGISTER sip:sip.linphone.org SIP/2.0
Call-ID: 0a0f14355fa76ae6435b98bfe085baf9@223.1.1.128
CSeq: 1 REGISTER
From: <sip:vkslabs@sip.linphone.org>;tag=-1427592833
To: <sip:vkslabs@sip.linphone.org>
Max-Forwards: 70
Via: SIP/2.0/TCP 223.1.1.128:5060;branch=z9hG4bK-323532-2a454f4ec2a4213f6d6928eba479521d
Contact: <sip:vkslabs@223.1.1.128;transport=tcp>
Content-Length: 0
[/code]
Now lets see how to construct the above request using the NIST SIP Stack.
First step is to create a class that implements the SIPListener. Make sure your SIP Stack is
Initializing NIST JAIN SIP Stack.
1. Create
Call-ID header
[java] CallIdHeader callIdHeader = this.sipProvider.getNewCallId(); [/java]
2. Create
CSeq header
[java] CSeqHeader cSeqHeader = this.headerFactory.createCSeqHeader(cseq, "REGISTER"); [/java]
3. Create
From header
[java] Address fromAddress = addressFactory.createAddress("sip:" + username + '@' + server);
FromHeader fromHeader = this.headerFactory.createFromHeader(fromAddress, String.valueOf(this.tag));
[/java]
4. Create
To Header
[java] ToHeader toHeader = this.headerFactory.createToHeader(fromAddress, null); [/java]
5. Create
Max-Forwards header
[java] MaxForwardsHeader maxForwardsHeader = this.headerFactory.createMaxForwardsHeader(70); [/java]
6. Create a
Via header
[java]
ArrayList viaHeaders = new ArrayList();
ViaHeader viaHeader = this.headerFactory.createViaHeader(this.ip, this.port, "tcp", null);
viaHeaders.add(viaHeader);
[/java]
7. Create
contact header
[java]
this.contactAddress = this.addressFactory.createAddress("sip:" + this.username + '@' + this.ip + "transport=tcp");
// Create the contact header used for all SIP messages.
this.contactHeader = this.headerFactory.createContactHeader(contactAddress);
[/java]
Once all the headers are created it is time to create the request itself.
[java]
request = this.messageFactory.createRequest("REGISTER sip:" + server + "SIP/2.0\r\n\r\n");
request.addHeader(callIdHeader);
request.addHeader(cSeqHeader);
request.addHeader(fromHeader);
request.addHeader(toHeader);
request.addHeader(maxForwardsHeader);
request.addHeader(viaHeader);
request.addHeader(contactHeader);
[/java]
Now that the request object is created with all the necessary headers it is time to send the request.
[java] inviteTid = sipProvider.getNewClientTransaction(request);
// send the request out.
inviteTid.sendRequest();
[/java]
Once the request is sent successfully the response will be passed to the application using the processResponse callback in SIPListener.
[java]
public void processResponse(ResponseEvent responseEvent) {
int statusCode = responseEvent.getResponse().getStatusCode();
}
[/java]
Code[java]
public void register(Response response) {
try {
cseq++;
ArrayList viaHeaders = new ArrayList();
ViaHeader viaHeader = this.headerFactory.createViaHeader(this.ip,
this.port, "tcp", null);
viaHeaders.add(viaHeader);
// The "Max-Forwards" header.
MaxForwardsHeader maxForwardsHeader = this.headerFactory
.createMaxForwardsHeader(70);
// The "Call-Id" header.
CallIdHeader callIdHeader = this.sipProvider.getNewCallId();
// The "CSeq" header.
CSeqHeader cSeqHeader = this.headerFactory.createCSeqHeader(cseq,
"REGISTER");
Address fromAddress = addressFactory.createAddress("sip:"
+ username + '@' + server);
FromHeader fromHeader = this.headerFactory.createFromHeader(
fromAddress, String.valueOf(this.tag));
// The "To" header.
ToHeader toHeader = this.headerFactory.createToHeader(fromAddress,
null);
// this.contactHeader = this.headerFactory
// .createContactHeader(contactAddress);
request = this.messageFactory.createRequest("REGISTER sip:"
+ server + " SIP/2.0\r\n\r\n");
request.addHeader(callIdHeader);
request.addHeader(cSeqHeader);
request.addHeader(fromHeader);
request.addHeader(toHeader);
request.addHeader(maxForwardsHeader);
request.addHeader(viaHeader);
request.addHeader(contactHeader);
if (response != null) {
retry = true;
AuthorizationHeader authHeader = Utils.makeAuthHeader(headerFactory, response,
request, username, password);
request.addHeader(authHeader);
}
inviteTid = sipProvider.getNewClientTransaction(request);
// send the request out.
inviteTid.sendRequest();
this.dialog = inviteTid.getDialog();
// Send the request statelessly through the SIP provider.
// this.sipProvider.sendRequest(request);
// Display the message in the text area.
logger.debug("Request sent:\n" + request.toString() + "\n\n");
} catch (Exception e) {
// If an error occurred, display the error.
e.printStackTrace();
logger.debug("Request sent failed: " + e.getMessage() + "\n");
}
}
[/java]
Download the complete working code from
here.
