sip-parser

A simple npm package for parsing and stringifying SIP messages.

Install

npm install sip-parser

Features

* Parse raw SIP messages into JavaScript objects.
* Stringify JS objects into SIP messages.
* Distinguishes requests and responses automatically.
* TypeScript typing.

Usage

parse and stringify functions automatically recognize whether the message in question is a request or a response. In the parsed object, requests have a method field while responses have a statusCode field.

Requests

$3

Use the parse(message) function to parse a raw SIP message into a JavaScript object.
``JavaScript
import { parse } from 'sip-parser';

// In a real use case, maybe you get this from a TCP socket.
const messageString =
'INVITE sip:bob@biloxi.com SIP/2.0\r\n' +
'Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKkjshdyff\r\n' +
'To: Bob \r\n' +
'From: Alice ;tag=88sja8x\r\n' +
'Max-Forwards: 70\r\n' +
'Subject: I know you are there\r\n' +
' pick up the phone\r\n' +
' and answer!\r\n' +
'Call-ID: 987asjd97y7atg\r\n' +
'CSeq: 986759 INVITE';

const parsedMessage = parse(messageString);

console.log(JSON.stringify(parsedMessage, null, 4));
`
This will print:
`JSON
{
"method": "INVITE",
"version": "2.0",
"requestUri": {
"user": "bob",
"host": "biloxi.com"
},
"headers": [
{
"fieldName": "Via",
"fieldValue": "SIP/2.0/UDP pc33.atlanta.com",
"parameters": [
{
"name": "branch",
"value": "z9hG4bKkjshdyff"
}
]
},
{
"fieldName": "To",
"fieldValue": "Bob "
},
{
"fieldName": "From",
"fieldValue": "Alice ",
"parameters": [
{
"name": "tag",
"value": "88sja8x"
}
]
},
{
"fieldName": "Max-Forwards",
"fieldValue": "70"
},
{
"fieldName": "Subject",
"fieldValue": "I know you are there pick up the phone and answer!"
},
{
"fieldName": "Call-ID",
"fieldValue": "987asjd97y7atg"
},
{
"fieldName": "CSeq",
"fieldValue": "986759 INVITE"
}
],
"content": ""
}
`

$3


Essentially, stringify(messageObject) is an inverse opration of parse. In the following example, we first parse a message and then stringify it back to SIP format. In your application, you most likely want to manipulate the message a bit more or create it from scratch in your application logic.

`JavaScript
import { parse, stringify } from 'sip-parser';

const messageString =
'INVITE sip:bob@biloxi.com SIP/2.0\r\n' +
'Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKkjshdyff\r\n' +
'To: Bob \r\n' +
'From: Alice ;tag=88sja8x\r\n' +
'Max-Forwards: 70\r\n' +
'Subject: I know you are there\r\n' +
' pick up the phone\r\n' +
' and answer!\r\n' +
'Call-ID: 987asjd97y7atg\r\n' +
'CSeq: 986759 INVITE';

// In a real use case, you would build the message object in your
// application logic, whatever it might be.
const parsedMessage = parse(messageString);
// See the format of the parsed message in the previous example.
const stringifiedMessage = stringify(parsedMessage)
console.log(stringifiedMessage)
`
This would print:
`
INVITE sip:bob@biloxi.com SIP/2.0
Via: SIP/2.0/UDP pc33.atlanta.com;branch=z9hG4bKkjshdyff
To: Bob
From: Alice ;tag=88sja8x
Max-Forwards: 70
Subject: I know you are there pick up the phone and answer!
Call-ID: 987asjd97y7atg
CSeq: 986759 INVITE
`

Responses


SIP responses are very similar to requests; they only differ in the start line. Parsed responses have statusCode and reason fields:
`JavaScript
import { parse } from 'sip-parser';

const sipResponse =
'SIP/2.0 200 OK\r\n' +
'Via: SIP/2.0/UDP bobspc.biloxi.com:5060;branch=z9hG4bKnashds7\r\n' +
' ;received=192.0.2.4\r\n' +
'To: Bob ;tag=2493k59kd\r\n' +
'From: Bob ;tag=456248\r\n' +
'Call-ID: 843817637684230@998sdasdh09\r\n' +
'CSeq: 1826 REGISTER\r\n' +
'Contact: \r\n' +
'Expires: 7200\r\n' +
'Content-Length: 0';

const parsedResponse = parse(sipResponse);
console.log(JSON.stringify(parsedResponse, null, 4));
`
Prints:
`JSON
{
"version": "2.0",
"statusCode": 200,
"reason": "OK",
"headers": [
{
"fieldName": "Via",
"fieldValue": "SIP/2.0/UDP bobspc.biloxi.com:5060",
"parameters": [
{
"name": "branch",
"value": "z9hG4bKnashds7"
},
{
"name": "received",
"value": "192.0.2.4"
}
]
},
{
"fieldName": "To",
"fieldValue": "Bob ",
"parameters": [
{
"name": "tag",
"value": "2493k59kd"
}
]
},
{
"fieldName": "From",
"fieldValue": "Bob ",
"parameters": [
{
"name": "tag",
"value": "456248"
}
]
},
{
"fieldName": "Call-ID",
"fieldValue": "843817637684230@998sdasdh09"
},
{
"fieldName": "CSeq",
"fieldValue": "1826 REGISTER"
},
{
"fieldName": "Contact",
"fieldValue": ""
},
{
"fieldName": "Expires",
"fieldValue": "7200"
},
{
"fieldName": "Content-Length",
"fieldValue": "0"
}
],
"content": ""
}
`
Obviously, stringifying the resulting object returns a valid SIP response string.

Types


You can easily import all types, if you want to use them in the definitions of your own functions and variables:
`JavaScript
import { types as SipTypes } from 'sip-parser';

export function getHeader(message: SipTypes.SIPMessage, headerName: string): SipTypes.Header | undefined {
return message.headers.find(h => h.fieldName.toLocaleLowerCase() === headerName.toLocaleLowerCase());
}
``