JSONRPC-S Module

Daniel-Constantin Mierla

   <miconda@gmail.com>

Edited by

Daniel-Constantin Mierla

   <miconda@gmail.com>

   Copyright © 2014 asipto.com
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview

              1.1. Limitations

        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1. pretty_format (int)
              3.2. transport (int)
              3.3. fifo_name (str)
              3.4. fifo_mode (int)
              3.5. fifo_group (int or str)
              3.6. fifo_user (int or str)
              3.7. fifo_reply_dir (str)

        4. Functions

              4.1. jsonrpc_dispatch()
              4.2. jsonrpc_exec(cmd)

        5. JSONRPC Transports

              5.1. JSONRPC Over HTTP
              5.2. JSONRPC Over FIFO

   List of Examples

   1.1. Set pretty_format parameter
   1.2. Set transport parameter
   1.3. Set fifo_name parameter
   1.4. Set fifo_mode parameter
   1.5. Set fifo_group parameter
   1.6. Set fifo_user parameter
   1.7. Set fifo_reply_dir parameter
   1.8. jsonrpc_dispatch usage
   1.9. jsonrpc_exec usage
   1.10. JSONRPC Over Fifo Command
   1.11. JSONRPC Over Fifo Command From Termina

Chapter 1. Admin Guide

   Table of Contents

   1. Overview

        1.1. Limitations

   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Parameters

        3.1. pretty_format (int)
        3.2. transport (int)
        3.3. fifo_name (str)
        3.4. fifo_mode (int)
        3.5. fifo_group (int or str)
        3.6. fifo_user (int or str)
        3.7. fifo_reply_dir (str)

   4. Functions

        4.1. jsonrpc_dispatch()
        4.2. jsonrpc_exec(cmd)

   5. JSONRPC Transports

        5.1. JSONRPC Over HTTP
        5.2. JSONRPC Over FIFO

1. Overview

   1.1. Limitations

   This module provides a JSON-RPC v2 server over HTTP implementation,
   tailored for the needs of Kamailio. It implements the Kamailio RPC
   interface over JSON-RPC.

   The specification for JSON-RPC is available at:
   http://www.jsonrpc.org/specification.

   The JSONRPC-S module uses the xHTTP module to handle HTTP/S requests.
   Read the documentation of the xHTTP module for more details.

1.1. Limitations

     * This module does not implement asynchronous RPC commands. It is
       unlikely that asynchronous RPC commands will be executed from an
       JSON-RPC over HTTP client.
     * This module does not accept parameters embedded in a structure (see
       the RPC documentation for more info about how parameters can be
       passed to RPC).

2. Dependencies

   2.1. Kamailio Modules
   2.2. External Libraries or Applications

2.1. Kamailio Modules

   The following modules must be loaded before this module:
     * xhttp - xHTTP.

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * None

3. Parameters

   3.1. pretty_format (int)
   3.2. transport (int)
   3.3. fifo_name (str)
   3.4. fifo_mode (int)
   3.5. fifo_group (int or str)
   3.6. fifo_user (int or str)
   3.7. fifo_reply_dir (str)

3.1. pretty_format (int)

   Pretty format for JSON-RPC response document.

   Default value is '0'.

   Example 1.1. Set pretty_format parameter
...
modparam("jsonrpc-s", "pretty_format", 1)
...

3.2. transport (int)

   Control what transports are enabled. The value can be:
     * 0 - all transports that can be enabled. For http, the xhttp module
       must be loaded. For FIFO, the fifo_name parameter must be set.
     * 1 - only HTTP transport
     * 2 - only FIFO transport

   Default value is '0'.

   Example 1.2. Set transport parameter
...
modparam("jsonrpc-s", "transport", 1)
...

3.3. fifo_name (str)

   The name of the FIFO file to be created for listening and reading
   external commands. If the given path is not absolute, the fifo file is
   created relative to run_dir (global parameter).

   Default value is NONE.

   Example 1.3. Set fifo_name parameter
...
modparam("jsonrpc-s", "fifo_name", "/tmp/kamailio_jsonrpc_fifo")
...

3.4. fifo_mode (int)

   Permission to be used for creating the listening FIFO file. It follows
   the UNIX conventions.

   Default value is 0660 (rw-rw----).

   Example 1.4. Set fifo_mode parameter
...
modparam("jsonrpc-s", "fifo_mode", 0600)
...

3.5. fifo_group (int or str)

   System Group to be used for creating the listening FIFO file.

   Default value is the inherited one (process group).

   Example 1.5. Set fifo_group parameter
...
modparam("jsonrpc-s", "fifo_group", 0)
modparam("jsonrpc-s", "fifo_group", "root")
...

3.6. fifo_user (int or str)

   System User to be used for creating the listening FIFO file.

   Default value is the inherited one (process user).

   Example 1.6. Set fifo_user parameter
...
modparam("jsonrpc-s", "fifo_user", 0)
modparam("jsonrpc-s", "fifo_user", "root")
...

3.7. fifo_reply_dir (str)

   Directory to be used for creating the reply FIFO files.

   Default value is “/tmp/”

   Example 1.7. Set fifo_reply_dir parameter
...
modparam("jsonrpc-s", "fifo_reply_dir", "/home/kamailio/tmp/")
...

4. Functions

   4.1. jsonrpc_dispatch()
   4.2. jsonrpc_exec(cmd)

4.1.  jsonrpc_dispatch()

   Handle the JSONRPC request and generate a response.

   Example 1.8. jsonrpc_dispatch usage
...
#!KAMAILIO

memdbg=5
memlog=5

debug=3
log_stderror=yes

fork=yes
children=2

tcp_accept_no_cl=yes

mpath="modules/"

loadmodule "sl.so"
loadmodule "pv.so"
loadmodule "xhttp.so"
loadmodule "jsonrpc-s.so"

request_route {
        send_reply("404", "not found");
        exit;
}

event_route[xhttp:request] {
    if(src_ip!=127.0.0.1) {
        xhttp_reply("403", "Forbidden", "text/html",
            "<html><body>Not allowed from $si</body></html>");
        exit;
        }
        if ($hu =~ "^/RPC") {
                jsonrpc_dispatch();
        } else {
        xhttp_reply("200", "OK", "text/html",
            "<html><body>Wrong URL $hu</body></html>");
    }
    return;
}
...

4.2.  jsonrpc_exec(cmd)

   Execute a JSON-RPC command given as a parameter.

   The parameter has to be a valid full JSON-RPC document. It can be a
   dynamic string with variables. The result of the command can be
   accessed via $jsonrpl(key) pseudo variables.

   Example 1.9. jsonrpc_exec usage
...
jsonrpc_exec({"jsonrpc": "2.0", "method": "dispatcher.reload", "id": 1}');
...

5. JSONRPC Transports

   5.1. JSONRPC Over HTTP
   5.2. JSONRPC Over FIFO

   JSONRPC specifications do not enforce a specific transport to carry the
   JSON documents. Very common is JSONRPC over HTTP or HTTPS, and they are
   supported by Kamailio. In addition, Kamailio supports receiving JSON
   documents via a local FIFO file.

5.1. JSONRPC Over HTTP

   It requires that XHTTP module is loaded. HTTPS can be used if you
   enable TLS for Kamailio. The JSONRPC requests have to be sent to the
   TCP or TLS ports of Kamailio.

   The 'transport' parameter has to be 0 or 1.

   The format of the JSON document must follow the JSONRPC specifications.

5.2. JSONRPC Over FIFO

   This module can retrive JSONRPC requests via a local FIFO file. To
   enable this feature, 'fifo_name' parameter must be set and 'transport'
   parameter has to be 0 or 2.

   The format of the JSON document must follow the JSONRPC specifications
   plus an additional field named 'reply_name'. The value for this field
   must be the name of the FIFO file were to write the JSONRPC response.
   The reply FIFO file is created in the folder specified by
   'fifo_reply_dir'. Next is an example showing a JSONRPC command to be
   sent via FIFO transport.

   Example 1.10. JSONRPC Over Fifo Command
...
{
 "jsonrpc": "2.0",
  "method": "core.psx",
  "reply_name": "kamailio_jsonrpc_reply_fifo",
  "id": 1
}
...

   Next is an example of how to test it from a terminal, assuming that the
   parameter 'fifo_name' is set to '/tmp/kamailio_jsonrpc_fifo'.

   Example 1.11. JSONRPC Over Fifo Command From Termina
...
mkfifo /tmp/kamailio_jsonrpc_reply_fifo
cat /tmp/kamailio_jsonrpc_reply_fifo &
echo '{"jsonrpc": "2.0", "method": "core.psx", \
          "reply_name": "kamailio_jsonrpc_reply_fifo", "id": 1}' \
     > /tmp/kamailio_jsonrpc_fifo
rm /tmp/kamailio_jsonrpc_reply_fifo
