[sr-dev] git:mgw/json: json: use libjansson instead of libjson-c in order to support JSONPath access to object values ; provide tests

[Matthew Williams]

Last night I pushed an updated json module to branch mgw/json. It has
significant improvements over the previous version, including:

* A way to access nested elements, using a subset of JSONPath.
* The ability to loop over arrays

Note that there is a change in the external dependency from libjson-c to
libjansson.

Matthew Williams



Documentation:


JSON Module

Joe Hillenbrand

   <joe at flowroute.com>

Edited by

Matthew Williams

   <matthew at flowroute.com>

   Copyright © 2013 Flowroute LLC (flowroute.com)
     __________________________________________________________________

   Table of Contents

   1. Admin Guide

        1. Overview
        2. Dependencies

              2.1. Kamailio Modules
              2.2. External Libraries or Applications

        3. Parameters

              3.1.

        4. Functions

              4.1. json_path_get(json_string, json_path, destination)
              4.2. json_array_size(json_string, json_path, destination)
              4.3. json_get_field(json_string, field_name, destination)

   List of Examples

   1.1. json_path_get usage
   1.2. json_array_size usage
   1.3. json_get_field usage

Chapter 1. Admin Guide

   Table of Contents

   1. Overview
   2. Dependencies

        2.1. Kamailio Modules
        2.2. External Libraries or Applications

   3. Parameters

        3.1.

   4. Functions

        4.1. json_path_get(json_string, json_path, destination)
        4.2. json_array_size(json_string, json_path, destination)
        4.3. json_get_field(json_string, field_name, destination)

1. Overview

   This module provides operations on json strings.

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:
     * None

2.2. External Libraries or Applications

   The following libraries or applications must be installed before
   running Kamailio with this module loaded:
     * jansson (http://www.digip.org/jansson/), tested with: 2.2+

3. Parameters

   3.1.

   None

4. Functions

   4.1. json_path_get(json_string, json_path, destination)
   4.2. json_array_size(json_string, json_path, destination)
   4.3. json_get_field(json_string, field_name, destination)

4.1.  json_path_get(json_string, json_path, destination)

   Copy the value at the path from json object 'json_string' and store it
   in pvar 'destination'.

   The path string supports dot delimited notation (e.g. foo.bar.baz),
   array notation (e.g. list[0]), or a combination of the two (e.g.
   foo.bar[0][1].baz).

   The function can put a string, integer, null, or new json string into
   destination.

   Example 1.1. json_path_get usage
...
json_path_get($var(myjson), "inner.deep.num", "$var(n)");
xlog("foo is $var(n)");
...

4.2.  json_array_size(json_string, json_path, destination)

   Puts size of the array in 'json_string' at 'json_path' into the pvar
   'destination'.

   This is particularly useful for looping through an array. See example.

   Example 1.2. json_array_size usage
...
$var(array) = "{\"loopme\":[0,1,2,3,4,5]}";
$var(count) = 0;
json_array_size($var(array), "loopme", "$var(size)");
while($var(count) < $var(size)) {
    json_path_get($var(array), "loopme[$var(count)]", "$var(v)");
    xlog("loopme[$var(count)] == $var(v)\n");
    $var(count) = $var(count) + 1;
}
...

4.3.  json_get_field(json_string, field_name, destination)

   Copy field 'field_name' from json object 'json_string' and store it in
   pvar 'destination'.

   This function is deprecated but kept for backwards compatibility. Right
   now it is just a wrapper around json_path_get, and its functionality is
   the same.

   Example 1.3. json_get_field usage
...
json_get_field("{'foo':'bar'}", "foo", "$var(foo)");
xlog("foo is $var(foo)");
...
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