C: How to parse a value from Json request? - c

Question

I am attempting to use the cJSON library, written by Dave Gamble, to read in the following JSON request:
{"id":"8358441244995838759","jsonrpc":"2.0","method":"addext",
"params":["<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>
<trunks id=\"0\"><end_ch>3</end_ch>
<gateway>172.20.222.52</gateway>
<interface_type>E231</interface_type>
<name>Mumbai_Avaya</name>
<start_ch>12</start_ch>
<sub_type>E1PRI</sub_type></trunks>"]}
I am able to retrieve the "id" and "method" by using below code, but not able to retrieve or print the values inside "params" which is an XML string.
I want to print whatever inside the "params".
cJSON *cjson, *method_obj;
char *methodname;
char *params;
cjson = cJSON_Parse(buf);
method_obj = cJSON_GetObjectItem(cjson, "method");
methodname = method_obj->valuestring;
printf("method name %s\n", methodname);
method_obj = cJSON_GetObjectItem(cjson, "id");
id = method_obj->valueint;
char *str = method_obj->valuestring;
printf("id %s\n", str);
method_obj = cJSON_GetObjectItem(cjson, "params");
params=method_obj->valuestring;
printf("Params [ ] %s\n", params);
Please provide any suggestion.
Thanks in Advance.

Answer 1

Either change method_obj->valuestring to method_obj->child->valuestring (after checking that child != NULL), or have the service, that generates the JSON request, not use an array if none is needed.

Answer 2

params of field type is JSON Array.
use cJSON_GetArrayItem (and cJSON_GetArraySize) API like this:
method_obj = cJSON_GetObjectItem(cjson, "params");
int size = cJSON_GetArraySize(method_obj);
for(int i = 0; i < size; ++i){
params = cJSON_GetArrayItem(method_obj, i)->valuestring;
printf("Params [ ] %s\n", params);
}