c++ - Parse JSON array as std::string with Boost ptree

Question

I have this code that I need to parse/or get the JSON array as std::string to be used in the app.

std::string ss = "{ "id" : "123", "number" : "456", "stuff" : [{ "name" : "test" }] }";

ptree pt2;
std::istringstream is(ss);
read_json(is, pt2);
std::string id = pt2.get<std::string>("id");
std::string num= pt2.get<std::string>("number");
std::string stuff = pt2.get<std::string>("stuff"); 

What is needed is the "stuff" to be retrieved like this as std::string [{ "name" : "test" }]

However the code above stuff is just returning empty string. What could be wrong

Answer 1

Arrays are represented as child nodes with many "" keys:

docs

• JSON arrays are mapped to nodes. Each element is a child node with an empty name. If a node has both named and unnamed child nodes, it cannot be mapped to a JSON representation.

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#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>

using boost::property_tree::ptree;

int main() {
    std::string ss = "{ "id" : "123", "number" : "456", "stuff" : [{ "name" : "test" }, { "name" : "some" }, { "name" : "stuffs" }] }";

    ptree pt;
    std::istringstream is(ss);
    read_json(is, pt);

    std::cout << "id:     " << pt.get<std::string>("id") << "
";
    std::cout << "number: " << pt.get<std::string>("number") << "
";
    for (auto& e : pt.get_child("stuff")) {
        std::cout << "stuff name: " << e.second.get<std::string>("name") << "
";
    }
}

Prints

id:     123
number: 456
stuff name: test
stuff name: some
stuff name: stuffs