h1-mod/deps/json/docs/examples/parse__istream__parser_callback_t.cpp

57 lines
1.3 KiB
C++
Raw Normal View History

2024-03-07 00:54:15 -05:00
#include <iostream>
#include <iomanip>
#include <sstream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
// a JSON text
auto text = R"(
{
"Image": {
"Width": 800,
"Height": 600,
"Title": "View from 15th Floor",
"Thumbnail": {
"Url": "http://www.example.com/image/481989943",
"Height": 125,
"Width": 100
},
"Animated" : false,
"IDs": [116, 943, 234, 38793]
}
}
)";
// fill a stream with JSON text
std::stringstream ss;
ss << text;
// parse and serialize JSON
json j_complete = json::parse(ss);
std::cout << std::setw(4) << j_complete << "\n\n";
// define parser callback
json::parser_callback_t cb = [](int depth, json::parse_event_t event, json & parsed)
{
// skip object elements with key "Thumbnail"
if (event == json::parse_event_t::key and parsed == json("Thumbnail"))
{
return false;
}
else
{
return true;
}
};
// fill a stream with JSON text
ss.clear();
ss << text;
// parse (with callback) and serialize JSON
json j_filtered = json::parse(ss, cb);
std::cout << std::setw(4) << j_filtered << '\n';
}