json_lines.md

JSON Lines Support

JSON Lines is in the form of an iterator daw::json::json_lines_iterator and a range daw::json::json_lines_range like object. They allow iteration over each lines in the JSON Lines file.

Parsing JSON Lines

A working example can be seen at json_lines_test.cpp

{
  "a": 1,
  "b": false
}
{
  "a": 2,
  "b": true
}

The code to iterate over these elements can look like

struct Element {
  int a;
  bool b;
};

namespace daw::json {
  template<>
  struct json_data_contract<Element> {
    static constexpr char const a[] = "a";
    static constexpr char const b[] = "b";
    using type = json_member_list<json_link<a, int>, json_link<b, bool>>;
  };
} // namespace daw::json

int main( ) {
  auto jl_range = daw::json::json_lines_range<Element>( json_lines_doc );
  for( Element e : jl_range ) {
    std::cout << e.a << ", " << e.b << '\n';
  }  
}

Serializing to JSON Lines

Staring with the Element type in the previous example, one can output to a JSON Line document as follows.

std::vector<Element> elements = get_element_vector( );
auto result = std::string( );
for( auto const & e : elements ) {
  daw::json::to_json( e, result );
  result += '\n';
}