iterate and retrieve nested object in JSON using rapidjson

Question

I am parsing a JSON structure which is similar as follows

{
    \"item1\" : \"value1\"
    \"item2\" : \"value2\"
    // ...
    \"itemn\" : {
          


        

Answer 1

I was wondering the same very recently, here is what i got :

#include "rapidjson\filereadstream.h"
#include "rapidjson\document.h"
#include "rapidjson\istreamwrapper.h"
#include 
#include 

using namespace rapidjson;

// Documentation : using file stream instead of C FILE pointers
// http://rapidjson.org/md_doc_stream.html#FileStreams
ifstream file_stream(filepath);
IStreamWrapper isw(file_stream);

Document doc;
doc.ParseStream(isw);
file_stream.close();

if(doc.HasMember(CONF_NODE)){
Value *config_node = &(doc[CONF_NODE]);
// Now I can use it like so:
std::cout << (*config_node)["My Other Json node"].GetString() << std::endl;
}

I used this trick several times to avoid using unterminably long accessing request like

 doc["Node1"]["Node2"]["Node3"]...["NodeX"].GetType() 

and instead rely on pointers that could be used to virtually "split" the doc chain:

doc["Node1"]["Node2"]["Node3"]...["NodeX"].GetType()
                     |            |
                 pointer1         |
                                  pointer2
(*pointer_on_Node_N)["Node N+1"] = doc["Node1"][...]["NodeN"]["Node N+1]

That was particularly handy when I needed to iterate over my file (when facing arrays).