Json string Comparision

Question

I am working on a c++ project where I need to compare two or more Json string that will be passed to me as arguments in a function and i have to return a bool accordingly. I am using Jsoncpp but I am unable to compare the entirety of the two Json datas. I want to know the best procedure to loop in the key and value and check the value with corresponding value of another json string (both String will be passed to the function and will be parsed using reader.parse() of jsoncpp and then i need to compare them both and return the bool value). Can anyone help me with this please? thank you in advance. The place where I am stuck:

class test {
public:
static bool isequalstring(const std::string &item1, const std::string 
&item2, const std::string &temp) {

    Document d1;
    d1.Parse(item1.c_str());
    Document d2;
    d2.Parse(item2.c_str());

    Document d3;
    d3.Parse(temp.c_str());


    bool matched = true;
    //itr= iterate through the third json to get the keys and match the keys in first and second
    for (auto itr = d3.MemberBegin(); itr != d3.MemberEnd(); itr++) {

        if (d1.HasMember(itr->name) && d2.HasMember(itr->name)) {       // if the member doesn't exist in both, break
            if (d1[itr->name] != d2[itr->name]) {
                // value doesn't match, then break
                matched = false;

                break;

            }

        } else {
            matched = false;
            break;
        }
    }
    return matched;
}
  };
bool testDeepNestedJson_should_succeed(){
bool expectedTestResult = true;
bool testResult;

// Input 1 JSON Object
const char* input1 = "{\"array\":[1,2,3],\"boolean\":true,\"null\":null,\"number\":123,\"object\":{\"a\":\"b\",\"c\":\"d\",\"e\":\"f\"},\"string\":\"Hello World\",\"object_array\":[{\"key\":\"value1\"},{\"key\":\"value2\"},{\"key\":\"value3\"}],\"deep_nested_array\":[{\"object_array\":[{\"key\":\"value1\"},{\"key\":\"value2\"},{\"key\":\"value3\"}]},{\"object_array\":[{\"key\":\"value4\"},{\"key\":\"value5\"},{\"key\":\"value6\"}]}]}";
const char* input2 = "{\"array\":[1,2,3],\"justsomedata\":true,\"boolean\":true,\"null\":null,\"object\":{\"a\":\"b\",\"c\":\"d\",\"e\":\"f\"},\"number\":123,\"object_array\":[{\"key\":\"value1\"},{\"key\":\"value2\"},{\"key\":\"value3\"}],\"deep_nested_array\":[{\"object_array\":[{\"key\":\"value1\"},{\"key\":\"value2\"},{\"key\":\"value3\"}]},{\"object_array\":[{\"key\":\"value4\"},{\"key\":\"value5\"},{\"key\":\"value6\",\"ignoreme\":12346}]}],\"string\":\"Hello World\"}";
const char* stencil = "{\"array\":[null],\"boolean\":null,\"null\":null,\"object\":{\"a\":null,\"c\":null,\"e\":null},\"number\":null,\"object_array\":[{\"key\":null}],\"deep_nested_array\":[{\"object_array\":[{\"key\":null}]}],\"string\":null}";

testResult = test::isequalstring(input1, input2, stencil);

if(testResult != expectedTestResult){
    std::cout<<"testDeepNestedJson_should_succeed:"<<std::endl;
    std::cout<<"Item1:"<<input1<<std::endl;
    std::cout<<"Item2:"<<input2<<std::endl;
    std::cout<<"Stencil:"<<stencil<<std::endl;

    std::cout<<"Test Failed result is: False expected was: True"<<std::endl;

    return false;
}

std::cout<<"PASSED: testDeepNestedJson_should_succeed"<<std::endl;

return true;
}
int main() {
testDeepNestedJson_should_succeed();
return 0;
}

Answer 1

Using RapidJSON, the code would be something like this

#include "rapidjson/document.h"
#include "rapidjson/writer.h"
#include "rapidjson/stringbuffer.h"
#include <iostream>


using namespace rapidjson;


//({ id: 1, name : "test", randomNo : 1 }, { id: 1, name : "test", randomNo : 1 }, { id: null, name : null, randomNo : null }) //shoult assert true 
//isEqualItem({id: 1, name: "test", randomNo: 1}, {id: 1, name: "test", randomNo: 2}, {id: null, name: null, randomNo: null}) //shoult assert false 
//isEqualItem({id: 1, name: "test", randomNo: 1}, {id: 1, name: "test", randomNo: 3}, {id: null, name: null}) //shoult assert true

bool is_same(const std::string& s1, const std::string& s2, const std::string& s3) {

    Document d1;
    d1.Parse(s1.c_str());
    Document d2;
    d2.Parse(s2.c_str());

    Document d3;
    d3.Parse(s3.c_str());

    bool matched = true;
    // iterate through the third json to get the keys and match the keys in first and second
    for (Value::ConstMemberIterator itr = d3.MemberBegin(); itr != d3.MemberEnd(); itr++) {
        if (d1.HasMember(itr->name) && d2.HasMember(itr->name)) {       // if the member doesn't exist in both, break
            if (d1[itr->name] != d2[itr -> name]) {                     // value doesn't match, then break
                matched = false;
                break;
            }
        }
        else {
            matched = false;
            break;
        }
    }
    return matched;
}

int main() {
    // 1. Parse a JSON string into DOM.
    const char* json = "{\"id\":1,\"name\":\"test\",\"randomNo\":1}";
    const char* json2 = "{\"id\":1,\"name\":\"test\",\"randomNo\":2}";
    const char* keys = "{\"id\":\"null\",\"name\":\"null\"}";


    if (is_same(json, json2,keys)) {
        std::cout << "Both are same" << std::endl;
    }
    return 0;
}

Answer 2

You could iterate over root2, get name of keys using name(), access values with that names in root and root1 using operator[], and compare them using operator==:

for (auto it = root2.begin(); it != root2.end(); ++it) {
    auto name = it.name();
    if (root[name] != root1[name])
        return false;
}
return true;

---

_{BTW. You parse item1 to root, item2 to root1 and temp to root2. You could be more consistent in naming things.}