JSON

This JSON utility was created with ease of use in mind while still providing a simple, yet performant way of working with JSON structures in C++.

Usage

In order to work with the primitive types provided by JSON, JSONkit maps each of them to a C++ class as shown below

JSON	C++
String	JsonString
Number	JsonNumber
Object	JsonObject
Array	JsonArray
true & false	JsonBoolean
null	JsonNull

Parsing a JSON String

{
  "name" : "wubalubadubdub",
  "age"  : 60
}

std::string str = "{\"name\":\"wubalubadubdub\", \"age\":60}";
JsonObject json_obj(str);
JsonString json_str = json_obj.get_string("name");
JsonNumber json_nbr = json_obj.get_number("age");

// Prints wubalubadubdub 
std::cout << json_str.get_string() << std::endl;

// Prints 60
std::cout << json_nbr.get_int() << std::endl;

Serializing a JSON Object

std::string str = "{\"name\":\"wubalubadubdub\", \"age\":60}";
JsonObject json_obj(str);

// Prints {"name":"wubalubadubdub", "age":60}
std::cout << json_obj.stringify() << std::endl; 

obj.set("num_toes", JsonNumber(7));

// Prints {"name":"wubalubadubdub", "age":60, "num_toes":7}
std::cout << json_obj.stringify() << std::endl; 

Note that while Jsontring, JsonNumber, JsonBoolean and JsonNull are immutable classes, both JsonObject and JsonArray are mutable. This means that it is possible to dynamically add and remove objects from either of these two class's objects.

More examples of what can be done with this utility can be found in the unittests.cpp file.

Purpose

Why write another C++ JSON library?

1. I didn't want to install Boost or any other libraries
2. I didn't want to install any programs/scripts
3. I wanted an interface that was easy to use
4. I wanted it to be reasonably fast

Installation

Adding this library to a project can be done through the CMake FetchContent api. For example, include the following to your relevant CMakeLists.txt file.

include(FetchContent)
FetchContent_Declare(
    Json
    GIT_REPOSITORY <git url>
    GIT_TAG <git tag>
)
FetchContent_MakeAvailable(Json)

target_link_libraries(
    <target>
    PRIVATE
    Json::Json
)

The api from the library can be accessed by including the header files; for example jsonstring.hpp can be included as shown below.

#include <json/jsonstring.hpp>

Naive Benchmarks

Although execution speed was a concern for this project, it was not the main focus. However I conducted some naive benchmarks against another very popular C++ utility and generated the results below.

Although my benchmarks are not extensive, I am very interested in any profiling, testing and benchmarking results regarding this library. However, note that when performing any comparisons, this utility does not parse everything that is passed into it; it will only parse what is needed.

Parsing

Library Name	Time (ms)	Webpage
json	0.439	N/A
SuperEasyJson	6.715	sourceforge.net/projects/supereasyjson/

License

Licensed under the MIT License.