joc

Overview

The objective of joc project is to facilitate schema association and JSON conversion, of any(*) user defined C++ data type.

Example:

struct Contact : public JsonObject
{
  Contact() : JsonObject({{"name", name},
                          {"address", address},
                          {"age", age},
                          {"e-mail", email}
                         }) {}
  std::string name;
  std::string address;
  int age;
  std::optional<std::string> email;
};

struct ContactBook : public JsonObject
{
  ContactBook() : JsonObject({{"owner", owner},
                              {"contact_list", contactList}
                             }) {}
  std::string owner;
  std::list<Contact> contactList;
};

...and can be used like so:

Contact mary;
mary.name    = "Mary";
mary.age     = 52;
mary.address = "Olof Str. 4";

Contact peter;
peter.refreshFromJson(nlohmann::json({{"name", "Peter"},{"address", "Rua das Amendoas 4"}, {"age", 34}}));

ContactBook myBook;
myBook.owner = "John";
myBook.contactList = {mary, peter};

std::cout << mary.toJson().dump(2) << std::endl;
std::cout << peter.toJson().dump(2) << std::endl;
std::cout << myBook.toJson().dump(2) << std::endl;

...with output:

Optional field: 'e-mail': is not provided
{
  "address": "Olof Str. 4",
  "age": 52,
  "name": "Mary",
  "type": "Friend"
}
{
  "address": "Rua das Amendoas 4",
  "age": 34,
  "name": "Peter",
  "type": "Work"
}
{
  "contact_list": [
    {
      "address": "Olof Str. 4",
      "age": 52,
      "name": "Mary",
      "type": "Friend"
    },
    {
      "address": "Rua das Amendoas 4",
      "age": 34,
      "name": "Peter",
      "type": "Work"
    }
  ],
  "owner": "John"
}

(*)- This is work in progress, some things are not possible such as:

• Representing a JSON other than a JSON object. Any C++ class will be represented as a JSON object. Each member will be present with a key-value pair in the JSON object. However, the value on a kay-value JSON pair can be a JSON array, by means of a std::list or std::vector, or another JSON object, via std::map or a joc JsonObject.
• Move semantics should not be hard to implement but it's not included.

Install

Make sure git submodules are initialized and up to date. joc lib is built on top of nlohmann::json library.

git submodule update --init --recursive

Compile sample

The main CMakeLists.txt includes building the joc library, plus a sample executable.

$ mkdir -p build && cd build
$ cmake ..
$ make
$ ./joc_sample

Compile unit-tests

Jump to tests/ directory and run the same commands as shown above:

$ cd tests/
$ mkdir -p build && cd build
$ cmake ..
$ make
$ ./jsonobjectconverter_test