JsonAPI

JsonAPI is a C++ wrapper library for jansson JSON C library. It is well-suited to run on microcontrollers but can also run on the desktop.

Design

The JsonAPI uses the Stratify Labs API framework which is based on the following design principles

• Thread Local Error Contexts
• Method Chaining
• Filesystem Inspired Abstraction
• Strong Arguments
• RAII Everywhere

More details of these principles are available at https://github.com/StratifyLabs/API.

Building

The JsonAPI library is designed to be a CMake sub-project. To build, please use one of these projects:

• Desktop Command Line Interface
• Stratify OS on Nucleo-144

Usage

Under the hood, all memory management is handled by jansson. The C++ objects just hold pointers to the jansson handled memory. So all objects should be passed by value rather than by reference.

You can easily create a JSON object using method chaining:

#include <json.hpp>

//create an object
auto object = JsonObject()
                      .insert("string", JsonString("string"))
                      .insert("integerString", JsonString("100"))
                      .insert("integer", JsonInteger(10))
                      .insert("integerZero", JsonInteger(0))
                      .insert("real", JsonReal(2.2f))
                      .insert("realString", JsonString("2.2f"))
                      .insert("realZero", JsonReal(0.0f))
                      .insert("true", JsonTrue())
                      .insert("false", JsonFalse())
                      .insert("null", JsonNull())
                      .insert("trueString", JsonString("true"))
                      .insert(
                        "array",
                        JsonArray()
                          .append(JsonString("string"))
                          .append(JsonInteger(5))
                          .append(JsonReal(2.5f))
                          .append(JsonTrue())
                          .append(JsonFalse())
                          .append(JsonNull()));

//access an object
const auto str = object.at("string").to_cstring();
const auto b = object.at("true").to_bool();

You can load and save JSON documents using JsonDocument.

#include <fs.hpp>
#include <json.hpp>

//using the object above
JsonDocument().save(object, File(File::IsOverwrite::yes, "object.json"));
auto loaded_object = JsonDocument().load(File("object.json"));