Basic Service (C++)

Here is a basic service definition. Place example.cpp and CMakeLists.txt in an empty folder.

example.cpp

#include <psibase/psibase.hpp>

// The service
struct ExampleService
{
   // Add two numbers
   int32_t add(int32_t a, int32_t b) { return a + b; }

   // Multiply two numbers
   int32_t multiply(int32_t a, int32_t b) { return a * b; }
};

// Reflect the service's methods. This enables
// PSIBASE_DISPATCH and other mechanisms to operate.
PSIO_REFLECT(ExampleService,  //
             method(add, a, b),
             method(multiply, a, b))

// Allow users to invoke reflected methods inside transactions.
// Also allows other services to invoke these methods.
PSIBASE_DISPATCH(ExampleService)

CMakeLists.txt

# All cmake projects need these
cmake_minimum_required(VERSION 3.16)
project(example)

# Generate compile_commands.json to aid vscode and other editors
set(CMAKE_EXPORT_COMPILE_COMMANDS on)

# Libraries for building services and tests
find_package(psibase REQUIRED)

# Build example.wasm service
add_executable(example example.cpp)
target_link_libraries(example Psibase::service)

# Create a package
psibase_package(
    NAME Example
    VERSION 1.0.0
    DESCRIPTION "An example service"
    # The account that the service will run on
    SERVICE example
        # The CMake target that builds the service
        TARGET example
)

Building

This will create a psibase package, Example.psi:

mkdir build
cd build
cmake `psidk-cmake-args` ..
make -j $(nproc)

Deploying the service

This, when run on a local test chain, will:

• Create the example account, if it doesn't already exist. The account will be owned by the root account.
• Deploy the example.wasm service on that service.

psibase install ./Example.psi