This is an implementation of Varlink in C++17 built on top of asio. It's not yet feature complete, but in general it's working.
It is using nlohmann/json as data format and provides a
std::function service callback interface. I consider it work in progress still, API may change.
include(VarlinkWrapper)
# Generate C++ header
varlink_wrapper(org.example.more.varlink)
# Add to taret
add_executable(example [...] org.example.more.varlink.hpp)#include <varlink/server.hpp>
#include "org.example.more.varlink.hpp"
...
{
// varlink_server class provides encapsulation for an async_server and a varlink_service
// and resolves varlink-uris to the corresponding asio endpoints
varlink::net::io_context ctx{};
auto varlink_srv = varlink::varlink_server(ctx, "unix:/tmp/example.varlink",
{"vendor", "product", "version", "url"});
// interfaces can only be added once and callbacks can't be changed
varlink_srv.add_interface(org_example_more_varlink, varlink::callback_map{
// varlink_callback is a macro containing the callback parameter list
{"Ping", [] varlink_callback { send_reply({{"pong", parameters["ping"]}}, /* continues = */ false); }}
});
varlink_srv.async_serve_forever();
ctx.run();
}#include <varlink/client.hpp>
...
{
// Connect on creation
varlink::net::io_context ctx{};
auto client = varlink::varlink_client{ctx, "unix:/tmp/example.varlink"};
// .call returns a json object of the result ["parameters"]
auto reply = client.call("org.example.more.Ping", R"({"ping":"Test"})"_json);
// all parameters are validated by the server
assert(reply["pong"].get<std::string>() == "Test");
// .call_more returns a callable object
auto more = client.call_more("org.example.more.TestMore", json{{"n","1"}});
reply = more();
}#include <varlink/client.hpp>
...
{
// Connect on creation
varlink::net::io_context ctx{};
auto client = varlink::varlink_client{ctx, "unix:/tmp/example.varlink"};
json reply{};
// async_call (currently) captures the message by value
client.async_call(varlink::varlink_message("org.example.more.Ping", R"({"ping":"Test"})"_json),
[&](auto ec, const json& rep){
reply = rep;
});
ctx.run();
assert(reply["pong"].get<std::string>() == "Test");
}