Examples » Asynchronous Queries

This example shows how to use the libogmios library to asynchronously execute multiple queries. This is useful for applications that need to query the chain frequently:

// Third-party libraries
#include <nlohmann/json.hpp>
#include <ogmios/client.hpp>
#include <spdlog/spdlog.h>

using json = nlohmann::json;

auto main() -> int
{
    auto batch_size = 10;

    // Create a client to manage the Ogmios server connection.
    // The URL defaults to ws://localhost:1337
    auto client = ogmios::Client();

    // Setup the logging callback to print information to stdout.
    spdlog::set_level(spdlog::level::debug);  // Set global log level
    client.setLoggerCallback(
        [](int level, const std::string &msg)
        { spdlog::log(static_cast<spdlog::level::level_enum>(level), msg); }
    );

    // Make calls without waiting for a response.
    auto future_results = std::vector<std::future<json>>();
    for (auto i = 0; i < batch_size; i++)
        future_results.push_back(client.queryBlockHeight());

    // Accumulate all the results
    auto results = std::vector<json>();
    for (auto &future : future_results) results.push_back(future.get());

    for (auto &result : results)
        spdlog::info(
            "Block height: {} (ID: \"{}\")",
            result["result"].get<size_t>(),
            result["id"].get<std::string>()
        );

    return 0;
}  // main

Example output:

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