Integrations

Concepts
concept	uvco::WithTxFn

Classes
class	uvco::Pqxx

Functions
template<typename R , typename F > requires WithTxFn<R, F>
Promise< R >	uvco::Pqxx::withTx (F f)

Detailed Description

Function Documentation

withTx()

template<typename R , typename F >
requires WithTxFn<R, F>

Promise< R > uvco::Pqxx::withTx

(

F

f

)

Run a query on the database. The supplied function MUST be thread-safe, for example, by owning all the data it interacts with.

The callable F is expected to take a pqxx::work & as its only argument. Its return value is forwarded to the caller.

                           {
  // We use one connection per thread-pool thread. That's the best balance
  // between efficiency and safety.
  ThreadLocalKey<std::optional<pqxx::connection>> threadLocalConn{conn_};
  auto connectionString = connectionString_;
 
  auto work = [threadLocalConn = std::move(threadLocalConn),
               connectionString = std::move(connectionString),
               f = std::forward<F>(f)]() mutable -> R {
    auto &maybeConnection = threadLocalConn.getOrDefault();
    if (!maybeConnection.has_value()) {
      maybeConnection = std::make_optional(pqxx::connection{connectionString});
    }
    pqxx::work tx{maybeConnection.value()};
    if constexpr (std::is_void_v<R>) {
      f(tx);
      tx.commit();
      return;
    } else {
      R result{f(tx)};
      tx.commit();
      return result;
    }
  };
 
  return submitWork<R>(loop_, work);
}