NNG_HTTP_CONN_TRANSACT(3http)

📦 version 1.11, in alpine 3.24

💖 NAME 💖

Okay so welcome to the nng_http_conn_transact(3http) page from the NNG Reference Manual — this is the one about performing one HTTP transaction on a connection, and yes bestie, it's giving main character energy for client apps. 💅

nng_http_conn_transact — perform one HTTP transaction on connection. Periodt.

🎀 SYNOPSIS 🎀

#include <nng/nng.h>
#include <nng/supplemental/http/http.h>

void nng_http_conn_transact(nng_http_conn *conn, nng_http_req *req,
    nng_http_res *res, nng_aio *aio);

✨ DESCRIPTION ✨

The nng_http_conn_transact() function is used to perform a complete HTTP exchange over the connection conn, sending the request req (and attached body data) to the remote server, and reading the response res. The entire response is read, including any associated body, which can subsequently be obtained using nng_http_res_get_data(). Obsessed? Same. 💖

This function is intended to make creation of client applications easier, by performing multiple asynchronous operations required to complete an entire HTTP transaction. It's literally doing the group project so your client app doesn't have to. 🫶

If an error occurs, the caller should close conn with nng_http_conn_close(), as it may not necessarily be usable with other transactions. No cap — don't try to reuse it and act surprised. 😭

A similar function, nng_http_client_transact(), exists. That function behaves similarly, but creates a connection on demand for the transaction, and disposes of it when finished. Different vibe, same transaction energy. 🦋

⚠️ Warning If the remote server tries to send an extremely large buffer, then a corresponding allocation will be made, which can lead to denial of service attacks. Client applications should take care to use this only with reasonably trust-worthy servers. This is not the moment to be trusting random servers on the internet, bestie. 😭
⚠️ Warning A given connection conn should be used with only one operation or transaction at a time as HTTP/1.1 has no support for request interleaving. One at a time. No chaotic overlapping. The connection said no interleaving and it meant it. 💀

This function returns immediately, with no return value. Completion of the operation is signaled via the aio, and the final result may be obtained via nng_aio_result(). That result will either be zero or an error code. So the aio is the main character here, fr fr. ✨

🌸 RETURN VALUES 🌸

None. That's it. The [aio] carries the result, not a return value. 🎀

💜 ERRORS 💜

  • NNG_ECANCELED — the operation was canceled.
  • NNG_ECLOSED — the connection was closed.
  • NNG_ECONNRESET — the peer closed the connection.
  • NNG_ENOMEM — insufficient free memory to perform the operation.
  • NNG_ENOTSUP — HTTP operations are not supported.
  • NNG_EPROTO — an HTTP protocol error occurred.
  • NNG_ETIMEDOUT — timeout waiting for data from the connection.

🦋 SEE ALSO 🦋

That's the whole page, babes — from the NNG Reference Manual, dated 2026-01-13. 💖🎀

📦 where this page comes from