= nng_http_conn_write_res(3http)
//
// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
// Copyright 2018 Capitar IT Group BV <info@capitar.com>
//
// This document is supplied under the terms of the MIT License, a
// copy of which should be located in the distribution where this
// file was obtained (LICENSE.txt).  A copy of the license may also be
// found online at https://opensource.org/licenses/MIT.
//

== NAME

nng_http_conn_write_res - write HTTP response

== SYNOPSIS

[source, c]
----
#include <nng/nng.h>
#include <nng/supplemental/http/http.h>

void nng_http_conn_write_res(nng_http_conn *conn, nng_http_res *res,
    nng_aio *aio);
----

== DESCRIPTION

The `nng_http_conn_write_res()` function starts an asynchronous write of
the HTTP response _res_ to the connection _conn_.
The entire response is sent,
including headers, and if present, the response body data.
(The response body can be set with
xref:nng_http_res_set_data.3http.adoc[`nng_http_res_set_data()`] or
xref:nng_http_res_copy_data.3http.adoc[`nng_http_res_copy_data()`].)

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 xref:nng_aio_result.3.adoc[`nng_aio_result()`].
That result will either be zero or an error code.

=== Persistent Connections

By default, for `HTTP/1.1` connections, the connection is kept open, and
will be reused to receive new requests.

If however the _res_ contains a header of `Connection:` with a value
of `Close` (case-insensitive) or the response corresponds to `HTTP/1.0`,
then the connection is immediately after sending the response.

NOTE: Consider using the
xref:nng_http_client_transact.3http.adoc[`nng_http_client_transact()`] or
xref:nng_http_conn_transact.3http.adoc[`nng_http_conn_transact()`] functions,
which provide a simpler interface for performing a complete HTTP client
transaction.

== RETURN VALUES

None.

== ERRORS

[horizontal]
`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_ETIMEDOUT`:: Timeout waiting for data from the connection.

== SEE ALSO

[.text-left]
xref:nng_aio_alloc.3.adoc[nng_aio_alloc(3)],
xref:nng_aio_result.3.adoc[nng_aio_result(3)],
xref:nng_http_client_connect.3http.adoc[nng_http_client_connect(3http)],
xref:nng_http_client_transact.3http.adoc[nng_http_client_transact(3http)],
xref:nng_http_conn_read_all.3http.adoc[nng_http_conn_read_all(3http)],
xref:nng_http_conn_transact.3http.adoc[nng_http_conn_transact(3http)],
xref:nng_strerror.3.adoc[nng_strerror(3)],
xref:nng.7.adoc[nng(7)]