= nng_http_client_transact(3http)
|
//
|
// Copyright 2020 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_client_transact - perform one HTTP transaction
|
|
== SYNOPSIS
|
|
[source, c]
|
----
|
#include <nng/nng.h>
|
#include <nng/supplemental/http/http.h>
|
|
void nng_http_client_transact(nng_http_client *client, nng_http_req *req,
|
nng_http_res *res, nng_aio *aio);
|
----
|
|
== DESCRIPTION
|
|
The `nng_http_client_transact()` function is used to perform a complete
|
HTTP exchange.
|
It creates a new connection using _client_, performs the transaction by
|
sending the request _req_
|
(and attached body data) to the remote server, then reading the response
|
_res_, and finally closes the connection that it created.
|
The entire response is read, including any associated body, which can
|
subsequently be obtained using
|
xref:nng_http_res_get_data.3http.adoc[`nng_http_res_get_data()`].
|
|
This function is intended to make creation of client applications easier,
|
by performing multiple asynchronous operations required to complete an
|
entire HTTP transaction.
|
|
A similar function,
|
xref:nng_http_conn_transact.3http.adoc[`nng_http_conn_transact()`],
|
exists.
|
That function behaves similarily, but uses an existing connection, which
|
can be reused.
|
|
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 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.
|
|
== 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, or peer sent chunked encoding.
|
`NNG_EPROTO`:: An HTTP protocol error occurred.
|
`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_strerror.3.adoc[nng_strerror(3)],
|
xref:nng_http_client_connect.3http.adoc[nng_http_client_connect(3http)],
|
xref:nng_http_conn_transact.3http.adoc[nng_http_conn_transact(3http)],
|
xref:nng_http_res_get_data.3http.adoc[nng_http_res_get_data(3http)],
|
xref:nng.7.adoc[nng(7)]
|
