84 lines
2.8 KiB
Text
84 lines
2.8 KiB
Text
= nng_http_client_transact(3http)
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//
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// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
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// Copyright 2018 Capitar IT Group BV <info@capitar.com>
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//
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// This document is supplied under the terms of the MIT License, a
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// copy of which should be located in the distribution where this
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// file was obtained (LICENSE.txt). A copy of the license may also be
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// found online at https://opensource.org/licenses/MIT.
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//
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== NAME
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nng_http_client_transact - perform one HTTP transaction
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== SYNOPSIS
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[source, c]
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----
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#include <nng/nng.h>
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#include <nng/supplemental/http/http.h>
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void nng_http_client_transact(nng_http_client *client, nng_http_req *req,
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nng_http_res *res, nng_aio *aio);
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----
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== DESCRIPTION
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The `nng_http_client_transact()` function is used to perform a complete
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HTTP exchange.
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It creates a new connection using _client_, performs the transaction by
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sending the request _req_
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(and attached body data) to the remote server, then reading the response
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_res_, and finally closes the connection that it created.
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The entire response is read, including any associated body, which can
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subsequently be obtained using
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xref:nng_http_res_get_data.3http.adoc[`nng_http_res_get_data()`].
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This function is intended to make creation of client applications easier,
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by performing multiple asynchronous operations required to complete an
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entire HTTP transaction.
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A similar function,
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xref:nng_http_conn_transact.3http.adoc[`nng_http_conn_transact()`],
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exists.
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That function behaves similarily, but uses an existing connection, which
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can be reused.
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WARNING: If the remote server tries to send an extremely large buffer,
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then a corresponding allocation will be made, which can lead to denial
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of service attacks.
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Client applications should take care to use this only with reasonably
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trust-worthy servers.
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This function returns immediately, with no return value.
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Completion of the operation is signaled via the _aio_, and the final result
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may be obtained via xref:nng_aio_result.3.adoc[`nng_aio_result()`].
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That result will either be zero or an error code.
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== RETURN VALUES
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None.
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== ERRORS
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[horizontal]
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`NNG_ECANCELED`:: The operation was canceled.
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`NNG_ECLOSED`:: The connection was closed.
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`NNG_ECONNRESET`:: The peer closed the connection.
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`NNG_ENOMEM`:: Insufficient free memory to perform the operation.
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`NNG_ENOTSUP`:: HTTP operations are not supported, or peer sent chunked encoding.
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`NNG_EPROTO`:: An HTTP protocol error occurred.
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`NNG_ETIMEDOUT`:: Timeout waiting for data from the connection.
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== SEE ALSO
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[.text-left]
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xref:nng_aio_alloc.3.adoc[nng_aio_alloc(3)],
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xref:nng_aio_result.3.adoc[nng_aio_result(3)],
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xref:nng_strerror.3.adoc[nng_strerror(3)],
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xref:nng_http_client_connect.3http.adoc[nng_http_client_connect(3http)],
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xref:nng_http_conn_transact.3http.adoc[nng_http_conn_transact(3http)],
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xref:nng_http_res_get_data.3http.adoc[nng_http_res_get_data(3http)],
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xref:nng.7.adoc[nng(7)]
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