nng_http_conn_transact(3http)

NNG_HTTP_CONN_TRANSACT(3http)

NNG Reference Manual

NNG_HTTP_CONN_TRANSACT(3http)

NAME

nng_http_conn_transact - perform one HTTP transaction on connection

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().

This function is intended to make creation of client applications easier, by performing multiple asynchronous operations required to complete an entire HTTP transaction.

If an error occurs, the caller should close conn with nng_http_conn_close(), as it may not necessarily be usable with other transactions.

A similar function, nng_http_client_transact(), exists. That function behaves similarily, but creates a connection on demand for the transaction, and disposes of it when finished.

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.

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.

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.

RETURN VALUES

None.

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.