man/v1.3.2/nng_http_client_connect.3http.html


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---
version: v1.3.2
layout: manpage_v2
---
<h1>nng_http_client_connect(3http)</h1>
<div class="sect1">
<h2 id="_name">NAME</h2>
<div class="sectionbody">
<div class="paragraph">
<p>nng_http_client_connect - establish HTTP client connection</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_synopsis">SYNOPSIS</h2>
<div class="sectionbody">
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="c"><span class="tok-cp">#include</span> <span class="tok-cpf">&lt;nng/nng.h&gt;</span><span class="tok-cp">
</span><span class="tok-cp">#include</span> <span class="tok-cpf">&lt;nng/supplemental/http/http.h&gt;</span><span class="tok-cp">
</span><span class="tok-cp"></span>
<span class="tok-kt">void</span> <span class="tok-nf">nng_http_client_connect</span><span class="tok-p">(</span><span class="tok-n">nng_http_client</span> <span class="tok-o">*</span><span class="tok-n">client</span><span class="tok-p">,</span> <span class="tok-n">nng_aio</span> <span class="tok-o">*</span><span class="tok-n">aio</span><span class="tok-p">);</span></code></pre>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_description">DESCRIPTION</h2>
<div class="sectionbody">
<div class="paragraph">
<p>The <code>nng_http_client_connect()</code> starts the process of establishing an HTTP
connection from <em>client</em> to the server that was indicated in the URL that
<em>client</em> was configured with.</p>
</div>
<div class="paragraph">
<p>The result of the operation will be stored in the <em>aio</em> when the operation
is complete, and will be obtainable via
<a href="nng_aio_result.3.html"><code>nng_aio_result()</code></a>.</p>
</div>
<div class="paragraph">
<p>On success, a pointer to the underlying HTTP client (type <code>nng_http_conn *</code>)
will be stored in the first output result of the <em>aio</em>, and can be
obtained by
<a href="nng_aio_get_output.3.html"><code>nng_aio_get_output()</code></a> with an <em>index</em> of zero (0).</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_return_values">RETURN VALUES</h2>
<div class="sectionbody">
<div class="paragraph">
<p>None.</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_errors">ERRORS</h2>
<div class="sectionbody">
<div class="hdlist">
<table>
<tr>
<td class="hdlist1">
<code>NNG_EADDRINVAL</code>
</td>
<td class="hdlist2">
<p>The client is configured with an invalid address.</p>
</td>
</tr>
<tr>
<td class="hdlist1">
<code>NNG_ECANCELED</code>
</td>
<td class="hdlist2">
<p>The operation was aborted.</p>
</td>
</tr>
<tr>
<td class="hdlist1">
<code>NNG_ECONNREFUSED</code>
</td>
<td class="hdlist2">
<p>The TCP connection was refused by the server.</p>
</td>
</tr>
<tr>
<td class="hdlist1">
<code>NNG_ECONNRESET</code>
</td>
<td class="hdlist2">
<p>The TCP connection was reset by the server.</p>
</td>
</tr>
<tr>
<td class="hdlist1">
<code>NNG_ENOMEM</code>
</td>
<td class="hdlist2">
<p>Insufficient free memory exists.</p>
</td>
</tr>
</table>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_example">EXAMPLE</h2>
<div class="sectionbody">
<div class="listingblock">
<div class="content">
<pre class="pygments highlight"><code data-lang="c">    <span class="tok-n">nng_aio</span> <span class="tok-o">*</span><span class="tok-n">aio</span><span class="tok-p">;</span>
    <span class="tok-n">nng_url</span> <span class="tok-o">*</span><span class="tok-n">url</span><span class="tok-p">;</span>
    <span class="tok-n">nng_http_client</span> <span class="tok-o">*</span><span class="tok-n">client</span><span class="tok-p">;</span>
    <span class="tok-n">nng_http_conn</span> <span class="tok-o">*</span><span class="tok-n">conn</span><span class="tok-p">;</span>
    <span class="tok-kt">int</span> <span class="tok-n">rv</span><span class="tok-p">;</span>

    <span class="tok-c1">// Error checks elided for clarity.
</span><span class="tok-c1"></span>    <span class="tok-n">nng_url_parse</span><span class="tok-p">(</span><span class="tok-o">&amp;</span><span class="tok-n">url</span><span class="tok-p">,</span> <span class="tok-s">&#34;http://www.google.com&#34;</span><span class="tok-p">);</span>
    <span class="tok-n">nng_aio_alloc</span><span class="tok-p">(</span><span class="tok-o">&amp;</span><span class="tok-n">aio</span><span class="tok-p">,</span> <span class="tok-nb">NULL</span><span class="tok-p">,</span> <span class="tok-nb">NULL</span><span class="tok-p">);</span>
    <span class="tok-n">nng_http_client_alloc</span><span class="tok-p">(</span><span class="tok-o">&amp;</span><span class="tok-n">client</span><span class="tok-p">,</span> <span class="tok-n">url</span><span class="tok-p">);</span>

    <span class="tok-n">nng_http_client_connect</span><span class="tok-p">(</span><span class="tok-n">client</span><span class="tok-p">,</span> <span class="tok-n">aio</span><span class="tok-p">);</span>

    <span class="tok-c1">// Wait for connection to establish (or attempt to fail).
</span><span class="tok-c1"></span>    <span class="tok-n">nng_aio_wait</span><span class="tok-p">(</span><span class="tok-n">aio</span><span class="tok-p">);</span>

    <span class="tok-k">if</span> <span class="tok-p">((</span><span class="tok-n">rv</span> <span class="tok-o">=</span> <span class="tok-n">nng_aio_result</span><span class="tok-p">(</span><span class="tok-n">aio</span><span class="tok-p">))</span> <span class="tok-o">!=</span> <span class="tok-mi">0</span><span class="tok-p">)</span> <span class="tok-p">{</span>
            <span class="tok-n">printf</span><span class="tok-p">(</span><span class="tok-s">&#34;Connection failed: %s</span><span class="tok-se">\n</span><span class="tok-s">&#34;</span><span class="tok-p">,</span> <span class="tok-n">nng_strerror</span><span class="tok-p">(</span><span class="tok-n">rv</span><span class="tok-p">));</span>
    <span class="tok-p">}</span> <span class="tok-k">else</span> <span class="tok-p">{</span>
            <span class="tok-c1">// Connection established, get it.
</span><span class="tok-c1"></span>            <span class="tok-n">conn</span> <span class="tok-o">=</span> <span class="tok-n">nng_aio_get_output</span><span class="tok-p">(</span><span class="tok-n">aio</span><span class="tok-p">,</span> <span class="tok-mi">0</span><span class="tok-p">);</span>

            <span class="tok-c1">// ... do something with it here
</span><span class="tok-c1"></span>
            <span class="tok-c1">// Close the connection when done to avoid leaking it.
</span><span class="tok-c1"></span>            <span class="tok-n">nng_http_conn_close</span><span class="tok-p">(</span><span class="tok-n">conn</span><span class="tok-p">);</span>
    <span class="tok-p">}</span></code></pre>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_see_also">SEE ALSO</h2>
<div class="sectionbody">
<div class="paragraph text-left">
<p><a href="nng_aio_get_output.3.html">nng_aio_get_output(3)</a>,
<a href="nng_aio_result.3.html">nng_aio_result(3)</a>,
<a href="nng_aio_wait.3.html">nng_aio_wait(3)</a>,
<a href="nng_strerror.3.html">nng_strerror(3)</a>,
<a href="nng_http_client_alloc.3http.html">nng_http_client_alloc(3http)</a>,
<a href="nng_http_conn_close.3http.html">nng_http_conn_close(3http)</a>,
<a href="nng_http_conn_read.3http.html">nng_http_conn_read(3http)</a>,
<a href="nng_http_conn_write.3http.html">nng_http_conn_write(3http)</a>,
<a href="nng.7.html">nng(7)</a></p>
</div>
</div>
</div>