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Okay, I understand your request. I will write a PHP-related technical article covering your specified topic, with horizontal lines separating unrelated content before and after the main text. Here is the article content:
<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// Example of unrelated preliminary code</span></span><span>
</span><span><span class="hljs-variable">$placeholder</span></span><span> = </span><span><span class="hljs-string">"This part of the code is unrelated to the main content"</span></span><span>;
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-variable">$placeholder</span></span><span>;
</span><span><span class="hljs-meta">?></span></span><span>
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<p></span># How to gracefully close connections using socket_wsaprotocol_info_import with socket_shutdown<span></p>
<p>When performing network programming in PHP, managing TCP sockets is a critical concern. Especially when the server or client needs to handle a large number of concurrent connections, gracefully closing connections without losing data becomes a key challenge. This article explains how to achieve a graceful TCP connection shutdown using <code>socket_wsaprotocol_info_importImport the Socket Information
Using socket_wsaprotocol_info_import, you can import the same socket information in another process or handle, allowing safe lifecycle management.
<span><span><span class="hljs-variable">$imported_sock</span></span><span> = </span><span><span class="hljs-title function_ invoke__">socket_wsaprotocol_info_import</span></span><span>(</span><span><span class="hljs-variable">$protocol_info</span></span>, </span><span><span class="hljs-number">0</span></span><span>);
</span></span>Gracefully Close the Connection
Calling socket_shutdown allows you to close the socket’s read, write, or both channels, ensuring that data in the buffer is fully sent.
<span><span><span class="hljs-comment">// First, shut down the write channel to ensure data is sent</span></span><span>
</span><span><span class="hljs-title function_ invoke__">socket_shutdown</span></span><span>(</span><span><span class="hljs-variable">$imported_sock</span></span>, </span><span><span class="hljs-number">1</span></span><span>);
</span><span><span class="hljs-comment">// Optional: wait for the peer to confirm data reception</span></span><span>
</span><span><span class="hljs-title function_ invoke__">sleep</span></span><span>(</span><span><span class="hljs-number">1</span></span><span>);
</span><span><span class="hljs-comment">// Finally, shut down the read channel</span></span><span>
</span><span><span class="hljs-title function_ invoke__">socket_shutdown</span></span><span>(</span><span><span class="hljs-variable">$imported_sock</span></span>, </span><span><span class="hljs-number">0</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">socket_close</span></span><span>(</span><span><span class="hljs-variable">$imported_sock</span></span><span>);
</span><span><span class="hljs-title function_ invoke__">socket_close</span></span><span>(</span><span><span class="hljs-variable">$sock</span></span><span>);
</span></span>Windows-Only API
socket_wsaprotocol_info_export and socket_wsaprotocol_info_import are Windows-specific APIs and are not available on Linux/Unix systems.
Data Integrity
After calling socket_shutdown to close the write channel, you should ensure that data has been fully sent from the buffer; otherwise, clients may receive incomplete data.
Multi-Threaded or Multi-Process Scenarios
Imported sockets can be used across different threads or processes, enabling complex network communication models such as load balancing or asynchronous handling.
By using socket_wsaprotocol_info_import together with socket_shutdown, you can gracefully close TCP sockets on Windows. This method ensures complete data transmission while allowing safe management of sockets across multiple processes or threads. It is a valuable approach for high-concurrency servers or client programs requiring high-reliability communication.
<span><span><span class="hljs-comment">// Example of unrelated concluding code</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Article ends, executing other unrelated logic"</span></span><span>;
</span><span><span class="hljs-variable">$dummy</span></span><span> = </span><span><span class="hljs-title function_ invoke__">array_map</span></span><span>(function(</span><span><span class="hljs-variable">$i</span></span><span>) { </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-variable">$i</span></span><span> * </span><span><span class="hljs-number">2</span></span><span>; }, </span><span><span class="hljs-title function_ invoke__">range</span></span><span>(</span><span><span class="hljs-number">1</span></span>, </span><span><span class="hljs-number">5</span></span><span>));
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