PHP main 函数如何处理 POST 和 GET 请求？详细步骤解析

gitbox 2025-09-02

一、GET 请求的处理

GET 请求主要用于向服务器获取数据，它通过 URL 参数传递数据。在 PHP 中，$_GET 超全局数组用来接收 GET 请求中传递的参数。

1.1 接收 GET 请求

<span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">main</span></span><span>(</span><span><span class="hljs-params"></span></span><span>) {
    </span><span><span class="hljs-comment">// 检查是否有 GET 请求的参数</span></span><span>
    </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-keyword">isset</span></span><span>(</span><span><span class="hljs-variable">$_GET</span></span><span>[</span><span><span class="hljs-string">'name'</span></span><span>])) {
        </span><span><span class="hljs-variable">$name</span></span><span> = </span><span><span class="hljs-variable">$_GET</span></span><span>[</span><span><span class="hljs-string">'name'</span></span><span>];  </span><span><span class="hljs-comment">// 获取 GET 请求中的参数 'name'</span></span><span>
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Hello, "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">htmlspecialchars</span></span><span>(</span><span><span class="hljs-variable">$name</span></span><span>);  </span><span><span class="hljs-comment">// 输出 'Hello, &lt;name&gt;'</span></span><span>
    } </span><span><span class="hljs-keyword">else</span></span><span> {
        </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"No name provided!"</span></span><span>;
    }
}
</span></span>

在上面的代码中，$_GET['name'] 获取了 URL 中的参数。如果 URL 是 example.com/?name=John，那么输出结果将是：

<span><span>Hello, John
</span></span>

1.2 URL 参数的编码与安全性

在处理 GET 请求时，尤其是处理用户输入的数据时，安全性是必须要考虑的因素。为了避免 XSS 攻击，使用 htmlspecialchars() 函数对输出的数据进行编码是非常重要的。该函数将用户输入中的 HTML 标签转义，从而避免恶意代码的注入。

二、POST 请求的处理

POST 请求通常用于向服务器发送数据，尤其是需要提交表单数据时。在 PHP 中，$_POST 超全局数组用来接收 POST 请求的数据。

2.1 接收 POST 请求

<span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">main</span></span><span>(</span><span><span class="hljs-params"></span></span><span>) {
    </span><span><span class="hljs-comment">// 检查是否是 POST 请求</span></span><span>
    </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$_SERVER</span></span><span>[</span><span><span class="hljs-string">'REQUEST_METHOD'</span></span><span>] === </span><span><span class="hljs-string">'POST'</span></span><span>) {
        </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-keyword">isset</span></span><span>(</span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'username'</span></span><span>]) &amp;&amp; </span><span><span class="hljs-keyword">isset</span></span><span>(</span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'password'</span></span><span>])) {
            </span><span><span class="hljs-variable">$username</span></span><span> = </span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'username'</span></span><span>];
            </span><span><span class="hljs-variable">$password</span></span><span> = </span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'password'</span></span><span>];
            
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Username: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">htmlspecialchars</span></span><span>(</span><span><span class="hljs-variable">$username</span></span><span>) . </span><span><span class="hljs-string">"&lt;br&gt;"</span></span><span>;
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Password: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">htmlspecialchars</span></span><span>(</span><span><span class="hljs-variable">$password</span></span><span>);
        } </span><span><span class="hljs-keyword">else</span></span><span> {
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Please fill in the required fields!"</span></span><span>;
        }
    }
}
</span></span>

在这个示例中，POST 请求的数据通过 $_POST['username'] 和 $_POST['password'] 获取。如果表单通过 POST 请求提交，输出结果将显示用户名和密码。

2.2 表单验证和数据清理

在处理 POST 请求时，用户输入的内容可能不符合预期或者带有恶意代码。通常，我们需要进行数据验证和清理。比如，可以检查用户输入是否为空、是否符合特定格式等。

<span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">main</span></span><span>(</span><span><span class="hljs-params"></span></span><span>) {
    </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$_SERVER</span></span><span>[</span><span><span class="hljs-string">'REQUEST_METHOD'</span></span><span>] === </span><span><span class="hljs-string">'POST'</span></span><span>) {
        </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-keyword">isset</span></span><span>(</span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'email'</span></span><span>])) {
            </span><span><span class="hljs-variable">$email</span></span><span> = </span><span><span class="hljs-title function_ invoke__">filter_var</span></span><span>(</span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'email'</span></span><span>], FILTER_SANITIZE_EMAIL);
            </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">filter_var</span></span><span>(</span><span><span class="hljs-variable">$email</span></span><span>, FILTER_VALIDATE_EMAIL)) {
                </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Valid email: "</span></span><span> . </span><span><span class="hljs-title function_ invoke__">htmlspecialchars</span></span><span>(</span><span><span class="hljs-variable">$email</span></span><span>);
            } </span><span><span class="hljs-keyword">else</span></span><span> {
                </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Invalid email format!"</span></span><span>;
            }
        } </span><span><span class="hljs-keyword">else</span></span><span> {
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Email is required!"</span></span><span>;
        }
    }
}
</span></span>

在这段代码中，我们使用了 filter_var() 函数来清理和验证电子邮件地址，确保其格式是有效的。

三、结合 GET 和 POST 请求

有时，我们需要同时处理 GET 和 POST 请求。为了更好地管理请求，可以在 main 函数中同时判断请求的方式，并根据不同的需求分别处理。

<span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">main</span></span><span>(</span><span><span class="hljs-params"></span></span><span>) {
    </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-variable">$_SERVER</span></span><span>[</span><span><span class="hljs-string">'REQUEST_METHOD'</span></span><span>] === </span><span><span class="hljs-string">'POST'</span></span><span>) {
        </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-keyword">isset</span></span><span>(</span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'message'</span></span><span>])) {
            </span><span><span class="hljs-variable">$message</span></span><span> = </span><span><span class="hljs-title function_ invoke__">htmlspecialchars</span></span><span>(</span><span><span class="hljs-variable">$_POST</span></span><span>[</span><span><span class="hljs-string">'message'</span></span><span>]);
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Received POST message: "</span></span><span> . </span><span><span class="hljs-variable">$message</span></span><span>;
        }
    } </span><span><span class="hljs-keyword">elseif</span></span><span> (</span><span><span class="hljs-variable">$_SERVER</span></span><span>[</span><span><span class="hljs-string">'REQUEST_METHOD'</span></span><span>] === </span><span><span class="hljs-string">'GET'</span></span><span>) {
        </span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-keyword">isset</span></span><span>(</span><span><span class="hljs-variable">$_GET</span></span><span>[</span><span><span class="hljs-string">'id'</span></span><span>])) {
            </span><span><span class="hljs-variable">$id</span></span><span> = </span><span><span class="hljs-title function_ invoke__">intval</span></span><span>(</span><span><span class="hljs-variable">$_GET</span></span><span>[</span><span><span class="hljs-string">'id'</span></span><span>]);  </span><span><span class="hljs-comment">// 获取 GET 请求中的 id 参数</span></span><span>
            </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"Requested GET ID: "</span></span><span> . </span><span><span class="hljs-variable">$id</span></span><span>;
        }
    }
}
</span></span>

在这个例子中，PHP 根据请求的类型判断是处理 POST 请求中的消息还是 GET 请求中的 ID。

四、总结

通过使用 $_GET 和 $_POST 超全局数组，PHP 可以方便地处理 GET 和 POST 请求。无论是获取 URL 参数还是提交表单数据，我们都可以在 main 函数中进行逻辑处理。在实际开发中，处理请求时还需要特别注意安全性，确保用户输入的内容经过验证和清理，以防止 SQL 注入、XSS 攻击等安全隐患。