header

实例

例子 1

发送三个 HTTP 标头以防止页面缓存：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token comment">// 过去的日期</span>
<span class="token function">header</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Expires: Mon, 26 Jul 1997 05:00:00 GMT"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">header</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Cache-Control: no-cache"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token function">header</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Pragma: no-cache"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>html</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>body</span><span class="token punctuation">></span></span>
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注意：用户可能会设置一些选项来改变浏览器的默认缓存设置。通过发送上述的标头，您将覆盖这些设置并强制浏览器不进行缓存！

例子 2

提示用户保存生成的 PDF 文件（使用 Content-Disposition 头部来提供一个推荐的文件名，并强制浏览器显示保存对话框）：

<span class="token php language-php"><span class="token delimiter important"><?php</span>
<span class="token function">header</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Content-type:application/pdf"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// 它将被命名为 downloaded.pdf  </span>
<span class="token function">header</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"Content-Disposition:attachment;filename='downloaded.pdf'"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>

<span class="token comment">// PDF 源文件在 original.pdf 中</span>
<span class="token function">readfile</span><span class="token punctuation">(</span><span class="token string double-quoted-string">"original.pdf"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
<span class="token delimiter important">?></span></span>

<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>html</span><span class="token punctuation">></span></span>
<span class="token tag"><span class="token tag"><span class="token punctuation"><</span>body</span><span class="token punctuation">></span></span>

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