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使用 PHP 从 URL 创建缩略图

发布于 2024-10-14 18:23:51 字数 162 浏览 1 评论 0原文

我想生成网站的缩略图。我发现一些网站可以使用 API 来处理它，例如 http://www.websnapr.com/

如何使用 PHP 来完成此操作，以便我可以处理服务器上的所有请求？

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萌酱 2024-10-21 18:23:51

PHP 无法自行完成此操作，因为它不包含 HTML 渲染库。

不过，您可以找到捕获屏幕截图的外部方法，并使用 PHP 与该方法进行通信。

首先，您需要设置一个用于截取屏幕截图的系统。查看 IECapt (http://iecapt.sourceforge.net/)、CutyCapt (http://cutycapt.sourceforge.net/) 或 khtml2png (http://khtml2png.sourceforge.net/) 并在系统。

然后设置一个 PHP 脚本，该脚本将 exec() 屏幕截图应用程序并将数据返回到浏览器。

例如：

<?php
$in_url = 'http://' . $_REQUEST['url']; // !!INSECURE!! In production, make sure to sanitize this input!
$filename = '/var/cutycapt/images/' . $_REQUEST['url'] . '.png'; // Will probably need to normalize filename too, this is just an illustration

// First check the file does not exist, if it does exist skip generation and reuse the file
// This is a super simple caching system that will help to reduce the resource requirements
if(!file_exists($filename)) {
  exec('/usr/local/bin/CutyCapt --url="' . $_REQUEST['url'] . '" --out="' . $filename . '"');
}

// Second check if the file exists, either from a previous run or from the above generation routine
if(file_exists($filename)) {
  header('Content-type: image/png');
  print file_get_contents($filename);
} else {
  header('Status: 500 Internal Server Error');
}
?>

然后您可以按以下方式调用脚本：

http://localhost/screenshot.php?url=www.google.com

构建屏幕截图将占用 CPU 资源，因此我强烈建议构建某种文件缓存（即保存输出结果并检查是否你已经在某处有一个屏幕截图），甚至可能是一个排队系统，这样你的屏幕截图服务器就不会被淹没。

PHP can't do this on it's own as it does not include an HTML rendering library.

You can find an external method of capturing the screenshots and communicate with that method using PHP, though.

First you'll need a system set up to take screenshots. Look into IECapt (http://iecapt.sourceforge.net/), CutyCapt (http://cutycapt.sourceforge.net/) or khtml2png (http://khtml2png.sourceforge.net/) and configure one of those on a system.

Then set up a PHP script that will exec() the screenshot taking application and return the data to the browser.

For example:

<?php
$in_url = 'http://' . $_REQUEST['url']; // !!INSECURE!! In production, make sure to sanitize this input!
$filename = '/var/cutycapt/images/' . $_REQUEST['url'] . '.png'; // Will probably need to normalize filename too, this is just an illustration

// First check the file does not exist, if it does exist skip generation and reuse the file
// This is a super simple caching system that will help to reduce the resource requirements
if(!file_exists($filename)) {
  exec('/usr/local/bin/CutyCapt --url="' . $_REQUEST['url'] . '" --out="' . $filename . '"');
}

// Second check if the file exists, either from a previous run or from the above generation routine
if(file_exists($filename)) {
  header('Content-type: image/png');
  print file_get_contents($filename);
} else {
  header('Status: 500 Internal Server Error');
}
?>

You can then call the script in the following way:

http://localhost/screenshot.php?url=www.google.com

Building the screenshots is going to be CPU intensive so I'd strongly recommend building in some kind of file caching (ie. save the results of the output and check to see if you already have a screenshot somewhere), perhaps even a queuing system so your screenshot server does not get overwhelmed.

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