Introducing three methods of obtaining external images in PHP

In website development, it is often necessary to obtain external images to display on your website. When developing using PHP, how to obtain external images is a common question. This article will introduce several methods to obtain external images, I hope it will be helpful to everyone.

Method 1: file_get_contents

The file_get_contents function is a built-in function in PHP that can be used to read file contents. Its first parameter is the file path to be obtained, and the second parameter is a Boolean parameter indicating whether to read the entire content of the file into a string. The same principle applies to reading images. You only need to set the file path to the URL address of the image. The sample code is as follows:

$url = 'http://example.com/image.jpg'; // 图片 URL 地址
$img = file_get_contents($url);       // 读取图片
file_put_contents('image.jpg', $img); // 将图片保存到本地文件

This method is simple and easy to understand, with less code, but the performance is not efficient enough.

Method 2: curl

curl is a commonly used network request library that can be used to obtain web page content. Can also be used to get pictures. The code example is as follows:

$url = 'http://example.com/image.jpg'; // 图片 URL 地址
$ch = curl_init();                     // 创建 curl 句柄
curl_setopt($ch, CURLOPT_URL, $url);   // 设置 curl 请求的 URL
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);  // 不将 curl 结果直接输出到浏览器
$img = curl_exec($ch);                 // 获取图片内容
curl_close($ch);                       // 关闭 curl 句柄
file_put_contents('image.jpg', $img);  // 将图片保存到本地文件

This method has higher performance than file_get_contents, but the amount of code is relatively large.

Method 3: Remote download tool

You can also use some remote download tools, such as wget or aria2, etc. These tools can download specified images through the command line and save them to local files. For example, use the wget command to download an image:

wget http://example.com/image.jpg -O image.jpg

This method requires the installation of the corresponding download tool, which may not be very friendly to PHP developers.

Summary

Getting external images is a common problem. When developing with PHP, you can choose file_get_contents, curl or some remote download tools to achieve it. Just choose a method based on actual needs.

It is worth noting that when obtaining external pictures, you must pay attention to copyright issues and do not download and use them illegally. At the same time, for applications that frequently obtain external images, a caching mechanism should be added to avoid excessive consumption of network and server resources.

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