正则表达式，解析img src内容并用另一个链接替换它 [英] Regular expression, parsing img src content and replacing it with another links

问题描述

我需要在我的网站上创建下一个功能：用户写文章并在其中添加图像，图像通常不会存储在本地主机上。我需要将这些图像下载到本地主机，并将链接替换为本地图像。

例如：

 < img ... src =http://bob.com/img/image1.png...> 
< img ... src =http://bob.com/img/image2.png....> 
  

脚本会找到 src 内容，下载图片并将其替换为：

 < img ... src =/ images / image1.png...> ; 
< img ... src =/ images / image2.png....> 
  

我理解如何解析所有 src 代码：

  $ subject =＃我会在那里放置文章内容（使用img标签等）
 $ result = array （）; 
 preg_match（/< img。*？src =（。*？）。*？> /，$ subject，$ result）; 
  

现在 $ result 数组将包含所有链接图像。尼斯。现在我有一些问题。
$ b

1）如果我使用 preg_replace ，它会帮我解决这个任务？在我看来不是，因为 preg_replace 会立即替换内容（所以我不能下载镜像，创建新的链接存储在本地主机映像上，并以某种方式将其设置为 preg_replace ，因为它还在运行）。我对这个假设是否正确？

2）好的。就像我说的，我可以组成一个阵列。之后，我从该阵列下载所有图像。之后，不知何故，我会替换所有旧图像，以获取新图像。我认为这是更现实的。我对吗？

类似的东西：

  $ subject =＃我会把有文章内容（带有img标签等）
 $ result = array（）; 
 preg_match（/< img。*？src =（。*？）。*？> /，$ subject，$ result）; 
 
 foreach（$ result as $ src）
 {
 $ new_src = downloadImage（$ src）; 
＃以某种方式将旧图像替换为新图像。怎么样？ 
} 
  

3）我会用第二种方法吗？

解决方案

我想你需要 preg_replace_callback ，但请记住 downloadImage 可能会失败。所以优雅地处理失败（后备图像或重试队列）

I need to make next feature on my site: user writing an article and attach image in it, images are often stored not on localhost. I need to download this images to localhost and replace links to localhost images.

For example:

<img ... src="http://bob.com/img/image1.png" ... >
<img ... src="http://bob.com/img/image2.png" .... >

Script will find src content, download images and replace it like this:

<img ... src="/images/image1.png" ... >
<img ... src="/images/image2.png" .... >

I understand how to parse all src from code:

$subject = # i will put there article content (with img tags etc)
$result = array();
preg_match("/<img.*?src="(.*?)".*?>/", $subject, $result);

Now $result array will contain all link to images. Nice. Now I have some questions.

1) If I use preg_replace, will it help me to solve this task? In my opinion not, because preg_replace will replace content instantly (so I can't download image, create new link for stored on localhost image and somehow set this as argument for preg_replace, because it is run yet). Am I right with this assumption?

2) Okay. I can form an array, like I said. After that I download all images from this array. After that, somehow, I will replace all old images, for new images. I think it is more realistic. Am I right?

Something like that:

$subject = # i will put there article content (with img tags etc)
$result = array();
preg_match("/<img.*?src="(.*?)".*?>/", $subject, $result);

foreach($result as $src)
{
 $new_src = downloadImage($src);
 # somehow replace old image with new image there. How?
}

3) How exactly I can replace links if I will use 2nd method?

解决方案

I think you need preg_replace_callback but keep in mind that downloadImage may fail. so handle the failure gracefully (a fallback image or a retry queue)

这篇关于正则表达式，解析img src内容并用另一个链接替换它的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！