扩展 PHP 正则表达式以覆盖“srcset"和“风格"属性 [英] Extend PHP regex to cover "srcset" and "style" attributes

问题描述

我创建了一个 WordPress 插件，可以将所有链接转换为 协议相关 URL(删除 http: 和 https:)基于我在 $tag 和 $ 中列出的标签和属性属性 变量.这是功能的一部分.为了节省空间，其余的代码可以在这里找到.

I've created a WordPress plugin that turn all links into protocol-relative URLs (removing http: and https:) based off the tags and attributes that I list in the $tag and $attribute variables. This is part of the function. To save space, the rest of the code can be found here.

$content_type = NULL;
# Check for 'Content-Type' headers only
foreach ( headers_list() as $header ) {
    if ( strpos( strtolower( $header ), 'content-type:' ) === 0 ) {
        $pieces = explode( ':', strtolower( $header ) );
        $content_type = trim( $pieces[1] );
        break;
    }
}
# If the content-type is 'NULL' or 'text/html', apply rewrite
if ( is_null( $content_type ) || substr( $content_type, 0, 9 ) === 'text/html' ) {
    $tag = 'a|base|div|form|iframe|img|link|meta|script|svg';
    $attribute = 'action|content|data-project-file|href|src|srcset|style';
    # If 'Protocol Relative URL' option is checked, only apply change to internal links
    if ( $this->option == 1 ) {
        # Remove protocol from home URL
        $website = preg_replace( '/https?:\/\//', '', home_url() );
        # Remove protocol from internal links
        $links = preg_replace( '/(<(' . $tag . ')([^>]*)(' . $attribute . ')=["\'])https?:\/\/' . $website . '/i', '$1//' . $website, $links );
    }
    # Else, remove protocols from all links
    else {
        $links = preg_replace( '/(<(' . $tag . ')([^>]*)(' . $attribute . ')=["\'])https?:\/\//i', '$1//', $links );
    }
}
# Return protocol relative links
return $links;

这按预期工作，但不适用于以下示例:

This works as intended, but it doesn't work on these examples:

<!-- Within the 'style' attribute -->
<div class="some-class" style='background-color:rgba(255,255,255,0);background-image:url("http://placehold.it/300x200");background-position:center center;background-repeat:no-repeat'>
<!-- Within the 'srcset' attribute -->
<img src="http://placehold.it/600x300" srcset="http://placehold.it/500 500x, http://placehold.it/100 100w">

但是，代码部分适用于这些示例.

However, the code partially works for these examples.

<div class="some-class" style='background-color:rgba(255,255,255,0);background-image:url("http://placehold.it/300x200");background-position:center center;background-repeat:no-repeat'>
<img src="http://placehold.it/600x300" srcset="//placehold.it/500 500x, http://placehold.it/100 100w">

我已经尝试向 $tag 和 $attribute 变量添加附加值，但这并没有帮助.我假设我需要更新我的正则表达式的其余部分以涵盖这两个额外的标签?或者是否有不同的方法来处理它，例如 DOMDocument?

I've played around with adding additional values to the $tag and $attribute variables, but that didn't help. I'd assume I need to update the rest of my regex to cover these two additional tags? Or is there is a different way to approach it, such as DOMDocument?

推荐答案

我能够通过执行以下操作来简化代码:

I was able to simplify the code by doing the following:

$content_type = NULL;
# Check for 'Content-Type' headers only
foreach ( headers_list() as $header ) {
    if ( strpos( strtolower( $header ), 'content-type:' ) === 0 ) {
        $pieces = explode( ':', strtolower( $header ) );
        $content_type = trim( $pieces[1] );
        break;
    }
}
# If the content-type is 'NULL' or 'text/html', apply rewrite
if ( is_null( $content_type ) || substr( $content_type, 0, 9 ) === 'text/html' ) {
    # Remove protocol from home URL
    $website = $_SERVER['HTTP_HOST'];
    $links = str_replace( 'https?://' . $website, '//' . $website, $links );
    $links = preg_replace( '|https?://(.*?)|', '//$1', $links );
}
# Return protocol relative links
return $links;

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