Relative urls in a proxied website don't work

问题

in PHP, I've written a proxy function that accepts a url, user agent, and other settings. Then the function makes a curl request for the website, and prints out that output with proper html content type headers into an iframe (this is necessary only because of my need to change some headers).

That proxied output often has lots of assets with relative URLS and actually inheret the hostname of my site, not the proxied site:

example: [http://MYSITE.com/proxy?url=http://somesite.com] would return the html of [http://somesite.com]

in the response html, there is stuff like this:

<link rel="apple-touch-icon-precomposed" sizes="144x144" href="assets/ico/apple-touch-icon-144-precomposed.png">

The problem:

Instead of the asset looking for that asset at http://somesite.com/assets/ico/apple-touch-icon-144-precomposed.png, it actually tries to find it at http://MYSITE.com/assets/ico/apple-touch-icon-144-precomposed.png which is wrong.

The Question:

What do i need to do to get their relative-path assets to load properly via the proxy?

回答1:

How about the <base> tag? You can place it in the head and it will inform the browser what to use as the base path for all relative URLs on the page:

<head>
    <base href="http://somesite.com/">
</head>

You could add it to each page that you serve with DOMDocument (Note this is for PHP5.4 because of the array dereferencing, but that's easy fixed for earlier versions):

if($contentType == 'text/html') {
    $doc = DOMDocument::loadHTML($html);
    $head = $doc->getElementsByTagName('head')[0];

    if(count($head->getElementsByTagName('base')) == 0) {
        $base = DOMDocument::createElement('base');
        $base->setAttribute('href', $urlOfPageDir);
    }

    $head->appendChild($base);
    echo $doc->saveHTML();
}

Take note that $urlOfPageDir must be the absolute URL of the directory in which the page resides. See this SO question for more on the base tag: Is it recommended to use the <base> html tag?

来源：https://stackoverflow.com/questions/12994611/relative-urls-in-a-proxied-website-dont-work

标签

php

proxy

relative-path