[wordpress] Relative URLs in WordPress

I've always found it frustrating in WordPress that images, files, links, etc. are inserted into WordPress with an absolute URL instead of relative URL. A relative url is much more convenient for switching domain names, changing between http and https etc. Today I discovered that if you define WP_CONTENT_URL with a relative url then when you insert files into posts they use the relative url for the src instead of absolute url. Just what I've always wanted! But the official WordPress documentation says that you should use a full URI if you are defining WP_CONTENT_URL.

WordPress codex says:

Set WP_CONTENT_URL to the full URI of this directory (no trailing slash), e.g.

define( 'WP_CONTENT_URL', 'http://example/blog/wp-content');

Everything seems to work fine when I use a relative URL, e.g.

define( 'WP_CONTENT_URL', '/my-content-folder');

But is there some problem with using a relative URI? I'm just thinking that there must be a reason for WordPress stating that it should be defined with a full URI.

I agree with Rup. I guess the main reason is to avoid confusion on relative paths. I think wordpress can work from scratch with relative paths but the problem might come when using multiple plugins, how the theme is configured etc.

I've once used this plugin for relative paths, when working on testing servers:

Root Relative URLs
Converts all URLs to root-relative URLs for hosting the same site on multiple IPs, easier production migration and better mobile device testing.

There is an easy way

Instead of /pagename/ use index.php/pagename/ or if you don't use permalinks do the following :

Post

index.php?p=123

Page

index.php?page_id=42

Category

index.php?cat=7

More information here : http://codex.wordpress.org/Linking_Posts_Pages_and_Categories

should use get_home_url(), then your links are absolute, but it does not affect if you change the site url

Under Settings => Media, there's an option for 'Full URL-path for files'. If you set this to the default media directory path '/wp-content/uploads' instead of blank, it will insert relative paths e.g. '/wp-content/uploads/2020/06/document.pdf'.

I'm not sure if it makes all links relative, e.g. to posts, but at least it handles media, which probably is what most people are worried about.

What i think you do is while you change domain names, the sql dump file that you have you can replace all instances of old domain name with new one. This is only option available as there are no plugins that will help you do this.

This is quickest way ..

<?php wp_make_link_relative( $link ) ?>

Convert full URL paths to relative paths.

Removes the http or https protocols and the domain. Keeps the path '/' at the beginning, so it isn't a true relative link, but from the web root base.

Reference: Wordpress Codex

I solved it in my site making this in functions.php

add_action("template_redirect", "start_buffer");
add_action("shutdown", "end_buffer", 999);

function filter_buffer($buffer) {
    $buffer = replace_insecure_links($buffer);
    return $buffer;
}
function start_buffer(){
    ob_start("filter_buffer");
}

function end_buffer(){
    if (ob_get_length()) ob_end_flush();
}

function replace_insecure_links($str) {

   $str = str_replace ( array("http://www.yoursite.com/", "https://www.yoursite.com/") , array("/", "/"), $str);

   return apply_filters("rsssl_fixer_output", $str);

}

I took part of one plugin, cut it into pieces and make this. It replaced ALL links in my site (menus, css, scripts etc.) and everything was working.