How do I get a page’s current URL in Twig for Drupal 9

Having access to a site’s URL in your templates can come in handy for many different use cases, such as determining if your on the admin/people page as apposed to admin/reports/dblog or admin/content.  These three pages might seem to bear on common relationship, however there is at least one.  Users.

I edited the user in the admin/people page so rather than showing just username, know shows:

• Firstname
• Lastname
• Email
• Username

However, in making this change I discovered that when on admin/content or admin/reports/dblog pages it would also so all the details.  So I needed to add an if statement to catch which page I was on.  Subsequently, you can get the current URL and parse it for a substring like this:

{% set site_url = url("<current>") %}
{% if 'people' in site_url['#markup']|render|render %}
  <div class="tw-pt-2">
    <div class="tw-inline-block tw-w-52 tw-text-gray-400">{{ name }}</div>
    <div class="tw-inline-block tw-pl-10 tw-text-gray-500">{{ mail }}</div>
  </div>
{% endif %}

Note, this doesn't show the full example of how to change the details, I wanted to focus on determining the people.

Other options

Absolute URL to the front page:

<a href="{{ url('<front>') }}">{{ 'Home'|t }}</a>

An absolute URL to a specific node:

<a href="{{ url('entity.node.canonical', { 'node': 123 }) }}">{{ 'Visit node 123'|t }}</a>

What about if you are working in a node template and have a node variable available, you can generate an absolute URL to the current node:

<a href="{{ url('entity.node.canonical', { 'node': node.id() }) }}">{{ 'Visit this page'|t }}</a>

Extra notes

If you are using url('<front>'), note this is an array.  I was using the 'front' is the following way

{% set frontUrl = url('<front>') %}

{% set path = 'related-projects' %}

{% set hrefPathTag = 'f[0]'|url_encode ~ '=' ~ 'tags:'|url_encode %}

{% for tag in items|slice(startPos, length) %}

  {% set tag = drupal_field('name', 'taxonomy_term', tag.content['#options'].entity.tid.value) %}

  {% set tagTitle = tag|render|striptags|trim %}

  {% set href = '?' ~ hrefPathTag ~ tagTitle|url_encode %}

  <a href="{{ frontUrl|render ~ path ~ href }}" alt="{{ tagTitle|title }}" class="tw-no-underline">

    <div class="dark-blue-tag">{{ tagTitle|title }}</div>

  </a>

{% endfor %}

So the 'front' path renders correctly, add |render

frontUrl|render