wagtail-caching/slides.md

---
title: Wagtail & Caching
class: text-center
highlighter: shiki
transition: slide-left
monaco: false
mdc: true
themeConfig:
  primary: '#2e1f5e'
---

# Wagtail & Caching

### Jake Howard{style="color: #e85537;" }

<ul class="list-none! text-sm [&>li]:m-0! mt-1 uppercase">
  <li><em>Senior Systems Engineer</em> @ Torchbox <mdi-fire class="fill-white"/></li>
  <li><em>Security Team</em> & <em>Performance Working Group</em> @ Wagtail <logos-wagtail class="fill-white"/></li>
</ul>

<ul class="list-none! text-xs [&>li]:m-0! mt-3 font-light">
  <li><mdi-earth /> theorangeone.net</li>
  <li><mdi-twitter /> @RealOrangeOne</li>
  <li><mdi-github /> @RealOrangeOne</li>
  <li><mdi-mastodon /> @jake@theorangeone.net</li>
</ul>

---
layout: fact
---

# Disclaimer{style="color: #fd5765;" }

---
layout: cover
---

# What _is_ caching?

---
layout: center
---


# Scale

<style>
@keyframes grow {
  from {

  }

  to {
    font-size: 30rem;
  }
}

h1 {
  animation-name: grow;
  animation-duration: 30s;
  animation-timing-function: linear;
  animation-fill-mode: forwards;
}

</style>

---
layout: cover
---

# <logos-wagtail class="fill-white"/> Caching <em>in Wagtail</em>

---
layout: section
---

## 1:
# Template Fragment Caching

---
layout: image
image: https://d1nvwtjgmbo5v5.cloudfront.net/media/images/Screen_Shot_2015-05-14_at_09.01.5.2e16d0ba.fill-1200x996.png
backgroundSize: cover
---

<style>
.slidev-layout {
  background-position: top center !important;
}
</style>

---
layout: none
---

```html
<div class="one-half--medium one-third--large">
  <div class="card card--link">
    <a href="/developers/springload/made-wagtail/" class="project-image">
      <img src="https://d1nvwtjgmbo5v5.cloudfront.net/media/images/Screen_Shot_2015-05-14_at_09.01.52.2e16d0ba.fill-680x564.png" alt="" title="">
  </a>
  <div class="project__links">
    <a class="project__info" href="/developers/springload/made-wagtail/">
      <span class="u-sr-only">Project info</span>
      <svg class="i i--grey i--hover">
        <use xlink:href="#i-info"></use>
      </svg>
    </a>
    <a class="project__visit" href="http://madewithwagtail.org/" title="Project link" data-analytics="Project|Link click">
      <span class="u-sr-only">Project link</span>
      <svg class="i i--grey i--hover">
        <use xlink:href="#i-visit"></use>
      </svg>
    </a>
  </div>
</div>
<h4 class="project-title">
  Made with Wagtail
</h4>
<p class="project-author">
  <a href="/developers/springload/" title="View the company page of Springload">
    Springload
  </a>
</p>
```

<style>
.slidev-page, .slidev-code-wrapper, .slidev-code {
  height: 100%;
}
</style>


---
layout: cover
background: /website-homepage.png
---

# An example

---
layout: image
image: /website-posts.png
---

---
layout: none
---

````md magic-move
```html
{% load wagtailcore_tags util_tags %}

<article class="media listing-item">
  <div class="columns">
    <figure class="media-left column is-{{ show_listing_images|yesno:'3,1' }} image-column">
      {% if page.list_image_url %}
        <a href="{% pageurl page %}" class="image" title="{{ page.title }}">
          <img src="{{ page.list_image_url }}" alt="{{ page.hero_image_alt }}" loading="lazy" decoding="async" referrerpolicy="no-referrer" />
        </a>
      {% endif %}
    </figure>
    <div class="media-content column">
      <div>
        {% if breadcrumbs %}
          {% include "common/breadcrumbs.html" with parents=page.get_parent_pages %}
        {% endif %}
        <h2 class="title is-3">
          <a href="{% pageurl page %}">{{ page.title }}</a>
        </h2>
        {% include "common/content-details.html" %}
        <p>{{ page.summary }}</p>
      </div>
    </div>
  </div>
</article>
```

```html {all|1|3,27|4-26|all}
{% load wagtailcore_tags wagtail_cache util_tags %}

{% wagtailpagecache FRAGMENT_CACHE_TTL "listing-item" breadcrumbs show_listing_images %}
  <article class="media listing-item">
    <div class="columns">
      <figure class="media-left column is-{{ show_listing_images|yesno:'3,1' }} image-column">
        {% if page.list_image_url %}
          <a href="{% pageurl page %}" class="image" title="{{ page.title }}">
            <img src="{{ page.list_image_url }}" alt="{{ page.hero_image_alt }}" loading="lazy" decoding="async" referrerpolicy="no-referrer" />
          </a>
        {% endif %}
      </figure>
      <div class="media-content column">
        <div>
          {% if breadcrumbs %}
            {% include "common/breadcrumbs.html" with parents=page.get_parent_pages %}
          {% endif %}
          <h2 class="title is-3">
            <a href="{% pageurl page %}">{{ page.title }}</a>
          </h2>
          {% include "common/content-details.html" %}
          <p>{{ page.summary }}</p>
        </div>
      </div>
    </div>
  </article>
{% endwagtailpagecache %}
```
````

<style>
.slidev-page, .slidev-code-wrapper, .slidev-code {
  height: 100%;
}
</style>


---
layout: cover
background: /website-search.png
---

# Duplication

---
layout: center
---

```html {3}
<section class="container">
  {% for page in listing_pages %}
    {% include "common/listing-item.html" %}
  {% endfor %}
</section>
```

<style>
code {
  font-size: 1.5rem !important;
}
</style>

---
layout: image
image: /website-search.png
---

---

# Cache invalidation

<v-click>

```python
>>> BlogPostPage.objects.first().cache_key
```

</v-click>

<v-click>

```python
@property
def cache_key(self) -> str:
    """
    A generic cache key to identify a page in its current state.
    Should the page change, so will the key.

    Customizations to the cache key should be made in :attr:`get_cache_key_components`.
    """
    ...
```

</v-click>

<style>
code {
  font-size: 1rem !important;
}
</style>

---
layout: center
---

# What about Django?

```jinja
{% load cache %}
{% cache 500 sidebar request.user.username %}
    .. sidebar for logged in user ..
{% endcache %}
```
<Transform :scale="1.4">
<v-clicks>

- Current page
- Current site
- Preview
- Cache invalidation

</v-clicks>
</Transform>

<style>
code {
  font-size: 1.5rem !important;
}
</style>

---
layout: section
---

## 2:
# Frontend Caching