Strange (caching?) issue concerning date/time

MathijsDelva · ‎03-31-2022

Hi!

My goal is to schedule a promotion based upon three datetimes:

1. now

2. promotion_start_date

3. promotion_end_date

If 'now' is between promotion_start_date & promotion_end_date, the promotion must be shown. promotion_end_date & promotion_end_date values come from metafields. I have this code:

{% assign seconds = 5 | times: 24 | times: 60 %}
{% assign current_date = 'now' | date: "%d/%m/%Y, %H:%M:%S" %}
{% assign promotion_start_date = shop.metafields.promotion.promotion_start | date: "%s" | minus: seconds | date: "%d/%m/%Y, %H:%M:%S" %}
{% assign promotion_end_date = shop.metafields.promotion.promotion_end | date: "%s" | minus: seconds | date: "%d/%m/%Y, %H:%M:%S" %}
{% if current_date > promotion_start_date and current_date < promotion_end_date %}
    {% capture promotion_is_live %}{{shop.metafields.promotion.is_active}}{% endcapture %}
{% endif %}

I've included this inside a snippet and added it to theme.liquid's <head>. There, this works perfectly. I continuously update the metafields values to toggle the promotion on and off, and upon refresh, i get a nice "{{ current_date }}" printed (which is perfectly live and not cached) and a conditional output as per test:

{{ current_date }}
{% if promotion_is_live %}
promotion_is_live
{% else %}
promotion_is_not_live
{% endif %}

Now the issue i have is the following:

When using the "{% if promotion_is_live %}" conditional in my templates, it doesn't work. As per the same test, i also added the output (promotion_is_live & promotion_is_not_live) as in the <head>. So now i see "promotion_is_live" in the <head> but "promotion_is_not_live" in the template ..

How is this possible?

FYI: shop.metafields.promotion.is_active outputs a boolean.

Jason · ‎04-01-2022

You should always assume that now will return the time that the view was cached, not the current now.

Updating a metafield would clear the cache so when you view the page again you would see a freshly cached view with new time. On a second viewing (and assuming the metafield hasn't been changed) you'd still see that initial now time.

This is the intended outcome so you may need to tweak your approach.

★ I jump on these forums in my free time to help and share some insights. Not looking to be hired, and not looking for work. http://freakdesign.com.au ★

Alopwer · ‎04-04-2024

Hi, is there any documentation on what triggers cache revalidation and how does it behave? Does it revalidate the whole website or only the files the metafield is used in? What about metaobjects, does the metaobject field update triggers the revalidate?

Strange (caching?) issue concerning date/time

Strange (caching?) issue concerning date/time

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