I want to output a line conditionally in nunjucks, but don't want to have an empty line if the condition is false.
Example:
Before
{{ 'Something' if false }}
After
renders like this:
Before
After
I would like to remove the empty line without lowering the readability of the template. Is there a nice way to do that?
I would expect something like {{- 'Something' if false }} but that doesn't work.
Nunjucks has it's own conditional methods. Note the percent symbol instead of double moustaches.
https://mozilla.github.io/nunjucks/templating.html#if
{% if hungry %}
I am hungry
{% elif tired %}
I am tired
{% else %}
I am good!
{% endif %}
Related
Let's say I have the following Jinja2 variables:
'dev_ami' = 'ami-123456'
'dev_located_ami' = 'ami-123456'
'prod_ami' = 'ami-654321'
'prod_located_ami' = 'ami-654321'
I would like to set a condition upon when the 'dev_ami' variable is equal to the 'dev_located_ami' variable. This would easily be done as shown in the following statement:
{% if dev_ami == dev_located_ami %}
... do some stuff
{% else %}
... do some other stuff
{% endif %}
But I would like to dynamically compare amis based on the deployment environment contained in a list ['dev','prod', etc...]. The following contains a templating error since there is an expression within a statement as such - {% {{ .. }} %}:
{% for env_type in ['dev','prod'] %}
{% if {{ env_type }}_ami == {{ env_type }}_located_ami %}
... do stuff
{% else %}
... do other stuff
{% endif %}
{% endfor %}
I have tried to set variables to represent the expressions I would like in the following code but unfortunately they are compiled literally as 'dev_ami' and 'dev_located_ami' whereas I would like them compiled to their corresponding variable values 'ami-123456' and 'ami-123456':
{% for env_type in ['dev','prod'] %}
{% set ami = "%s_ami"|format(env_type) %}
{% set located_ami = "%s_located_ami"|format(env_type) %}
{% if ami == located_ami %}
... do stuff
{% else %}
... do other stuff
{% endif %}
{% endfor %}
I have checked through various filters and so far have had no success. Would appreciate advice on getting this specific implementation to work properly. Thank you in advance.
I think you might be approaching the problem with the wrong datastructure in mind.
Dynamically generating variable names in order to compare amis in different environemts sounds like a massive overkill to me. Are you familiar with lists & dictionaries?
Try to start from something like this (pseudocode):
dict = { environments:
prod:
ami1: foo
ami1_located: foo
dev:
ami1: bar
ami1_located:baz
}
for env in dict[environments]:
if env[ami1] == env[ami1_located]:
[...]
This works perfectly fine:
{% capture foo %}{% include test.html %}{% endcapture %}
I want to do this:
frontmatter.md:
---
baaz: test.html
layout: layout.html
---
layout.html:
{% capture foo %}{% include {{ page.baaz }} %}{% endcapture %}
But when I do I'm given this error:
"Liquid Exception: Invalid syntax for include tag. File contains invalid characters or sequences: Valid syntax: {% include file.ext param='value' param2='value' %}"
I've seen this addressed in several other questions, with the most recent explanation I've found being this:
"...dynamic filename paths can't be added due to the fact that the included files are calculated and added at the compilation phase and not at run time phase. And compilation phase means dynamic paths aren't yet recognized."
But that source is nearly two years old. Does anyone have a solution to this yet? Or a workaround that would allow me to include a file defined as a variable in frontmatter?
You can try {% include page.baaz %}
Edit : after some investigations, it appears that your syntax is correct, and that the error fires only when page.baaz is not present.
This ends up in an include tag which looks like this for liquid :
{% include %}
In order to avoid this error on certain pages/post with no baaz set, you can use a condition.
{% if page.baaz %}
{% capture foo %}{% include {{ page.baaz }} %}{% endcapture %}
{% endif %}
I just came to this case recently. I assume the syntax works as expected. See sample and result.
{% include {{ page.baaz }} %}
However in your case it might be the page name could not be put in a variable as the error stated:
Error: Invalid syntax for include tag:
File contains invalid characters or sequences
Valid syntax:
***% include file.ext param='value' param2='value' %***
So to come out from the problem I would suggest you to inventory all file names and choose it:
{% case page.baaz %}
{% when 'test.html' %}
{% capture foo %}{% include test.html %}{% endcapture %}
{% when 'othertest.html' %}
{% capture foo %}{% include othertest.html %}{% endcapture %}
{% else %}
This is not a test
{% endcase %}
I had a similar issue... I have found a very usable work-around. Allow me to share my experience and solution. I hope it helps you to find a suitable solution for your problem.
What I wanted to build
I wanted to make a page with multiple sections. The sections should be reusable, be able to contain includes and they should be easy to manage in the CloudCannon CMS.
What I came up with
I ended up using the following front matter:
---
title: Lorem ipsum
description: Lorem ipsum
image: /img/default.jpg
section_blocks:
- section: sectionwithinclude
- section: anothersection
- section: andyetanothersection
---
... and the following tempate:
{% for item in page.section_blocks %}
{% for section in site.sections %}
{% if item.section == section.slug %}
<div class="section {{ item.section }}">
{{ section.content }}
</div>
{% endif %}
{% endfor %}
{% endfor %}
Within the _sections folder/collection I have a file called sectionwithinclude.md that looks like this:
---
---
{% include mycustominclude.html %}
Why this is great
When you edit your page, CloudCannon will show the section_blocks as an array with reorder buttons. Additionally, CloudCannon will automagically recognize section as a collection and show the options in a dropdown. Therefore adding a section is a matter of adding an empty item to the array, selecting a section from the dropdown and reordering it with the array buttons. On the same time, the inline editing option of CloudCannon still works. So management of text can be WYSIWYG, while block management can be done in the front matter array.
Super easy and powerful for (you and) your editors.
PS. You might find out that you will have some 'scope' issues, because page no longer relates to the actual page, but to the section. To solve this you can/should alter the loop in the template. You can let the loop manage the include instead of the section.
It is possible to expand a variable into a post Front-Matter?
I use a series of items for links into my template, like:
related_links:
- text: foo
link: bar
But sometimes I need to refer to other posts into my site. Normally I would use just /bar into link, but this is also used as shownotes into a podcast, I want to expand the link for http://example.com/bar. But using {% post_url YYYY-MM-DD-bar %} results into:
Error: could not read file [REDACTED]: (<unknown>): found character that cannot start any token while scanning for the next token at line 33 column 12
Any tips?
If you use
related_links:
- text: foo
link: {% post_url YYYY-MM-DD-bar %}
you will get an error because the { will start a flow style mapping and % cannot start a token in YAML. You have to put the whole scalar in (double) quotes:
related_links:
- text: foo
link: "{% post_url YYYY-MM-DD-bar %}"
What you want to do does not work because of Jekyll's pipeline:
parse YAML front matter
process rest of document with Liquid
parse result of previous step with Markdown
{% post_url YYYY-MM-DD-bar %} is a Liquid command. As you see, Liquid processes just the part of your file below the YAML front matter. Therefore, no Liquid replacement takes place there.
You can instead write something like this below the front matter:
{% assign link = post_url YYYY-MM-DD-bar %}
And then use {{link}} elsewhere. If you have multiple links, things get hacky. Something like this might work, but I am not enough of a Liquid user to know for sure:
{% capture nl %}
{% endcapture %}
{% capture rawlinks %}
{% post_url YYYY-MM-DD-bar %}
{% post_url YYYY-MM-DD-bar %}
{% endcapture %}
{% assign links = rawlinks | split nl %}
You can then specify indexes in your YAML front matter:
related_links:
- text: foo
linkindex: 0
And finally, somewhere in your document:
{{ links[related_link.linkindex] }}
YMMV if this level of uglyness is justified for your use-case.
I found a more elegant at my own:
{% assign real_link=link.link %}
{% assign link_start = real_link | slice: 0 %}
{% if link_start == "/" %}{% assign real_link = real_link | prepend: site.url %}{% endif %}
As I start al my locak links with a / to warrant that the link will be related with the root in the site, that was a better way for me.
Any .html template for django-registration module works fine with {% blocktrans %} and {% trans %} template blocks. With {% load i18n %} in place, of course.
But I cannot make use of i18n tags in activation_email.txt and activation_email_subject.txt templates. Strings marked for translation just don't appear in .po file after makemessages.
Also, when wrapping a text with {% blocktrans %}{% endblocktrans %}, all variables such as {{ site.domain }} and {{ site.name }} are not processed.
Can you suggest what I am doing wrong?
That was my bad, I just improperly used makemessages. By default it processes only .html files.
In my case
django-admin.py makemessages -a -e html,txt
does all the work.
As for variables, {% blocktrans %}{% endblocktrans %} cannot process variables inside object, so we have to retrieve them before translation:
{% blocktrans with site.name as site_name and site.domain as site_domain %}
Good examples of templates for django-registration are given here.
I'm using Jekyll to create a new blog. It uses Liquid underneath.
Jekyll defines certain "variables": site, content, page, post and paginator. These "variables" have several "members". For instance, post.date will return the date of a post, while post.url will return its url.
My question is: can I access a variable's member using another variable as the member name?
See the following example:
{% if my_condition %}
{% assign name = 'date' %}
{% else %}
{% assign name = 'url' %}
{% endif %}
I have a variable called name which is either 'date' or 'url'.
How can I make the liquid equivalent of post[name] in ruby?
The only way I've found is using a for loop to iterate over all the pairs (key-value) of post. Beware! It is quite horrible:
{% for property in post %}
{% if property[0] == name %}
{{ property[1] }}
{% endif %}
{% endfor %}
Argh! I hope there is a better way.
Thanks.
I don't know what I was thinking.
post[name] is a perfectly valid liquid construction. So the for-if code above can be replaced by this:
{{ post[name] }}
I thought that I tried this, but apparently I didn't. D'oh!
Liquid admits even fancier constructs; the following one is syntactically correct, and will return the expected value if post, element, categories, etc are correctly defined:
{{ post[element.id].categories[1].name }}
I am greatly surprised with Liquid. Will definitively continue investigating.
Actually, this did not work for me. I tried a bunch of different combinations and what finally worked was
<!-- object myObj.test has the string value "this is a test" -->
{% assign x = 'test' %}
{{ myObj.[x] }}
Output:
this is a test