In the Jeykll in documentation to Liquid I found the notation {% … %} but in some plugins or example code snippets I saw also {%- … -%} (with a dash after and before percentage symbol). What is the right usage?
a) {%- include header.html -%}
b) {% include header.html %}
Or is it even dependent from the command / option / function which I am using inside the block?
The dashes give you the ability to control the whitespace around your tags. This often isn’t necessary for HTML generation, but can come in handy for certain uses in pre-formatted text. Or, if you are just picky about what your final HTML looks like ;)
Check out the docs here: https://shopify.github.io/liquid/basics/whitespace/
Related
I'd like to create something like a shortcode for a blockquote in Jekyll. It should include the quote source in a nicely formatted way.
The shortcode could look like this:
{% quote author="My Author" %}
This is the quoted content
spanning multiple lines
And paragraphs
{% endquote %}
What's the best way to achieve this in Jekyll? Can it be that there is no way to provide multiple arguments to a Jekyll tag plugin?
I have found a blog post that provides multiple attributes using string concatenation or JSON.
My Research
I have found two systems in Jekyll that can be used similar to shortcodes:
HTML Includes
Custom Tags
To summarize, both methods only provide a single attribute to the Ruby code, the content. Below, you will find the limitations of both solutions.
HTML Includes limiations
https://jekyllrb.com/docs/includes/
An include in use looks like this:
{% include note.html content=download_note %}
It is possible to use content from captures for parameters, so we could create the following include file:
<blockquote>
{{ include.quote | markdownify }}
<p><em>{{ include.author }}</em></p>
</blockquote>
And use it in a blog post like this:
{% capture quote %}
This is the quote content
spanning multiple lines
And paragraphs
{% endcapture %}
{% include quote.html quote=quote author="My Author" %}
It works, but in my opinion, it's not really a nice approach to use when writing blog posts.
Custom Tags limiations
https://jekyllrb.com/docs/plugins/tags/
Sounds promising, but the documentation only shows two ways to use them:
{% render_time page rendered at: %}
and
{% render_time %}
page rendered at:
{% endrender_time %}
I'm building an admin for Flask and SQLAlchemy, and I want to pass the HTML for the different inputs to my view using render_template. The templating framework seems to escape the HTML automatically, so all <"'> characters are converted to HTML entities. How can I disable that so that the HTML renders correctly?
To turn off autoescaping when rendering a value, use the |safe filter.
{{ something|safe }}
Only do this on data you trust, since rendering untrusted data without escaping is a cross-site scripting vulnerability.
MarkupSafe provides Jinja's autoescaping behavior. You can import Markup and use it to declare a value HTML safe from the code:
from markupsafe import Markup
value = Markup('<strong>The HTML String</strong>')
Pass that to the templates and you don't have to use the |safe filter on it.
From the Jinja docs section HTML Escaping:
When automatic escaping is enabled everything is escaped by default
except for values explicitly marked as safe. Those can either be
marked by the application or in the template by using the |safe
filter.
Example:
<div class="info">
{{data.email_content|safe}}
</div>
When you have a lot of variables that don't need escaping, you can use an autoescape override block:
{% autoescape false %}
{{ something }}
{{ something_else }}
<b>{{ something_important }}</b>
{% endautoescape %}
For handling line-breaks specifically, I tried a number of options before finally settling for this:
{% set list1 = data.split('\n') %}
{% for item in list1 %}
{{ item }}
{% if not loop.last %}
<br/>
{% endif %}
{% endfor %}
The nice thing about this approach is that it's compatible with the auto-escaping, leaving everything nice and safe. It can also be combined with filters, like urlize.
Of course it's similar to Helge's answer, but doesn't need a macro (relying instead on Jinja's built-in split function) and also doesn't add an unnecesssary <br/> after the last item.
Some people seem to turn autoescape off which carries security risks to manipulate the string display.
If you only want to insert some linebreaks into a string and convert the linebreaks into <br />, then you could take a jinja macro like:
{% macro linebreaks_for_string( the_string ) -%}
{% if the_string %}
{% for line in the_string.split('\n') %}
<br />
{{ line }}
{% endfor %}
{% else %}
{{ the_string }}
{% endif %}
{%- endmacro %}
and in your template just call this with
{{ linebreaks_for_string( my_string_in_a_variable ) }}
Use the safe filter in your template, and then sanitize the HTML with the bleach library in your view. Using bleach, you can whitelist the HTML tags that you need to use.
This is the safest, as far as I know. I tried both the safe filter and the Markup class, and both ways allowed me to execute unwanted JavaScript. Not very safe!
I have this Liquid template which looks like this:
# /_includes/slideshow.html
{% for image in {{ include.images }} %}
...
{% endfor %}
which I'm trying to use with a YAML file (for my Jekyll site) like this:
# /index.md
{% include slideshow.html images='site.data.homepage_images' %}
The reason I see this failing is because my include variable {{ include.images }} resolves to a string within the for loop. Is there a different way to accomplish this? I'm still rather new to Liquid, YAML, Jekyll, and well, web development altogether, so any help in doing this is much appreciated!
(Note: the problem goes away if I replace {{ include.images }} with site.data.homepage_images.)
Additionally, the reason why I'm doing this (and why that crude fix isn't the solution I'm looking for) is for the ability to inject my image slideshow elsewhere around my site. It'd save a lot of code to abuse my include variable in this way.
Correct syntax in for loop is : {% for image in include.images %}
Is there something like multiple language highlight syntax in Sublime Text? For example my code might look like this:
{% extends "template.html" %}
{% block content %}
{% if task == 'archimed_spiral' %}
<p>
$\frac{2}{3}$
</p>
{% elif task == 'gcd' %}
{% endif %}
{% endblock %}
Which is LaTeX inside html inside Jinja2. It gets pretty hard to read it properly.
Note
I know about Jinja2 package for Sublime, so it does highlight Jinja2 + html. Maybe I am just asking for too much..
Yes you can embed syntax highlighting. You basically define a start and end pattern, then include an existing scope. See Sublime Text 2: Different language highlighting based on context? (a la Webstorm).
I use GitHub Pages for my blog, and am running into a problem with Jekyll. My post.html has a block like this:
{% for testpost in site.posts %}
{% four %}
{% lines of %}
{% processing %}
{% goes here %}
{% endfor %}
The part in the middle doesn't matter. The important part is the end of the line which is outside of the {% %} markup, and is therefore rendered into the html. Since this is in a loop, it's putting about 1000 blank lines into the middle of by HTML page. It doesn't affect the display, but it make a View/Source troublesome.
Any ideas on how to avoid those extra blank lines?
Since Liquid v4 (included in Jekyll from v3.5) there is a Whitespace control, which finally resolved case with blank line, white space, etc.
Link to documentation: https://shopify.github.io/liquid/basics/whitespace/
There's a nice workaround, that I found out in https://github.com/plusjade/jekyll-bootstrap/blob/master/_includes/JB/setup, and which is compatible with github pages.
Just enclose your loop in a capture statement, and assign nil to the resulting var.
{% capture cache %}
{% for p in site.posts %}
do stuff here
{% endfor %}
{% endcapture %}{% assign cache = nil %}
How about
{{ page.content | escape | strip_newlines }}
There is Jekyll plugin that strips the whitespace.
Jekyll plugins by Aucor: Plugins for eg. trimming unwanted
newlines/whitespace and sorting pages by weight attribute.
You can get it directly from its Github repository. So basically you wrap your code with {% strip %}{% endstrip %}. Even if this doesn't suit you needs, you can easily change the ruby script.
For example:
{% strip %}
{% for testpost in site.posts %}
{% four %}
{% lines of %}
{% processing %}
{% goes here %}
{% endfor %}
{% endstrip %}
However, please remember the nature of Jekyll plugins, you can't run them on the Github Pages server.
Quote from Jekyll Doccumentation:
GitHub Pages is powered by Jekyll, however all Pages sites are generated using the --safe option to disable custom plugins for security reasons. Unfortunately, this means your plugins won’t work if you’re deploying to GitHub Pages.
You can still use GitHub Pages to publish your site, but you'll need to convert the site locally and push the generated static files to your GitHub repository instead of the Jekyll source files.
Actually there is a new solution for this problem which works without any plugin.
A Jekyll layout that compresses HTML. At a glance:
removes unnecessary whitespace;
removes optional end tags;
removes optional start tags;
removes comments;
preserves whitespace within <pre>;
GitHub Pages compatible;
ignores development environments;
configurable affected elements;
profile mode;
automatically tested.
http://jch.penibelst.de/
If you - for some reason - do not want to use this here is a nice article, which describes some workarounds:
Compressing Liquid generated code - sylvain durand