I have very few hours of use with Twig so I probably missed an important tip; please forgive me if this is a trivial question.
I'm using Twig with PHP for the generation of markdown files.
My twig file contains one or more {% for %}...{% endfor %} block and inside a for-loop, a few {% if %}...{% endif %} and ... I can't make any indentation in my Twig otherwise the spaces are also present in my output.
A very stupid example: https://twigfiddle.com/fb6nzq (use the Show raw result to make sure to see the spaces before the word true).
If I don't indent my {% if %}...{% endif %}, I got the correct result (https://twigfiddle.com/fb6nzq/2) but I don't have anymore indentation of blocks in my template.
In my real world twig file, I can have multiple {% endif %} like below and it becomes unreadable.
{% for (variable) %}
{% if (condition) %}
{% if (condition) %}
{% if (condition) %}
{% endif %}
{% endif %}
{% endif %}
{% endfor%}
So ... do you know if there is a wonderful trick to keep an indentation in your code but without having an impact on the output?
Desired twig template:
{% for (variable) %}
{% if (condition) %}
{% if (condition) %}
{% if (condition) %}
{% endif %}
{% endif %}
{% endif %}
{% endfor%}
You can use a dash - on any opening or closing twig expression where:
a dash on the closing expression would do a trim on the left.
{% if true -%}
a dash on the opening expression would do a trim on the right
{%- if true %}
a dash on the both the opening and closing expression would do a trim on the both sides
{%- if true -%}
Mind that: this is acting as a PHP trim, so that means that it will also trim your line feeds!
Here is an example:
{% for i in 1..5 %}
{% if true %}
{% if true %}
{%- if true %}
foo
{%- endif %}
{%- endif %}
{% endif %}
{% endfor %}
That renders:
foo
foo
foo
foo
foo
This is testable here: https://twigfiddle.com/1awhzk
Also note: that there is a spaceless tag to achieve those kind of things.
Related
My template like as blow
{% if hostvars[inventory_hostname].local_zk_server_id is defined %}
zookeeperServers={% for host in {{ groups[{{ target_hosts }}] %}}
"{{ hostvars[host].inventory_hostname }}:2181,"
{% endfor %}
{% endif %}
output ishost1:2181,host2:2181,host3:2181,
How to trim last comma
There are several possible gotchas in your above template regarding variables access. Moreover, rather than trimming the last character in your string, the best solution is probably not to write it. Here is a better solution IMO in my below example fixing all the problems I'm referring to:
{% set zookeeperServers=[] %}
{% if hostvars[inventory_hostname].local_zk_server_id is defined %}
{% for host in groups[target_hosts] %}
{% zookeeperServers.append(hostvars[host].inventory_hostname + ":2181") %}
{% endfor %}
zookeeperServers="{{ zookeeperServers | join(',') }}"
{% endif %}
A for loop in my jinja template is like this
{% for m in grp %}
abc {{ m.length }}
pqr
xyz
{% if m.flag is defined and m.flag == "f" %}
yes f {% endif %}
{% for r in uv %}
abcdef
{% endfor %}
{% endfor %}
Now the problem is in some members of grp don't have the flag variable. Wherever flag is present, the option true line is getting added properly. But when if condition is not satisfied, it just adds one blank line. These 4 or 5 lines are supposed to be without extra blank lines otherwise the generated config file gets marked as invalid.
Can anyone please help me with this?
Put {% endif %} to the next line
{% if m.flag is defined and m.flag == "f" %}
yes f
{% endif %}
Whitespace Control might be useful too.
If you add a minus sign (-) to the start or end of a block (e.g. a For tag), a comment, or a variable expression, the whitespaces before or after that block will be removed.
{% if m.flag is defined and m.flag == "f" %} yes f
{% endif -%}
I got this piece of YAML and i want jinja2 to assign and create item.menu, if it is not previously defined.
data:
- name: bar
menu: blah
- name: foo
This is my code, the error-output ist "template error while templating string: expected token 'end of statement block'"
{% for item in data %}
{% if item.menu is not defined %}
{% set item.menu=item.name %}
{% endif %}
{% endfor %}
Any Help about what I did wrong would be much apretiated :)
Greetings, Hendrik
You're question is not clear but here is my answer. I'll make everything explicit :
{% for item in data %}
{% if item.menu is not defined %}
{{ item.name }}
{% else %}
{{ item.menu }}
{% endif %}
{% endfor %}
I'm working on custom solution for Shopify store and my problem is that I can't manage how to avoid adding ' / ' after the last matched tag in the case statement.
I've tried to use some if statements with a forloop filters with no result.
The last thing on my mind was finding the last matched tag in the loop that will help us avoiding ' / ' after the last element, but unfortunately I can't manage how to do that.
Expected result: Wool/Nylon/Viscose
Here is the part of the code that compares all tags assigned to the product with the list of tags(clothing materials) required for the output.
Considering that product has such tags as Wool, Nylon and Viscose and others, non material.
Example 1
Actual & Expected Result: WoolNylonViscose
{% for tag in product.tags %}
{% case tag %}
{% when 'Viscose' %}
Viscose
{% when 'Wool' %}
Wool
{% when 'Polyamide' %}
Polyamide
{% when 'Nylon' %}
Nylon
{% else %}
{% endcase %}
{% endfor %}
Example 2
Filter forloop.last was used to define the last element of the loop, but the problem is that material tags(Wool, Nylon, Viscose) can be in the middle of the product tag array. Considering product has 10 tags and material tags are spread among the array we will see next result.
Result: ///Wool/Nylon////Viscose//
{% for tag in product.tags %}
{% if forloop.last == true %}
{% case tag %}
{% when 'Viscose' %}
Viscose
{% when 'Wool' %}
Wool
{% when 'Nylon' %}
Nylon
{% else %}
{% endcase %}
{% else %}
{% case tag %}
{% when 'Viscose' %}
Viscose
{% when 'Wool' %}
Wool
{% when 'Nylon' %}
Nylon
{% else %}
{% endcase %}
/
{% endif %}
{% endfor %}
I would appreciate if you could please point on my mistakes and suggest me how can i achieve solution.
This should work:
{% capture tag_string %}{% endcapture %}
{% for tag in product.tags %}
{% if tag == 'Viscose' %}{% capture tag_string %}{{ tag_string }}Viscose/{% endcapture %}
{% elsif tag == 'Wool' %}{% capture tag_string %}{{ tag_string }}Wool/{% endcapture %}
{% elsif tag == 'Polyamide' %}{% capture tag_string %}{{ tag_string }}Polyamide/{% endcapture %}
{% elsif tag == 'Nylon' %}{% capture tag_string %}{{ tag_string }}Nylon/{% endcapture %}
{% endif %}
{% endfor %}
{{ tag_string | split: "" | reverse | join: "" | remove_first: "/" | split: "" | reverse }}
More on string filters: https://help.shopify.com/themes/liquid/filters/string-filters
You can try the following:-
{% for tag in product.tags %}
{% case tag %}
{% when 'Viscose' %}
{{ 'Viscose' | append: '/' }}
{% when 'Wool' %}
{{ 'Wool' | append: '/' }}
{% when 'Polyamide' %}
{{ 'Polyamide' | append: '/' }}
{% when 'Nylon' %}
{{ 'Nylon' }}
{% else %}
{% endcase %}
{% endfor %}
Jinja2 in Ansible templates allows this type of expression in templates:
{% if foobar is defined %} foo_bar = {{foobar}} {% endif %}
{% if barfoo is defined %} bar_foo = {{barfoo}} {% endif %}
etc.
Is there any shorter version to say 'do not print this line if its variable is not defined?
Something like foo_bar = {{foobar|skip_this_line_if_undefined}}?
You can use the default(omit) filter. For details have a look at the documentation.
You could use a macro.
{% macro line(key, value) -%}
{% if not value|none %}{{ key }} = {{ value }}{% endif %}
{%- endmacro %}
Then just call the macro for every key/value pair.
{{ line('foo_bar', foobar) }}
{{ line('bar_foo', barfoo) }}
Could be problematic in edge cases though. If foobar or barfoo are not defined it probably will raise an error. In the macro, value in any case would be defined, so the condition is defined doesn't make sense any more. But if null/none actually is a valid value for any of the variables, you hit the wall...
A bit longer but probably water proof:
{% macro line(key, value) -%}
{% if value != omit %}{{ key }} = {{ value }}{% endif %}
{%- endmacro %}
{{ line('foo_bar', foobar|default(omit)) }}
{{ line('bar_foo', barfoo|default(omit)) }}