Specially crafted filters:
Filter name | Description |
|---|
json_value
| Encodes a value as a json value |
json_casted_value
| Encodes a value as a json value but first tries to cast to int, etc |
json_escape
| Escapes a json string |
json_decode
| Decode a json string for further processing |
| |
rawurlencode
| Escapes spaces (and other special chars) for url with a % symbol |
boolify
| Convert 'on', 'off', 'true', '1', 1 etc to boolean values |
bool_switch
| Boolifies the value and return the first or the second argument |
exists
| Check if a variable with a name exists in the current scope |
value
| Retrieve a value by name from the current context, or a default,or null |
apply_mapping
| Maps variables by name from the current context or an object to another object |
extract_objects
| Create objects from numbered variable names in the current scope |
objects_from_prefix
| Create objects from variables in the current scope sharing the same prefix |
tidy
| Clean up extra newlines in texts and attempts to fix indentation |
json_value
Example (VAR can be a string, number, boolean, null). Note that environment variables are always strings, so you need to cast them to the correct type.
{
"foo": {{ VAR | json_value }}
}
json_casted_value
json_casted_value tries to cast the value to a boolean, number or null before encoding it as a json value.
[
{{ 'True' | json_casted_value }},
{{ 'false' | json_casted_value }},
{{ 'null' | json_casted_value }},
{{ '124.5' | json_casted_value }},
{{ 'null' | json_casted_value }},
{{ 'foo' | json_casted_value }}
]
Result:
[
true,
false,
null,
124.5,
null,
"foo"
]
json_escape
[
"-- {{ '"To be or not to be" - Shakespeare' | json_escape }} --"
]
Result:
[
"-- \"To be or not to be\" - Shakespeare --"
]
json_decode
{% set json = '{"foo": "bar", "foobar": 2}' %}
{% for key, value in json | json_decode %}
{{ key }}: {{ value }}
{% endfor %
rawurlencode
Raw url encode is also called path encoding. It encodes spaces and other special characters with a percent symbol.
{{ 'To be or not to be' | rawurlencode }}
Result:
To%20be%20or%20not%20to%20be
boolify
Convert various formats to a boolean.
Integer and float values (or strings that convert to an int or float) that are not 0 return true. Integer and float values (or strings that convert to an int or float) that equal 0 return false. null returns false The following strings return true: 'true', 'on', 'yes', 'y', 'enable', 'enabled' The following strings return false: 'false', 'off', 'no', 'n', 'disable', 'disabled'
Examples:
{% if 'on' | boolify %}
true
{% endif %}
{% if 'On' | boolify %}
true
{% endif %}
{% if 'EnAbLed' | boolify %}
true
{% endif %}
{% if 0.1 | boolify %}
true
{% endif %}
{% if 'false' | boolify %}
false
{% endif %}
bool_switch
Return one of the arguments dependent upon the boolified value.
Example:
{{ 'enabled' | bool_switch('the switch is enabled', 'the switch is disabled' }}
{{ 'off' | bool_switch('the switch is enabled', 'the switch is disabled' }}
Results:
the switch is enabled
the switch is disabled
exists
{% set foo = 'bar' %}
Foo: {% if "foo" | exists %}{{ foo }}{% elseif %}does not exist{% endif %}
Xyz: {% if "xyz" | exists %}{{ xyz }}{% elseif %}does not exist{% endif %}
value
Return a value of a variable by name in the current scope, or a default value if specified.
{% set foo = "foo_value" %}
{{ "foo" | value("default_foo") }}
{{ "bar" | value("default_bar") }}
Output:
foo
default_bar
apply_mapping
A powerful filter that maps variables by name from the current context or an object, to another object.
Useful to create uniform objects from .env parameters like:
HOST1=.., HOST2=..
PORT1=.., PORT2=..
Examples:
{# map properties from one object to another #}
{% set source = {"foo": "foo_value", "bar": "bar_value"} %}
{% set mapping = {"attr1": "foo", "attr2": "bar", "attr3": "notexist"} %}
{% set obj = mapping|apply_mapping(source) %}
{{ obj.attr1 }}-{{ obj.attr2 }}-{{ obj.attr3 }}
{# prints: `foo_value-bar_value-` }
{# create an object from variables in the current scope, with a default if they do not exists #}
{% set default = "default_value" %}
{% set foo = "foo_value" %}
{% set bar = "bar_value" %}
{% set obj = {"attr1": "foo", "attr2": "bar", "attr3": "notexist"} | apply_mapping(nil, nil, default) %}
{{ obj.attr1 }}-{{ obj.attr2 }}-{{ obj.attr3 }}
{# prints: `foo_value-bar_value-default_value` #}
{# create an object from variables in the current scope with a suffix, useful to create arrays of objects #}
{# from environment variables like VARIABLE1=, VARIABLE2= #}
{% set HOST1 = "example.com" %}
{% set PORT1 = "443" %}
{% set HOST2 = "foobar.com" %}
{% set PORT2 = "80" %}
{% set mapping = {"host": "HOST", "port": "PORT"} %}
{% set obj1 = mapping|apply_mapping(nil, "1") %}
{% set obj2 = mapping|apply_mapping(nil, "2") %}
{{ obj1.host }}:{{ obj1.port }}
{{ obj2.host }}:{{ obj2.port }}
{# prints: #}
{# example.com:443 #}
{# foobar.com:80 #}
extract_objects is a powerful filter that can be used to extract objects from the current scope.
Example:
{% set HOST = "foo" %}
{% set PORT = "80" %}
{% set HOST_0 = "bar" %}
{% set PORT_0 = "81" %}
{% set HOST_1 = "qux" %}
{% set PORT_1 = "82" %}
{# included because it is the first key in the mapping #}
{% set HOST_70 = "fooqux" %}
{# NOT included becausethe first key in the mapping is missing #}
{% set PORT_71 = "fooqux" %}
{# try to map from 0...100 #}
{% set params = {"host": "HOST", "port": "PORT"} | extract_objects(100, "HOST", "undefined") %}
{{ params | json_encode }}
{# output: [{"host":"foo","port":"80"},{"host":"bar","port":"81"},{"host":"qux","port":"82"},{"host":"fooqux","port":"undefined"}]} #}
{% for paramObj in params %}{{ paramObj.host }}:{{ paramObj.port }}
{% endfor %}
objects_from_prefix
This filter returns a list of objects from variables with the same prefix. The prefix is the first part of the variable name before the first underscore. A number may be added after the prefix so multiple objects can be returned. You can specify an optional default value.
{% set proxy_host = "host" %}
{% set proxy_port = "port" %}
{% set proxy1_host = "host1" %}
{% set proxy1_port = "port1" %}
{% set proxy4_host = "host4" %}
{% set proxy4_port = "port4" %}
{% set objects = "proxy" | objects_from_prefix(10) %}
{{ objects | json_encode }}
Expect:
[{"host":"host","port":"port"},{"host":"host1","port":"port1"},{"host":"host4","port":"port4"}]
.. with default values
{% set default = {"generator": "tango", "host": "default_host"} %}
{% set proxy5_port = "port5" %}
{% set objects = "proxy" | objects_from_prefix(10, default) %}
{{ objects | json_encode }}
Expect:
[{"generator":"tango","host":"host","port":"port"},{"generator":"tango","host":"host1","port":"port1"},{"generator":"tango","host":"host4","port":"port4"},{"generator":"tango","host":"default_host","port":"port5"}]
tidy
Clean up multiple newlines and attempts to fix standardization. Converts tabs to spaces. Very useful in templates. Assumes indentation of 4 spaces.
{% set contents %}
foo
baz
bar
qwe
qux
test
{% endset %}
======
{{ contents|tidy }}
======
Output:
======
foo
baz
bar
qwe
qux
test
======
Last modified: 02 januari 2024