DocsConcepts and ExpressionsExpressionFilterString Filters

String Filters​String ​Filters

String filters are used to manipulate strings i.e. textual data.

Each section below represents a built-in filter.

abbreviate

The abbreviate filter will abbreviate a string using an ellipsis. It takes one argument which is the max width of the desired output including the length of the ellipsis.

twig
{{ "this is a long sentence." | abbreviate(7) }}

The above example will output the following:

twig
this...

Arguments

  • length

base64decode

The base64decode filter takes the given input, base64-decodes it, and returns the byte array converted to UTF-8 string.

Applying the filter on an incorrect base64-encoded string will throw an exception.

twig
{{ "dGVzdA==" | base64decode }}

The above example will output the following:

test

base64encode

The base64encode filter takes the given input, converts it to an UTF-8 String (.toString()) and Base64-encodes it.

twig
{{ "test" | base64encode }}

The above example will output the following:

dGVzdA==

capitalize

The capitalize filter will capitalize the first letter of the string.

twig
{{ "article title" | capitalize }}

The above example will output the following:

twig
Article title

title

The title filter will capitalize the first letter of each word.

twig
{{ "article title" | title }}

The above example will output the following:

twig
Article Title

default

The default filter will render a default value if and only if the object being filtered is empty. A variable is empty if it is null, an empty string, an empty collection, or an empty map.

twig
{{ user.phoneNumber | default("No phone number") }}

In the following example, if foo, bar, or baz are null the output will become an empty string which is a perfect use case for the default filter:

twig
{{ foo.bar.baz | default("No baz") }}

Note that the default filter will suppress any AttributeNotFoundException exceptions that will usually be thrown.

Arguments

  • default

escapeChar

The escapeChar filter sanitizes given string using a selected string escape sequence.

Precede every ' character with \:

twig
{{ "Can't be here" | escapeChar('single') }}
{# results in: Can\'t be here #}

Precede every " character with \:

twig
{{ '"Quoted"' | escapeChar('double') }}
{# results in: \"Quoted\" #}

Safely pass a rendered Pebble variable as literal value to a shell, replacing every ' character with the '\'' escape sequence:

twig
{# inputs.param value set to: Can't be here #}
echo '{{ inputs.param | escapeChar('shell') }}'
{# results in: echo 'Can'\''t be here' #}

Arguments

  • type: escape sequence type single, double, or shell

lower

The lower filter makes an entire string lower case.

twig
{{ "THIS IS A LOUD SENTENCE" | lower }}

The above example will output the following:

twig
this is a loud sentence

replace

The replace filter formats a given string by replacing the placeholders (placeholders are free-form) or using regular expression:

twig
{{ "I like %this% and %that%." | replace({'%this%': foo, '%that%': "bar"}) }}
twig
{{ 'aa1bb2cc3dd4ee5' | replace({'(\d)': '-$1-'}, regexp=true) }}

Arguments

  • replace_pairs: an object with key the search string and value the replace string
  • regexp: use regexp for search and replace pattern (default is false)

sha256

The sha256 filter returns the SHA-256 hash of the given UTF-8 String.

twig
{{ "test" | sha256 }}

The above example will output the following:

9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08

startsWith

The startsWith() filter returns true if the input string starts with the specified prefix. This filter is useful for string comparisons and conditional logic in your workflows.

yaml
id: compare_strings
namespace: company.team

inputs:
  - id: myvalue
    type: STRING
    defaults: "hello world!"

tasks:
  - id: log_true
    type: io.kestra.plugin.core.log.Log
    message: "{{ inputs.myvalue | startsWith('hello') }}"

  - id: log_false
    type: io.kestra.plugin.core.log.Log
    message: "{{ inputs.myvalue | startsWith('Hello') }}"

slugify

The slugify filter removes non-word characters (alphanumerics and underscores) and converts spaces to hyphen. Also strips leading and trailing whitespace.

twig
{{ "Joel is a slug" | slugify }}
{# will output 'joel-is-a-slug' #}

substringAfter

The substringAfter filter returns the substring before the first occurrence of a separator. The separator is not returned.

twig
{{ 'a.b.c' | substringAfter('.') }}
{# results in: 'b.c' #}

Arguments

  • separator: the string to search for

substringAfterLast

The substringAfterLast filter returns the substring after the last occurrence of a separator. The separator is not returned.

twig
{{ 'a.b.c' | substringAfterLast('.') }}
{# results in: 'c' #}

Arguments

  • separator: the string to search for

substringBefore

The substringBefore filter returns the substring before the first occurrence of a separator. The separator is not returned.

twig
{{ 'a.b.c' | substringBefore('.') }}
{# results in: 'a' #}

Arguments

  • separator: the string to search for

substringBeforeLast

The substringBeforeLast filter returns the substring before the last occurrence of a separator. The separator is not returned.

twig
{{ 'a.b.c' | substringBeforeLast('.') }}
{# results in: 'a.b' #}

Arguments

  • separator: the string to search for

trim

The trim filter is used to trim whitespace off the beginning and end of a string.

twig
{{ "    This text has too much whitespace.    " | trim }}

The above example will output the following:

twig
This text has too much whitespace.

upper

The upper filter makes an entire string upper case.

twig
{{ "this is a quiet sentence." | upper }}

The above example will output the following:

twig
THIS IS A QUIET SENTENCE.

urldecode

The urldecode translates a string into application/x-www-form-urlencoded format using the "UTF-8" encoding scheme.

twig
{{ "The+string+%C3%BC%40foo-bar" | urldecode }}

The above example will output the following:

twig
The string ü@foo-bar

urlencode

The urlencode translates a string into application/x-www-form-urlencoded format using the "UTF-8" encoding scheme.

twig
{{ "The string ü@foo-bar" | urlencode }}

The above example will output the following:

twig
The+string+%C3%BC%40foo-bar

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