Grav - Twig Filters and Functions

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In this chapter, let's study about Twig Filters and Functions. Filters are used to format the data the way you want with the required output too. Functions are used to generate contents.

Twig templates are text files that contain expressions and variables replaced by values. Twig uses three types of tags.

  • Output tags − The following syntax is used to display the evaluated expressions result here.

{{  Place Your Output Here  }}

  • Action Tags − The following syntax is used to execute statements here.

{%  executable statements are placed here  %}

  • Comment tags − The following syntax is used to write comments in the Twig template file.

{#  write your comment here  #}

Twig Filters

Twig Filters uses the | character to apply filters to Twig variable followed by the filter name. Arguments can be passed in parenthesis similarly like Twig functions.

The following table shows Twig Filters used in Grav −

Sr.No. Filter & Description Example
1

Absolute URL

It takes the relative path and converts it to an absolute URL.

 
'<img src="/some/path/img.jpg"/>' |absolute_url

converts to −

<img src="http://learn.getGrav.org/some/path/img.jpg" />
2

Camelize

It converts a string to CamelCase format.

 
'contact_us'| camelize

converts to −

ContactUs
3

Contains

if it finds the string.

 
'This is some string' | contains('some')

the output is −

1
4

Defined

You can check if some variable is defined or not. If variable is not defined, you can provide a default value.

 
set header_image_width = 
page.header.header_image_width|defined(900)

It sets header_image_width with value 900 if it’s not defined.
5

Ends-With

You can determine whether a string ends with a given string by using Ends-With filter.

 
'this is an example for ends-with filter' | ends_with('filter')

it is displayed as −

True
6

FieldName

It filters the field name by changing dot into array notation.

 
'field.name'|fieldName

it is displayed as −

field[name]
7

Humanize

It is used to convert a string to human readable format.

 
'some_text_to_read'|humanize

it is displayed as −

Some text to read
8

Ksort

It sorts an array map using key.

 
{% set ritems = {'orange':1, 'apple':2, 'peach':3}|ksort %}
{% for key, value in ritems %}{{ key }}:{{ value }}, {% endfor %}

it is displayed as −

apple:2, orange:1, peach:3,
9

Left Trim

It is used to remove white spaces at the beginning of a string and removes the matching character given from the left side of the string.

 
'/strip/leading/slash/'|ltrim('/')

it is displayed as −

strip/leading/slash/
10

Markdown

It is used to convert the string containing markdown into HTML using the markdown parser of Grav.

 
'## some text with markdown'|markdown

it is displayed as −

some text with markdown
11

MD5

The md5 hash for the string can be created by using this filter.

 
'something'|md5

it is displayed as −

437b930db84b8079c2dd804a71936b5f
12

Monthize

By using Monthize filter, we can convert an integer number of days to number of months.

 
'61'|monthize

it is displayed as −

2
13

Nice Time

By using the Nice Time filter, we can get a date in nice human readable time format as output.

 
page.date|nicetime(false)

it is displayed as −

3 hrs ago
14

Ordinalize

Ordinals ( like 1st, 2nd, 3rd ) can be given to integers by using Ordinalize filter.

 
'78'| ordinalize

it is displayed as −

78th
15

Pluralize

A string can be converted to its plural English form by using Pluralize filter.

 
'child'|pluralize

it is displayed as −

children
16

Randomize

This filter helps randomize the provided list. If parameter contains any values then those values are skipped from randomizing.

 
{% set ritems = ['one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten']|randomize(3) %}
{% for ritem in ritems %}{{ ritem }}, {% endfor %}

it is displayed as −

one, two, three, eight, six, five, nine, seven, ten, four,
17

Right Trim

It is quite similar to left trim except it removes whitespaces and matched character from right side of the string.

 
'/strip/leading/slash/'|rtrim('/')

it is displayed as −

/strip/leading/slash
18

Singularize

A string can be converted to English singular version by using Singular filter.

 
'vehicles'|singularize

it is displayed as −

vehicle
19

Safe Email

Safe Email filter is used to convert an email address into ASCII characters so that it makes harder for an email to be spammed.

 
"someoneemailaddress@domain.com"|safe_email

the output is −

someoneemailaddress@domain.com
20

SortByKey

It is used to sort the array map using keys.

 
{% set people = [{'email':'john@gmail.com', 'id':3}, {'email':'melw@fdd.com', 'id':1}, {'email':'nancy@fb.com', 'id':7}]|sort_by_key('id') %}
{% for person in people %}{{ person.email }}:{{ person.id }}, {% endfor %}

it displays −

melw@fdd.com:1, john@gmail.com:3, nancy@fb.com:7,
21

Starts-With

You can determine whether a string starts with a given string by using Starts-With filter.

 
'this is an example for starts-with filter' |starts_with('this')

the output is −

true
22

Translate

for more detailed information.

 
MY_LANGUAGE_KEY_STRING

it displays −

'Some text in English'
23

Translate Admin

It translates a string into current language which is set in the user.yaml file.
24

Titleize

A string is converted into Title Case format by using Titleize.

 
'welcome page'|titleize

it is displayed as −

Welcome Page
25

UnderScoreize

format by using UnderScoreize filter.

 
'ContactUs'|underscorize

it is converted to −

contact_us
26

Truncate a string

You can use Truncate to truncate a string or shorten the string, you must specify number of characters.

 
'one sentence. two sentences'|truncate(5)

it truncates to −

one s...

You can use true as parameter if you don't want to truncate the string to closest sentence-end after the given number of characters.

'one sentence. two sentences'|truncate(5, true)

it truncates to −

one sentence
You can also strip HTML text, but you should use striptags filter before truncate filter. 
'<p>one <strong>sentence<strong>. two sentences</p>'|striptags|truncate(5)

it is displayed as −

one s

Twig Functions

Twig Functions are directly called by passing the parameter. Following table lists the functions −

Sr.No. Function & Description Example
1

Array

This function cast a value to array.

 
array(value)
2

Authorize

This function makes an authenticated user is authorized to see a resource and accepts permission string or array of permission strings.

 
authorize(['admin.statistics', 'admin.super'])
3

Dump

It accepts a valid twig variable and dumps it into the Grav debugger panel. However, the debugger should be enabled to see message tab values.

 
dump(page.header)
4

Debug

This works same as the dump() function.
5

Gist

This function creates the Gist embed code based on the Github Gist ID.
6

Random String Generation

This function will create a random string with the specified number of characters. These strings can be used as unique id or key.

 
generate_random_string(10)
7

Repeat

This function will repeat the string for given amount of time.

 
repeat('Grav ', 10) will repeat Grav 10 times.
8

String

Generates a random string of specified character length.

 
ta (23)
9

Translate Array

It is a function connected with |ta filter.
10

Url

This filter will create a URL and it will also convert PHP URL streams into valid HTML resources. If the URL cannot be resolved a default value can be passed.

 
url('theme://images/logo.png') | default('http://www.placehold.it/150x100/f4f4f4')
11

Translate

Using the Translate filter, a string is translated as the |t filter.

 
t('SITE_NAME')

is translated to −

Site Name
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