Additional Template Filters¶

Introduction¶

Nautobot uses 2 template engines internally, Django Template and Jinja2. Django Template is used to render the UI pages and Jinja2 is used for features such as computed fields, custom links, export templates, etc.

Note

Jinja2 and Django Template are very similar, the main difference between them is the syntax of the template. Historically, Django Template has been the go-to solution to generate webpage in Django and Jinja2 is the industry standard outside of Django.

Both Django Template and Jinja2 can be extended with a library of functions, called filters, that apply formatting or transformations to a provided input. Nautobot provides many built-in filters, including network specific filters from the netutils library.

Netutils Filters¶

Added in version 1.2.0

Netutils is an external library, maintained by Network to Code, that is focusing on providing a collection of functions for common network automation tasks. Please check the netutils documentation to see the list of available functions.

These functions are available automatically in Jinja2 rendered by Nautobot. For example you could define a computed field on Circuit objects, using the Netutils bits_to_name function, to display the "Commit Rate" as a human-readable value by using the template code {{ (obj.commit_rate * 1000) | bits_to_name }}. (This particular example is contrived, as the Nautobot UI already humanizes the raw commit_rate value for display, but it demonstrates the kinds of things that these filters can be used for.)

In general the syntax for using a netutils filter in a Jinja2 template is something like {{ arg1 | function_name }} for functions that take a single argument, and {{ arg1 | function_name(arg_name2=arg2, arg_name3=arg3) }} for functions that take multiple arguments.

Added in version 1.5.11

Netutils functions are also available in Django templates after using the {% load netutils %} directive in a template. The syntax to use these functions is then generally {% function_name arg_name1=arg1 arg_name2=arg2 %}.

Nautobot Built-In Filters¶

The Nautobot project also provides the following built-in filters that can be used in both Jinja2 and Django Template.

as_range¶

Given a list of n items, return a corresponding range of n integers.

# Django template
{% for i in record.parents|as_range %}
    <i class="mdi mdi-circle-small"></i>
{% endfor %}

bettertitle¶

Alternative to the built-in title filter; capitalizes words without replacing letters that are already uppercase.

For example, title("IP address") == "Ip Address", while bettertitle("IP address") == "IP Address".

{{ obj_type.name|bettertitle }}

divide¶

Return x/y (rounded).

# Django Template
{{ powerfeed.available_power|divide:3 }}VA

# Jinja
{{ powerfeed.available_power|divide(3) }}

fgcolor¶

Return the ideal foreground color (black "#000000" or white "#ffffff") given an arbitrary background color in RRGGBB format.

color: {{ object.status.color|fgcolor }}

get_docs_url¶

Return the static URL of the documentation for the specified model.

{{ obj | get_docs_url }}

get_item¶

Access a specific item/key in a dictionary.

# Django Template
{{ labels|get_item:key }}

# Jinja
{{ labels|get_item(key) }}

queryset_to_pks¶

Return all object's in a queryset UUIDs/pks as a string separated by a comma.

# Django Template
{{ ip.tags.all | queryset_to_pks }}

has_one_or_more_perms¶

Return True if the user has at least one of the permissions in the list.

# Django Template
{{ request.user|has_one_or_more_perms:panel_details.permissions }}

# Jinja
{{ request.user|has_one_or_more_perms(panel_details.permissions) }}

has_perms¶

Return True if the user has all permissions in the list.

# Django Template
{{ request.user|has_perms:group_item_details.permissions }}

# Jinja
{{ request.user|has_perms(group_item_details.permissions) }}

humanize_speed¶

Humanize speeds given in Kbps. 1544 => "1.544 Mbps" 100000 => "100 Mbps" 10000000 => "10 Gbps"

{{ speed_value | humanize_speed }}

hyperlinked_email¶

Added in version 2.2.0

Render an email address, if any, as a mailto: hyperlink, or render a placeholder if no email is given.

hyperlinked_phone_number¶

Added in version 2.2.0

Render a phone number string, if any, as a tel: hyperlink, or render a placeholder if no phone number is given.

hyperlinked_object¶

Added in version 1.4.0

Render and link to a Django model instance, if any, or render a placeholder if not.

Uses object.display if available, otherwise uses the string representation of the object. If the object defines get_absolute_url() this will be used to hyperlink the displayed object; additionally if there is an object.description this will be used as the title of the hyperlink.

{{ device|hyperlinked_object }}

Added in version 1.5.0

This filter now accepts an optional field parameter, which allows you to use a field other than object.display for the object representation if desired. For example, to display the object's name field instead:

# Django Template
{{ location|hyperlinked_object:"name" }}

# Jinja
{{ location|hyperlinked_object("name") }}

meta¶

Return the specified Meta attribute of a model.

{{ obj | meta('app_label') }}

meters_to_feet¶

Convert a length from meters to feet.

{{ meter_value | meters_to_feet }}

percentage¶

Return x/y as a percentage.

# Django Template
{{ powerfeed.available_power|percentage:total_power }}VA

# Jinja
{{ powerfeed.available_power|percentage(total_power) }}

placeholder¶

Render a muted placeholder (—) if value is falsey, else render the provided value.

{{ html | placeholder }}

render_boolean¶

Render HTML from a computed boolean value.

If value is (for example) a non-empty string or True or a non-zero number, this renders 

If value is (for example) "" or 0 or False, this renders 

If value is None this renders —

{{ value | render_boolean }}

render_json¶

Render a dictionary as formatted JSON.

Changed in version 2.2.0

Unless syntax_highlight=False is specified, the returned string will be wrapped in a <code class="language-json> HTML tag to flag it for syntax highlighting by highlight.js.

{{ data | render_json }}

render_markdown¶

Render and sanitize Markdown text into HTML. A limited subset of HTML tags and attributes are permitted in the text as well; non-permitted HTML will be stripped from the output for security.

{{ text | render_markdown }}

Permitted HTML Tags and Attributes¶

Added in version 2.1.2

The set of permitted HTML tags is defined in nautobot.core.constants.HTML_ALLOWED_TAGS, and their permitted attributes are defined in nautobot.core.constants.HTML_ALLOWED_ATTRIBUTES. As of Nautobot 2.1.2 the following are permitted:

Full list of HTML tags and attributes

Tag	Attributes
`<a>`	`href`, `hreflang`
`<abbr>`
`<acronym>`
`<b>`
`<bdi>`
`<bdo>`	`dir`
`<blockquote>`	`cite`
`<br>`
`<caption>`
`<center>`
`<cite>`
`<code>`
`<col>`	`align`, `char`, `charoff`, `span`
`<colgroup>`	`align`, `char`, `charoff`, `span`
`<dd>`
`<del>`	`cite`, `datetime`
`<details>`
`<div>`
`<dl>`
`<dt>`
`<em>`
`<h1>`
`<h2>`
`<h3>`
`<h4>`
`<h5>`
`<h6>`
`<hgroup>`
`<hr>`	`align`, `size`, `width`
`<i>`
`<img>`	`align`, `alt`, `height`, `src`, `width`
`<ins>`	`cite`, `datetime`
`<kbd>`
`<li>`
`<mark>`
`<ol>`	`start`
`<p>`
`<pre>`
`<q>`	`cite`
`<rp>`
`<rt>`
`<rtc>`
`<ruby>`
`<s>`
`<samp>`
`<small>`
`<span>`
`<strike>`
`<strong>`
`<sub>`
`<summary>`
`<sup>`
`<table>`	`align`, `char`, `charoff`, `summary`
`<tbody>`	`align`, `char`, `charoff`
`<td>`	`align`, `char`, `charoff`, `colspan`, `headers`, `rowspan`
`<th>`	`align`, `char`, `charoff`, `colspan`, `headers`, `rowspan`, `scope`
`<thead>`	`align`, `char`, `charoff`
`<time>`
`<tr>`	`align`, `char`, `charoff`
`<tt>`
`<u>`
`<ul>`
`<var>`
`<wbr>`

render_yaml¶

Render a dictionary as formatted YAML.

Changed in version 2.2.0

Unless syntax_highlight=False is specified, the returned string will be wrapped in a <code class="language-yaml> HTML tag to flag it for syntax highlighting by highlight.js.

{{ data | render_yaml }}

settings_or_config¶

Get a value from Django settings (if specified) or Constance configuration (otherwise).

{{ "RELEASE_CHECK_URL" | settings_or_config }}

Added in version 2.0.0

This filter now accepts an optional app_name parameter, which allows you to use this filter for Third-Party Nautobot Apps.

# Django Template
{{ "SAMPLE_VARIABLE" | settings_or_config:"example_app" }}
{{ "lowercase_example" | settings_or_config:"example_app" }}

slugify¶

Slugify a string.

# Django Template
{{ string | slugify }}

# Jinja
{{ string | slugify }}

split¶

Split a string by the given value (default: comma)

# Django Template
{{ string | split }}
{{ string | split:';' }}

# Jinja
{{ string | split }}
{{ string | split(';') }}

tzoffset¶

Returns the hour offset of a given time zone using the current time.

{{ object.time_zone|tzoffset }}

validated_viewname¶

Return the view name for the given model and action if valid, or None if invalid.

# Django Template
{{ obj | validated_viewname:'list' }}

# Jinja
{{ obj | validated_viewname('list') }}

validated_api_viewname¶

Return the API view name for the given model and action if valid, or None if invalid.

# Django Template
{{ obj | validated_api_viewname:'detail' }}

# Jinja
{{ obj | validated_api_viewname('detail') }}

viewname¶

Return the view name for the given model and action. Does not perform any validation.

# Django Template
{{ obj | viewname:'list' }}

# Jinja
{{ obj | viewname('list') }}