Mechanic filters

This page defines filters that are unique to Mechanic Liquid. Mechanic also supports many filters from Shopify Liquid.

Liquid filters should not be confused with event filters, which are used to conditionally ignore incoming events.

Data filters

browser

This filter converts a browser user agent string into an object that represents the browser itself. Data from Browserscope is used to match user agents.

{% assign browser = "Mozilla/5.0 (iPhone; CPU iPhone OS 12_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) GSA/79.0.259819395 Mobile/16G77 Safari/604.1" | browser %}

{{ browser }}

name: {{ browser.name }}

version: {{ browser.version }}
major version: {{ browser.version.major }}
minor version: {{ browser.version.minor }}

os: {{ browser.os }}
os name: {{ browser.os.name }}
os version: {{ browser.os.version }}
os major version: {{ browser.os.version.major }}
os minor version: {{ browser.os.version.minor }}

device: {{ browser.device }}
device name: {{ browser.device.name }}
device brand: {{ browser.device.brand }}
device model: {{ browser.device.model }}

Google 79.0.259819395

name: Google

version: 79.0.259819395<br>major version: 79<br>minor version: 0

os: iOS 12.4<br>os name: iOS<br>os version: 12.4<br>os major version: 12<br>os minor version: 4

device: iPhone<br>device name: iPhone<br>device brand: Apple<br>device model: iPhone

csv, parse_csv

Supports converting a two-dimensional array to a CSV string, and back again.

The parse_csv filter accepts a "headers" option; when set to true, this filter will interpret the first line of input as containing headers for the CSV table, and will return an array of hashes whose keys map to items in that header row.

{% capture two_dimensional_array_json %}
  [
    [
      "Order Name",
      "Order ID",
      "Order Date"
    ],
    [
      "#1234",
      1234567890,
      "2021/03/23"
    ],
    [
      "#1235",
      1234567891,
      "2021/03/24"
    ]
  ]
{% endcapture %}

{% assign two_dimensional_array = two_dimensional_array_json | parse_json %}

{% assign csv_string = two_dimensional_array | csv %}

{% comment %}
  Note the dashes used in the capture/endcapture tags!
  They make sure that we don't end up with blank lines
  at the beginning and end of our CSV string.
{% endcomment %}
{% capture csv_string -%}
Order Name,Order ID,Order Date
#1234,1234567890,2021/03/23
#1235,1234567891,2021/03/24
{%- endcapture %}

{% assign csv_rows = csv_string | parse_csv %}

{% assign orders = array %}
{% for row in csv_rows %}
  {% comment %}
    Skip the header row
  {% endcomment %}
  {% if forloop.first %}
    {% continue %}
  {% endif %}

  {% assign order = hash %}
  {% assign order["name"] = row[0] %}
  {% comment %}
    We're using `times: 1` to convert our string ID to an integer
  {% endcomment %}
  {% assign order["id"] = row[1] | times: 1 %}
  {% assign order["date"] = row[2] %}

  {% assign orders[orders.size] = order %}
{% endfor %}

{{ orders | json }}

{% comment %}
  Note the dashes used in the capture/endcapture tags!
  They make sure that we don't end up with blank lines
  at the beginning and end of our CSV string.
{% endcomment %}
{% capture csv_string -%}
Order Name,Order ID,Order Date
#1234,1234567890,2021/03/23
#1235,1234567891,2021/03/24
{%- endcapture %}

{% comment %}
  Note: the order ID is a string, in this resulting set of
  hashes, not an integer!
{% endcomment %}
{% assign orders = csv_string | parse_csv: headers: true %}

{{ orders | json }}
{% comment %}
  The result:

  [
    {
      "Order Name": "#1234",
      "Order ID": "1234567890",
      "Order Date": "2021/03/23"
    },
    {
      "Order Name": "#1235",
      "Order ID": "1234567891",
      "Order Date": "2021/03/24"
    }
  ]
{% endcomment %}

date, parse_date

Mechanic's date filter is based on Shopify's date filter. Mechanic's implementation has all the functionality of Shopify's. It accepts a date format, using the same format as Ruby's strftime. (Sites like strfti.me offer convenient references for this format.) Under the hood, this filter uses ActiveSupport::TimeZone#strptime, and inherits its behavior with regard to missing upper components.

Choosing a timezone

Mechanic's date filter supports a tz option, which accepts a timezone name from the TZ database. If given, the resulting time string will be in the specified timezone. If this option is not provided, the store's local timezone will be used instead.

{{ "now" | date: "%Y-%m-%d %H:%M %z" }}
=> "2019-01-01 09:00 +0900"

{{ "now" | date: "%Y-%m-%d %H:%M %z", tz: "UTC" }}
=> "2019-01-01 00:00 +0000"

Using the current time

This filter also accepts the special value "now", and values offset from now, as in "now + 5 days" or "now - 5 weeks". In this way, the filter supports simple date math. Note that durations are calculated using variable duration lengths, given the naturally varying length of specific days, weeks, months, and years, given DST and other calendar variances, all informed by the store's timezone. This math is backed by ActiveSupport::TimeWithZone#+. An example, quoting from that documentation: "a time + 24.hours will advance exactly 24 hours, while a time + 1.day will advance 23-25 hours, depending on the day".

{{ "now + 6 weeks" | date: "%Y-%m-%d %H:%M %z" }}
{{ "now + 3 months" | date: "%Y-%m-%d %H:%M %z" }}
{{ "now - 3 months" | date: "%Y-%m-%d %H:%M %z" }}

=> "2021-02-15 14:06 -0500"
=> "2021-04-04 14:06 -0400"
=> "2020-10-04 14:06 -0400"

Parsing dates

Use parse_date to parse a date string, when its exact format is known. This filter is useful for strings that contain an ambiguous date value, like "01/01/01".

This filter returns an ISO8601 string, representing the parsed date value in the store's local timezone. If the supplied date string cannot be parsed successfully, the filter will return nil.

{{ "01-01-20" | parse_date: "%m-%d-%y" }}
=> "2020-01-01T00:00:00+11:00"

{{ "01-01-20" | parse_date: "%m-%d-%y" | date: "%Y-%m-%d" }}
=> "2020-01-01"

{{ "ab-cd-ef" | parse_date: "%m-%d-%y" }}
=> nil

gzip, gunzip

These filters allow you to compress and decompress strings, using gzip compression.

In general, all strings passing through Mechanic must be UTF-8, and must ultimately be valid when represented as JSON. However, because gzip'd content may not be UTF-8, and because it may be important to preserve the original encoding, the gunzip filter supports a force_utf8: false option. Use this when you're certain the original encoding must be preserved, if you ultimately intend to pass along the string in a JSON-friendly representation. (For example, you might gunzip a value, and then use the base64 filter to represent it safely within JSON.)

{{ "testing" | gzip | gunzip }}
=> "testing"

{{ "hello world" | gzip | base64 }}
=> "H4sIABwbfl8AA8tIzcnJVyjPL8pJAQCFEUoNCwAAAA=="

{{ "H4sIANAafl8AA8tIzcnJVyjPL8pJAQCFEUoNCwAAAA==" | decode_base64: force_utf8: false | gunzip }}
=> "hello world"

{% assign base64_non_utf8_string = "H4sIACP1fV8AAyvPSCxRSMlPLVbILFHITU3MUyjJV0hKVXjUMKc4J7/8UcNcewAYP+lTIwAAAA==" %}
{{ base64_non_utf8_string | decode_base64: force_utf8: false | gunzip: force_utf8: false }}
=> (a string that is not UTF-8, and cannot be exported to JSON as-is)

{% assign base64_non_utf8_string = "H4sIACP1fV8AAyvPSCxRSMlPLVbILFHITU3MUyjJV0hKVXjUMKc4J7/8UcNcewAYP+lTIwAAAA==" %}
{{ base64_non_utf8_string | decode_base64: force_utf8: false | gunzip }}
=> "what does it mean to be “slow”?"

graphql_arguments

Useful for preparing key-value pairs of GraphQL query or mutation arguments.

Across the documentation and task library, you'll frequently see json used for serializing argument values. Users have reported some rare cases where this filter is insufficient, and where graphql_arguments does the trick instead.

graphql_arguments is typically used for rendering GraphQL values into the final GraphQL query string itself. Instead, consider extracting your values as GraphQL variables. This approach can result in more reusable query code.

To try this using a Shopify action, use the GraphQL with variables syntax.

To try this using the shopify filter, use the variables argument.

{% assign inputs = hash %}
{% assign inputs["a_string"] = "yep this is a string" %}
{% assign inputs["a_more_complex_type"] = hash %}
{% assign inputs["a_more_complex_type"]["id"] = "gid://something/Or?other" %}
{% assign inputs["an_array"] = array %}
{% assign inputs["an_array"][0] = 1 %}
{% assign inputs["an_array"][1] = 2 %}

{% action "shopify" %}
  mutation {
    anExample({{ inputs | graphql_arguments }}) {
      result
    }
  }
{% endaction %}

This results in a GraphQL Shopify action containing the following GraphQL:

mutation {
  anExample(
    a_string: "yep this is a string"
    a_more_complex_type: { id: "gid://something/Or?other" }
    an_array: [1, 2]
  ) {
    result
  }
}

For a more complex example, see Set product or variant metafields values in bulk from the task library.

json, parse_json

Allows converting objects to their JSON representations, and parsing that JSON into hashes.

{% assign order_as_json = order | json }}
{% assign plain_order = order_as_json | parse_json %}

The parse_json filter raises an error when invalid JSON. To ignore parse errors, and to return null when an error is encountered, add silent: true to the filter's options:

{% assign should_be_nil = "{{" | parse_json: silent: true %}

jsonl, parse_jsonl

Allows for rendering an iterable object (i.e. an array) as a series of JSON lines, separated by simple newlines.

{{ shop.customers | jsonl }}

The parse_jsonl filter can be used to parse a series of JSON strings, each on their own line, into an array of hashes. Useful when preparing stub data for bulk operations.

{% capture jsonl_string %}
  {"id":"gid://shopify/Customer/12345","email":"foo@bar.baz"}
  {"id":"gid://shopify/Customer/67890","email":"bar@baz.qux"}
{% endcapture %}

{% assign json_objects = jsonl_string | parse_jsonl %}

{{ json_objects | map: "email" | join: ", " }}

The parse_jsonl filter raises an error when invalid JSONL is received.

parse_xml

Use this filter to parse an XML string. (Under the hood, this filter calls Hash::from_xml.) Useful for processing output from third-party APIs, either by responding to "http" actions, or by parsing content from inbound webhooks.

{% capture xml_string %}
<foo>
  <bar>baz</bar>
  <bar>
    <qux>quux</qux>
  </bar>
</foo>
{% endcapture %}

{% assign xml = xml_string | parse_xml %}

{{ xml | json }}

{"foo":{"bar":["baz",{"qux":"quux"}]}}

shopify

This filter accepts a GraphQL query string, sends it to Shopify, and returns the full response – including "data" and "errors".

Use Shopify's GraphiQL query builder to quickly and precisely assemble your queries.

{% capture query %}
  query {
    shop {
      primaryDomain {
        host
      }
    }
  }
{% endcapture %}

{% assign result = query | shopify %}

{% log result %}

{
  "log": {
    "data": {
      "shop": {
        "primaryDomain": {
          "host": "example.com",
        },
      }
    },
    "extensions": {
      "cost": {
        "requestedQueryCost": 2,
        "actualQueryCost": 2,
        "throttleStatus": {
          "maximumAvailable": 1000.0,
          "currentlyAvailable": 998,
          "restoreRate": 50.0
        }
      }
    }
  }
}

GraphQL variables

This filter also supports GraphQL variables, via an optional named argument called variables.

Variables can be a useful part of making queries reusable within a task, or for working around Shopify's 50,000 character limit for GraphQL queries.

{% capture query %}
  query ProductQuery($id: ID!) {
    product(id: $id) {
      title
    }
  }
{% endcapture %}

{% assign variables = hash %}
{% assign variables["id"] = product_id %}

{% assign result = query | shopify: variables: variables %}

{% log result %}


{% comment %}
  Alternate style, avoiding the `variables: variables` construction:
{% endcomment %}

{% assign query_options = hash %}
{% assign query_options["variables"] = hash %}
{% assign query_options["variables"]["id"] = product_id %}

{% assign result = query | shopify: query_options %}

String filters

e164

This filter accepts a phone number – country code is required! – and outputs it in standard E.164 format. If the number does not appear valid, the filter returns nil.

{{ "1 (312) 456-7890" | e164 }}
=> "13124567890"

{{ "+43 670 1234567890" | e164 }}
=> "436701234567890"

{{ "000" | e164 | json }}
=> "null"

match

Use this filter to match a string with a Ruby-compatible regular expression pattern (see Regexp).

This filter returns the entire matched string (i.e. MatchData#to_s). Use the "captures" or "named_captures" lookups to receive an array or hash of captures, respectively (i.e. MatchData#captures, MatchData#named_captures).

This filter only returns the first match found. To find all available matches in a string, use scan.

{{ "It's a lovely day!" | match: "(?<=a ).*(?= day)" }}
=> "lovely"

{% assign match = "It's a lovely day!" | match: "a (bucolic|lovely) day" %}
{{ match.captures }}
=> ["lovely"]

{% assign match = "It's a lovely day!" | match: "a (?<adjective>bucolic|lovely) day" %}
{{ match.named_captures }}
=> {"adjective" => "lovely"}

{% assign match = "It's a lovely day!" | match: "a (?i:LOVELY) day" %}
{{ match }}
=> "a lovely day"

{{ "Matt and Megan love to travel and travel." | replace: 'travel', 'party' }}
{{ "Matt and Megan love to travel and travel | replace_first : 'travel', 'party' }}

Matt and Megan love to party and party.
Matt and Megan love to party and travel.

hmac_sha512

Works like hmac_sha256 from Shopify Liquid, but uses SHA-512 instead.

rsa_sha256, rsa_sha512

Accepts string input, given an RSA PEM key string as a filter option.

This filter is useful for generating JSON Web Signatures!

{{ input | rsa_sha256: private_key_pem }}
{{ input | rsa_sha256: private_key_pem, binary: true | base64_encode }}

{{ input | rsa_sha512: private_key_pem }}
{{ input | rsa_sha512: private_key_pem, binary: true | base64_encode }}

scan

Use this filter to find all available matches in a string, using a Ruby-compatible regular expression pattern (see Regexp).

This filter returns an array of matches, consisting of each matched string (i.e. MatchData#to_s). Use the "captures" or "named_captures" lookups on individual matches to receive an array or hash of captures, respectively (i.e. MatchData#captures, MatchData#named_captures).

This filter returns an array of matches. To only find the first match, use match.

{{ "It's a lovely day!" | scan: "[\w']+" }}
=> ["It's", "a", "lovely", "day"]

{{ "It's a lovely day!" | scan: "(bucolic|lovely|day)" | map: "captures" }}
=> [["lovely"], ["day"]]

{{ "It's a lovely day!" | scan: "(?<punctuation>[[:punct:]])" | map: "named_captures" }}
=> [{"punctuation" => "'"}, {"punctuation" => "!"}]

sha512

Works like sha256 from Shopify Liquid, but uses SHA-512 instead.

unindent

Use this filter on strings to remove indentation from strings.

{% capture message %}
  Hello, friend!
  It's a mighty fine day!
{% endcapture %}

{{ message }}
{{ message | unindent }}

  Hello, friend!
  It's a mighty fine day!


Hello, friend!
It's a mighty fine day!

Math filters

currency

Formats a number (given as an integer, float, or string) as currency. Called with no arguments, this filter uses the store's primary currency and default locale.

A three-character ISO currency code may be specified as the first argument; currency support is drawn from the money project. The locale may be overridden as a named option; locale support is drawn from rails-i18n.

{{ "100000.0" | currency }}
{{ 100000.0 | currency: "EUR" }}
{{ 100000 | currency: "EUR", locale: "fr" }}
{{ 100000 | currency: locale: "fr" }}

$100,000.00
€100,000.00
€100 000,00
$100 000,00

Note that this filter does not automatically append the currency ISO code (e.g. it will not generate output resembling "€100,000.00 EUR"). To add the ISO code manually, use one of these examples:

{{ price | currency }} {{ shop.currency }}
{{ price | currency | append: " " | append: shop.currency }}

Array filters

in_groups

This filter is an implementation of Array#in_groups. It accepts an array, and an integer count, and – optionally – a "fill_with" option.

{{ "1,2,3" | split: "," | in_groups: 2 | json }}

[["1","2"],["3",null]]

{{ "1,2,3" | split: "," | in_groups: 2, fill_with: false | json }}

[["1","2"],["3"]]

in_groups_of

This filter is an implementation of Array#in_groups_of. It accepts an array, and an integer count, and – optionally – a "fill_with" option.

This filter is particularly useful when performing work in batches, by making it easy to split an array of potentially large size into smaller pieces of controlled size.

{{ "1,2,3,4,5" | split: "," | in_groups_of: 2 | json }}

[["1","2"],["3","4"],["5",null]]

{{ "1,2,3,4,5" | split: "," | in_groups_of: 2, fill_with: false | json }}

[["1","2"],["3","4"],["5"]]

index_by

This filter accepts the name of an object property or attribute, and returns a hash that whose values are every element in the array, keyed by every element's corresponding property or attribute.

{% capture variants_json %}
  [
    {
      "id": 12345,
      "sku": "ONE"
    },
    {
      "id": 67890,
      "sku": "TWO"
    }
  ]
{% endcapture %}

{% assign variants = variants_json | parse_json %}

{{ variants | index_by: "sku" | json }}

{
  "ONE": {
    "id": 12345,
    "sku": "ONE"
  },
  "TWO": {
    "id": 67890,
    "sku": "TWO"
  }
}

push

This filter appends any number of arguments onto the provided array, returning a new array, leaving the original unmodified.

{% assign count_to_three = "one,two,three" | split: "," %}

{% assign count_to_five = count_to_three | push: "four", "five" %}

{{ count_to_five | join: newline }}

one
two
three
four
five

sample

This filter can be used on any array. Used without any arguments, it returns a single random element from the array. Provide an integer argument to return another array of that size, containing a random subset of the input array.

{{ "1,2,3" | split: "," | sample }}
=> "2"

{{ "1,2,3" | split: "," | sample: 2 | join: "," }}
=> "3,1"

slice

When applied to an array, this filter accepts an integer offset, and an optional integer length (defaulting to 1). If the length is 1, it returns the single element found at that index of the input array. Otherwise, it returns a slice of the array, beginning at the provided index, having the provided length.

Negative offsets begin counting from the end of the array.

{{ "1,2,3,4,5" | split: "," | slice: 3 }}
=> "4"

{{ "1,2,3,4,5" | split: "," | slice: 3, 2 | join: "," }}
=> "4,5"

{{ "1,2,3,4,5" | split: "," | slice: -3, 2 | join: "," }}
=> "3,4"

sort_naturally

Sorts an array uses the human-friendly sort order defined by naturally. Accepts a single optional parameter, specifying an attribute to sort.

This filter complements Shopify Liquid's sort and sort_natural filters. Choose your sort filter intentionally: machine audiences are typically happier with "sort", and human audiences are typically happier with "sort_naturally".

{% assign set = "order #10.b,Order #10.a,Order #2.c,order #2.d" | split: "," %}

unsorted:
  {{ set | join: ", " }}
sort:
  {{ set | sort | join: ", " }}
sort_natural:
  {{ set | sort_natural | join: ", " }}
sort_naturally:
  {{ set | sort_naturally | join: ", " }}

unsorted:
  order #10.b, Order #10.a, Order #2.c, order #2.d
sort:
  Order #10.a, Order #2.c, order #10.b, order #2.d
sort_natural:
  Order #10.a, order #10.b, Order #2.c, order #2.d
sort_naturally:
  Order #2.c, Order #10.a, order #2.d, order #10.b

unshift

This filter prepends any number of arguments onto the provided array, returning a new array, leaving the original unmodified.

{% assign count_two_three = "two,three" | split: "," %}

{% assign count_to_three_and_start_at_zero = count_two_three | unshift: "zero", "one" %}

{{ count_to_three_and_start_at_zero | join: newline }}

zero
one
two
three

Hash filters

compact

When applied to a hash, this filter returns a new hash which omits all keys having nil values.

{% assign foo = hash %}
{% assign foo["bar"] = "baz" %}
{% assign foo["qux"] = nil %}
{{ foo | json }}
{{ foo | compact | json }}

{"bar":"baz","qux":null}
{"bar":"baz"}

except

This filter accepts one or more string arguments, corresponding to keys that should be left out of the output. The filter returns a new hash, containing all the key/value pairs of the original hash except those keys named as arguments.

{% assign foo = hash %}
{% assign foo["bar"] = "bar" %}
{% assign foo["baz"] = "baz" %}
{% assign foo["qux"] = "qux" %}

{{ foo | except: "bar", "baz" | json }}

{"qux":"qux"}

keys

Returns an array of keys found in the supplied hash.

slice

When applied to a hash, the slice filter accepts one or more string arguments, corresponding to keys that the hash may contain. This filter will then return a new hash, containing only matching key/value pairs from the original hash.

{% assign foo = hash %}
{% assign foo["bar"] = "bar" %}
{% assign foo["baz"] = "baz" %}
{% assign foo["qux"] = "qux" %}

{{ foo | slice: "bar", "baz" | json }}

{"bar":"bar","baz":"baz"}

values

Returns an array of values found in the supplied hash.

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