Conditions

Conditions in Hookah are used to determine whether a matched event should trigger a request to the destination webhook. They define rules that check if specific values in the incoming request meet certain criteria before forwarding the event.

Condition Syntax

Conditions use a simple and readable templating language. The basic syntax is:

{<left-value>} {<operator>} {<right-value>}

Where:

• {Header.X-Foo} refers to a request header or query parameter.
• {Body.foo.bar} refers to a nested field in the request body.
• {Body.foo[].bar} performs array projection, collecting all .bar fields from the array foo.
• {Body.items[0].name} accesses a specific index in an array (e.g., the first item in the items array).

This syntax allows for powerful and flexible matching based on various parts of the request payload.

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Examples

Match Header and Body

"{Header.x-user-id} {eq} {Body.user.id}"

Checks if the x-user-id header matches the user.id field in the request body.

Value Not Equal

"{Body.user.age} {ne} {30}"

Checks if user.age is not equal to 30.

Check Value in Array

"{Header.x-label} {in} {Body.labels[].title}"

Checks if the value of the x-label header exists in any of the title fields in the labels array.

String Starts With

"{Body.username} {startsWith} {admin_}"

Checks if the username starts with the string "admin_".

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Supported Operators

The following operators can be used to compare the values:

Operator	Description
{eq}	Equal to
{ne}	Not equal to
{in}	Left-hand value exists in the right-hand list or array projection
{notIn}	Left-hand value does not exist in the right-hand list
{contains}	Left-hand string contains the right-hand string
{startsWith}	Left-hand string starts with the right-hand string
{endsWith}	Left-hand string ends with the right-hand string

These operators allow for a wide variety of conditions to match your webhook events, ensuring only the relevant requests are forwarded.

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Array Support

You can access and manipulate array elements in conditions in two key ways:

• Indexed Access:
  You can access specific items in an array by index. For example, {Body.items[0].name} retrieves the name of the first item in the items array.

• Array Projection:
  Projecting over arrays allows you to collect all values of a specific field from an array. For example, {Body.items[].name} returns a list of all name fields from the items array. This is particularly useful with operators like {in} and {notIn} to check if a value exists in any array element.