# # Filter Rules

> Permissions, validation, and the API's `filter` parameter all rely on a specific JSON structure to define their rules. This page describes the syntax for creating flat, relational, or complex filter rules.

- Syntax
- Filter Operators
- Relational
- Logical Operators
- Dynamic Variables

## # Syntax

- Field — Any valid root field, relational field, or logical operator
- Operator — Any valid filter operator
- Value — Any valid static value, or dynamic variable

    {
    	<field>: {
    		<operator>: <value>
    	}
    }

### # Examples

    {
    	"title": {
    		"_contains": "Directus"
    	}
    }

    {
    	"owner": {
    		"_eq": "$CURRENT_USER"
    	}
    }

    {
    	"datetime": {
    		"_lte": "$NOW"
    	}
    }

## # Filter Operators

Operator Title (in app) | Operator | Description
--- | --- | ---
Equals | `_eq` | Equal to
Doesn't equal | `_neq` | Not equal to
Less than | `_lt` | Less than
Less than or equal to | `_lte` | Less than or equal to
Greater than | `_gt` | Greater than
Greater than or equal to | `_gte` | Greater than or equal to
Is one of | `_in` | Matches any of the values
Is not one of | `_nin` | Doesn't match any of the values
Is null | `_null` | Is `null`
Isn't null | `_nnull` | Is not `null`
Contains | `_contains` | Contains the substring
Doesn't contain | `_ncontains` | Doesn't contain the substring
Starts with | `_starts_with` | Starts with
Doesn't start with | `_nstarts_with` | Doesn't start with
Ends with | `_ends_with` | Ends with
Doesn't end with | `_nends_with` | Doesn't end with
Is between | `_between` | Is between two values (inclusive)
Isn't between | `_nbetween` | Is not between two values (inclusive)
Is empty | `_empty` | Is empty (`null` or falsy)
Isn't empty | `_nempty` | Is not empty (`null` or falsy)
Intersects | `_intersects` [1] | Value intersects a given point
Doesn't intersect | `_nintersects` [1] | Value does not intersect a given point
Intersects Bounding box | `_intersects_bbox` [1] | Value is in a bounding box
Doesn't intersect bounding box | `_nintersects_bbox` [1] | Value is not in a bounding box

The following operator has no Title on the Filter Interface as it is only available in validation permissions:

Operator | Description
--- | ---
`_regex` [2] | Field has to match regex

[1] Only available on Geometry types.
[2] JavaScript "flavor" regex. Make sure to escape backslashes.

## # Relational

You can target related values by nesting field names. For example, if you have a relational Many-to-One `author` field, you can set a rule for the `author.name` field using the following syntax.

    {
    	"author": {
    		"name": {
    			"_eq": "Rijk van Zanten"
    		}
    	}
    }

## # Logical Operators

You can nest or group multiple rules using the `_and` or `_or` logical operators. Each logical operator holds an array of Filter Rules, allowing for more complex filtering. Also note in the example that Logical Operators can be sub-nested into Logical Operators. However, they cannot be sub-nested into Filter Rules.

    {
    	"_or": [
    		{
    			"_and": [
    				{
    					"user_created": {
    						"_eq": "$CURRENT_USER"
    					}
    				},
    				{
    					"status": {
    						"_in": ["published", "draft"]
    					}
    				}
    			]
    		},
    		{
    			"_and": [
    				{
    					"user_created": {
    						"_neq": "$CURRENT_USER"
    					}
    				},
    				{
    					"status": {
    						"_in": ["published"]
    					}
    				}
    			]
    		}
    	]
    }

### # Some vs None in One-to-Many

When applying filters to a one-to-many field, Directus will default to a "some" search, for example in:

    {
    	"categories": {
    		"name": {
    			"_eq": "Recipe"
    		}
    	}
    }

the top level parent will be returned if one of the categories has the name `Recipe`. This behavior can be overridden by using the explicit `_some` and `_none` operators, for example:

    {
    	"categories": {
    		"_none": {
    			"name": {
    				"_eq": "Recipe"
    			}
    		}
    	}
    }

will fetch all parent items that don't have the category "Recipe"

## # Dynamic Variables

In addition to static values, you can also filter against dynamic values using the following variables.

- `$CURRENT_USER` — The primary key of the currently authenticated user
- `$CURRENT_ROLE` — The primary key of the role for the currently authenticated user
- `$NOW` — The current timestamp
- `$NOW(<adjustment>)` - The current timestamp plus/minus a given distance, for example `$NOW(-1 year)`, `$NOW(+2 hours)`

Functions

You can also use Function Parameters when building Filters.

Nested User / Role variables in Permissions

When configuring permissions, `$CURRENT_USER` and `$CURRENT_ROLE` allow you to specify any (nested) field under the current user/role as well as the root ID. For example: `$CURRENT_ROLE.name` or `$CURRENT_USER.avatar.filesize`. This includes custom fields that were added to the directus_users/directus_roles tables.

Note: This feature is only available for permissions, validation, and presets. Regular filters and conditional fields currently only support the root ID.