Permissions
Introduction
Access control rules are essential for securing your data and ensuring that only authorized users can access it. In Hasura, these are referred to as permissions. You can use permissions to control access to certain rows or columns in your database, or to restrict access to certain operations or fields in your GraphQL API.
The following types of permissions can be defined:
Type | Description |
---|---|
TypePermissions | Define which fields are allowed to be accessed by a role on an output type. |
ModelPermissions | Define which objects or rows within a model are allowed to be accessed by a role. |
CommandPermissions | Define whether the command is executable by a role. |
Permissions are written in your various HML files. If you're using a compatible editor (such as VS Code with the Hasura extension), LSP-assisted authoring will help you write permissions more efficiently. LSP will provide you with auto-completion, syntax highlighting, and error checking as you write your permissions.
Metadata structure
TypePermissions
Definition of permissions for an OpenDD type.
Key | Value | Required | Description |
---|---|---|---|
kind | TypePermissions | true | |
version | v1 | true | |
definition | TypePermissionsV1 | true | Definition of permissions for an OpenDD type. |
TypePermissionsV1
Definition of permissions for an OpenDD type.
Key | Value | Required | Description |
---|---|---|---|
typeName | CustomTypeName | true | The name of the type for which permissions are being defined. Must be an object type. |
permissions | [TypePermission] | true | A list of type permissions, one for each role. |
Example:
typeName: article
permissions:
- role: admin
output:
allowedFields:
- article_id
- author_id
- title
- role: user
output:
allowedFields:
- article_id
- author_id
TypePermission
Defines permissions for a particular role for a type.
Key | Value | Required | Description |
---|---|---|---|
role | Role | true | The role for which permissions are being defined. |
output | TypeOutputPermission / null | false | Permissions for this role when this type is used in an output context. If null, this type is inaccessible for this role in an output context. |
Example:
role: user
output:
allowedFields:
- article_id
- author_id
TypeOutputPermission
Permissions for a type for a particular role when used in an output context.
Key | Value | Required | Description |
---|---|---|---|
allowedFields | [FieldName] | true | Fields of the type that are accessible for a role |
FieldName
The name of a field in a user-defined object type.
Value: string
Role
The role for which permissions are being defined.
Value: string
CustomTypeName
The name of a user-defined type.
Value: string
ModelPermissions
Definition of permissions for an OpenDD model.
Key | Value | Required | Description |
---|---|---|---|
kind | ModelPermissions | true | |
version | v1 | true | |
definition | ModelPermissionsV1 | true | Definition of permissions for an OpenDD model. |
ModelPermissionsV1
Definition of permissions for an OpenDD model.
Key | Value | Required | Description |
---|---|---|---|
modelName | ModelName | true | The name of the model for which permissions are being defined. |
permissions | [ModelPermission] | true | A list of model permissions, one for each role. |
Example:
modelName: Articles
permissions:
- role: admin
select:
filter: null
- role: user
select:
filter:
fieldComparison:
field: author_id
operator: _eq
value:
sessionVariable: x-hasura-user-id
ModelPermission
Defines the permissions for an OpenDD model.
Key | Value | Required | Description |
---|---|---|---|
role | Role | true | The role for which permissions are being defined. |
select | SelectPermission / null | false | The permissions for selecting from this model for this role. If this is null, the role is not allowed to query the model. |
Example:
role: user
select:
filter:
fieldComparison:
field: author_id
operator: _eq
value:
sessionVariable: x-hasura-user-id
argument_presets:
- field: likes_dogs
value:
literal: true
SelectPermission
Defines the permissions for selecting a model for a role.
Key | Value | Required | Description |
---|---|---|---|
filter | null / ModelPredicate | true | Filter expression when selecting rows for this model. Null filter implies all rows are selectable. |
argumentPresets | [ArgumentPreset] | false | Preset values for arguments for this role |
ArgumentPreset
Preset value for an argument
Key | Value | Required | Description |
---|---|---|---|
argument | ArgumentName | true | Argument name for preset |
value | ValueExpression | true | Value for preset |
ArgumentName
Argument name for preset
Value: string
ModelPredicate
A predicate that can be used to restrict the objects returned when querying a model.
Must have exactly one of the following fields:
Key | Value | Required | Description |
---|---|---|---|
fieldComparison | FieldComparisonPredicate | false | Field comparison predicate filters objects based on a field value. |
fieldIsNull | FieldIsNullPredicate | false | Predicate to check if the given field is null. |
relationship | RelationshipPredicate | false | Relationship predicate filters objects of a source model based on a predicate on the related model. |
and | [ModelPredicate] | false | |
or | [ModelPredicate] | false | |
not | ModelPredicate | false |
Example:
fieldComparison:
field: author_id
operator: _eq
value:
sessionVariable: x-hasura-user-id
RelationshipPredicate
Relationship predicate filters objects of a source model based on a predicate on the related model.
Key | Value | Required | Description |
---|---|---|---|
name | RelationshipName | true | The name of the relationship of the object type of the model to follow. |
predicate | ModelPredicate / null | false | The predicate to apply on the related objects. If this is null, then the predicate evaluates to true as long as there is at least one related object present. |
RelationshipName
The name of the GraphQL relationship field.
Value: string
FieldIsNullPredicate
Predicate to check if the given field is null.
Key | Value | Required | Description |
---|---|---|---|
field | FieldName | true | The name of the field that should be checked for a null value. |
FieldComparisonPredicate
Field comparison predicate filters objects based on a field value.
Key | Value | Required | Description |
---|---|---|---|
field | FieldName | true | The field name of the object type of the model to compare. |
operator | string | true | The name of the operator to use for comparison. |
value | ValueExpression | true | The value expression to compare against. |
ValueExpression
An expression which evaluates to a value that can be used in permissions.
Must have exactly one of the following fields:
Key | Value | Required | Description |
---|---|---|---|
literal | false | ||
sessionVariable | string | false |
FieldName
The name of a field in a user-defined object type.
Value: string
Role
The role for which permissions are being defined.
Value: string
ModelName
The name of data model.
Value: string
CommandPermissions
Definition of permissions for an OpenDD command.
Key | Value | Required | Description |
---|---|---|---|
kind | CommandPermissions | true | |
version | v1 | true | |
definition | CommandPermissionsV1 | true | Definition of permissions for an OpenDD command. |
CommandPermissionsV1
Definition of permissions for an OpenDD command.
Key | Value | Required | Description |
---|---|---|---|
commandName | CommandName | true | The name of the command for which permissions are being defined. |
permissions | [CommandPermission] | true | A list of command permissions, one for each role. |
Example:
commandName: get_article_by_id
permissions:
- role: admin
allowExecution: true
- role: user
allowExecution: true
CommandPermission
Defines the permissions for a role for a command.
Key | Value | Required | Description |
---|---|---|---|
role | Role | true | The role for which permissions are being defined. |
allowExecution | boolean | true | Whether the command is executable by the role. |
argumentPresets | [ArgumentPreset] | false | Preset values for arguments for this role |
Example:
role: user
allowExecution: true
argumentPresets:
- argument: user_id
value:
session_variable: x-hasura-user_id
ArgumentPreset
Preset value for an argument
Key | Value | Required | Description |
---|---|---|---|
argument | ArgumentName | true | Argument name for preset |
value | ValueExpression | true | Value for preset |
ValueExpression
An expression which evaluates to a value that can be used in permissions.
Must have exactly one of the following fields:
Key | Value | Required | Description |
---|---|---|---|
literal | false | ||
sessionVariable | string | false | Used to represent the name of a session variable, like "x-hasura-role". |
ArgumentName
Argument name for preset
Value: string
Role
The role for which permissions are being defined.
Value: string
CommandName
The name of a command.
Value: string