Add this line to your application's Gemfile:
gem 'graphql-pundit', '~> 0.7.0'
And then execute:
$ bundle
If you're upgrading from an earlier version, make sure to delete your
bootsnap
cache, to avoid a load error (see
this issue).
The cache files are usually located in the tmp
directory in your
repository and are named bootsnap-compile-cache
and
bootsnap-load-path-cache
.
To use graphql-pundit
with the class based API introduced in graphql
version 1.8, the used Field
class must be changed:
It is recommended to have application-specific base classes, from which the
other types inherit (similar to having an ApplicationController
from which
all other controllers inherit). That base class can be used to define a
custom field class, on which the new graphql-pundit
API builds.
class BaseObject < GraphQL::Schema::Object
field_class GraphQL::Pundit::Field
end
All other object types now inherit from BaseObject
, and that is all that is
needed to get graphql-pundit
working with the class based API.
In case you already use a custom field type, or if you want to use a context
key other than :current_user
to make your current user available, you can
include graphql-pundit
's functionality into your field type:
class MyFieldType < GraphQL::Schema::Field
prepend GraphQL::Pundit::Scope
prepend GraphQL::Pundit::Authorization
current_user :me # if the current_user is passed in as context[:me]
end
When using this, make sure the order of prepend
s is correct, as you usually want the authorization to happen first, which means that it needs to be prepend
ed after the scopes (if you need them).
class Car < BaseObject
field :trunk, CarContent, null: true,
authorize: true
end
The above example shows the most basic usage of this gem. The example would
use CarPolicy#trunk?
for authorizing access to the field, passing in the
parent object (in this case probably a Car
model).
Two styles of declaring fields is supported:
- the inline style, passing all the options as a hash to the field method
- the block style
Both styles are presented below side by side.
To use authorization on a field, you must pass either the authorize
or
authorize!
option. Both options will cause the field to return nil
if the
access is unauthorized, but authorize!
will also add an error message (e.g.
for usage with mutations).
authorize
and authorize!
can be passed three different things:
class User < BaseObject
# will use the `UserPolicy#display_name?` method
field :display_name, ..., authorize: true
field :display_name, ... do
authorize
end
# will use the passed lambda instead of a policy method
field :password_hash, ..., authorize: ->(obj, args, ctx) { ... }
field :password_hash, ... do
authorize ->(obj, args, ctx) { ... }
end
# will use the `UserPolicy#personal_info?` method
field :email, ..., authorize: :personal_info
field :email, ... do
authorize :personal_info
end
end
true
will trigger the inference mechanism, meaning that the method that will be called on the policy class will be inferred from the (snake_case) field name.- a lambda function that will be called with the parent object, the arguments of the field and the context object; if the lambda returns a truthy value, authorization succeeds; otherwise (including thrown exceptions), authorization fails
- a string or a symbol that corresponds to the policy method that should be called minus the "?"
policy
is an optional argument that can also be passed three different values:
class User < BaseObject
# will use the `UserPolicy#display_name?` method (default inference)
field :display_name, ..., authorize: true, policy: nil
field :display_name do
authorize policy: nil
end
# will use OtherUserPolicy#password_hash?
field :password_hash, ...,
authorize: true,
policy: ->(obj, args, ctx) { OtherUserPolicy }
field :password_hash, ... do
authorize policy: ->(obj, args, ctx) { OtherUserPolicy }
end
# will use MemberPolicy#email?
field :email, ..., authorize: true, policy: MemberPolicy
field :email, ... do
authorize policy: MemberPolicy
end
end
nil
is the default behavior and results in inferring the policy class from the record (see below)- a lambda function that will be called with the parent object, the arguments of the field and the context object; the return value of this function will be used as the policy class
- an actual policy class
record
can be used to pass a different value to the policy. Like policy
,
this argument also can receive three different values:
class User < BaseObject
# will use the parent object
field :display_name, ..., authorize: true, record: nil
field :display_name do
authorize record: nil
end
# will use the current user as the record
field :password_hash, ...,
authorize: true,
record: ->(obj, args, ctx) { ctx[:current_user] }
field :password_hash, ... do
authorize record: ->(obj, args, ctx) { ctx[:current_user] }
end
# will use AccountPolicy#email? with the first account as the record (the policy was inferred from the record class)
field :email, ..., authorize: true, record: Account.first
field :email, ... do
authorize record: Account.first
end
end
nil
is again used for the inference; in this case, the parent object is used- a lambda function, again called with the parent object, the field arguments and the context object; the result will be used as the record
- any other value that will be used as the record
Using record
can be helpful for e.g. mutations, where you need a value to
initialize the policy with, but for mutations there is no parent object.
before_scope
and after_scope
can be used to apply Pundit scopes to the
fields. Both options can be combined freely within one field. The result of
before_scope
is passed to the resolver as the "parent object", while the
result of after_scope
is returned as the result of the field.
class User < BaseObject
# will use the `PostPolicy::Scope` before the resolver
field :posts, ..., before_scope: true
field :posts, ... do
before_scope
end
# will use the passed lambda after the resolver
field :comments, ..., after_scope: ->(comments, args, ctx) { ... }
field :comments, ... do
after_scope ->(comments, args, ctx) { ... }
end
# will use the `FriendPolicy::Scope`
field :friends, ..., after_scope: FriendPolicy
field :friends, ... do
after_scope FriendPolicy
end
end
true
will trigger the inference mechanism, where the policy class, which contains the scope class, is inferred based on either the parent object (forbefore_scope
) or the result of the resolver (forafter_scope
).- a lambda function, that will be called with the parent object (for
before_scope
) or the result of the resolver (forafter_scope
), the field arguments and the context - a policy class that contains a
Scope
class (this does not actually have to be a policy class, but could also be a module containing aScope
class)
All options can be combined with one another (except authorize
and authorize!
; please don't do that). Examples:
# MemberPolicy#name? initialized with the parent
field :display_name, ..., authorize: :name,
policy: MemberPolicy
# UserPolicy#display_name? initialized with user.account_data
field :display_name, ..., do
authorize policy: UserPolicy,
record: ->(obj, args, ctx) { obj.account_data }
end
The legacy define
based API will be supported until it is removed from the
graphql
gem (as planned for version 1.10).
Add the following to your GraphQL schema:
MySchema = GraphQL::Schema.define do
...
instrument(:field, GraphQL::Pundit::Instrumenter.new)
...
end
By default, ctx[:current_user]
will be used as the user to authorize. To change that behavior, pass a symbol to GraphQL::Pundit::Instrumenter
.
GraphQL::Pundit::Instrumenter.new(:me) # will use ctx[:me]
For each field you want to authorize via Pundit, add the following code to the field definition:
field :email do
authorize # will use UserPolicy#email?
resolve ...
end
By default, this will use the Policy for the parent object (the first argument passed to the resolve proc), checking for :email?
for the current user. Sometimes, the field name will differ from the policy method name, in which case you can specify it explicitly:
field :email do
authorize :read_email # will use UserPolicy#read_email?
resolve ...
end
Now, in some cases you'll want to use a different policy, or in case of mutations, the passed object might be nil
:
field :createUser
authorize! :create, policy: User # or User.new; will use UserPolicy#create?
resolve ...
end
This will use the :create?
method of the UserPolicy
. You can also pass in objects instead of a class (or symbol), if you wish to authorize the user for the specific object.
If you want to pass a different value to the policy, you can use the keyword argument record
:
field :createUser
authorize! :create, record: User.new # or User.new; will use UserPolicy#create?
resolve ...
end
You can also pass a lambda
as a record. This receives the usual three arguments (parent value, arguments, context) and returns the value to be used as a record.
You might have also noticed the use of authorize!
instead of authorize
in this example. The difference between the two is this:
authorize
will set the field tonil
if authorization failsauthorize!
will set the field tonil
and add an error to the response if authorization fails
You would normally want to use authorize
for fields in queries, that only e.g. the owner of something can see, while authorize!
would be usually used in mutations, where you want to communicate to the client that the operation failed because the user is unauthorized.
If you still need more control over how policies are called, you can pass a lambda to authorize
:
field :email
authorize ->(obj, args, ctx) { UserPolicy.new(obj, ctx[:me]).private_data?(:email) }
resolve ...
end
If the lambda returns a falsy value or raises a Pundit::UnauthorizedError
the field will resolve to nil
, if it returns a truthy value, control will be passed to the resolve function. Of course, this can be used with authorize!
as well.
Pundit scopes are supported by using before_scope
and after_scope
in the field definition
field :posts
after_scope
resolve ...
end
Passing no arguments to after_scope
and before_scope
will infer the policy to use from the value it is passed: before_scope
is run before resolve
and will receive the parent object, after_scope
will be run after resolve
and receives the output of resolve
. You can also pass a proc or a policy class to both _scope
s:
field :posts
before_scope ->(_root, _args, ctx) { Post.where(owner: ctx[:current_user]) }
resolve ->(posts, args, ctx) { ... }
end
field :posts
after_scope PostablePolicy
resolve ...
end
After checking out the repo, run bin/setup
to install dependencies. Then, run rake spec
to run the tests. You can also run bin/console
for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install
. To release a new version, update the version number in version.rb
, and then run bundle exec rake release
, which will create a git tag for the version, push git commits and tags, and push the .gem
file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/ontohub/graphql-pundit.
The gem is available as open source under the terms of the MIT License.