From your application, you can push updates to GraphQL clients with .trigger.
Events are triggered by name, and the name must match fields on your Subscription Type
# Update the system with the new blog post:
MySchema.subscriptions.trigger("postAdded", {}, new_post)
The arguments are:
name, which corresponds to the field on subscription typearguments, which corresponds to the arguments on subscription type (for example, if you subscribe to comments on a certain post, the arguments would be {postId: comment.post_id}.)object, which will be the root object of the subscription updatescope: (shown below) for implicitly scoping the clients who will receive updates.To send updates to certain clients only, you can use scope: to narrow the trigger’s reach.
Scopes are based on query context: a value in context: is used as the scope; an equivalent value must be passed with .trigger(... scope:) to update that client. (The value is serialized with GraphQL::Subscriptions::Serialize)
To specify that a topic is scoped, edit the field definition on your root Subscription type. Use the subscription_scope: option to name a context: key, for example:
# For a given viewer, this will be triggered
# whenever one of their posts gets a new comment
field :comment_added, CommentType,
null: false,
description: "A comment was added to one of the viewer's posts"
subscription_scope: :current_user_id
Then, subscription operations should have a context: { current_user_id: ... } value, for example:
# current_user_id will be the scope for some subscriptions:
MySchema.execute(query_string, context: { current_user_id: current_user.id })
Finally, when events happen in your app, you should provide the scoping value as scope:, for example:
# A new comment is added
comment = post.comments.create!(attrs)
# notify the author
author_id = post.author.id
MySchema.subscriptions.trigger("commentAdded", {}, comment, scope: author_id)
Since this trigger has a scope:, only subscribers with a matching scope value will be updated.