GraphQL Query Generation
GraphQL Request and Response
Following where we left off from Getting Started with GraphQL, we'll explore what the GraphQL requests and responses look like for different queries defined with the AshGraphql DSL.
defmodule Helpdesk.Support.Ticket. do
use Ash.Resource,
...,
extensions: [
AshGraphql.Resource
]
attributes do
# Add an autogenerated UUID primary key called `:id`.
uuid_primary_key :id
# Add a string type attribute called `:subject`
attribute :subject, :string
end
actions do
# Add a set of simple actions. You'll customize these later.
defaults [:read, :update, :destroy]
end
graphql do
type :ticket
queries do
# create a field called `get_ticket` that uses the `read` read action to fetch a single ticket
get :get_ticket, :read
end
end
end
For the get_ticket
query defined above, the corresponding GraphQL would look like this:
query($id: ID!) {
get_ticket(id: $id) {
id
subject
}
}
And the response would look similar to this:
{
"data": {
"get_ticket": {
"id": "",
"subject": ""
}
}
}
Let's look at an example of querying a list of things.
graphql do
type :ticket
queries do
# create a field called `get_ticket` that uses the `read` read action to fetch a single ticket
get :get_ticket, :read
# create a field called `list_tickets` that uses the `read` read action to fetch a list of tickets
list :list_tickets, :read
end
end
This time, we've added list :list_tickets, :read
, to generate a GraphQL query for listing tickets.
The request would look something like this:
query {
list_tickets {
id
subject
}
}
And the response would look similar to this:
{
"data": {
"list_tickets": [
{
"id": "",
"subject": ""
}
]
}
}
Now, let's say we want to add query parameters to list_tickets
. How do we do that?
Consider list :list_tickets, :read
and the actions
section:
actions do
# Add a set of simple actions. You'll customize these later.
defaults [:read, :update, :destroy]
end
graphql do
type :ticket
queries do
# create a field called `list_tickets` that uses the `read` read action to fetch a list of tickets
list :list_tickets, :read
end
end
The second argument to list :list_tickets, :read
is the action that will be called when the query is run.
In the current example, the action is :read
, which is the generic Read action.
Let's create a custom action in order to define query parameters for the list_tickets
query.
We'll call this action :query_tickets
:
actions do
defaults [:read, :update, :destroy]
read :query_tickets do
argument :representative_id, :uuid
filter(
expr do
is_nil(^arg(:representative_id)) or representative_id == ^arg(:representative_id)
end
)
end
end
graphql do
type :ticket
queries do
# create a field called `list_tickets` that uses the `:query_tickets` read action to fetch a list of tickets
list :list_tickets, :query_tickets
end
end
In the graphql
section, the list/2
call has been changed, replacing the :read
action with :query_tickets
.
The GraphQL request would look something like this:
query($representative_id: ID) {
list_tickets(representative_id: $representative_id) {
id
representative_id
subject
}
}
More GraphQL Docs
If you haven't already, please turn on the documentation tag for AshGraphql. Tags can be controlled at the top of the left navigation menu, under "Including Libraries:".