Issue with RANGE_ADD in Relay Mutations - graphql

Question

I was going through the relay docs and came to following code in RANGE_ADD.
class IntroduceShipMutation extends Relay.Mutation {
// This mutation declares a dependency on the faction
// into which this ship is to be introduced.
static fragments = {
faction: () => Relay.QL`fragment on Faction { id }`,
};
// Introducing a ship will add it to a faction's fleet, so we
// specify the faction's ships connection as part of the fat query.
getFatQuery() {
return Relay.QL`
fragment on IntroduceShipPayload {
faction { ships },
newShipEdge,
}
`;
}
getConfigs() {
return [{
type: 'RANGE_ADD',
parentName: 'faction',
parentID: this.props.faction.id,
connectionName: 'ships',
edgeName: 'newShipEdge',
rangeBehaviors: {
// When the ships connection is not under the influence
// of any call, append the ship to the end of the connection
'': 'append',
// Prepend the ship, wherever the connection is sorted by age
'orderby(newest)': 'prepend',
},
}];
}
/* ... */
}
Now over here it is mentioned that edgeName is required for adding new node to the connection. Looks well and fine.
Now, I move further down the documentation and reached the GraphQL implementation of this mutation.
mutation AddBWingQuery($input: IntroduceShipInput!) {
introduceShip(input: $input) {
ship {
id
name
}
faction {
name
}
clientMutationId
}
}
Now according to docs this mutation gives me output as
{
"introduceShip": {
"ship": {
"id": "U2hpcDo5",
"name": "B-Wing"
},
"faction": {
"name": "Alliance to Restore the Republic"
},
"clientMutationId": "abcde"
}
}
I cannot see edgeName being present here.
I was using graphene for my project. Over there also I saw something similar only
class IntroduceShip(relay.ClientIDMutation):
class Input:
ship_name = graphene.String(required=True)
faction_id = graphene.String(required=True)
ship = graphene.Field(Ship)
faction = graphene.Field(Faction)
#classmethod
def mutate_and_get_payload(cls, input, context, info):
ship_name = input.get('ship_name')
faction_id = input.get('faction_id')
ship = create_ship(ship_name, faction_id)
faction = get_faction(faction_id)
return IntroduceShip(ship=ship, faction=faction)
Over here also I cannot see edgeName anywhere.
Any help please? I am working on mutations for the first so wanted to confirm a m I missing something or is something wrong here?

Answer 1

This example might be either simplified or a bit obsoloete, because in practice there is need to return edge and that's exactly what is fetched by relay (other fields in RANGE_ADD are more a kind of declaration and are not necessarily fetched).
Here is how you can do it in graphene:
# Import valid as of graphene==0.10.2 and graphql-relay=0.4.4
from graphql_relay.connection.arrayconnection import offset_to_cursor
class IntroduceShip(relay.ClientIDMutation):
class Input:
ship_name = graphene.String(required=True)
faction_id = graphene.String(required=True)
ship = graphene.Field(Ship)
faction = graphene.Field(Faction)
new_ship_edge = graphene.Field(Ship.get_edge_type().for_node(Ship))
#classmethod
def mutate_and_get_payload(cls, input, context, info):
ship_name = input.get('ship_name')
faction_id = input.get('faction_id')
ship = create_ship(ship_name, faction_id)
faction = get_faction(faction_id)
ship_edge_type = Ship.get_edge_type().for_node(Ship)
new_ship_edge = edge_type(
# Assuming get_ships_number supplied
cursor=offset_to_cursor(get_ships_number())
node=ship
)
return cls(ship=ship, faction=faction, new_ship_edge=new_ship_edge)