public static async Task <ISubscribeResult> CreateSourceEventStreamAsync(
IExecutorContext context,
GraphQLOperationDefinition subscription,
Dictionary <string, object> coercedVariableValues,
object initialValue,
CancellationToken cancellationToken)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (subscription == null)
{
throw new ArgumentNullException(nameof(subscription));
}
if (coercedVariableValues == null)
{
throw new ArgumentNullException(nameof(coercedVariableValues));
}
cancellationToken.ThrowIfCancellationRequested();
var schema = context.Schema;
var subscriptionType = schema.Subscription;
var groupedFieldSet = SelectionSets.CollectFields(
context.Schema,
context.Document,
subscriptionType,
subscription.SelectionSet,
coercedVariableValues
);
var fields = groupedFieldSet.Values.First();
var fieldName = fields.First().Name.Value;
var fieldSelection = fields.First();
var coercedArgumentValues = Arguments.CoerceArgumentValues(
schema,
subscriptionType,
fieldSelection,
coercedVariableValues);
var field = schema.GetField(subscriptionType.Name, fieldName);
var path = new NodePath();
var resolveContext = new ResolverContext(
schema,
subscriptionType,
initialValue,
field,
fieldSelection,
coercedArgumentValues,
path,
context);
var subscriber = schema.GetSubscriber(subscriptionType.Name, fieldName);
if (subscriber == null)
{
throw new GraphQLError(
$"Could not subscribe. Field '{subscriptionType}:{fieldName}' does not have subscriber");
}
var subscribeResult = await subscriber(resolveContext, cancellationToken)
.ConfigureAwait(false);
return(subscribeResult);
}
