private static IList <LambdaExpression> BuildFieldResolver_BuildMethodArguments(MethodInfo methodInfo, Type?sourceType, FieldType?fieldType)
{
List <LambdaExpression> expressions = new();
foreach (var parameterInfo in methodInfo.GetParameters())
{
var typeInformation = new TypeInformation(parameterInfo);
typeInformation.ApplyAttributes(); // typically this is unnecessary, since this is primarily used to control the graph type of generated query arguments
var argumentInfo = new ArgumentInformation(parameterInfo, sourceType, fieldType, typeInformation);
argumentInfo.ApplyAttributes(); // necessary to allow [FromSource], [FromServices] and similar attributes to work
var(queryArgument, expression) = argumentInfo.ConstructQueryArgument();
if (queryArgument != null)
{
// even though the query argument is not used, it is necessary to apply attributes to the generated argument in case the name is overridden,
// as the generated query argument's name is used within the expression for the call to GetArgument
var attributes = parameterInfo.GetCustomAttributes <GraphQLAttribute>();
foreach (var attr in attributes)
{
attr.Modify(queryArgument);
}
}
expression ??= GetParameterExpression(
parameterInfo.ParameterType,
queryArgument ?? throw new InvalidOperationException("Invalid response from ConstructQueryArgument: queryArgument and expression cannot both be null"));
expressions.Add(expression);
}
return(expressions);
}
/// <summary>
/// Analyzes a method parameter and returns an instance of <see cref="ArgumentInformation"/>
/// containing information necessary to build a <see cref="QueryArgument"/> and <see cref="IFieldResolver"/>.
/// Also applies any <see cref="GraphQLAttribute"/> attributes defined on the <see cref="ParameterInfo"/>
/// to the returned <see cref="ArgumentInformation"/> instance.
/// </summary>
protected virtual ArgumentInformation GetArgumentInformation <TParameterType>(FieldType fieldType, ParameterInfo parameterInfo)
{
var typeInformation = GetTypeInformation(parameterInfo);
var argumentInfo = new ArgumentInformation(parameterInfo, typeof(TSourceType), fieldType, typeInformation);
argumentInfo.ApplyAttributes();
return(argumentInfo);
}
