/// <summary>
/// Returns all of the variable values defined for the operation from the attached <see cref="Inputs"/> object.
/// </summary>
public Variables GetVariableValues(ISchema schema, VariableDefinitions variableDefinitions, Inputs inputs, IVariableVisitor visitor = null)
{
if ((variableDefinitions?.List?.Count ?? 0) == 0)
{
return(Variables.None);
}
var variables = new Variables(variableDefinitions.List.Count);
if (variableDefinitions != null)
{
foreach (var variableDef in variableDefinitions.List)
{
// find the IGraphType instance for the variable type
var graphType = variableDef.Type.GraphTypeFromType(schema);
if (graphType == null)
{
ReportError(new InvalidVariableError(this, variableDef, variableDef.Name, $"Variable has unknown type '{variableDef.Type.Name()}'"));
continue;
}
// create a new variable object
var variable = new Variable(variableDef.Name);
// attempt to retrieve the variable value from the inputs
if (inputs.TryGetValue(variableDef.Name, out var variableValue))
{
// parse the variable via ParseValue (for scalars) and ParseDictionary (for objects) as applicable
try
{
variable.Value = GetVariableValue(graphType, variableDef, variableValue, visitor);
}
catch (ValidationError error)
{
ReportError(error);
continue;
}
}
else if (variableDef.DefaultValue != null)
{
// if the variable was not specified in the inputs, and a default literal value was specified, use the specified default variable value
// parse the variable literal via ParseLiteral (for scalars) and ParseDictionary (for objects) as applicable
try
{
variable.Value = ExecutionHelper.CoerceValue(graphType, variableDef.DefaultValue, variables, null).Value;
}
catch (Exception ex)
{
ReportError(new InvalidVariableError(this, variableDef, variableDef.Name, "Error coercing default value.", ex));
continue;
}
variable.IsDefault = true;
}
else if (graphType is NonNullGraphType)
{
ReportError(new InvalidVariableError(this, variableDef, variable.Name, "No value provided for a non-null variable."));
continue;
}
// if the variable was not specified and no default was specified, do not set variable.Value
// add the variable to the list of parsed variables defined for the operation
variables.Add(variable);
}
}
// return the list of parsed variables defined for the operation
return(variables);
}