/// <summary>
/// Return the specified variable's value for the document from the attached <see cref="Inputs"/> object.
/// <br/><br/>
/// Validates and parses the supplied input object according to the variable's type, and converts the object
/// with <see cref="ScalarGraphType.ParseValue(object)"/> and
/// <see cref="IInputObjectGraphType.ParseDictionary(IDictionary{string, object})"/> as applicable.
/// <br/><br/>
/// Since v3.3, returns null for variables set to null rather than the variable's default value.
/// </summary>
private object GetVariableValue(IGraphType graphType, VariableDefinition variableDef, object input, IVariableVisitor visitor)
{
return(ParseValue(graphType, variableDef, variableDef.Name, input, visitor));
// Coerces a value depending on the graph type.
object ParseValue(IGraphType type, VariableDefinition variableDef, VariableName variableName, object value, IVariableVisitor visitor)
{
if (type is IInputObjectGraphType inputObjectGraphType)
{
var parsedValue = ParseValueObject(inputObjectGraphType, variableDef, variableName, value, visitor);
visitor?.VisitObject(this, variableDef, variableName, inputObjectGraphType, value, parsedValue);
return(parsedValue);
}
else if (type is NonNullGraphType nonNullGraphType)
{
if (value == null)
{
throw new InvalidVariableError(this, variableDef, variableName, "Received a null input for a non-null variable.");
}
return(ParseValue(nonNullGraphType.ResolvedType, variableDef, variableName, value, visitor));
}
else if (type is ListGraphType listGraphType)
{
var parsedValue = ParseValueList(listGraphType, variableDef, variableName, value, visitor);
visitor?.VisitList(this, variableDef, variableName, listGraphType, value, parsedValue);
return(parsedValue);
}
else if (type is ScalarGraphType scalarGraphType)
{
var parsedValue = ParseValueScalar(scalarGraphType, variableDef, variableName, value);
visitor?.VisitScalar(this, variableDef, variableName, scalarGraphType, value, parsedValue);
return(parsedValue);
}
else
{
throw new InvalidVariableError(this, variableDef, variableName, $"The graph type '{type.Name}' is not an input graph type.");
}
}
// Coerces a scalar value
object ParseValueScalar(ScalarGraphType scalarGraphType, VariableDefinition variableDef, VariableName variableName, object value)
{
try
{
return(scalarGraphType.ParseValue(value));
}
catch (Exception ex)
{
throw new InvalidVariableError(this, variableDef, variableName, $"Unable to convert '{value}' to '{scalarGraphType.Name}'", ex);
}
}
IList <object> ParseValueList(ListGraphType listGraphType, VariableDefinition variableDef, VariableName variableName, object value, IVariableVisitor visitor)
{
if (value == null)
{
return(null);
}
// note: a list can have a single child element which will automatically be interpreted as a list of 1 elements. (see below rule)
// so, to prevent a string as being interpreted as a list of chars (which get converted to strings), we ignore considering a string as an IEnumerable
if (value is IEnumerable values && !(value is string))
{
// create a list containing the parsed elements in the input list
if (values is IList list)
{
var valueOutputs = new object[list.Count];
for (int index = 0; index < list.Count; index++)
{
// parse/validate values as required by graph type
valueOutputs[index] = ParseValue(listGraphType.ResolvedType, variableDef, new VariableName(variableName, index), list[index], visitor);
}
return(valueOutputs);
}
else
{
var valueOutputs = new List <object>(values is ICollection collection ? collection.Count : 0);
int index = 0;
foreach (object val in values)
{
// parse/validate values as required by graph type
valueOutputs.Add(ParseValue(listGraphType.ResolvedType, variableDef, new VariableName(variableName, index++), val, visitor));
}
return(valueOutputs);
}
}
/// <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);
}
public abstract T Visit <T>(IVariableVisitor <T> visitor);
public override T Visit <T>(IVariableVisitor <T> visitor)
{
return(visitor.Visit(this));
}
/// <summary>
/// Return the specified variable's value for the document from the attached <see cref="Inputs"/> object.
/// <br/><br/>
/// Validates and parses the supplied input object according to the variable's type, and converts the object
/// with <see cref="ScalarGraphType.ParseValue(object)"/> and
/// <see cref="IInputObjectGraphType.ParseDictionary(IDictionary{string, object})"/> as applicable.
/// <br/><br/>
/// Since v3.3, returns null for variables set to null rather than the variable's default value.
/// </summary>
private object GetVariableValue(IGraphType graphType, VariableDefinition variableDef, object input, IVariableVisitor visitor)
{
return(ParseValue(graphType, variableDef, variableDef.Name, input, visitor));
// Coerces a value depending on the graph type.
object ParseValue(IGraphType type, VariableDefinition variableDef, VariableName variableName, object value, IVariableVisitor visitor)
{
if (type is IInputObjectGraphType inputObjectGraphType)
{
var parsedValue = ParseValueObject(inputObjectGraphType, variableDef, variableName, value, visitor);
visitor?.VisitObject(this, variableDef, variableName, inputObjectGraphType, value, parsedValue);
return(parsedValue);
}
else if (type is NonNullGraphType nonNullGraphType)
{
if (value == null)
{
throw new InvalidVariableError(this, variableDef, variableName, "Received a null input for a non-null variable.");
}
return(ParseValue(nonNullGraphType.ResolvedType, variableDef, variableName, value, visitor));
}
else if (type is ListGraphType listGraphType)
{
var parsedValue = ParseValueList(listGraphType, variableDef, variableName, value, visitor);
visitor?.VisitList(this, variableDef, variableName, listGraphType, value, parsedValue);
return(parsedValue);
}
else if (type is ScalarGraphType scalarGraphType)
{
var parsedValue = ParseValueScalar(scalarGraphType, variableDef, variableName, value);
visitor?.VisitScalar(this, variableDef, variableName, scalarGraphType, value, parsedValue);
return(parsedValue);
}
else
{
throw new InvalidVariableError(this, variableDef, variableName, $"The graph type '{type.Name}' is not an input graph type.");
}
}
// Coerces a scalar value
object ParseValueScalar(ScalarGraphType scalarGraphType, VariableDefinition variableDef, VariableName variableName, object value)
{
try
{
// Convert input scalar type into correct one.
// example.: type is int. value is '10'.
// This value can be parsed from string into int and solution is very practical for wide usage.
// Maybe best practice should be add new global switch which enable/disable this option.
if (SchemaTypes.BuiltInScalarMappings.Where(m => m.Value == scalarGraphType.GetType()).Any())
{
var type = SchemaTypes.BuiltInScalarMappings.Where(m => m.Value == scalarGraphType.GetType()).FirstOrDefault().Key;
if (type != null)
{
value = Convert.ChangeType(value, type);
}
}
return(scalarGraphType.ParseValue(value));
}
catch (Exception ex)
{
throw new InvalidVariableError(this, variableDef, variableName, $"Unable to convert '{value}' to '{scalarGraphType.Name}'", ex);
}
}
IList <object> ParseValueList(ListGraphType listGraphType, VariableDefinition variableDef, VariableName variableName, object value, IVariableVisitor visitor)
{
if (value == null)
{
return(null);
}
// note: a list can have a single child element which will automatically be interpreted as a list of 1 elements. (see below rule)
// so, to prevent a string as being interpreted as a list of chars (which get converted to strings), we ignore considering a string as an IEnumerable
if (value is IEnumerable values && !(value is string))
{
// create a list containing the parsed elements in the input list
if (values is IList list)
{
var valueOutputs = new object[list.Count];
for (int index = 0; index < list.Count; index++)
{
// parse/validate values as required by graph type
valueOutputs[index] = ParseValue(listGraphType.ResolvedType, variableDef, new VariableName(variableName, index), list[index], visitor);
}
return(valueOutputs);
}
else
{
var valueOutputs = new List <object>(values is ICollection collection ? collection.Count : 0);
int index = 0;
foreach (object val in values)
{
// parse/validate values as required by graph type
valueOutputs.Add(ParseValue(listGraphType.ResolvedType, variableDef, new VariableName(variableName, index++), val, visitor));
}
return(valueOutputs);
}
}
