func Execute(p ExecuteParams) (result *Result) {
result = &Result{}
exeContext, err := buildExecutionContext(BuildExecutionCtxParams{
Schema: p.Schema,
Root: p.Root,
AST: p.AST,
OperationName: p.OperationName,
Args: p.Args,
Errors: nil,
Result: result,
})
if err != nil {
result.Errors = append(result.Errors, gqlerrors.FormatError(err))
return
}
defer func() {
if r := recover(); r != nil {
var err error
if r, ok := r.(error); ok {
err = gqlerrors.FormatError(r)
}
exeContext.Errors = append(exeContext.Errors, gqlerrors.FormatError(err))
result.Errors = exeContext.Errors
}
}()
return executeOperation(ExecuteOperationParams{
ExecutionContext: exeContext,
Root: p.Root,
Operation: exeContext.Operation,
})
}
func completeValueCatchingError(eCtx *ExecutionContext, returnType Type, fieldASTs []*ast.Field, info ResolveInfo, result interface{}) (completed interface{}) {
// catch panic
defer func() interface{} {
if r := recover(); r != nil {
//send panic upstream
if _, ok := returnType.(*NonNull); ok {
panic(r)
}
if err, ok := r.(gqlerrors.FormattedError); ok {
eCtx.Errors = append(eCtx.Errors, err)
}
return completed
}
return completed
}()
if returnType, ok := returnType.(*NonNull); ok {
completed := completeValue(eCtx, returnType, fieldASTs, info, result)
return completed
}
completed = completeValue(eCtx, returnType, fieldASTs, info, result)
resultVal := reflect.ValueOf(completed)
if resultVal.IsValid() && resultVal.Type().Kind() == reflect.Func {
if propertyFn, ok := completed.(func() interface{}); ok {
return propertyFn()
}
err := gqlerrors.NewFormattedError("Error resolving func. Expected `func() interface{}` signature")
panic(gqlerrors.FormatError(err))
}
return completed
}
func completeValue(eCtx *ExecutionContext, returnType Type, fieldASTs []*ast.Field, info ResolveInfo, result interface{}) interface{} {
// TODO: explore resolving go-routines in completeValue
resultVal := reflect.ValueOf(result)
if resultVal.IsValid() && resultVal.Type().Kind() == reflect.Func {
if propertyFn, ok := result.(func() interface{}); ok {
return propertyFn()
}
err := gqlerrors.NewFormattedError("Error resolving func. Expected `func() interface{}` signature")
panic(gqlerrors.FormatError(err))
}
if returnType, ok := returnType.(*NonNull); ok {
completed := completeValue(eCtx, returnType.OfType, fieldASTs, info, result)
if completed == nil {
err := NewLocatedError(
fmt.Sprintf("Cannot return null for non-nullable field %v.%v.", info.ParentType, info.FieldName),
FieldASTsToNodeASTs(fieldASTs),
)
panic(gqlerrors.FormatError(err))
}
return completed
}
if isNullish(result) {
return nil
}
// If field type is List, complete each item in the list with the inner type
if returnType, ok := returnType.(*List); ok {
resultVal := reflect.ValueOf(result)
err := invariant(
resultVal.IsValid() && resultVal.Type().Kind() == reflect.Slice,
"User Error: expected iterable, but did not find one.",
)
if err != nil {
panic(gqlerrors.FormatError(err))
}
itemType := returnType.OfType
completedResults := []interface{}{}
for i := 0; i < resultVal.Len(); i++ {
val := resultVal.Index(i).Interface()
completedItem := completeValueCatchingError(eCtx, itemType, fieldASTs, info, val)
completedResults = append(completedResults, completedItem)
}
return completedResults
}
// If field type is Scalar or Enum, serialize to a valid value, returning
// null if serialization is not possible.
if returnType, ok := returnType.(*Scalar); ok {
serializedResult := returnType.Serialize(result)
if isNullish(serializedResult) {
return nil
}
return serializedResult
}
if returnType, ok := returnType.(*Enum); ok {
serializedResult := returnType.Serialize(result)
if isNullish(serializedResult) {
return nil
}
return serializedResult
}
// ast.Field type must be Object, Interface or Union and expect sub-selections.
var objectType *Object
switch returnType := returnType.(type) {
case *Object:
objectType = returnType
case Abstract:
objectType = returnType.ObjectType(result, info)
if objectType != nil && !returnType.IsPossibleType(objectType) {
panic(gqlerrors.NewFormattedError(
fmt.Sprintf(`Runtime Object type "%v" is not a possible type `+
`for "%v".`, objectType, returnType),
))
}
}
if objectType == nil {
return nil
}
// If there is an isTypeOf predicate function, call it with the
// current result. If isTypeOf returns false, then raise an error rather
// than continuing execution.
if objectType.IsTypeOf != nil && !objectType.IsTypeOf(result, info) {
panic(gqlerrors.NewFormattedError(
fmt.Sprintf(`Expected value of type "%v" but got: %T.`, objectType, result),
))
}
// Collect sub-fields to execute to complete this value.
subFieldASTs := map[string][]*ast.Field{}
visitedFragmentNames := map[string]bool{}
for _, fieldAST := range fieldASTs {
if fieldAST == nil {
continue
}
selectionSet := fieldAST.SelectionSet
if selectionSet != nil {
innerParams := CollectFieldsParams{
ExeContext: eCtx,
OperationType: objectType,
SelectionSet: selectionSet,
Fields: subFieldASTs,
VisitedFragmentNames: visitedFragmentNames,
}
subFieldASTs = collectFields(innerParams)
}
}
executeFieldsParams := ExecuteFieldsParams{
ExecutionContext: eCtx,
ParentType: objectType,
Source: result,
Fields: subFieldASTs,
}
results := executeFields(executeFieldsParams)
return results.Data
}
/**
* Resolves the field on the given source object. In particular, this
* figures out the value that the field returns by calling its resolve function,
* then calls completeValue to complete promises, serialize scalars, or execute
* the sub-selection-set for objects.
*/
func resolveField(eCtx *ExecutionContext, parentType *Object, source interface{}, fieldASTs []*ast.Field) (result interface{}, resultState resolveFieldResultState) {
// catch panic from resolveFn
var returnType Output
defer func() (interface{}, resolveFieldResultState) {
if r := recover(); r != nil {
var err error
if r, ok := r.(string); ok {
err = NewLocatedError(
fmt.Sprintf("%v", r),
FieldASTsToNodeASTs(fieldASTs),
)
}
if r, ok := r.(error); ok {
err = gqlerrors.FormatError(r)
}
// send panic upstream
if _, ok := returnType.(*NonNull); ok {
panic(gqlerrors.FormatError(err))
}
eCtx.Errors = append(eCtx.Errors, gqlerrors.FormatError(err))
return result, resultState
}
return result, resultState
}()
fieldAST := fieldASTs[0]
fieldName := ""
if fieldAST.Name != nil {
fieldName = fieldAST.Name.Value
}
fieldDef := getFieldDef(eCtx.Schema, parentType, fieldName)
if fieldDef == nil {
resultState.hasNoFieldDefs = true
return nil, resultState
}
returnType = fieldDef.Type
resolveFn := fieldDef.Resolve
if resolveFn == nil {
resolveFn = defaultResolveFn
}
// Build a map of arguments from the field.arguments AST, using the
// variables scope to fulfill any variable references.
// TODO: find a way to memoize, in case this field is within a List type.
args, _ := getArgumentValues(fieldDef.Args, fieldAST.Arguments, eCtx.VariableValues)
// The resolve function's optional third argument is a collection of
// information about the current execution state.
info := ResolveInfo{
FieldName: fieldName,
FieldASTs: fieldASTs,
ReturnType: returnType,
ParentType: parentType,
Schema: eCtx.Schema,
Fragments: eCtx.Fragments,
RootValue: eCtx.Root,
Operation: eCtx.Operation,
VariableValues: eCtx.VariableValues,
}
// TODO: If an error occurs while calling the field `resolve` function, ensure that
// it is wrapped as a Error with locations. Log this error and return
// null if allowed, otherwise throw the error so the parent field can handle
// it.
result = resolveFn(ResolveParams{
Source: source,
Args: args,
Info: info,
})
completed := completeValueCatchingError(eCtx, returnType, fieldASTs, info, result)
return completed, resultState
}