Function cantCoerceScalar

query/outputnode_graphql.go:1365–1395

cantCoerceScalar tells whether a scalar value can be coerced to its corresponding GraphQL scalar.

(val []byte, field gqlSchema.Field)

// cantCoerceScalar tells whether a scalar value can be coerced to its corresponding GraphQL scalar.
func cantCoerceScalar(val []byte, field gqlSchema.Field) bool {
	switch field.Type().Name() {
	case "Int":
		// Although GraphQL layer would have input coercion for Int,
		// we still need to do this as there can be cases like schema migration when Int64 was
		// changed to Int, or if someone was using DQL mutations but GraphQL queries. The GraphQL
		// layer must always honor the spec.
		// valToBytes() uses []byte(strconv.FormatInt(num, 10)) to convert int values to byte slice.
		// so, we should do the reverse, parse the string back to int and check that it fits in the
		// range of int32.
		if _, err := strconv.ParseInt(string(val), 0, 32); err != nil {
			return true
		}
	case "String", "ID", "Boolean", "Int64", "Float", "DateTime":
		// do nothing, as for these types the GraphQL schema is same as the dgraph schema.
		// Hence, the value coming in from fastJson node should already be in the correct form.
		// So, no need to coerce it.
	default:
		enumValues := field.EnumValues()
		// At this point we should only get fields which are of ENUM type, so we can return
		// an error if we don't get any enum values.
		if len(enumValues) == 0 {
			return true
		}
		// Lets check that the enum value is valid.
		if !x.HasString(enumValues, toString(val)) {
			return true
		}
	}
	return false
}

// toString converts the json encoded string value val to a go string.
// It should be used only in scenarios where the underlying string is simple, i.e., it doesn't