Trait async_graphql::ScalarType

pub trait ScalarType: Sized + Send {
    fn parse(value: Value) -> InputValueResult<Self>;
    fn to_value(&self) -> Value;

    fn is_valid(_value: &Value) -> bool { ... }
}

Represents a GraphQL scalar

You can implement the trait to create a custom scalar.

Examples

use async_graphql::*;

struct MyInt(i32);

#[Scalar]
impl ScalarType for MyInt {
    fn parse(value: Value) -> InputValueResult<Self> {
        if let Value::Number(n) = &value {
            if let Some(n) = n.as_i64() {
                return Ok(MyInt(n as i32));
            }
        }
        Err(InputValueError::ExpectedType(value))
    }

    fn to_value(&self) -> Value {
        Value::Number(self.0.into())
    }
}

Required methods

fn parse(value: Value) -> InputValueResult<Self>

Parse a scalar value, return Some(Self) if successful, otherwise return None.

fn to_value(&self) -> Value

Convert the scalar to Value.

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Provided methods

fn is_valid(_value: &Value) -> bool

Checks for a valid scalar value.

Implementing this function can find incorrect input values during the verification phase, which can improve performance.

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Implementations on Foreign Types

impl ScalarType for bool

The Boolean scalar type represents true or false.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for DateTime<Utc>

Implement the DateTime scalar

The input/output is a string in RFC3339 format.

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

impl ScalarType for f32

The Float scalar type represents signed double-precision fractional values as specified by IEEE 754.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for f64

The Float scalar type represents signed double-precision fractional values as specified by IEEE 754.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for i8

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for i16

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for i32

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for i64

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for u8

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for u16

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for u32

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for u64

The Int scalar type represents non-fractional whole numeric values.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for NaiveDate

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

impl ScalarType for NaiveTime

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

impl ScalarType for String

The String scalar type represents textual data, represented as UTF-8 character sequences. The String type is most often used by GraphQL to represent free-form human-readable text.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for Uuid

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

impl ScalarType for ObjectId

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

impl ScalarType for UtcDateTime

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

impl ScalarType for Url

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

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Implementors

impl ScalarType for Any

The _Any scalar is used to pass representations of entities from external services into the root _entities field for execution.

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(_value: &Value) -> bool

fn to_value(&self) -> Value

impl ScalarType for ID

fn parse(value: Value) -> InputValueResult<Self>

fn is_valid(value: &Value) -> bool

fn to_value(&self) -> Value

impl<T: DeserializeOwned + Serialize + Send + Sync> ScalarType for Json<T>

A scalar that can represent any JSON value.

fn parse(value: Value) -> InputValueResult<Self>

fn to_value(&self) -> Value

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