[−][src]Trait async_graphql::resolver_utils::ScalarType

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

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

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`[src]

The Boolean scalar type represents true or false.

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for char`[src]

The Char scalar type represents a unicode char. The input and output values are a string, and there can only be one unicode character in this string.

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for f32`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for f64`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for i8`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for i16`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for i32`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for i64`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for u8`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for u16`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for u32`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for u64`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl<T> ScalarType for BTreeMap<String, T> where T: OutputValueType + InputValueType + Send + Sync,` [src]

A scalar that can represent any JSON Object value.

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn to_value(&self) -> Value`[src]

`impl<T> ScalarType for HashMap<String, T> where T: OutputValueType + InputValueType + Send + Sync,` [src]

A scalar that can represent any JSON Object value.

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroI8`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroI16`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroI32`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroI64`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroU8`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroU16`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroU32`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for NonZeroU64`[src]

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

`fn parse(value: Value) -> InputValueResult<Self>`[src]

`fn is_valid(value: &Value) -> bool`[src]

`fn to_value(&self) -> Value`[src]

`impl ScalarType for String`[src]

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.