async-graphql/docs/en/src/input_value_validators.md

Input value validators

Async-graphql has some common validators built-in, you can use them on the parameters of object fields or on the fields of InputObject.

• maximum=N the number cannot be greater than N.
• minimum=N the number cannot be less than N.
• multiple_of=N the number must be a multiple of N.
• max_items=N the length of the list cannot be greater than N.
• min_items=N the length of the list cannot be less than N.
• max_length=N the length of the string cannot be greater than N.
• min_length=N the length of the string cannot be less than N.
• chars_max_length=N the count of the unicode chars cannot be greater than N.
• chars_min_length=N the count of the unicode chars cannot be less than N.
• email is valid email.
• url is valid url.
• ip is valid ip address.
• regex=RE is match for the regex.

use async_graphql::*;

struct Query;

#[Object]
impl Query {
    /// The length of the name must be greater than or equal to 5 and less than or equal to 10.
    async fn input(#[graphql(validator(min_length = 5, max_length = 10))] name: String) {
    }
}

Check every member of the list

You can enable the list attribute, and the validator will check all members in list:

use async_graphql::*;

struct Query;

#[Object]
impl Query {
    async fn input(#[graphql(validator(list, max_length = 10))] names: Vec<String>) {
    }
}

Custom validator

struct MyValidator {
    expect: i32,
}

impl MyValidator {
    pub fn new(n: i32) -> Self {
        MyValidator { expect: n }
    }
}

impl CustomValidator<i32> for MyValidator {
    fn check(&self, value: &i32) -> Result<(), String> {
        if *value == self.expect {
            Ok(())
        } else {
            Err(format!("expect 100, actual {}", value))
        }
    }
}

struct Query;

#[Object]
impl Query {
    /// n must be equal to 100
    async fn value(
        &self,
        #[graphql(validator(custom = "MyValidator::new(100)"))] n: i32,
    ) -> i32 {
        n
    }
}