Serde Valid

This is JSON Schema based validation tool using with serde.

Usage

You derive Validate trait, and write validations.

use serde_valid::Validate;

#[derive(Validate)]
struct Data {
    #[validate(minimum = 0)]
    #[validate(maximum = 10)]
    val: i32,
}

#[derive(Validate)]
enum DataEnum {
    Named {
        #[validate]
        a: Data,
    },
}

let s = DataEnum::Named {
    a: Data { val: 5 },
};

assert!(s.validate().is_ok());

Feature Flags

• toml - provide serialization/deserialization in toml format.
• yaml - provide serialization/deserialization in yaml format.
• i128 - support i128/u128 type (default).
• flatten - change formatting to flattened error messages ( jsonschema crate style).

Validations

Serde Valid support standard validation based JSON Schema.

Type	Serde Valid(validate derive)	Serde Valid(validate trait)	Json Schema
String	#[validate(max_length = 5)]	[ValidateMaxLength]	maxLength
String	#[validate(min_length = 5)]	[ValidateMinLength]	minLength
String	#[validate(pattern = r"^\d{5}$")]	[ValidatePattern]	pattern
Numeric	#[validate(maximum = 5)]	[ValidateMaximum]	maximum
Numeric	#[validate(minimum = 5)]	[ValidateMinimum]	minimum
Numeric	#[validate(exclusive_maximum = 5)]	[ValidateExclusiveMaximum]	exclusiveMaximum
Numeric	#[validate(exclusive_minimum = 5)]	[ValidateExclusiveMinimum]	exclusiveMinimum
Numeric	#[validate(multiple_of = 5)]	[ValidateMultipleOf]	multipleOf
Object	#[validate(max_properties = 5)]	[ValidateMaxProperties]	maxProperties
Object	#[validate(min_properties = 5)]	[ValidateMinProperties]	minProperties
Array	#[validate(max_items = 5)]	[ValidateMaxItems]	maxItems
Array	#[validate(min_items = 5)]	[ValidateMinItems]	minItems
Array	#[validate(unique_items)]	[ValidateUniqueItems]	uniqueItems
Generic	#[validate(enumerate(5, 10, 15))]	[ValidateEnumerate]	enum

Complete Constructor (Deserialization)

Serde Valid support complete constructor method using by serde_valid::json::FromJsonValue trait.

use serde::Deserialize;
use serde_valid::Validate;
use serde_valid::json::{json, FromJsonValue};

#[derive(Debug, Deserialize, Validate)]
struct Data {
    #[validate(maximum = 100)]
    val: i32,
}

// Deserialization and Validation!! 🚀
let err = Data::from_json_value(json!({ "val": 123 })).unwrap_err();

assert_eq!(
    err.as_validation_errors().unwrap().to_string(),
    json!({
        "errors": [],
        "properties": {
            "val": {
                "errors": ["The number must be `<= 100`."]
            }
        }
    })
    .to_string()
);

You can force validation by only deserialization through serde_valid, and removing serde_json from Cargo.toml of your project.

Serialization

For serialization, provides serde_valid::json::ToJsonString trait.

use serde::Serialize;
use serde_valid::Validate;
use serde_valid::json::{json, ToJsonString};

#[derive(Debug, Serialize, Validate)]
struct Data {
    #[validate(maximum = 100)]
    val: i32,
}

assert_eq!(
    Data{ val: 12i32 }.to_json_string().unwrap(),
    json!({ "val": 12i32 }).to_json_string().unwrap()
);

Custom Message

For user custom message, Serde Valid provides message_fn or message.

use serde_json::json;
use serde_valid::Validate;

#[inline]
fn min_error_message(_params: &serde_valid::MinItemsError) -> String {
    "this is min custom message_fn.".to_string()
}

#[derive(Validate)]
struct Data {
    #[validate(min_items = 4, message_fn(min_error_message))]
    #[validate(max_items = 2, message = "this is max custom message.")]
    val: Vec<i32>,
}

let s = Data { val: vec![1, 2, 3] };

assert_eq!(
    s.validate().unwrap_err().to_string(),
    json!({
        "errors": [],
        "properties": {
            "val": {
                "errors": [
                    "this is min custom message_fn.",
                    "this is max custom message."
                ]
            }
        }
    })
    .to_string()
);

Fluent localization

You can also use fluent localization by using fluent feature.

use unic_langid::LanguageIdentifier;
use serde_json::json;
use serde_valid::{fluent::Localize, Validate};


#[derive(Validate)]
struct Data (
    #[validate(min_length = 3, fluent("name-min-length", min_length = 3))]
    String,
);

assert_eq!(
    Data("田中".to_string()).validate()
        .unwrap_err()
        .localize(&get_bundle("name-min-length = 名前の長さは { $min_length } 文字以上でないといけません。"))
        .to_string(),
    json!({
        "errors": ["名前の長さは \u{2068}3\u{2069} 文字以上でないといけません。"]
    })
    .to_string()
);

Custom method

You can use your custom validation using by #[validate(custom)].

use serde_valid::Validate;

fn user_validation(_val: &i32) -> Result<(), serde_valid::validation::Error> {
    Ok(())
}

#[derive(Validate)]
struct Data {
    #[validate(custom(user_validation))]
    val: i32,
}

let s = Data { val: 1 };

assert!(s.validate().is_ok());

And you can also use closure.

use serde_valid::Validate;

fn user_validation(_val: &i32, param1: bool) -> Result<(), serde_valid::validation::Error> {
    Ok(())
}

#[derive(Validate)]
struct Data {
    #[validate(custom(|v| user_validation(v, true)))]
    val: i32,
}

let s = Data { val: 1 };

assert!(s.validate().is_ok());

Multi Fields Validation

Custom Validation

Now, you can use #[validate(custom)] for multi fields validation.

use serde_json::json;
use serde_valid::Validate;

fn sample_validation(val1: i32, val2: &str) -> Result<(), serde_valid::validation::Error> {
    Ok(())
}

#[derive(Validate)]
#[validate(custom(|s| sample_validation(s.val1, &s.val2)))]
struct Data {
    val1: i32,
    val2: String,
}

let s = Data {
    val1: 1,
    val2: "val2".to_owned(),
};

assert!(s.validate().is_ok());

Rules

🚸 Warning 🚸 : this feature is deprecated. Please use #[validate(custom)] instead.

If you want to check multi fields validation, can use #[rule].

use serde_json::json;
use serde_valid::Validate;

fn sample_rule(_val1: &i32, _val2: &str) -> Result<(), serde_valid::validation::Error> {
    Err(serde_valid::validation::Error::Custom(
        "Rule error.".to_owned(),
    ))
}

#[derive(Validate)]
#[rule(sample_rule(val2, val1))]
struct Data {
    val1: String,
    val2: i32,
}

let s = Data {
    val1: "val1".to_owned(),
    val2: 1,
};

let errors = s.validate().unwrap_err();

assert_eq!(
    errors.to_string(),
    json!({
        "errors": ["Rule error."],
        "properties": {}
    })
    .to_string()
);

If you want to use rule to unnamed fields struct, just like this,

use serde_json::json;
use serde_valid::Validate;

fn sample_rule(_val1: &i32, _val2: &str) -> Result<(), serde_valid::validation::Error> {
    Ok(())
}

#[derive(Validate)]
#[rule(sample_rule(0, 1))]
struct Data(i32, String);

let s = Data(0, "1".to_owned());

assert!(s.validate().is_ok());

And you can also use closure.

use serde_json::json;
use serde_valid::Validate;

fn sample_rule(_val1: &i32, _val2: &str) -> Result<(), serde_valid::validation::Error> {
    Ok(())
}

#[derive(Validate)]
#[rule(|val1, val2| sample_rule(val2, val1))]
struct Data {
    val1: String,
    val2: i32,
}

let s = Data {
    val1: "val1".to_owned(),
    val2: 1,
};

assert!(s.validate().is_ok());

use serde_json::json;
use serde_valid::Validate;

fn sample_rule(_val1: &i32, _val2: &str) -> Result<(), serde_valid::validation::Error> {
    Ok(())
}

#[derive(Validate)]
#[rule(|_0, _1| sample_rule(_0, _1))]
struct Data(i32, String);

let s = Data(0, "1".to_owned());

assert!(s.validate().is_ok());

Validate Traits

By implementing the validation trait, Your original type can uses Serde Valid validations.

use serde_valid::Validate;

struct MyType(String);

impl serde_valid::ValidateMaxLength for MyType {
    fn validate_max_length(&self, max_length: usize) -> Result<(), serde_valid::MaxLengthError> {
        self.0.validate_max_length(max_length)
    }
}

#[derive(Validate)]
struct Data {
    #[validate(max_length = 5)]
    val: MyType,
}

let s = Data {
    val: MyType(String::from("😍👺🙋🏽👨‍🎤👨‍👩‍👧‍👦")),
};

assert!(s.validate().is_ok());

Validation Errors Format

Named Struct

Field errors are output to properties.

use serde_json::json;
use serde_valid::Validate;

#[derive(Validate)]
struct Data {
    #[validate(maximum = 4)]
    val: u32,
}

let s = Data { val: 5 };

assert_eq!(
    s.validate().unwrap_err().to_string(),
    json!({
        "errors": [],
        "properties": {
            "val": {
                "errors": ["The number must be `<= 4`."]
            }
        }
    })
    .to_string()
);

Unnamed Struct

Field errors are output to items. The key for items is guaranteed to be a string of positive numbers.

use serde_json::json;
use serde_valid::Validate;

#[derive(Validate)]
struct Data (
    #[validate(maximum = 4)] u32,
    #[validate(maximum = 3)] u32,
);

let s = Data ( 5, 4 );

assert_eq!(
    s.validate().unwrap_err().to_string(),
    json!({
        "errors": [],
        "items": {
            "0": {
                "errors": ["The number must be `<= 4`."]
            },
            "1": {
                "errors": ["The number must be `<= 3`."]
            }
        }
    })
    .to_string()
);

New Type

Field errors are output to errors.

use serde_json::json;
use serde_valid::Validate;

#[derive(Validate)]
struct Data (
    #[validate(maximum = 4)] u32
);

let s = Data (5);

assert_eq!(
    s.validate().unwrap_err().to_string(),
    json!({
        "errors": ["The number must be `<= 4`."]
    })
    .to_string()
);

Named Enum

Variant errors are output to properties.

use serde_json::json;
use serde_valid::Validate;

#[derive(Validate)]
enum Data {
    Named {
        #[validate(maximum = 5)]
        a: i32,
        #[validate(maximum = 5)]
        b: i32,
    },
}

let s = Data::Named { a: 6, b: 6 };

assert_eq!(
    s.validate().unwrap_err().to_string(),
    json!({
        "errors": [],
        "properties": {
            "a": {
                "errors": ["The number must be `<= 5`."]
            },
            "b": {
                "errors": ["The number must be `<= 5`."]
            }
        }
    })
    .to_string()
);

Unnamed Enum

Variant errors are output to items. The key for items is guaranteed to be a string of positive numbers.

use serde_json::json;
use serde_valid::Validate;

#[derive(Validate)]
enum Data {
    Unnamed (
        #[validate(maximum = 5)] i32,
        #[validate(maximum = 5)] i32,
    ),
}

let s = Data::Unnamed ( 6, 6 );

assert_eq!(
    s.validate().unwrap_err().to_string(),
    json!({
        "errors": [],
        "items": {
            "0": {
                "errors": ["The number must be `<= 5`."]
            },
            "1": {
                "errors": ["The number must be `<= 5`."]
            }
        }
    })
    .to_string()
);

Newtype Enum

Variant errors are output to errors.

use serde_json::json;
use serde_valid::Validate;

#[derive(Validate)]
enum Data {
    NewType (
        #[validate(maximum = 5)] i32,
    ),
}

let s = Data::NewType ( 6 );

assert_eq!(
    s.validate().unwrap_err().to_string(),
    json!({
        "errors": ["The number must be `<= 5`."]
    })
    .to_string()
);