https://github.com/nesk/akkurate
The expressive validation library for Kotlin
https://github.com/nesk/akkurate
constraints dsl kotlin kotlin-library multiplatform validation validation-library
Last synced: 7 months ago
JSON representation
The expressive validation library for Kotlin
- Host: GitHub
- URL: https://github.com/nesk/akkurate
- Owner: nesk
- License: apache-2.0
- Created: 2023-05-07T13:22:50.000Z (over 2 years ago)
- Default Branch: main
- Last Pushed: 2025-01-27T13:14:17.000Z (10 months ago)
- Last Synced: 2025-04-10T01:15:22.454Z (7 months ago)
- Topics: constraints, dsl, kotlin, kotlin-library, multiplatform, validation, validation-library
- Language: Kotlin
- Homepage: https://akkurate.dev
- Size: 994 KB
- Stars: 383
- Watchers: 6
- Forks: 13
- Open Issues: 11
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
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README
# Akkurate
[**Get started by reading the documentation**](https://akkurate.dev)
Akkurate is a validation library taking advantage of the expressive power of Kotlin. No need \
for 30+ annotations or complicated custom constraints; write your validation code in Kotlin with a beautiful declarative
API.
Designed from scratch to handle complex business logic, its role is to help you write qualitative and maintainable
validation code.
> [!WARNING]
> Akkurate is under development and, despite being heavily tested, its API isn't yet stabilized; _breaking changes
> might happen on minor releases._ However, we will always provide migration guides.
>
> Report any issue or bug in the GitHub repository.
## Showcase
Here's an example showcasing how you can constrain a book and its list of authors.
```kotlin
// Define your classes
@Validate
data class Book(
val title: String,
val releaseDate: LocalDateTime,
val authors: List,
)
@Validate
data class Author(val firstName: String, val lastName: String)
// Write your validation rules
val validateBook = Validator {
// First the property, then the constraint, finally the message.
title.isNotEmpty() otherwise { "Missing title" }
releaseDate.isInPast() otherwise { "Release date must be in past" }
authors.hasSizeBetween(1..10) otherwise { "Wrong author count" }
authors.each { // Apply constraints to each author
(firstName and lastName) {
// Apply the same constraint to both properties
isNotEmpty() otherwise { "Missing name" }
}
}
}
// Validate your data
when (val result = validateBook(someBook)) {
is Success -> println("Success: ${result.value}")
is Failure -> {
val list = result.violations
.joinToString("\n") { "${it.path}: ${it.message}" }
println("Failures:\n$list")
}
}
```
Notice how each constraint applied to a property can be read like a sentence. This code:
```kotlin
title.isNotEmpty() otherwise { "Missing title" }
```
can be read:
```text
Check if 'title' is not empty otherwise write "Missing title".
```
## Features
- [**Beautiful DSL and API**](https://akkurate.dev/docs/harness-the-dsl.html) \
Write crystal clear validation code and keep it DRY. Use loops and conditions when
needed; forget about annotation hell.
- [**Bundled with all the essential constraints**](https://akkurate.dev/docs/apply-constraints.html) \
Write custom constraints for your business logic and nothing more. The rest? It's on us!
- [**Easily and highly extendable**](https://akkurate.dev/docs/extend.html) \
No need to write verbose code to create custom constraints, within Akkurate they're as simple as a lambda with
parameters.
- [**Contextual and asynchronous**](https://akkurate.dev/docs/use-external-sources.html) \
Query sync/async data sources whenever you need to, like a database, or a REST API. Everything can happen inside
validation.
- [**Integrated with your favorite tools**](https://akkurate.dev/docs/integrations.html) \
Validate your data within any popular framework, we take care of the integrations for you.
- [**Code once, deploy everywhere**](https://akkurate.dev/docs/getting-started.html#installation) \
Take advantage of Kotlin Multiplatform; write your validation code once, use it both for front-end and back-end
usages.
- [**Testable out of the box**](https://akkurate.dev/docs/extend.html#test-your-code) \
Finding how to test your validation code shouldn't be one of your tasks. You will find all the tools you need to write
good tests.