uuid62

A small Kotlin set of utilities to convert UUIDs to and from Base62 encoded strings. Perfect for URLs!

Jackson and Spring Boot auto-configuration is supported out of the box!

Spring Boot Quick Start

You probably want to use this with Spring Boot. No problem, that's easy. Include the following in your build.gradle or pom.xml:

Gradle

implementation 'me.ccampo:uuid62-spring-boot-starter:0.1.1'

Maven

<dependency>
  <groupId>me.ccampo</groupId>
  <artifactId>uuid62-spring-boot-starter</artifactId>
  <version>0.1.1</version>
</dependency>

...and that's it! All UUIDs in your controller request parameters, bodies, etc., will be serialized and deserialized to/from Base62 strings.

For more detailed usage options and additional information, keep reading.

Background

According to Wikipedia:

In its canonical textual representation, the sixteen octets of a UUID are represented as 32 hexadecimal (base 16) digits, displayed in five groups separated by hyphens, in the form 8-4-4-4-12 for a total of 36 characters (32 alphanumeric characters and four hyphens). For example: 123e4567-e89b-12d3-a456-426655440000

Quite simply, UUIDs in that form are ugly in URLs. For starters, they're long, and they're composed of a lot of wasted space. Because they use the hexadecimal alphabet (a-f, 0-9), you're limited to four bits per characters. Additionally, the hyphen separators don't serve much purpose besides readability. This limits us to the long, 36 character string.

By switching to Base62, we can condense to roughly 6 bits per character. If we remove the separators, we can then get a new string representation of the same UUID, shortened to 22-26 characters total.

But why not just use Base64?

Standard base64 is not URL and filename safe, due to the + and / characters in the encoding's alphabet. RFC 4648 defines a scheme for URL and filename safe base 64 encoding, which may be fine for some users, however others still may not want any special characters at all. Therefore, base 62 presents one with an encoding scheme composed of only alphanumeric characters and a similar bit density to base64.

Usage

uuid62 can be used in a few different ways. Each is explained below.

As a Library

Perhaps the simplest usage of uuid62 is as a library. You can use uuid62-core as a typical Kotlin or Java library (Groovy, Scala, and other JVM languages should also be supported theoretically, but this has not been tested yet).

Gradle

implementation 'me.ccampo:uuid62-core:0.1.1'

Maven

<dependency>
  <groupId>me.ccampo</groupId>
  <artifactId>uuid62-core</artifactId>
  <version>0.1.1</version>
</dependency>

Kotlin

When using as a Kotlin library, the API is simplified by providing some extension methods for java.util.UUID. Additionally, a couple standalone (static) functions are available as well.

import me.ccampo.uuid62.core.util.uuidFromBase62String
import me.ccampo.uuid62.core.util.uuidFromByteArray

val uuid1 = uuidFromBase62String("el1IFnw8eEOUCdMZCKcsdG") // Equivalent to beac91e2-8479-4f38-94d0-3199a0706c67

val bytes = uuid1.toByteArray() // This is an extension method defined in me.ccampo.uuid62.core.util

val uuid2 = uuidFromByteArray(bytes)

assert(uuid1 == uuid2) // true

val uuid62String = uuid1.toBase62String() // Another extension from the same package

assert(uuid62String == "el1IFnw8eEOUCdMZCKcsdG") // true

Java

Extension methods don't exist in Java, so instead they're available as static utility methods.

import me.ccampo.uuid62.core.util.UUIDUtilsKt;

import java.util.UUID;

public class Example {
    
    public static void main(final String[] args) {
        
        final UUID uuid1 = UUIDUtilsKt.uuidFromBase62String("el1IFnw8eEOUCdMZCKcsdG");
        
        final byte[] bytes = UUIDUtilsKt.toByteArray(uuid1);
        
        final UUID uuid2 = UUIDUtilsKt.uuidFromByteArray(bytes);
        
        assert uuid1 == uuid2; // true
        
        final String uuid62String = UUIDUtilsKt.toBase62String(uuid1);
        
        assert uuid62String.equals("el1IFnw8eEOUCdMZCKcsdG"); // true
    }
}

See the Java unit tests in the core module for more examples of Java usage.

Jackson

uuid62 provides a Jackson JSON serializer and deserializer, as well as Jackson module, for parsing Base62 UUIDs.

Gradle

implementation 'me.ccampo:uuid62-jackson:0.1.1'

Maven

<dependency>
  <groupId>me.ccampo</groupId>
  <artifactId>uuid62-jackson</artifactId>
  <version>0.1.1</version>
</dependency>

You can then register the uuid62 module such as:

final ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(new UUID62Module());

Kotlin makes this a bit simpler, and there are some convenience and extension methods provided, so check out the jackson module in this project for more details.

Spring Boot

A Spring Boot auto-configuration class is available as well. See the Spring Boot Quick Start section above for more details on including it as a dependency. When this module is included, a Spring Boot auto-configuration will be instantiated and automatically provide you with uuid62 Jackson serializers and deserializers. If you are developing a web app, a custom Spring Converter will be registered as well, which will handle translating base62 UUID strings into java.util.UUID instances when passed to your Spring MVC controllers.

See the sample project for a simple example of a Spring Boot project, using the auto-configuration.

If you wish to disable the auto-configuration and wire it yourself, you can follow the standard Spring approach of selectively enabling auto-configuration classes (the uuid62 auto-configuration class is called me.ccampo.uuid62.springboot.autoconfigure.UUID62AutoConfiguration), OR you can provide the following property in your application.properties/application.yml file:

uuid62.autoconfigure.enabled=false

When that property is set to false, auto-configuration is turned off and you can wire it up manually yourself.

Development

Requires Java 8

To Build

macOS or *nix:

./gradlew build

Windows:

gradlew.bat build

Additionally, each sub-module can be built in the same fashion.

Publishing to Bintray

./gradlew -PbintrayUser="..." -PbintrayKey="..." clean build dokkaJar bintrayUpload