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# URL Encoder for Kotlin and Java

A simple library to encode/decode URL parameters.

This library was adapted from the [RIFE2 Web Application Framework](https://rife2.com).  
A pure Java version can also be found at [https://github.com/gbevin/urlencoder](https://github.com/gbevin/urlencoder).


For decades we've been using [java.net.URLEncoder](https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/net/URLEncoder.html) because of its improper naming. It is actually intended to encode HTML form parameters, not URLs, causing the wrong escape sequences to be used.

Additionally, `java.net.URLEncoder` allocates memory even when no encoding is necessary, significantly impacting performance. This library has a negligible performance impact when the specified string doesn't need to be encoded.


Android's [Uri.encode](https://developer.android.com/reference/android/net/Uri#encode(java.lang.String,%20java.lang.String)) also addresses these issues, but does not currently support [unicode surrogate pairs](https://learn.microsoft.com/en-us/globalization/encoding/surrogate-pairs).
## Examples (TL;DR)

```kotlin
UrlEncoder.encode("a test &") // -> a%20test%20%26
UrlEncoder.encode("%#okékÉȢ smile!😁") // -> %25%23ok%C3%A9k%C3%89%C8%A2%20smile%21%F0%9F%98%81
UrlEncoder.encode("?test=a test", allow = "?=") // -> ?test=a%20test

UrlEncoder.decode("a%20test%20%26") // -> a test &
UrlEncoder.decode("%25%23ok%C3%A9k%C3%89%C8%A2%20smile%21%F0%9F%98%81") // -> %#okékÉȢ smile!😁
```

## Gradle, Maven, etc.
To use with [Gradle](https://gradle.org/), include the following dependency in your build file:

```gradle
repositories {
    mavenCentral()
    maven { url = uri("https://oss.sonatype.org/content/repositories/snapshots") } // only needed for SNAPSHOT
}

dependencies {
    implementation("net.thauvin.erik:urlencoder:1.0.0")
}
```

Instructions for using with Maven, Ivy, etc. can be found on [Maven Central](https://maven-badges.herokuapp.com/maven-central/net.thauvin.erik/urlencoder).