Base 64 Kotlin extensions #406
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| import java.nio.charset.Charset | ||
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| /** | ||
| * From [String] to Base-64 encoded [String]. |
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This is a sentence fragment. Prefix it with a verb like "Convert".
| offset: Int = 0, | ||
| len: Int = this.length, | ||
| flags: Int = Base64.DEFAULT | ||
| ): String = Base64.encode(toByteArray(), offset, len, flags).toString(Charset.forName("US-ASCII")) |
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The toByteArray charset parameter should be hoisted onto this function as we cannot assume UTF-8 is the desired encoding. And below.
| offset: Int = 0, | ||
| len: Int = this.length, | ||
| flags: Int = Base64.DEFAULT | ||
| ): String = Base64.encode(toByteArray(), offset, len, flags).toString(Charset.forName("US-ASCII")) |
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Use http://kotlinlang.org/api/latest/jvm/stdlib/kotlin.text/-charsets/-u-s_-a-s-c-i-i.html instead of looking up charset by name. And below.
| import java.nio.charset.Charset | ||
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| /** | ||
| * From [String] to Base-64 encoded [String]. |
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Also nit: lowercase "Base" on all these
| /** | ||
| * From Base-64 encoded [String] to decoded [String]. | ||
| */ | ||
| fun String.fromBase64( |
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The Kotlin standard library typically puts "from" methods as extensions on the companion of the type on which they operate and take an instance as the first parameter.
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There is no companion object in ByteArray.
| /** | ||
| * From Base-64 encoded [ByteArray] to decoded [ByteArray]. | ||
| */ | ||
| fun ByteArray.fromBase64( |
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These can all be inline since they're aliases.
| assertEquals(expected, actual) | ||
| } | ||
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| @Test fun fromBase64String() { |
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pair of byte array tests too?
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@JakeWharton All fixed. What do you want to do about |
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We might have to leave it out until https://youtrack.jetbrains.com/issue/KT-11968 is fixed. I'll ask JetBrains about it at our weekly meeting next week. |
| len: Int = this.length, | ||
| flags: Int = Base64.DEFAULT, | ||
| charset: Charset = Charsets.US_ASCII | ||
| ): String = Base64.encode(toByteArray(), offset, len, flags).toString(charset) |
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The charset should be used for toByteArray and the default should be UTF_8. The ASCII charset is for toString().
| /** | ||
| * Convert [String] to base-64 encoded [String]. | ||
| */ | ||
| inline fun String.toBase64( |
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Let's call this .encodeBase64 as there's no Base64 type so we're not really going "to" it.
| /** | ||
| * Convert base-64 encoded [String] to decoded [String]. | ||
| */ | ||
| inline fun String.Companion.fromBase64( |
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This can go back to being an instance extension and be called decodeBase64().
| len: Int = input.length, | ||
| flags: Int = Base64.DEFAULT, | ||
| charset: Charset = Charsets.US_ASCII | ||
| ): String = Base64.decode(input.toByteArray(), offset, len, flags).toString(charset) |
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Pass US_ASCII to toByteArray.
| offset: Int = 0, | ||
| len: Int = input.length, | ||
| flags: Int = Base64.DEFAULT, | ||
| charset: Charset = Charsets.US_ASCII |
| */ | ||
| inline fun String.toBase64( | ||
| offset: Int = 0, | ||
| len: Int = this.length, |
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Length won't work here as you are using it as the length of the bytes whereas the parameter represents the number of characters. You need to do a substring before calling toByteArray and then pass the length of the byte array to Base64.
I would also write a test for this with two multi-byte UTF-8 characters in the source string and then a length of 1 which should thus encode more than one byte.
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I updated this PR with everything else.
How would this substring work?
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Any update on how you want this to work? Or do you mind if I just make the PR for the String to Base64 and Base64 to String?
@romainguy