Convert BaseHttpResponseParser to Kotlin (#1385)

* Convert BaseHttpResponseParser to Kotlin

* Fix spacing

Author: tdchow

SharedUtils/src/main/java/com/braintreepayments/api/sharedutils/BaseHttpResponseParser.java

@@ -0,0 +1,91 @@
+package com.braintreepayments.api.sharedutils
+
+import androidx.annotation.RestrictTo
+import java.io.ByteArrayOutputStream
+import java.io.IOException
+import java.io.InputStream
+import java.net.HttpURLConnection
+import java.net.HttpURLConnection.HTTP_ACCEPTED
+import java.net.HttpURLConnection.HTTP_BAD_REQUEST
+import java.net.HttpURLConnection.HTTP_CREATED
+import java.net.HttpURLConnection.HTTP_FORBIDDEN
+import java.net.HttpURLConnection.HTTP_INTERNAL_ERROR
+import java.net.HttpURLConnection.HTTP_OK
+import java.net.HttpURLConnection.HTTP_UNAUTHORIZED
+import java.net.HttpURLConnection.HTTP_UNAVAILABLE
+import java.nio.charset.StandardCharsets
+import java.util.zip.GZIPInputStream
+
+@RestrictTo(RestrictTo.Scope.LIBRARY_GROUP)
+class BaseHttpResponseParser : HttpResponseParser {
+
+    companion object {
+        private const val HTTP_UNPROCESSABLE_ENTITY = 422
+        private const val HTTP_UPGRADE_REQUIRED = 426
+        private const val HTTP_TOO_MANY_REQUESTS = 429
+
+        private const val BYTE_ARRAY_SIZE = 1024
+    }
+
+    @Throws(Exception::class)
+    override fun parse(responseCode: Int, connection: HttpURLConnection): String {
+        val responseBody = parseBody(responseCode, connection) ?: "empty responseBody"
+        return when (responseCode) {
+            HTTP_OK, HTTP_CREATED, HTTP_ACCEPTED -> responseBody
+            HTTP_BAD_REQUEST, HTTP_UNPROCESSABLE_ENTITY -> throw UnprocessableEntityException(responseBody)
+            HTTP_UNAUTHORIZED -> throw AuthenticationException(responseBody)
+            HTTP_FORBIDDEN -> throw AuthorizationException(responseBody)
+            HTTP_UPGRADE_REQUIRED -> throw UpgradeRequiredException(responseBody)
+            HTTP_TOO_MANY_REQUESTS -> {
+                throw RateLimitException("You are being rate-limited. Please try again in a few minutes.")
+            }
+            HTTP_INTERNAL_ERROR -> throw ServerException(responseBody)
+            HTTP_UNAVAILABLE -> throw ServiceUnavailableException(responseBody)
+            else -> throw UnexpectedException(responseBody)
+        }
+    }
+
+    @Throws(IOException::class)
+    private fun parseBody(responseCode: Int, connection: HttpURLConnection): String? {
+        val gzip = "gzip" == connection.contentEncoding
+        return when (responseCode) {
+            HTTP_OK, HTTP_CREATED, HTTP_ACCEPTED -> readStream(connection.inputStream, gzip)
+            HTTP_TOO_MANY_REQUESTS -> null
+            HTTP_UNAUTHORIZED,
+            HTTP_FORBIDDEN,
+            HTTP_BAD_REQUEST,
+            HTTP_UNPROCESSABLE_ENTITY,
+            HTTP_UPGRADE_REQUIRED,
+            HTTP_INTERNAL_ERROR,
+            HTTP_UNAVAILABLE -> readStream(connection.errorStream, gzip)
+            else -> readStream(connection.errorStream, gzip)
+        }
+    }
+
+    @Throws(IOException::class)
+    private fun readStream(inputStream: InputStream?, gzip: Boolean): String? {
+        if (inputStream == null) {
+            return null
+        }
+
+        val out = ByteArrayOutputStream()
+        var stream = inputStream
+        try {
+            if (gzip) {
+                stream = GZIPInputStream(inputStream)
+            }
+
+            val buffer = ByteArray(BYTE_ARRAY_SIZE)
+            var count: Int
+            while (stream.read(buffer).also { count = it } != -1) {
+                out.write(buffer, 0, count)
+            }
+            return String(out.toByteArray(), StandardCharsets.UTF_8)
+        } finally {
+            try {
+                inputStream.close()
+            } catch (_: IOException) {
+            }
+        }
+    }
+}