! httpx: decode should remove Content-Encoding header from message

This fixes #316 by changing Decoder.decode to remove the Content-Encoding header.

I added extra round-trip unit tests to the DeflateSpec and GzipSpec but I also added some basic unit tests for the Encoder and Decoder abstract classes themselves.

spray-httpx/src/main/scala/spray/httpx/encoding/Decoder.scala

@@ -17,14 +17,22 @@
 package spray.httpx.encoding
 
 import spray.http._
+import HttpHeaders._
 
 trait Decoder {
   def encoding: HttpEncoding
 
-  def decode[T <: HttpMessage](message: T): T#Self = message.mapEntity {
-    _.flatMap { case HttpBody(contentType, buffer) ⇒ HttpEntity(contentType, newDecompressor.decompress(buffer)) }
+  def decode[T <: HttpMessage](message: T): T#Self = message.entity match {
+    case HttpBody(contentType, buffer) if message.headers exists isContentEncodingHeader ⇒
+      message.withHeadersAndEntity(
+        headers = message.headers filterNot isContentEncodingHeader,
+        entity = HttpEntity(contentType, newDecompressor.decompress(buffer)))
+
+    case _ ⇒ message.message
   }
 
+  private val isContentEncodingHeader: HttpHeader ⇒ Boolean = _.isInstanceOf[`Content-Encoding`]
+
   def newDecompressor: Decompressor
 }
 
@@ -38,4 +46,4 @@ abstract class Decompressor {
   }
 
   protected def decompress(buffer: Array[Byte], offset: Int): Int
-}
+}

spray-httpx/src/test/scala/spray/httpx/ResponseTransformationSpec.scala

@@ -52,7 +52,7 @@ class ResponseTransformationSpec extends Specification with RequestBuilding with
 
     "support response decompression" in {
       val pipeline = encode(Gzip) ~> echo ~> decode(Gzip)
-      pipeline(Get("/abc", "Hello")).await === HttpResponse(200, "Hello", List(`Content-Encoding`(HttpEncodings.gzip)))
+      pipeline(Get("/abc", "Hello")).await === HttpResponse(200, "Hello")
     }
 
     "support request authentication" in {

spray-httpx/src/test/scala/spray/httpx/encoding/DecoderSpec.scala

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2011-2013 spray.io
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package spray.httpx.encoding
+
+import spray.http._
+import HttpHeaders._
+import org.specs2.mutable.Specification
+
+class DecoderSpec extends Specification with CodecSpecSupport {
+
+  "A Decoder" should {
+    "not transform the message if it doesn't contain a Content-Encoding header" in {
+      val request = HttpRequest(entity = HttpEntity(smallText))
+      DummyDecoder.decode(request) === request
+    }
+    "correctly transform the message if it contains a Content-Encoding header" in {
+      val request = HttpRequest(entity = HttpEntity(smallText), headers = List(`Content-Encoding`(DummyDecoder.encoding)))
+      val decoded = DummyDecoder.decode(request)
+      decoded.headers === Nil
+      decoded.entity === HttpEntity(dummyDecompress(smallText))
+    }
+  }
+
+  def dummyDecompress(s: String): String = new String(dummyDecompress(s.getBytes("UTF8")), "UTF8")
+  def dummyDecompress(bytes: Array[Byte]): Array[Byte] = DummyDecompressor.decompress(bytes)
+
+  case object DummyDecoder extends Decoder {
+    val encoding = HttpEncodings.compress
+    def newDecompressor = DummyDecompressor
+  }
+
+  case object DummyDecompressor extends Decompressor {
+    protected def decompress(buffer: Array[Byte], offset: Int) = {
+      output.write(buffer, 0, buffer.length)
+      output.write("compressed".getBytes("UTF8"))
+      -1
+    }
+  }
+}

spray-httpx/src/test/scala/spray/httpx/encoding/DeflateSpec.scala

@@ -16,6 +16,7 @@
 
 package spray.httpx.encoding
 
+import spray.http.{ HttpRequest, HttpEntity }
 import java.io.ByteArrayOutputStream
 import java.util.zip.{ InflaterOutputStream, DeflaterOutputStream }
 import org.specs2.mutable.Specification
@@ -41,6 +42,10 @@ class DeflateSpec extends Specification with CodecSpecSupport {
     "properly roundtip encode/decode a large string" in {
       ourInflate(ourDeflate(largeTextBytes)) must readAs(largeText)
     }
+    "properly roundtip encode/decode an HttpRequest" in {
+      val request = HttpRequest(entity = HttpEntity(largeText))
+      Deflate.decode(Deflate.encode(request)) === request
+    }
     "provide a better compression ratio than the standard Deflater/Inflater streams" in {
       ourDeflate(largeTextBytes).length must be_<(streamDeflate(largeTextBytes).length)
     }
@@ -68,4 +73,4 @@ class DeflateSpec extends Specification with CodecSpecSupport {
     val ios = new InflaterOutputStream(output); ios.write(bytes); ios.close()
     output.toByteArray
   }
-}
+}

spray-httpx/src/test/scala/spray/httpx/encoding/EncoderSpec.scala

@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2011-2013 spray.io
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package spray.httpx.encoding
+
+import spray.http._
+import HttpHeaders._
+import org.specs2.mutable.Specification
+
+class EncoderSpec extends Specification with CodecSpecSupport {
+
+  "An Encoder" should {
+    "not transform the message if messageFilter returns false" in {
+      val request = HttpRequest(entity = HttpEntity(smallText.getBytes("UTF8")))
+      DummyEncoder.encode(request) === request
+    }
+    "correctly transform the HttpMessage if messageFilter returns true" in {
+      val request = HttpRequest(entity = HttpEntity(smallText))
+      val encoded = DummyEncoder.encode(request)
+      encoded.headers === List(`Content-Encoding`(DummyEncoder.encoding))
+      encoded.entity === HttpEntity(dummyCompress(smallText))
+    }
+  }
+
+  def dummyCompress(s: String): String = new String(dummyCompress(s.getBytes("UTF8")), "UTF8")
+  def dummyCompress(bytes: Array[Byte]): Array[Byte] = DummyCompressor.compress(bytes).finish()
+
+  case object DummyEncoder extends Encoder {
+    val messageFilter = Encoder.DefaultFilter
+    val encoding = HttpEncodings.compress
+    def newCompressor = DummyCompressor
+  }
+
+  case object DummyCompressor extends Compressor {
+    def compress(buffer: Array[Byte]) = {
+      if (buffer.length > 0) output.write(buffer, 0, buffer.length)
+      output.write("compressed".getBytes("UTF8"))
+      this
+    }
+    def flush() = getBytes
+    def finish() = getBytes
+  }
+}

spray-httpx/src/test/scala/spray/httpx/encoding/GzipSpec.scala

@@ -16,6 +16,7 @@
 
 package spray.httpx.encoding
 
+import spray.http.{ HttpRequest, HttpEntity }
 import java.io.{ ByteArrayInputStream, ByteArrayOutputStream }
 import java.util.zip.{ ZipException, GZIPInputStream, GZIPOutputStream }
 import org.parboiled.common.FileUtils
@@ -43,6 +44,10 @@ class GzipSpec extends Specification with CodecSpecSupport {
     "properly roundtip encode/decode a large string" in {
       ourGunzip(ourGzip(largeTextBytes)) must readAs(largeText)
     }
+    "properly roundtip encode/decode an HttpRequest" in {
+      val request = HttpRequest(entity = HttpEntity(largeText))
+      Gzip.decode(Gzip.encode(request)) === request
+    }
     "provide a better compression ratio than the standard Gzipr/Gunzip streams" in {
       ourGzip(largeTextBytes).length must be_<(streamGzip(largeTextBytes).length)
     }
@@ -87,4 +92,4 @@ class GzipSpec extends Specification with CodecSpecSupport {
     output.toByteArray
   }
 
-}
+}