Add ability to rewrite arbitrary headers

src/main/scala/fakehttp/Proxy.scala

@@ -37,7 +37,7 @@ class Proxy(val interceptor: Interceptor, val port: Int, val sslMode: SslMode) {
 object Proxy {
   def main(args: Array[String]): Unit = {
     val port = args(0).toInt
-    val interceptor = new NoopInterceptor with HeaderBasedRedirection
+    val interceptor = new NoopInterceptor with HeaderBasedRedirection with HeaderRewriting
     val sslMode = new OpaqueSslMode() // ClearSslMode()
 
     val proxy = new Proxy(interceptor, port, sslMode)

src/main/scala/fakehttp/interceptor/HeaderRewriting.scala

@@ -0,0 +1,37 @@
+package fakehttp.interceptor
+
+import org.jboss.netty.handler.codec.http._
+
+/**
+ * This trait adds header rewriting to the interceptor.
+ * 
+ * To use, define a header with prefix "X-Fakehttp-Header-Rewrite-{header}".  The value of this header will be written
+ * into the "{header}" header.  These X-Fakehttp-Header-Rewrite-* headers will then be removed.
+ * 
+ * @author darren
+ *
+ */
+trait HeaderRewriting extends Interceptor {
+
+  import HeaderRewriting._
+  import scala.collection.JavaConversions._
+
+  override abstract def intercept(request: HttpRequest): InterceptResult = {
+    request.getHeaderNames filter { 
+      _.startsWith(PREFIX) 
+    } foreach { header =>
+      val value = request.getHeader(header)
+      request.setHeader(header.substring(PREFIX_LENGTH), value)
+      System.err.println("Setting header [%s] to [%s]".format(header.substring(PREFIX_LENGTH), value))
+      request.removeHeader(header)
+    }
+
+    super.intercept(request)
+  }
+
+}
+
+object HeaderRewriting {
+  val PREFIX = "X-Fakehttp-Header-Rewrite-"
+  val PREFIX_LENGTH = PREFIX.length
+}