Allow Decorators to short-circuit request processing by bailing out early

10 files changed, 85 insertions, 34 deletions

diff --git a/cask/src/cask/endpoints/FormEndpoint.scala b/cask/src/cask/endpoints/FormEndpoint.scala
index 2d9fc1f..2a7fbd2 100644
--- a/cask/src/cask/endpoints/FormEndpoint.scala
+++ b/cask/src/cask/endpoints/FormEndpoint.scala
@@ -1,6 +1,6 @@
 package cask.endpoints
 
-import cask.internal.Router
+import cask.internal.{Router, Util}
 import cask.main.Routes
 import cask.model.{FormValue, ParamContext, Response}
 import io.undertow.server.handlers.form.FormParserFactory
@@ -40,14 +40,21 @@ class postForm(val path: String, override val subpath: Boolean = false) extends
   type Input = Seq[FormValue]
   type InputParser[T] = FormReader[T]
   def getRawParams(ctx: ParamContext) = {
-    val formData = FormParserFactory.builder().build().createParser(ctx.exchange).parseBlocking()
-    val formDataBindings =
-      formData
-        .iterator()
-        .asScala
-        .map(k => (k, formData.get(k).asScala.map(FormValue.fromUndertow).toSeq))
-        .toMap
-    formDataBindings
+    for{
+      formData <-
+        try Right(FormParserFactory.builder().build().createParser(ctx.exchange).parseBlocking())
+        catch{case e: Exception => Left(cask.model.Response(
+          "Unable to parse form data: " + e + "\n" + Util.stackTraceString(e)
+        ))}
+    } yield {
+      val formDataBindings =
+        formData
+          .iterator()
+          .asScala
+          .map(k => (k, formData.get(k).asScala.map(FormValue.fromUndertow).toSeq))
+          .toMap
+      formDataBindings
+    }
   }
   def wrapPathSegment(s: String): Input = Seq(FormValue.Plain(s, new io.undertow.util.HeaderMap))
 }
diff --git a/cask/src/cask/endpoints/JsonEndpoint.scala b/cask/src/cask/endpoints/JsonEndpoint.scala
index 80fac9a..d9d39c3 100644
--- a/cask/src/cask/endpoints/JsonEndpoint.scala
+++ b/cask/src/cask/endpoints/JsonEndpoint.scala
@@ -1,6 +1,6 @@
 package cask.endpoints
 
-import cask.internal.Router
+import cask.internal.{Router, Util}
 import cask.internal.Router.EntryPoint
 import cask.main.Routes
 import cask.model.{ParamContext, Response}
@@ -28,7 +28,22 @@ class postJson(val path: String, override val subpath: Boolean = false) extends
   val methods = Seq("post")
   type Input = ujson.Js.Value
   type InputParser[T] = JsReader[T]
-  def getRawParams(ctx: ParamContext) =
-    ujson.read(new String(ctx.exchange.getInputStream.readAllBytes())).obj.toMap
+  def getRawParams(ctx: ParamContext) = {
+    for{
+      str <-
+        try Right(new String(ctx.exchange.getInputStream.readAllBytes()))
+        catch{case e: Throwable => Left(cask.model.Response(
+          "Unable to deserialize input JSON text: " + e + "\n" + Util.stackTraceString(e)
+        ))}
+      json <-
+        try Right(ujson.read(str))
+        catch{case e: Throwable => Left(cask.model.Response(
+          "Input text is invalid JSON: " + e + "\n" + Util.stackTraceString(e)
+        ))}
+      obj <-
+        try Right(json.obj)
+        catch {case e: Throwable => Left(cask.model.Response("Input JSON must be a dictionary"))}
+    } yield obj.toMap
+  }
   def wrapPathSegment(s: String): Input = ujson.Js.Str(s)
 }
diff --git a/cask/src/cask/endpoints/StaticEndpoints.scala b/cask/src/cask/endpoints/StaticEndpoints.scala
index 5d57144..31528aa 100644
--- a/cask/src/cask/endpoints/StaticEndpoints.scala
+++ b/cask/src/cask/endpoints/StaticEndpoints.scala
@@ -14,6 +14,6 @@ class static(val path: String) extends Routes.Endpoint[String] {
     Router.Result.Success(cask.model.Static(t + "/" + ctx.remaining.mkString("/")))
   }
 
-  def getRawParams(ctx: ParamContext) = Map()
+  def getRawParams(ctx: ParamContext) = Right(Map())
   def wrapPathSegment(s: String): Input = Seq(s)
 }
diff --git a/cask/src/cask/endpoints/WebEndpoints.scala b/cask/src/cask/endpoints/WebEndpoints.scala
index 82009df..cd707b8 100644
--- a/cask/src/cask/endpoints/WebEndpoints.scala
+++ b/cask/src/cask/endpoints/WebEndpoints.scala
@@ -11,10 +11,12 @@ import collection.JavaConverters._
 trait WebEndpoint extends Routes.Endpoint[BaseResponse]{
   type Input = Seq[String]
   type InputParser[T] = QueryParamReader[T]
-  def getRawParams(ctx: ParamContext) = ctx.exchange.getQueryParameters
-    .asScala
-    .map{case (k, vs) => (k, vs.asScala.toArray.toSeq)}
-    .toMap
+  def getRawParams(ctx: ParamContext) = Right(
+    ctx.exchange.getQueryParameters
+      .asScala
+      .map{case (k, vs) => (k, vs.asScala.toArray.toSeq)}
+      .toMap
+  )
   def wrapPathSegment(s: String) = Seq(s)
 }
 class get(val path: String, override val subpath: Boolean = false) extends WebEndpoint{
diff --git a/cask/src/cask/internal/Util.scala b/cask/src/cask/internal/Util.scala
index 59bc2ce..98c30c4 100644
--- a/cask/src/cask/internal/Util.scala
+++ b/cask/src/cask/internal/Util.scala
@@ -1,12 +1,25 @@
 package cask.internal
 
+import java.io.{PrintWriter, StringWriter}
+
+import scala.collection.generic.CanBuildFrom
+import scala.collection.mutable
+
 object Util {
   def pluralize(s: String, n: Int) = {
     if (n == 1) s else s + "s"
   }
-  def splitPath(p: String) =
+  def splitPath(p: String) = {
     p.dropWhile(_ == '/').reverse.dropWhile(_ == '/').reverse.split('/').filter(_.nonEmpty)
+  }
 
+  def stackTraceString(e: Throwable) = {
+    val trace = new StringWriter()
+    val pw = new PrintWriter(trace)
+    e.printStackTrace(pw)
+    pw.flush()
+    trace.toString
+  }
   def softWrap(s: String, leftOffset: Int, maxWidth: Int) = {
     val oneLine = s.lines.mkString(" ").split(' ')
 
@@ -28,4 +41,12 @@ object Util {
     }
     output.mkString
   }
+  def sequenceEither[A, B, M[X] <: TraversableOnce[X]](in: M[Either[A, B]])(
+    implicit cbf: CanBuildFrom[M[Either[A, B]], B, M[B]]): Either[A, M[B]] = {
+    in.foldLeft[Either[A, mutable.Builder[B, M[B]]]](Right(cbf(in))) {
+      case (acc, el) =>
+        for (a <- acc; e <- el) yield a += e
+    }
+      .map(_.result())
+  }
 }
diff --git a/cask/src/cask/main/ErrorMsgs.scala b/cask/src/cask/main/ErrorMsgs.scala
index c5ce978..e54ea88 100644
--- a/cask/src/cask/main/ErrorMsgs.scala
+++ b/cask/src/cask/main/ErrorMsgs.scala
@@ -97,12 +97,10 @@ object ErrorMsgs {
         val thingies = x.map{
           case Router.Result.ParamError.Invalid(p, v, ex) =>
             val literalV = literalize(v)
-            val trace = new StringWriter()
-            ex.printStackTrace(new PrintWriter(trace))
+            val trace = Util.stackTraceString(ex)
             s"${p.name}: ${p.typeString} = $literalV failed to parse with $ex\n$trace"
           case Router.Result.ParamError.DefaultFailed(p, ex) =>
-            val trace = new StringWriter()
-            ex.printStackTrace(new PrintWriter(trace))
+            val trace = Util.stackTraceString(ex)
             s"${p.name}'s default value failed to evaluate with $ex\n$trace"
         }
 
diff --git a/cask/src/cask/main/Main.scala b/cask/src/cask/main/Main.scala
index f28ae12..9ac0022 100644
--- a/cask/src/cask/main/Main.scala
+++ b/cask/src/cask/main/Main.scala
@@ -56,14 +56,22 @@ abstract class BaseMain{
       routeTries(exchange.getRequestMethod.toString.toLowerCase()).lookup(Util.splitPath(exchange.getRequestPath).toList, Map()) match{
         case None => writeResponse(exchange, handleError(404))
         case Some(((routes, metadata), bindings, remaining)) =>
-          val providers =
-            Seq(metadata.endpoint.getRawParams(ParamContext(exchange, remaining)) ++
-                bindings.mapValues(metadata.endpoint.wrapPathSegment)) ++
-            metadata.decorators.map(e => e.getRawParams(ParamContext(exchange, remaining)))
-
-          val result = metadata.entryPoint
-            .asInstanceOf[EntryPoint[cask.main.Routes, cask.model.ParamContext]]
-            .invoke(routes, ParamContext(exchange, remaining), providers)
+          val params = for{
+            endpointParams <- metadata.endpoint.getRawParams(ParamContext(exchange, remaining))
+            decoratorParams <- Util.sequenceEither(
+              metadata.decorators.map(e => e.getRawParams(ParamContext(exchange, remaining)))
+            )
+          } yield (endpointParams ++ bindings.mapValues(metadata.endpoint.wrapPathSegment)) +: decoratorParams
+
+          val result = params match{
+            case Left(resp) => resp
+            case Right(paramValues) =>
+              metadata.entryPoint
+                .asInstanceOf[EntryPoint[cask.main.Routes, cask.model.ParamContext]]
+                .invoke(routes, ParamContext(exchange, remaining), paramValues)
+          }
+
+
           result match{
             case Router.Result.Success(response: BaseResponse) => writeResponse(exchange, response)
             case e: Router.Result.Error =>
diff --git a/cask/src/cask/main/Routes.scala b/cask/src/cask/main/Routes.scala
index 76a84d0..957a293 100644
--- a/cask/src/cask/main/Routes.scala
+++ b/cask/src/cask/main/Routes.scala
@@ -16,7 +16,7 @@ object Routes{
     def wrapMethodOutput(ctx: ParamContext,t: R): cask.internal.Router.Result[Any] = {
       cask.internal.Router.Result.Success(t)
     }
-    def getRawParams(ctx: ParamContext): Map[String, Input]
+
     def wrapPathSegment(s: String): Input
 
   }
@@ -37,7 +37,7 @@ object Routes{
   trait BaseDecorator{
     type Input
     type InputParser[T] <: ArgReader[Input, T, ParamContext]
-    def getRawParams(ctx: ParamContext): Map[String, Input]
+    def getRawParams(ctx: ParamContext): Either[cask.model.Response, Map[String, Input]]
     def getParamParser[T](implicit p: InputParser[T]) = p
 
   }
diff --git a/cask/test/src/test/cask/Decorated.scala b/cask/test/src/test/cask/Decorated.scala
index c6e048a..e20149a 100644
--- a/cask/test/src/test/cask/Decorated.scala
+++ b/cask/test/src/test/cask/Decorated.scala
@@ -4,7 +4,7 @@ import cask.model.ParamContext
 
 object Decorated extends cask.MainRoutes{
   class myDecorator extends cask.Routes.Decorator {
-    def getRawParams(ctx: ParamContext) = Map("extra" -> 31337)
+    def getRawParams(ctx: ParamContext) = Right(Map("extra" -> 31337))
   }
 
   @myDecorator()
diff --git a/cask/test/src/test/cask/FailureTests.scala b/cask/test/src/test/cask/FailureTests.scala
index c2db0f4..03f3777 100644
--- a/cask/test/src/test/cask/FailureTests.scala
+++ b/cask/test/src/test/cask/FailureTests.scala
@@ -5,7 +5,7 @@ import utest._
 
 object FailureTests extends TestSuite {
   class myDecorator extends cask.Routes.Decorator {
-    def getRawParams(ctx: ParamContext) = Map("extra" -> 31337)
+    def getRawParams(ctx: ParamContext) = Right(Map("extra" -> 31337))
   }
   val tests = Tests{