Allow for optional query params

2 files changed, 9 insertions, 3 deletions

diff --git a/cask/src/cask/endpoints/WebEndpoints.scala b/cask/src/cask/endpoints/WebEndpoints.scala
index 70d16e0..2125b4d 100644
--- a/cask/src/cask/endpoints/WebEndpoints.scala
+++ b/cask/src/cask/endpoints/WebEndpoints.scala
@@ -58,6 +58,12 @@ object QueryParamReader{
       v.map(x => implicitly[QueryParamReader[T]].read(ctx, label, Seq(x)))
     }
   }
+  implicit def OptionParam[T: QueryParamReader] = new QueryParamReader[Option[T]]{
+    def arity = 1
+    def read(ctx: cask.model.ParamContext, label: String, v: Seq[String]): Option[T] = {
+      v.headOption.map(x => implicitly[QueryParamReader[T]].read(ctx, label, Seq(x)))
+    }
+  }
   implicit def paramReader[T: ParamReader] = new QueryParamReader[T] {
     override def arity = 0
 
diff --git a/readme.md b/readme.md
index 88f2523..b791c8d 100644
--- a/readme.md
+++ b/readme.md
@@ -172,9 +172,9 @@ object VariableRoutes extends cask.MainRoutes{
 You can bind variables to endpoints by declaring them as parameters: these are
 either taken from a path-segment matcher of the same name (e.g. `postId` above),
 or from query-parameters of the same name (e.g. `param` above). You can make
-`param` take a `: String` to match `?param=hello`, an `: Int` for `?param=123`
-or a `Seq[String]` (as above) for repeated params such as
-`?param=hello&param=world`.
+`param` take a `: String` to match `?param=hello`, an `: Int` for `?param=123` a
+`Seq[T]` (as above) for repeated params such as `?param=hello&param=world`, or
+`: Option[T]` for cases where the `?param=hello` is optional.
 
 If you need to capture the entire sub-path of the request, you can set the flag
 `subpath=true` and ask for a `: cask.Subpath` (the name of the param doesn't