Handle HEAD requests

src/main/kotlin/moe/kageru/kodeshare/Routes.kt

@@ -11,11 +11,13 @@ import io.ktor.http.content.streamProvider
 import io.ktor.locations.KtorExperimentalLocationsAPI
 import io.ktor.locations.Location
 import io.ktor.locations.get
+import io.ktor.locations.head
 import io.ktor.request.receiveMultipart
 import io.ktor.response.respond
 import io.ktor.response.respondText
 import io.ktor.routing.Routing
 import io.ktor.routing.get
+import io.ktor.routing.head
 import io.ktor.routing.post
 import moe.kageru.kodeshare.config.ServerSpec
 import moe.kageru.kodeshare.config.config
@@ -54,6 +56,26 @@ object Routes {
         get<TypedPasteRequest> { req ->
             call.handleGet(req)
         }
+        head("/") {
+            call.respond(HttpStatusCode.OK)
+        }
+        head<RawPasteRequest> { req ->
+            call.handleHead(req)
+        }
+        head<TypedPasteRequest> { req ->
+            call.handleHead(req)
+        }
+        head<PasteRequest> { req ->
+            call.handleHead(req)
+        }
+    }
+
+    private suspend fun ApplicationCall.handleHead(paste: AbstractPasteRequest) {
+        if (PasteDao.selectByUri(paste.uri) != null) {
+            respond(HttpStatusCode.OK)
+        } else {
+            respond(HttpStatusCode.NotFound)
+        }
     }
 
     @ExperimentalStdlibApi