add API endpoint to post private messages

app/controllers/LilaController.scala

@@ -608,6 +608,9 @@ abstract private[controllers] class LilaController(val env: Env)
   protected def jsonFormErrorDefaultLang(err: Form[_]) =
     jsonFormError(err)(lila.i18n.defaultLang)
 
+  protected def jsonFormErrorFor(err: Form[_], req: RequestHeader, user: Option[UserModel]) =
+    jsonFormError(err)(lila.i18n.I18nLangPicker(req, user))
+
   protected def pageHit(req: RequestHeader): Unit =
     if (HTTPRequest isHuman req) lila.mon.http.path(req.path).increment()
 

app/controllers/Msg.scala

@@ -74,11 +74,22 @@ final class Msg(
       )
   }
 
-  def compatAnswer(userId: String) = AuthBody { implicit ctx => me =>
+  def apiPost(username: String) = AuthOrScopedBody(_.Msg.Write)(
+    // compat
+    auth = ctx => me => doApiPost(me, username)(ctx.body),
+    // new API
+    scoped = req => me => doApiPost(me, username)(req)
+  )
+
+  private def doApiPost(
+      me: lila.user.User,
+      username: String
+  )(implicit req: play.api.mvc.Request[_]) = {
+    val userId = lila.user.User normalize username
     env.msg.compat
-      .reply(me, userId)(ctx.body)
+      .reply(me, userId)
       .fold(
-        jsonFormError,
+        err => jsonFormErrorFor(err, req, me.some),
         _ inject Ok(Json.obj("ok" -> true, "id" -> userId))
       )
   }

conf/routes

@@ -430,9 +430,10 @@ GET   /inbox/search                    controllers.Msg.search(q: String)
 GET   /inbox/unread-count              controllers.Msg.unreadCount
 GET   /inbox/:username                 controllers.Msg.threadWith(username: String)
 DELETE /inbox/:username                controllers.Msg.threadDelete(username: String)
+# Msg API/compat
+POST  /inbox/:username                 controllers.Msg.apiPost(username: String)
 # Msg compat
 POST  /inbox/new                       controllers.Msg.compatCreate
-POST  /inbox/:userId                   controllers.Msg.compatAnswer(userId: String)
 
 # Coach
 GET   /coach                           controllers.Coach.allDefault(page: Int ?= 1)

modules/oauth/src/main/OAuthScope.scala

@@ -37,6 +37,10 @@ object OAuthScope {
     case object Write extends OAuthScope("team:write", "Join, leave, and manage teams")
   }
 
+  object Msg {
+    case object Write extends OAuthScope("msg:write", "Send private messages to other players")
+  }
+
   object Bot {
     case object Play extends OAuthScope("bot:play", "Play as a bot")
   }
@@ -56,6 +60,7 @@ object OAuthScope {
     Tournament.Write,
     Puzzle.Read,
     Team.Write,
+    Msg.Write,
     Bot.Play
   )